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This week I wanted to share a round-up of news 'n' bits.
We're excited to announce that we're about to offer spoon carving tools from Ben & Lois Orford, British toolmakers and leatherworkers based in Herefordshire. You can't beat spoon carving in its ability to produce something beautiful and useful quickly. As some have said, just take some green wood, carve away the part that isn't a spoon, then soak in linseed oil. We currently stock spoon carving tools by Ray Iles but we love the Orford tools too and we wanted to give you all the options we could.
While we are on the subject of spooncarving the video above is a short, delightful video that features a young couple who carve spoons, sell their wares at markets, and travel around, enjoying their craft, their freedom and each other.
In other news, new Festool prices will be in effect April 1st. If you're thinking about purchasing a Domino, TS55 or a router, now is a good time to take advantage of the pricing. While we are out of some items (FS-RTAB.XX,router tables), for example, as long as the order it placed before the first we will honor the older price even if the item is backordered. The new Domino Connectors are being introduced in the US along with new batteries, and a rugged Bluetooth radio.
On Saturday, April 29, we'll be hosting the Festool Roadshow. We'll have a trailer full of Festool tools to play with, along with workstations and Festool trainers to stump. WE will be offering food and Festool will be providing some giftbags. If you're in the New York area, come join us. We think it will be a fun time. And if nothing else an excuse to visit Brooklyn, wander around, see some stuff and sample some of the local dining. See more information here.
That concludes this week's round-up; next time I'll be back to more typical blog fare. Stay tuned!
I try to write a new entry for my blog every week. I also try to make it useful or at least not boring. Sometimes I succeed. However because it's a weekly thing lots of content gets rolled under the covers and after a time lost. So this week I decided to take one of the earliest blogs I every wrote (#8 from a decade ago) and bring it current again. Yes I know everyone hates when magazines to a yearly article on the same subject again and again, but like magazines we have a lot of new readers who haven't see this topic.
(note: I shot a video for this yesterday but I didn't get a chance to finish editing it so check back over the weekend and I should have added it in).
Every time someone comes in and buys a marking or mortise gauge, I give them a quick demo on how to use it. It's not unusual for customers to know they need a gauge, but not how to use one. It's not their fault. There is a hell of a lot of misinformation on this subject, and using a gauge properly isn't intuitive.
The goal of a gauge is to provide a line that is just deep enough to catch a chisel or a pencil. Some people like deep cuts with a knife, but the deeper the gauge line, the more you will have to plane the finished surface - otherwise finish will catch in the line and the entire world will see the gauge line. The great woodworking writer Charles H. Hayward noted that when he apprenticed (around 1910) visible gauge lines in a finished work was considered sloppy but it was a common practice. These days, it is all too common and perversely considered a proud mark of "hand craftsmanship."
The problem that people have in using gauges is that when the gauge sits square on the wood, its pin will dig in, follow the grain, wobble, and give you a jerky cut. So various woodworking gurus have advocated filing the pins really short, so even if the gauge sort of works, you can't see where you are going; filing them into knives, so you get a deep line that is hard to get rid of later; remounting the pins on a diagonal; and giving up entirely and using a wheel gauge.
Here is how you really solve this problem:
1) Set the fence to the right setting.
2) With your hand curled around the fence and beam, tilt the gauge away from you and rest it on the long cornered edge of the beam (the corner away from you). The picture and diagram should make this easier to understand.
3) Put pressure on the fence in so the gauge is tight against the wood, and with the corner of the bean firmly on the wood, tilt the gauge towards you. With this method, with all the pressure going into the fence and edge of the beam, it is trivial to control the pressure on the pin. You can have a tiny bit of pressure on the pin that just leaves a mark for smooth visible wood, or you can just as easily bear down on with more pressure for rough wood so that you get a mark you can see.
3) Then push the gauge away from you, always keeping the long edge of the beam on the word. You push the gauge away from you so that you can see what you are doing. And of course with the pin tilted it won't dig into the wood.
4) You don't want the gauge to go off the the end of the board, because once the beam goes off the wood, you will lose control. So stop just before the end of the line and repeat from the other end of the board this time tilting the gauge towards you.
5) It's better to have a light mark than a dark one. If you have trouble seeing your scribe mark, just run a very sharp pencil in the groove.
6) That's it. A sharp pin isn't super important because in general you want a thin shallow line, but that's a personal preference. I don't think I have ever sharpened a pin in my life.
We sell gauges from about $15 and up. They all work. If you are getting just one gauge, I would suggest the Marples screw adjustable combination gauge. The screw adjust allows you to set the width of a mortise independently of the fence setting, which is a real boon. However, in a pinch all the gauges we sell work. You don't need the fancier Trial 1, although I do like the weight of it. Colen Clenton's gauges feel wonderful in the hand. You won't regret the purchase, but it's certainly a next gauge to get, when you settled into joinery and have the urge to splurge. Over the years I have acquired a lot of gauges because I will set a gauge to particular measure, and then put a piece of tape over the thumbscrew so that I don't accidentally move it, and I'll recognize that it's set for a particular project. On a long project, I can tie up gauges for months, so I have a bunch of gauges.
You'll see over the years and over your projects a hierarchy of favorite and "others" will naturally emerge.
PS - The scribe line in the picture looks a little ratty because it took a bunch of tries to get a shot in focus.
The traditional way of learning to carve was via an apprenticeship. Some kid who thought, or whose parents thought, that he had some talent for sculpture would be apprenticed at age 14 to a master carver. Ideally, seven years later the kid would be able to carve well enough and fast enough to make a living. Very talented youngsters, such as the young Grinling Gibbons, even had sponsors pay for their training. Amateur carving became a popular hobby in the 19th century, when shorter working hours made hobbies possible and the Arts & Crafts movement made craft hobbies attractive.
