The Backsaw Project
This is a project I've been contemplating for a long time, and finally was pushed over the edge when someone told me that it wasn't feasible for a home shop. "It requires a machine shop to be able to pull it off, and a sharpening service to cut the teeth...". I thought to myself, no way -I've done teeth without any fancy machine, and the old time saw makers of the 1800's surely didn't have all access to a machine shop, much less a modern one. I had to prove to myself that I could do it, and am thrilled that I can tell you here that I was successful - and that if you want to make your own back saw, I will be the last one to say you can't.
Because of multiple requests, I've created a 61 page, 2.1 Mb PDF of this entire article, available here.
I've arranged this writing of the steps of making a backsaw into different "chapters" and created an index that would make it easier for those who want to skip over certain parts - or to come back for information on a certain portion of the process.
However - if you are looking for a set of "plans" to build a saw off of - you aren't going to find it. I will try to provide all the information I've gathered and provide some basic patterns that are free to use. The real fun in this project for me was as much in devising the method or procedure I wanted to attempt as it was in executing that method, and I encourage the reader, if you are inclined to make your own back saw, to research what it is you want to accomplish rather than pull it off of a set of cookie cutter plans.
I've always wanted an open-handled back saw, but have been too cheap to buy one for what they are worth, and didn't want one that was all beat to death, either. I made up my mind to give making one a try - but didn't want to commit myself until I knew for sure that I could do it. I started researching it on the web, but found woefully little in the way of helpful information. I did find some early email conversations between modern saw makers on the oldtools discussion forum archive from early in their saw-making efforts - but all of them inserted their blades into a solid chunk of brass that they had milled a slot into using a milling machine (something I will never likely have).
A prototype was in order - so I made myself a makeshift small metal bending brake out of some angle iron, found myself a suitable piece of brass (a door kick plate), and successfully bent it over a piece of saw steel that I'd cut from a larger saw:
The brass was much too thin to really be of any use, but as a proof of concept, it worked beautifully and convinced me to go ahead and try to make some. As it turns out, after catching a lucky break on a piece of brass on eBay, I had enough to do a governor's dozen (that's 11 - one short of a real dozen), so went ahead and made them. This series of articles will document what I did in the process of making those saws.
First up - what to use for materials.
The second lot had a few winners in it that I hung on to rather than cut up, including a WWII era D-8 and D-7 that are in excellent shape, and the top lot included a 100 year old D-7 that I also kept. The rest were cut up for use in these back saws, at a final cost of about $1.00 a blade. I still have steel left for other saw projects I want to try.
I should talk about the thickness of the blades... Back saws made today are generally made from spring steel that is about .020" thick. Older standards varied, but were also down to that thickness. The steel in these saws vary in thickness, but are all thicker than .020" - some of the steel is up to almost .040" thick in places. Yes - I said "in places". Older, high quality saws were "taper ground" - this means that after the steel was forged, they were ground down to be thinner at the top of the blade than at the bottom. This is not the case for all saws, and is rarer today than ever (I believe Pax saws are still taper ground). The tapering is not uniform across the width of the blade, though - I saw a catalog that showed how Disston saws were tapered and it resembled this:
The blade, as shown in the diagram above, would be thickest at the right and the bottom, and vary in thickness between .010" and .015" or so. The tapering is done to help keep the saw from binding in its own cut. Many newer saws that you buy today will not have this feature.
- Added - 10/19 - From a book by Erv Schaffer called "Hand-Saw Makers of North America" - here is what he lists as the different types of back saws:
- I think the line is a bit more blurred, myself, but still, it's nice info to have...
Flat Shim Stock Strip Blue Tempered Spring Steel, .020" Thick, 6" X 25"
$ 13.70 Each (at the time this was written).
