Specialty Saws and Taper Grinding

Specialty saws

Classic crosscut and rip saws along with back saws cover 95% of the work done in my shop with a saw.  There are a few specialty saws that I've found very handy, and should review for this article as well...

Keyhole saws.  Keyhole saws have a narrow blade, and were used for all things - making keyholes in desks and drawers.  The narrow blade allows for tighter turns to be made - here is my version of a larger keyhole saw:

 

These saws come in all manner of shapes and sizes and can be much, much smaller, depending on their intended use, even as small as a pen knife.  They can have from 12 to 16 TPI for fine cutting, and are found in lengths ranging from around 6" to 16".  I find the saw pictured above extremely handy in making planes - it's perfect for cutting in the wedge pockets.  One of these is a must-have for any shop - and two is probably better (a smaller one).

Compass Saw.  A compass saw is larger than a keyhole saw, and is used for sawing more gently radiused curves.  The wider blade allows for, with practice, a smoother radius.  Slightly tighter radiuses can be achieved by using the saw closer to it's end.  Here's my version:

This one was modeled after an old Disston, as were most of these saws.  These are especially popular with boat builders, because of the many gently radiused cuts required in that craft.  They are handy at about 8-12 TPI to make short work of the cut, which is often smoothed out through the use of (what else but?) a compass plane.  Common lengths are from 12" to 20". 

I don't use this saw as much as I though I would.  The band saw gets the call most often for the kind of cuts that this one makes...  I'm not going to toss it yet, though - I'm sure a good use will pop up for it.  But it's not a must-have.

Coping Saws.  A coping saw is a thin saw blade held in a frame, and is used for making curved cuts in thin stock.  Most coping saws are used in installing trim, doing the cope cut (hence the name) for joining two pieces of trim in an inside corner.  A fret saw is almost the exact same saw, but has a deeper throat.  I've also seen the name applied to a jeweler's saw (basically an adjustable length coping saw), but I think this is a misnomer - the blade for a jewelers' saw is slightly different (see below).  The frame for a coping saw can either be a wooden bow-saw style, or the more commonly found metal framed version, like this offering from Stanley:

The blade has pin on each end, which are inserted into the carriage of the frame.  The blade is then tightened by turning the handle, tightening the screw that has the carriage on it.  The blade can be turned in the frame so it's angle is more convenient to use on a given piece of wood.  There are also different kinds of blades available for standard coping saws that are more like round files than saw blades, and can cut in any direction - very handy for small fretwork. 

These are saws that every furniture maker needs to have in his tool kit.  Avoid the cheap, stamped frames often seen in discount tools stores, as they will be a major source of frustration.  Better coping saws hold the tension on the blade better, allowing for smoother cuts.  The cheap ones have more tendency to vibrate, or to let loose of the blade.

Fret and Jeweler's saws.  These are deep throat (fret) or adjustable saws and adjustable depth (jeweler's) saws that hold very fine blades by crimping the end available also.  The blades have no pins to hold them in place, but are simply held in a clamp at each end of the saw frame.  The fine blades for a jeweler's saw can be expensive and may break, so the adjustable length and different clamping method is nice to hold blades that might not have worn much, but have broken during use.  

One thing to watch for - some older fret saws require a 6" blade, where most of the saws manufactured today (and thusly, the blades for them) are 5" in length.  Also make sure the holding mechanism for the blades is not cheap stamped metal.

Stair Builder's Saw.  One saw I wanted to mention here that doesn't get enough attention is a stair builder's saw.  It has many uses for the modern furniture maker including making stopped dados.  The body of the saw basically serves as a depth stop, and the depth of the blade can be adjusted by loosening the two screws that hold it in place.

This saw gets its name from the trade in which it was most frequently associated with, the stair maker.  Stairs made of wood are usually constructed without the 2x12 stringers most people are used to seeing - instead the stringers were along the wall, and the tread and risers are let into stopped dados in the stringers.  Only very specialized planes can make a stopped dado, and expensive ones at that - but a stair saw is relatively inexpensive and, with the help of a common router plane or chisels, accomplish the same task.  