When I was a young woodworker, you could study carving in three ways:
In person at a class:
When I studied at the Craft Students League, carving was always a popular course. In-person craft classes provide the opportunity to for a teacher (and your classmates) to observe you carving and suggest ideas and techniques to improve. It's certainly the best means of instruction. But nowadays many carving programs (like the Craft Students League) have closed, and realistic carving and decorative architectural woodwork have decidedly gone out of fashion. Longer work hours may make evening classes difficult, even if you are lucky enough to live near a class. One-time workshops and seminars can be treats, but they don't have the regular weekly practice that a local class can have.
From books and magazines:
This is a fine way of learning and still has tremendous value. Carving magazines are a great source of ideas and designs, overviews on tools, and written instruction. They fall short, however, because a picture or drawing, even a before-during-and after picture, cannot always illuminate the particular misunderstanding a student has on a specific area. I had that issue myself with lettering. I went back and forth over one paragraph and I still did not get how to do serifs without breaking off a bit. Obviously the writer (Chris Pye - who is and awesome writer of instructions) missed the particular situation that a thickheaded student could miss.
From videos -- VHS and television shows back in the day, and in the modern world, DVDs: DVDs are the best of the video presentations. You can see the project being made, and things that are hard to understand on the written page can be easily demonstrated. Professionally shot and edited videos, traditionally 45 minutes or longer, are expensive to make (and so their cost must be recouped) and generally designed for linear watching on a computer (or old school DVD player). Increasingly this is not how people consume "content" - viewers expect to be able to find short videos focusing on particular issues that can be watched on a phone or tablet.
But here comes an entirely new method.
A couple of years ago, Chris Pye set up a subscription website to teach carving. The site now offers several hundred videos, all short. You can watch them in a curated sequence, or individually to answer a question, or randomly to see what's up. This is how I sorted my serif problem. I just watched the snippet I needed on serifs and I was done. I didn't have to wait for a DVD to arrive in the mail, and I could watch it at my bench until I got it.
I realize the obvious rejoinder to the idea of subscribing to a service is, "Why would I pay for video when I can get it all for free on YouTube?" This is a valid point. There are three main advantages to subscribing rather than viewing on YouTube.
The first reason is coherence. If perchance you were to wake up one morning and have a burning desire to make a nameplate, you might type "how to carve letters into wood" into YouTube. You would immediately get a list of credible videos. Some might be good, but most topics get a mix of good, off-topic and waste of time. You could probably muddle through and learn a bit.
But this isn't what really learning carving is about. It's a question of coherence. A good teacher will want you to understand sharp tools, which tools, lettering fonts, basic technique, and then more complicated approaches. The whole point of a website devoted to teaching carving as taught by one person is to get the benefit of your instructor's worldview and best practices. You get the sequence of lessons you need to really master the breath of a skill, and -- because all the lessons are taught by the same person or school -- the approach is consistent. YouTube, for all it's many wonders, gives a platform for every approach and method on the planet, and consequently it lacks consistency and depth. I am learning to carve the Pye way. It's not the only way to learn, there are several excellent sites on learning to carve via subscription. But as I know from previous experiences, Pye's approach really speaks to me, and with each video and my practice, I am slowly building forward. I am not learning every possible way to do something, but one way, that works and can expand.
The second service that you get with a subscription is that you can ask questions. If you have a problem you can email Chris and get answers.
Third reason is one of support and belonging. By supporting a teacher's subscription service, you enable more videos to be produced. The money goes straight to the teacher and goes a lot further. Because there is a revenue stream, production values are professional, and the topics covered can have both breath and depth. And at the same time you are belonging to something. The school of carving that Chris has established, even though it's virtual, has a style and a method, and you now have studied and learned in the same way as all his other students. If you get together for a reunion, you can sing the old school songs and understand and support each other's carving in a way that schoolmates can. And as a matter of fact, that's why I periodically write about his site. I am learning to carve; I really like his approach; and like a good alumnus, I want to give something back so I work the old school tie into all the conversations I can.
N.B. The videos in this blog are from several sample lessons Chris has put on YouTube.
Mitre Planes and the Finest of Mouths: Why? What Evidence? What to Look for When Shopping for Mitre and Shoulder Planes
One of the crappy things about using old planes is that a tremendous percentage are worn out. A steel mitre plane (or "infill" to use the modern phrase) unless made by a modern maker will probably be at least 150 years old. Norris, Spiers, and a few other makers continued making mitre planes up until the mid twentieth century but those are rare beasts. The average mitre plane you come across will be pre 1850.
Rotten wood can be replaced, but the most important feature of a mitre or a shoulder plane is a fine mouth. And not just a kind of fine mouth, the finest of mouths, especially if you are using the plane on end grain. The planes in the picture have mouths (with the irons withdrawn) ranging from a fat 1/64" to a fat 1/32". That's very fine.
Let's talk about fine mouths for a second. First of all it is pretty well understood that a super fine mouth on a smoothing plane breaks the shaving and reduces tearout. All well and good. But what about mitre, shoulder, and block planes? All of them are bevel up and used primarily for planing endgrain. Certainly there is no need for a fine mouth if the shaving is endgrain and will disintegrate on its own.
So why do unaltered historical examples of mitre and should planes have such extremely fine mouths?
There are two dimensions that concern us: the open space from the front of the blade to the lip of the throat - the effective mouth. And the absolute mouth opening when the blade is removed. As you can see from the photographs the mouths of these planes - a late 18th century mitre plane and a C. 1920's Norris shoulder plane are ridiculously fine and I would say this is typical of any infill in good condition that I know of. You do get planes that are worn out, planes where someone has widened the mouth, but for any infill plane in basic decent condition a very fine mouth is to be expected.
As we've stated before, planing endgrain doesn't require a plane with a fine mouth, but there are two very important reasons for having a fine mouth, especially when planing with a bevel-up plane.