That steel is tempered blue, but that could be sanded off if you prefer (I've not tried it myself, but I do have it on good authority that it is easily done). RC hardness is listed at 44-51. I wouldn't use anything thinner than that, myself. If you can find polished swedish spring steel (i.e. made by Sandvik) that is essentially what the modern makers use. Any steel you use should be hardened to at least a minimum of 44 (48 and above is preferred) on the Rockwell hardness scale and a maximum of around 54 or so - the harder the steel is, the longer is will keep its edge, but the tougher it will be to sharpen. Too hard, and you won't be able to set the teeth without breaking them.
- Added 11/07: I have since made a few saws with the new spring steel mentioned above, and I have to say I like it quite a bit. I think there is an even higher quality available from mcmaster, too, but it might cost a bit more:
- This is text taken from mcmaster.com site:
Blue-Tempered and Polished 1095 Spring Steel
Made of hardened, tempered, and polished spring steel, this material combines maximum fatigue life with high tensile strength. Material is cold rolled. It can be machined with carbide tools. Rockwell hardness is C48-C51. Melting point is 2500° F. Not rated for yield strength.
Item # 9075K243
Blue-Tempered and Polished 1095 Spring Steel .020" Thick, 8" X 24" Sheet
In stock at $33.38 Each
- There are more sizes available than what I posted above - look at the catalog page on the web that contains that item number (it's not convenient to directly link to it because of formatting issues, otherwise I would). This might make for even better saw steel.
I'd love to have a metal cutting band saw - but not having one, I put together a makeshift "table saw" using my circular saw with a metal cut-off blade installed:
The saw's base is simply screwed to a piece of particle board. A piece of plywood screwed to the "table" serves as a fence, and I just clamp the whole affair to my bench, as you can see. If you do this, you'll probably need to wear a pair of gloves while cutting the steel, both because of the sharp edges and possibly because of the heat (bigger issue when cutting the brass than the steel). Keep an open pail of water handy to dunk the steel into to keep it from getting too hot. Make sure your fence is aligned properly, and your cuts are true - if not, the blade will want to bind against the steel which could throw it out of your control (do not stand in line of the blade!) or heat the blade up. You must avoid heating the blade up to avoid "tempering" (softening the steel) the blade. A very little bit of bluing along the very edge can be tolerated, so long as you take the time to file it off if it is on the cutting edge, but do try not to.
It's great for short cuts where the circular saw would be at a big disadvantage, though my air compressor can't keep up with it for longer cuts.
In any case - if you use existing saw blades, they will probably need a bit of clean-up, and this would be the time to do the majority of that work as it is more difficult to do once you have the backs in place. I used a belt sander with 120 grit paper for the bad ones, then used progressively finer grit sandpaper by hand until I had a decent enough polish on them - probably stopping at around 400 grit or so at this stage. I'll put a final polish on them after they are assembled but for now, getting any rust off is the most important. Do not use any blades that have been pitted with rust - a bit of surface rust is ok, but the pits will be a detriment to your new saw both functionally and aesthetically (a few won't hurt).
There are different alloys of brass that vary in hardness - here is what I used, ordered from McMaster.com:
Part #: 8956K42
Alloy 260 Brass Sheet (Cartridge Brass) 0.093" Thick, 12" X 12"
$ 21.37 Each (at the time of this writing).
Watch that you get Alloy 260 (or cartridge brass), as other alloys are much harder and you'll have to anneal them to get them to bend. I got 6 backs from one 12"x12" chunk of brass. If you find another source - it does not matter if you buy polished brass, as you'll be beating it silly anyway. Find the cheapest source you can. Some have used brass kickplates off of doors - this is fine, but be warned - first, the kickplate you'll find on sale at the local lumberyards are usually much too thin to use for back saws - you want your brass to be about 3/32" thick (.093") and at the very least nothing less than at least .08" or so. Also - the brass used in kickplates is often very hard, therefore difficult to bend without annealing. With the brass I used , I was able to get away without annealing it at all.