Extending the iron sole of a plane as far as possible under a bevel up blade gives the blade more support and makes it less likely to chatter. Steel-soled planes can do this easily, but cast planes can't - unless they have a steel sole (like the shoulder plane in the picture). With a bevel down iron, there is a lot of support in the blade to prevent the very tip from bending and chattering. On a bevel up plane, on the other hand, the iron wants to bend and chatter around the edge of the sole. The more support the sole gives the iron, the more strength the iron has at the cutting edge -- and the better the plane will work. Cast mitre planes, by the very nature of a casting, cannot get as close to total support as a steel-soled dovetailed plane, where the steel sole can taper to a knife edge.
Controlling the cut:
If you are planing endgrain, especially if you are holding the plane in one hand and wood in the other, and you hold the plane perfectly against the wood when you start your stroke, you can determine the exact thickness of your cut by setting your plane iron. But if you are even slightly off and the plane is tilted on the wood, your shaving thickness will increase depending on the size of the plane mouth. The second drawing shows an exaggerated example of this. The practical effect of this is that you try to take a fine shaving and your plane jams, skids off the end, and takes an uneven chunk off the edge. Worse, you can damage that nice low angle cutting edge on your iron. A very fine mouth mitigates this and makes the plane easier to use, even if you aren't perfectly sitting on the wood. There is simply less space for the wood to jam into.
Left to right: Christopher Gabriel - late 18th century, Norris 20E shoulder plane in nearly unused condition, I Smith - Mid 19th Century
These points are small and minor. I understand that. But I get frustrated when someone compares the performance of a worn out 200 year old plane to an new modern plane, possibly of a lesser design. If you are in the market for a mitre plane, or a shoulder plane, make sure the overall mouth is minuscule. Also make sure that the iron and wedge match the plane. It's not at all uncommon for an old infill to have a replaced blade and/or wedge. Just normal use can cause this. Mitre planes had tapered irons and the original iron and wedge would have been fitted together so that you get continuous contact on the bridge. When properly fitted, the iron will set properly, hold its setting, and be easily adjusted. An ill fitting wedge just won't work right. If a parallel iron had been used to replace what was supposed to be a tapered iron, you will never get proper action without adjusting the wedge. Depending on circumstances, you will probably have a replacement iron with the original wedge. If you do and they don't fit, just put the original wedge in a safe place for when you resell the plane, and make a new wedge. Most shoulder planes used parallel irons so any replacement should fit it properly. Check before buying.
Many bevel up planes have cosmetic issues that don't matter, including damaged wooden parts (easily replaced) and misaligned wedges (easily adjusted). But - unlike a bevel down plane - bevel up planes with wide mouths can't be fixed with a thicker iron. You might like the feel of the plane but it won't get the action you would have gotten two centuries ago. Flattening a sole of a bevel up plane can easily, accidentally, widen the mouth. The steel sole behind the blade forms a knife edge and can be damaged. Unlike cast planes which can easily warp over time, steel planes stay pretty flat. A few pits and dings aren't worth worrying about. I would stone down any raised dings, but otherwise leave the sole alone. Before you try to flatten anything see how the plane works.
This past weekend, in spite of coming down with a cold, I needed to get out of the house and went to see A Revolutionary Impulse: The Rise of the Russian Avant-Garde at MOMA. I should mention that if you are a NYC resident you can get a NYCID card which among other benefits gets you a free one year membership to MOMA. Which means in spite of being sick, I could pop in for an hour and a half, see the exhibit for free and not feel I had to spend all day because I paid a $25 admission fee (though it's free on Friday evenings).
I am a huge fan of Futurism in general so it was obvious I would want to see this exhibit before it closed. But while I was walking through the show I had a thought. Context! The exhibit consisted of pieces expressly made as "art" for gallery shows and other pieces - posters, books, and costume designs - that a century later are recognized as art and included at the show. I realized that I gravitated toward the posters, books and a dining set, my favorite piece, that I absolutely would love to have. I didn't get anything out of the pure art pieces (although a paper sculpture of a head was very cool).
What I realized is that the work intended for public consumption at the time had context. The artists and designers were trying to convey a message and they used the new vocabulary of the avant-garde to express the thought. And the works are POWERFUL. But the gallery material seems far more tentative and maybe experimental (and 15 years earlier, which might have something to do with it). They certainly doesn't hit me over the head. The context is different. The work was intended for a more limited audience that wanted to see "art" and was more forgiving and more indulgent. The message of the work is about the artist, not about some performance the artist was asked to promote in a poster.
Pondering this thought I went to test my theory.
The picture at the top of this blog is of a 1961 E-Type Jaguar, which is the centerpiece of an exhibit from the museum's collection of art from the 1960's. The car had the same impact as the avant-garde posters. First of all, the very fact the Jag was on exhibit shows us that it is now considered art. (To be fair, the car has been part of the MOMA design collection since the late 60's). It blows away everything else in the hall. While the works on the wall might define the 1960's for artists and collectors, for me at least the design vocabulary of the 60's was set by items such as this car. It influenced real world design much more than any art piece on display.
Maybe if I had to draw a conclusion, it would be that the art on the wall is commentary on what the artists saw and felt at the time, but the pieces from the outside world are what changed the world.
Just before leaving I stopped for a minute to see "Starry Night" by Vincent Van Gogh, probably one of the top five most famous pictures in the world. Many people stopped to look and take a picture of it. It didn't have to compete with any objects in the room, and it comes from a time when single paintings drew huge crowds (although not to impressionist work). My son, who is twelve and considers walking around a museum to be mind-boggingly boring, really had a hard time grasping that the picture behind the glass was the original painting and that was what was special about it. Times have changed and I think the ubiquity of electronic images make seeing the real thing less unique, less special. Seeing furniture in real life 3D on the other hand is still something the internet hasn't mastered. Although maybe with VR coming soon, maybe it will.
Modern furniture designers and makers are constantly being told that what they do is craft and not art. Woodworking certainly is craft, but as the Jag shows us, sometimes it's art. It's also pretty hard to make a piece of furniture that when people look at it they go "WOW."
But when they do: "WOW!"
This blog entry wass derailed - in a good way.
I was totally in the midst of working on a post about mitre plane geometry when I made a discovery that totally put me in another direction. In the picture above are 4 mitre planes. I had laid out four planes in what I thought was chronological order, using what I knew about the planes and their makers.
From left to right:
Spiers - Latter part of the 19th century.
I Smith - Mid 19th Century (1860's?)
??? - Very early 19th century - Unmarked, possibly by Gabriel.
Christopher Gabriel - late 18th century.
The maker's stamps on the Spiers and Smith planes are on the lever cap or bridge. This is sort of what we would expect from any iron plane after the 1820's. It was pretty easy to stamp the bridge, and it's a spot that didn't get a lot of wear.
In the very early iron planes - such as the first two on the right - the steel stamps used for stamping wooden planes weren't that hard and wouldn't last very long stamping wrought iron. They were designed for wood. So Christopher Gabriel stamped his name on the inside of the front infill. On wood. On the side of the front infill which is nearly is nearly impossible to stamp once the plane is assembled so it won't be over-stamped by owners over the years. This particular plane has some numbers stamped in the bridge, which was not unusual for a Gabriel plane, but number stamps were easier to replace than a custom-made name stamp. Why Gabriel stamped numbers on the planes has been a subject of much speculation over the years.
I pegged the second plane plane from the right as early because of its construction, and possibly by Gabriel, but it's unmarked where it should be - on the wood. There's also some discoloration on the bridge. Since the plane shared some styles with Gabriel, I thought it might have been one of his. The wedge is a replacement. The dealer who sold me the plane back in 2000 thought the same about all the dating.
Now, putting the planes in order for this blog entry shook everything up.
As I put the planes in order for the photograph, I saw a stamp that the dealer overlooked -- and I overlooked for nearly twenty years. The plane bears a stamp just under the hole in the front of the plane. The "WATER" part was pretty easy to read, but it took awhile to suss out the "BY" at the front. "BYWATER."
Richard Bywater made planes in London from 1790-1814. Christopher Gabriel owned a large firm that was also in London.
The chances of Bywater not knowing of Gabriel's iron planes would be zero. One characteristic of Gabriel's planes is the long toe. Like the Bywater plane. But why is the maker's name stamped on the toe?
Maybe it's not a maker's stamp but an owner's? It's possible, but I don't think so. I think the random chances of an unmarked early plane being stamped with the name of a planemaker isn't zero but it's small. (Even if the stamp doesn't exactly match any of the marks included in Goodman and Rees's "British Planemakers from 1700.") And if we are talking about Bywater the planemaker, it's more than possible he didn't make the plane himself as the tools of metalwork are different than the tools of woodwork. The reason the plane would have been marked on the toe is that there are very few planes on an assembled mitre plane where you can swing a hammer enough to mark the metal deeply without running the risk of bending something. I certainly wouldn't risk it.
If Bywater didn't make the plane, who did? Craftwork in 18th century London was done by small independent Little Meisters who either worked in their own small quarters or worked in a larger shop, working on their own but buying parts from the master, all paid on piecework. Did this plane come out of the Gabriel shops, wholesale, to be retailed by Bywater? Was it made by a Little Meister working for Gabriel, made on the sly to sell to Bywater?
I don't know: it's all speculation. Do you have any ideas?
Previous parts are found here:
Part 1 is here.
Part 2 is here.
Part 3 is here.
Part 4 is here.
Part 5 is here.
In previous blogs we discussed the need for grinding for a variety of reasons. This final reason is the most unfortunate one: you need to repair a damaged cutting edge. This problem could come about from dropping the chisel (see photo), burning the steel from incorrect grinding, or any number of crises. If we were to grind out the damage by just grinding the bevel like we normally do, we would burn the steel and create more damage. The drawing illustrates the problem. Constant grinding on the bevel heats up the entire bevel. When the damaged tip get heated, the heat has no place to go - especially when the rest of the bevel is heated up too. Even with a cool wheel, this will be a problem.
The solution to this problem is simple. We first level up the tool rest and grind the chisel end square past the damage. As we are only grinding at the tip, not the entire bevel, there is little heat, and the heat has someplace to go (see sketch).
I can free-hand grind pretty square on a crowned wheel, but a scribe line to guide your grinding can be useful. Or after grinding, a few passes on a stone to ensure a straight edge can be helpful. If you are a little off, it doesn't matter. Final honing fixes everything. As you can see in the picture, you want to grind back to an even flat just past the damage on the chisel.
Then we will reset the rest and grind to a wire edge, just like we did before in Part 5. The only difference is that instead of setting the rest to grind in the middle of the bevel, we want to grind a bit towards the back of the bevel to compensate for the blunt edge we just ground. If you are shortening the bevel angle and not really correcting damage, you would also grind a blunt end, but not move the bevel back.
In Part 5, when I ground the chisel I checked to see my bevel disappear, then stopped. In this case, the bevel will disappear fairly quickly, but my work will not be done until I have removed the blunt end. As I grind, I look to see that the flat end starts to disappear. In the first photo, the flat end is about half gone (and uneven). I continue the grinding, with more effort on the thick side, until both sides are even and the edge (seen as a white refection in the light) disappears. Then I am done and ready to hone.
This concludes this series on grinding. I hope it make sense to you and I hope the series encourages you to grind your tools for better geometry.
Here are links to some of the production I have mentioned in the series:
Norton 3X Grinding Wheels
Crowned CBN Grinding Wheels
Fancy Wheel Dressers
Plain Wheel Dressers
Custom Baldor Grinders that we have tricked out with better wheels, balance, and adjustments
For instructions on honing your freshly ground edges - click here.
Also searching my blog will turn up a lot of sharpening material from past years.
Finally if you are in the NYC area I will be teaching both grinding and honing in two free classes in March. Please see the events menu for the exact schedule, more classes will show up shortly.
Thanks for reading, Joel
Part 1 is here
Part 2 is here
Part 3 is here
Part 4 is here
In the last section, we prepared our grinding wheel so we are ready to grind our chisel.