I cut the brass using the same "table saw" set up I used to cut the steel blades. To get the most useable size out of the 12" square chunk of brass, I set the fence to cut 2-1/4" wide strips - cutting the first strip off, then rotating the brass 90 degrees and cutting the remainder, so I ended up with one 2-1/4" x 12" strip (which I later shortened to match the rest) and five 2-1/4" x 9-5/8" strips. I also had an odd sized piece of brass I got off of ebay that yielded enough for 5 more backs (two 8" long and the rest 10").
One of the benefits of using old saws as your source for saw steel is that they are also a supply of saw nuts. All of the saws I made used "recycled" saw nuts. If you want a medallion (like one that says "warranted superior" on it), or you want brass saw nuts, you really have no other choice than to use recycled saw nuts. If you aren't concerned with using a medallion, then chrome plated "replacement saw screws" are available from acehardware.com at $7.47 for a 10 pack plus shipping.
The advantage of brass split nuts are that you can file/sand them flush with the surface of the handle, and they make for a very professional appearance, though like I said, I doubt they provide any structural benefit over standard steel saw nuts. Most older saws you find will be sanded flush - when they were made, the saws were not designed to be disassembled, so sanding them flush was a nice solution. Unfortunately, this can also mean that they have been filed or sanded to the point where it is difficult to remove without damaging the brass (and also require a special tool) - which is why restoration of some of these old saws is difficult. This obviously wouldn't be an issue when using new brass split nuts, obviously.
To make the metal bending brake - you'll need:
three 10" long and two 18" long pieces of 1-1/2" x 1-1/2" x 1/8" angle iron;
two 1/8" x 1-1/2" x 18" pieces of flat steel;
a slug of #8 to #10 sized, 1" long flat head machine screws with appropriate nuts and washers;
four fairly thick washers (the thickness of the brass - or you can stack thinner ones)
a pair of door hinges.
Other Special Tools Needed
I've already mentioned the tools I used to cut the steel and the brass, so I won't again here.
Because I don't have much in the way of metal-smithing tools, I did most of the work for these saws making due with what tools I had on hand. There were a couple tools I needed to purchase, though - without which, I doubt I could have successfully made these saws.
The first two tools, and the most important in my mind, are a hammer and anvil. For the anvil, I happened to be in the local Harbor Freight when they had a sale going on, and picked up a "Made in China" 55 lb. anvil for $30. Not a fancy one, mostly because I'm not kidding myself into being any kind of a blacksmith - just need the mass that an anvil like this provides for bashing the backs over the blades.
You don't even have to spend that much. Dad has an anvil he's made from a short chunk of railroad track, mounted to an old I-beam, and it works just dandy.
I also used a 4 lb. hammer. That's right - a 4 pounder. Mine is wood handled, but here is an HF fiberglass handled one that retails for about $9.00 that would also work:
You *need* a 4 lb. hammer to make these back saws, in my opinion. A smaller one simply won't do - or will yield unsatisfactory results. The larger hammer made bending the brass a veritable breeze in comparison with anything else that I tried. It wasn't that I was swinging that hammer in a wide arc, quite the opposite. The weight of the hammer let me get by with much smaller swings, affording me more control over them - which subsequently meant doing less damage to the brass. Of course, your experiences may differ, especially if you are practiced in blacksmithing.
Finally, if you want to stamp your name into the brass you'll need some lettering stamps. The ones I used are 1/8" tall, and cost about $5. The rest of the tools I used are all standard issue woodworking tools you should be able to find in any good woodshop.
The Choice of Wood for the Handles
Finally, there's the wood for the handles. The saws I made here all use either beech or walnut handles - mostly because that's what I had on hand. Beech is a very good choice for tool handles, as it's a tough wood that's not open pored. Walnut is more aesthetically pleasing, but is a much more fragile wood - there's a much greater chance that if you drop it the walnut will split. I think just about any close grained hardwood that isn't open pored is a good candidate for a handle - cherry, walnut, maple.