Before you grind, you have to make sure that the back of the chisel is flat. Now I don't mean flat for its entire length. I mean, from left to right at the cutting edge only - maybe a 1/16". (For the reasons why you don't want to flatten the entire back, click here.)
We need flatness at the edge so that the back will be an accurate reference for grinding. If the back isn't flat when we hollow grind, we would hit the edge at different points and not have a straight ground edge.
Next, we have to set the rest at the right angle. In general, I don't try to measure the angle; I try to maintain the current primary angle of the tool. Put the tool flat on the rest and rub it back and forth against the wheel of a grinder that is turned off. Rub it a few times to establish where you are making contact. A sharpie applied to the bevel will make the scratches more prominent. If the scratches are in the center of the bevel, then you are simply maintaining the current angle of the chisel. If the scratches are past the center towards the body of the chisel, you are increasing the grind angle. If you find yourself with scratches forward of the center, you will be shortening the bevel angle. This latter condition is bad for two reasons. One: you rarely need to shorten a bevel angle. Two: even worse, when you grind, you will hit the fragile thin tip of the chisel before you touch the back bevel, resulting in an uneven grind. And if you continue grinding at the tip, you will most certainly burn the steel. There is a simple technique for shortening the bevel without danger, but we will save that for next time when we discuss repairing damaged chisels.
To get the rest in the right place, I use a mixture of moving it carefully and tapping with a chisel handle. When I think I am done, I will put on my eye protection, make sure all loose clothing and hair is tied away, lower the shields (although for the purposes of clarity in these pictures the shields are retracted), put a large cup of water within arms-reach and get ready to turn on the grinder.
As with wheel dressing, I stand to one side when I turn on the grinder and let it come up to speed. Then, with the chisel on the rest, I touch the bevel to the wheel and then pick up the chisel to look to see where I actually made contact. If I am grinding where I want to be then I will continue, otherwise I will tap the rest to move it slightly, or possibly loosen the rest a very, very tiny amount so that then I can tap it to the right place. Be very careful here. In theory, you will only need at most a minor adjustment but it is easy to slip, especially if you have loosened the rest too much, or are twisting by hand too hard. The rest could turn into the wheel, jamming it, with disastrous results.
With the rest set correctly, I start grinding.
As you can see from the video, I place the chisel firmly on the rest and just going back and forth on against the wheel. Periodically I check to see how far I have gone, and if I neglect one spot or another, I pay more attention to it. In the beginning I concentrate on the center of the tool; as I get further along, I start grinding towards the sides. As I approach the edge, I am trying to work in a uniform way. My finger rests on the back of the chisel, and if it gets warm, I will instantly dunk the tool in a water bath. However with these CBN wheels (or a well dressed, crowned, 3X wheel) I find myself not needing to dunk frequently if at all. Paying attention to what is actually happening is the key here.
I typically grind to a wire edge, but many people don't, and leave a smidgen at the edge. In either case there isn't much to hone away.
In the last picture, you can see a chisel that was ground freehand against a crowned wheel. It probably isn't perfect, but it's pretty close. Any variance in my grinding will be straightened out instantly when I start honing on any flat stone.
Next week we'll show what do to for a damaged chisel or one for which we want a shorter angle. We need to remove a lot of metal without overheating the tip.
N.B. As you can guess from the video, I am new at video making. I'm still learning, but I hope even in this crude way the information is getting across.
Part 1 is here
Part 2 is here
Part 3 is here
When you first mount a wheel on your grinder, the first thing to do is make sure the wheel makes a nice ringing sound when tapped. Tap the wheel gently with a handy bit of steel; it should ring with a fairly bright sound. If there is a defect in the wheel, you won't get a clear tone. Now to be fair, in general modern wheels are very safe, and it's rare that you will get a dud. I certainly have never had that misfortune. I only use new wheels from a reputable manufacturer. An old wheel from Ebay; a Brand X wheel; or a wheel that comes without protective packaging would all be far more susceptible to failure. If you don't get a clear ring when you tap the wheel, do not use the wheel.
You want make sure that the wheel is the correct bore for your spindle. In the case of these 3X wheels, Norton supplies plastic bushing so that the wheel will fit a variety of spindle diameters. There still is a little slop, but not much - it largely doesn't matter. When you clamp the wheel in the grinder (unplug the grinder first, of course), the wheel is sandwiched between two flanges. On either side of the wheel is a cardboard washer. In this case, the washer is glued to the wheel and contains branding. These washers are very important. Clamping between cardboard takes up any minor irregularities in the flanges or wheel and prevents a minor unevenness in the wheel from causing the wheel to crack when clamped up.
A couple of multi-point diamond wheel dressersWhen you first get a new wheel or if you are seeking the best performance from a wheel you already have, dressing the wheel is vital. Inevitably the wheel will not sit perfectly on the spindle. If it's mounted slightly off center, dress the wheel to make it centered. This step is important for the wheel to run smoothly. I know some vendors sell balancing kits, but I have never needed one. I am also going to set the rest approximately square to the wheel and fairly close to the wheel. Square because I want the dresser to approach the wheel square, and fairly close because I want to avoid any chances for the dresser (or anything) to get caught in the gaps between moving wheel and rest. After checking that my rest is clamped solid and the wheel can rotate freely by hand, I will lower the guard, put on my eye protection, and turn on the grinder.
Whenever I turn on a grinder I step aside as it comes up to speed and runs for a few seconds. The reason is that just in case there is a flaw in the wheel, or a chip got knocked out, or something is caught in the guards, I would rather not be in the line of fire if disaster happens.
For a new wheel, I want to hold my dresser firmly against the rest and push it forward to contact the wheel. As long as my dresser is held steady against the rest, any high or low spots on the wheel will get dressed off. Don't clamp it; you need to be able to move it forward, and your hand pressure is more than enough. In a few seconds the wheel will be tracking round and round and run smoothly. You might notice a wobble from left to right as the wheel rotates. There are two possible reasons for this. The first (and more common reason) is that the flanges aren't flat. Baldor and many other makers don't machine their flanges, they just die-cast them. We have seen plenty of wobbly flanges over the years, so one hop-up we do on our custom grinders is to machine the flanges. Cast flanges can result in wheel wobble. (We do not sell cast flanges.) A little left-to-right wobble is no big deal. Don't worry about it. DO NOT under any circumstances try to dress the sides of the wheel. Wheels aren't designed for that. They could explode. In any event you will probably make the matter worse. If you encounter a lot of vibrations, a lot of wobble, it could be caused by a uneven, poorly made wheel. In that case return it. There is no way to fix that.
Once the wheel is dressed round you can lighten up on the pressure on the rest.
We now want to dress the smallest of convexity, or crown, into the wheel. With a convexity we can be assured that every time to touch a tool to the wheel we are making contact somewhere in the center of the tool. If your wheel is straight, and your tool is basically straight, the wheel face will always contact the tool at one side or another -- unless your blade is 100% square to wheel, which is nearly impossible to do freehand. With a convex wheel you don't have to grind the corners of your tool until you have ground the middle, which is safer. In the middle of the tool, heat from grinding can go towards both sides and back into the body of the tool. At a corner, heat can't escape at one side, which will rapidly cause a corner to overheat and burn. With a convex wheel you have a controlled point of contact and as you feed the tool into the wheel, you get more and more contact - you aren't grinding just at that point on the wheel. We will go into this in the next chapter when we actually grind a tool. For now, suffice it to say that we need to is put the smallest convexity we can on the wheel.
My process of dressing the wheel: Turn on the grinder, wait until it comes up to speed, and then touch my dresser to the wheel and move it in a very wide arc across the wheel. While doing this, I eyeball everything. The basic step is contact the wheel in the center with the dresser, and then swing it around to either side. As you can see in the video, the process takes about 10 seconds.
With dressing done, we are now ready to grind. I repeat the dressing process just about every time I grind -- and whenever I think the wheel seems to be heating up too fast. Of course CBN wheels never need to be dressed and the wheels we stock have the crown built in.
Next time we are going to set the rest to the right angle and refresh the hollow on a tool.
A wheel properly dressed to a very slight convexity.
Part 1 is here.
Part 2 is here.
Up until the late 19th century, grinding wheels were made of natural rock. Sheffield, England - that great center of edge tool manufacture - became the center it did because it had a lot of water power and, right outside the city, mountains of sandstone perfect for making grindstones. To this day, in the mountains of Derbyshire around Sheffield you can see remnants of grinding wheels everywhere. The problem with natural stones is that they are rarely consistent. If you are lucky, the inconsistency is just a hard or soft spot in the stone. If you are unlucky, a hidden flaw could cause the stone to explode. Another problem with natural stones: their grit is whatever their grit is, regardless of your expectations or needs.
In the late 19th century, Norton, an American company, figured out how to make a vitrified stone. The basic concept is simple. You take abrasive powder and mix it with a binder. Then you press it into a wheel shape and bake it in an oven. By varying the grit and binder you can make wheels with all sorts of properties.
To alter the abrasive aspect of the stone, you can vary the grit size. Coarser grits grind cooler but rougher. The space between the larger grits have more air and turbulence and keep the grit cooler. You can also use different abrasive materials for different purposes. Silicon Carbide grinds quickly but shatters under pressure, so your wheel will grind very fast for a short mount of time, then heat up as it rubs more than cuts. Aluminum Oxide crystals fracture slowly and therefore run much cooler - at a slightly slower grinding speed. Newer materials such as "seeded gel" are designed to fracture slowly along a crystal structure so that they still cut fast, but also run cool. Our 3X wheels are a consumer version of seeded gel and are the coolest running vitrified grinding wheels available.
Vitrified wheels can also have variable "friability." Friability means how much force it takes for the abrasive to detach from the wheel. A very friable wheel will constantly be losing particles as you grind. This is very messy, but each time you lose a grain of abrasive you also lose the heat on the grain. More importantly, this particle loss exposes fresh, sharp abrasive.
Finally, just recently, CBN plated wheels have come on the market. These wheels are a totally different technology and need to be looked at separately.
Lower grits run cooler; softer wheels run cooler; Seeded Gel (3X) runs cooler than Aluminum Oxide (AO); and everything runs cooler than Silicon Carbide.
To keep a wheel sharp and cutting cool and fast, you will need to regularly dress the wheel. This is a very critical step. More (lots more) on this later.
If you look at the side of a vitrified wheel, you will see a coding showing the material the wheel is made of, the grit, and a letter indicating hardness. If you are sharpening High Speed Steel (HSS) turning tools, which are very resistant to overheating, you can be less worried about heat than about surface finish. For regular carbon steel, heat avoidance is an important issue.
With a light touch, a properly dressed wheel, and a coarse enough grit, you can grind just about anything without overheating. But softer wheels with cooler abrasives make the job much easier.
For regular grinding of edge tools, I prefer a 3X wheel in either 46 or 60 grit. The slightly finer texture is a personal preference. For aluminum oxide wheels, I would want something even coarser - maybe 36 grit? Because I'm not a woodturner, a softer, more friable wheel ("I" Grade) is my preference. If you are using a 3X wheel also for grinding turning tools, you might want a "K" grade wheel. The stock wheels that come with most grinders are typically very coarse and very hard. While you can make them work for grinding edge tools, this option is far from optimal.
None of these wheels will work properly unless they are regularly dressed. Dressing consists of rubbing a very hard stone or a row of diamonds against the rotating grinding wheel. This encounter rips off the top layer of the stone and exposes fresh, clean, SHARP grit. Sharp grit cuts faster and cooler. One way to make a hard grinding wheel run cooler is to dress is regularly. We also dress wheels to get any eccentricity out of them when we first mount them and when we want to curve the surface to make grinding easier. More on the technique of dressing later.
The typical wheel dresser is a block of rough diamonds, either plated to a stick or part of a matrix. What you need to know is that single point diamond dressers are used in tool post grinders for precisely shaping a grinding wheel. We are hand holding our dresser, so a multipoint dresser is far more effective.
Our final choice is plated wheels. The newest grinding technology uses CBN (Cubic Boron Nitride) abrasive, a synthetic, diamond-like material that is plated onto an aluminum substrate wheel. Diamonds, being carbon-based, have a serious issue when grinding tool steel. The carbon on the tools and diamonds want to bond, and - even worse - diamonds are heat insulators, so like vitrified wheels, they reflect heat back into the tool. CBN, on the other hand, absorbs heat and the aluminum wheel just soaks up more heat. So the single coolest way of grinding these days is on a CBN wheel. And the bonus that you do not have to dress the wheels. The only caveat is that non-ferrous metals will clog the CBN wheel so if you mount a CBN wheel on your grinder, keep one side for a traditional wheel so that you can grind other stuff besides tool edges.
My current favorite grinding wheel is a 60 or 80 grit, crowned CBN wheel. The crowning which I will talk about next time is an important step for dressing and since you don't have to dress a CBN wheel. my CBN wheels have the crown built in. The downside of CBN is that it is more than twice as expensive as my next choice - a 3X wheel. But I really like the lack of maintenance and with no wheel dust flying off every time you dress the wheel I like the less mess.
I forgot to include a picture of a wheel dresser. I'll make up next time in part 4 when we mount our wheel on a grinder and dress it.
Part 1 is here.
These days when shopping for a grinder you have a huge number of choices. From $50 dry grinders from Asia to very expensive slow speed wet grinders with lots of attachments and everything in between. When I was studying woodworking (a long time ago) my teacher, who knew a lot about lots of stuff was scared of grinding. I think this is a common fear. We had a high speed grinder, with who knows what kind of wheel, no wheel dresser, and the fear of burning (overheating) the chisel was real. Burning was way to easy to do and the cure was grinding past the burn - which exposed you to the same issue only with a shorter chisel.
So many people are so scared of burning that they do all their rough work on very coarse diamond stones. This isn't totally off base either. In Japan having a grinding wheel on a jobsite was uncommon and working coarse grits on a stone was very common. In England (and the US I think) up until the invention of the small electric motor in the 1900's most people did not have ready access to a grinder. This especially applied to carpenters and joiners who worked on site. Saturday was the big day for hardware stores when craftsman took their tools to be ground if needed. Hand cranked grinders existed going back centuries but you need an established shop to work in and grinding wheel technology was natural stones which cut slowly - so it made sense to pay someone else to do it.
The revelation for me was when Barry Iles of Ashley Iles visited my shop. He needed to grind something, found my grinder, took all the guards, jigs, and thingies off it. Turned the grinder on, dressed the wheel, then touched the chisel he needed to grind on the wheel and was done 5 seconds later. I said "hey - can you teach me that" And he did, turning my entire fear of grinder away. It's not hard to learn. Actually it's pretty easy to learn.
There are many factors involved in selecting a grinder.
Cost - that's pretty obvious. You can buy something that spins a grinding wheel for fifty bucks and it can work. As you work your way up the cost chain you get better materials, better motors, larger wheels, better bearings and more solid rests. Not to mention better customer service.
Wet or Dry
Professional grinders try to grind wet. This solves the cooling problem and you can grind fast. Until recently wet grinders were big complicated machines that were not designed for a home shop. In the past generation Tormak, a Swedish company, introduced a 10" grinder with a water bath for the wheel. Also available from Tormak are some of the best grinding jigs in the industry. It isn't an inexpensive piece of kit but the Tormak is very well made. My issue with the Tormak and all consumer wet grinders is that they are way too slow. The reason professionals grind on big wheels with a water spray is so that they can grind really really fast. The Tormak has a water bath (good) but it also turns really slowly and grinds really slowly (bad). As you get better at grinding the jigs are less and less useful.
Belt, Flat Grinder, or Wheel
Up until recently professional grinders all used large (4') grinding wheels but increasingly belt sanders of various sizes are also popular. A belt will run cooler, and you have a very large selection of grits. We have knife grinding equipment here and can easily hollow grind on a belt. However most less expensive equipment doesn't have that option and since one requirement of mine is being able to grind hollow, a belt sander isn't really a great choice for general woodworking tool sharpening. I have the same issue with flat grinding systems that use abrasive disks. In general they work slowly, I like a hollow grind, and I don't like having to replace disks. One point that should be mentioned. With some of the flat grinding system that use abrasive disks, and belt sanders (but to a lesser extent) you can not only rough grind but also polish. We power sharpen some carving tools on a Koch machine with uses paper wheels. Flat grinders can also polish but in general with a hollow grind I think hand honing is easier, less fussy, and faster.
How big a wheel
We stock two sizes of grinder: 6" and 8". 7" grinders had a certain vogue but currently there are fewer options for wheel selection. For normal woodworking a 6" grinder is all you need. You get a nice hollow grind, and the grinders aren't huge. Lots of turners however like an 8" grinder because the hollow is less and for some turning geometries a deep hollow is a disadvantage. An 8" grinder weight a lot more than the 6" which is great if you don't have to move it. My suggestion would be that unless you turn go with the 6".
The surface speed of a grinder is what dictates how fast we grind and at what speed. Many people recommend slow speed grinders - a 6" grinder running at 1800 RPM as a great way to avoid burning the steel (and it is). A 6" 3600 RPM runs twice as fast and grinds twice as fast, and by the end of this series you will be able to grind on it with no real risk of burning. We stock 8" 1800 RPM grinders which a surface speed between the 6" 1800 and 3600 machines. While faster (3600) grinders exist I don't recommend them, they grind very fast which can be an issue with heat, but also lots of the better 8" wheels aren't really designed for that speed.
A couple of vendors offer variable speed grinders for sale. In general the top speed is slower than 3600 so what you end up with is a slow speed grinder that can go slower. In addition variable speed electronics are just not as reliable as a fixed speed. And why would you want to grind slower once you learn to grind faster. So I cannot recommend them.
With modern wheels there really isn't much of a risk of a wheel exploding. But an exposed wheel is always a hazard. A spinning wheel can grab a loose thread or hair, and rip off your arm or head. A trip and fall can have you grab out to a spinning wheel or have a tool ripped out of your hand with disastrous results. Baldor grinders, which we stock use heavy cast iron guards. That might be overkill but no matter what grinder you use make sure it has guards.
Eyeshields are also important to prevent flying debris. However even with shields always wear eye protection. Hopefully you will never need it. Over the years I have - more than once.
Grinders spit burnt steel and abrasive dust behind them. Some grinders (like the Baldor) have proper dust ports built it. Unless you have a dust collection system only for metal DO NOT connect your grinder to the dust collector. Metal sparks from burning steel and wood dust on a container are EXPLOSIVE.
My grinder is just far enough away from a wall so that it doesn't make to much of a mess.
We want a rock solid rest that won't move or flex during grinding. Some people clamp the tool in a jib and move the jig on a specially designed rest. If you plan to do the latter I suppose no rest is needed because you are going to replace it. Most rests that come with grinders are either cast iron or aluminum or bent sheet metal. Sheet metal sucks - it just bends under pressure. Cast aluminum is fine although it does get scratched from the abrasive dust. The grinders we stock have rock solid cast iron rests. These are by far my favorite. Solid, heavy, and no flex whatsoever. I think no matter what grinder you get if the rests aren't solid either buy an aftermarket rest or make something solid. It doesn't have to be complicated. I adjust my rest by getting it into the approximate correct position and tightening the clamps and then tapping it to final position. The method looks cludgy but works well.
Unlike a printed magazine which has page limits on a blog you can go on and on and on. Which it seems I have done here. On one side this is far more information that anyone actually needs, but I am trying to cover all the questions that I regularly get. As I have gone on at such length I think I will put "Grinding Wheel Chemistry and Nominclature" in part 3.
Happy New Year! I thought I would start off the new year with some practical woodworking information. I have always thought that a grinder is one of the most important tools in the shop -- and it's also one of the least understood. While I do teach an occasional class on grinding at our shop (and will do so again in the future), most people don't live nearby, so written instruction seems in order. The last time I wrote on this subject, in the June 2008 issue of FWW, the response was overwhelming. But I have learned stuff since then, and technology has evolved.
This series on grinding will be in four parts:
1 Introduction + reasons for grinding
2 Grinding wheel and grinder technology
3 The angle to grind at, wheel dressing, and how to grind to maintain the existing bevel
4 Grinding to repair an edge
Parts three and four are hands-on; the rest is theory and background information.
There are three reasons to grind.
1 - To Maintain a Hollow Grind. Grinding an edge tool against a curved wheel will always result is some sort of curvature on the bevel. The larger the wheel, the less the curvature. We call this "hollow grinding" (see picture). Producing a hollow grind enables easier and faster honing. When you think about it a bit, the only part of the chisel that does any work is the cutting edge at the very tip. The rest of the chisel is just support for the edge. So the steel in the middle of the primary bevel is basically waste. With a hollow grind when you go off to hone the tool after grinding, you get a very stable platform of the tool solidly supported at the front and back edges of the bevel. You won't be wasting energy, stone wear, and time removing the middle of the bevel, you'll also get a simple way to make sure you are always honing at the edge. All the force is applied at the edge, and there is no tendency to wobble or rock the chisel. Hollow grinding GOOD!
2 - To Restore or Change the Geometry of the Primary Bevel Angle. Personally I am not fussy about bevel angles. The lower the angle of the primary bevel, the less force it will take to push the chisel into the wood. With less force comes more control. The trade-off is a thinner, weaker edge. A higher primary angle gives you a stronger edge, but more force is needed to punch it into the wood, and with that comes less control. The traditional angle of a bench chisel is 25° but a little more or less isn't a big deal. Paring chisels should really be lower by at least 5° and mortise chisel higher by the same amount. Every once in awhile I realize that my geometry on a particular chisel or plane blade is off enough to annoy me. This usually happens because after several years of honing I find the bevel angle getting steeper. These days, however, as I am hollow grinding to make honing easier and I don't have this problem at all. I'm also not personally adding new chisels to my toolbox - but certainly someone building a shop will always have "new to them" tools that need a geometry change.
3 - The Unfortunate Reason: To Restore a Damaged Edge. Probably the most frequent reason I end up grinding something. Chisels, plane irons and other display tools in our showroom get handled all the time and get dropped. Repairing a damaged edge is a little more involved than a just maintaining the hollow, but there really is no better way of repairing a damaged edge. Honing past damage, even with a coarse abrasive, just takes a lot of time and elbow grease.
The issue that many woodworkers are scared about when grinding is heat. The basic problem is that (with the exception of turning tools made from High Speed Steel (HSS)) if you heat up a hardened piece of steel past 400 degrees it will get start turning brown and blue and get softer -- and most importantly, it won't keep an edge anymore. HSS is called "High Speed Steel" because it can be heated up way past 400 degrees and yet stiff hold an edge. But in general, HSS won't hold a sharp enough edge for woodworking, and it's very hard to hone. The goal when grinding an edge is to achieve a ground edge without overheating or "burning" the edge. And a more important goal is to be able to consistently grind without burning because otherwise the crap shoot of what will happen is too scary.
There are three (or four) basic approaches to keeping cool when grinding. Use a very slow grinder. Use a grinding wheel that allows speedy steel removal without heat. Use some sort of coolant, such as water for wet grinding. Finally in parentheses: (grind really slowly and gingerly). The goal for me is to grind as fast as possible without any real danger so in Part Two we will talk about wheel and grinder selection, and how to keep a wheel grinding as cool as possible.