Here's one of my versions of a stair builder's saw - a copy of a Disston:

This is a must-have saw for the hand tool crowd, but other tools such as a router can take it's place.  But it does look cool - so why not have one just for that reason?

Patternmaker's Saw.  One saw I'm going to mention here is a patternmaker's saw, pictured here above a standard 9" dovetail saw.  I don't use it all that often, but it's been handy in a couple instances.  Again, I just think it's cool, so indulge me, please.

These were used by patternmakers for hollowing out forms for various molds.  The small size allows for fine work, the pointed nose allows access into tight areas, and the handle configuration allows the saw to be used above a plane of wood, often a requirement in patternmaking.

This one is 15 TPI, and is sharpened in the traditional manner of a patternmaker's saw.  Normal saws are filed with a triangular, therefore 60 degree, saw file.  These are sharpened with a cant saw file, which has a 30 degree cutting angle.  This allows for a much deeper gullet, which increases the ability of the saw to carry sawdust without losing it's fine-tooth configuration.

This is not a must have saw for the average woodworker, but I have found it handy on occasion.  It's a tough one to find, if you do go looking - most users I've seen have gone for over $60 and up to $100 on EBay.  If you find one in the wild on the cheap - grab it.

Flush Cut Saws.  A final type of saw I'll review is a flush cut saw.  I don't have a photo, or think one's really necessary, as you see these things in just about every woodworking store or internet catalog.  Often, these have a flexible blade that allows you to cut a dowel, plug, or protruding piece of wood from the center of a panel.  You can make one for yourself, if you are so inclined... The only trick to them is to use a flexible steel if you want to be able to bend it - I rarely find a need for that, and to set the saw on one side only so the set teeth won't rub against the face of the wood you are cutting the piece off of.

They aren't a must-have, but they are handy...  A back saw or keyhole saw along with a block plane can often do the same job.

Steel in hand saws - or, Rockwell - is it hard enough for you?

Taper Ground, 1095, Carbon, Spring, London Spring, Cast Steel, Special Cast Steel, Patented Cast Steel, Patent Tempered, Extra Special Patented Temper Spring In London With Tea for Two Steel. YADA YADA YADA   WHY SO MANY NAMES?   ---  I can answer that in pretty much one word.

Marketing.

That's not to say that some sawmakers didn't use better steel, or have better methods for treating it - quite the opposite.  But in comparing the different lines from a single manufacturer, at least one researcher found little difference in the steel used in their high end line from their mid-priced line.  So - while the steel is almost always a simple, high-carbon steel, it may be the most important part of manufacturing steel is in how it's hardened and tempered. 

A good saw steel should have high carbon steel  with a Rockwell hardness of over 50.  Most of the Disston line had a rating of Rc50 to Rc55.  I've made saws - like the dovetail saws pictured above - out of blue-tempered spring steel rated at Rc44 -Rc51 with success.  My guess it they will need sharpening more often than a harder steel would, but not excessively.  Too hard isn't any better than too soft - over Rc 55 and the saw will be too hard to sharpen properly, and may be too brittle to set.  

Taper Ground Saws- WTF is that about, anyway?  

There are two things I need to clear up first.  First - setting the teeth on a saw widens the kerf the saw is cutting in, allowing the blade behind the teeth to work in the same kerf without binding.  Second - the best way for sawmakers to guarantee their steel was flat is to grind it flat.  Since they were grinding the steel anyway, an enterprising sawmaker thought to take that process yet a step further, and grind the saw so it's thicker near the cutting edge, and thinner nearer the opposite side.  It's not evenly tapered across it's length, however...  A diagram I saw of how the blades were taper ground looked something like this:

The lines show gradations in thickness - the thinner portion of the saw is on the upper left, nearest to the toe of the saw, while the thicker part is to the right, nearest where the handle would be.  Note, this isn't exact since I'm going off of memory, and could have varied in different models of saws as well as from company to company.

Whether or not this helps the saw to cut is somewhat debatable.  The idea is the taper would reduce binding problems with the saw.  I believe the set of the teeth would far exceed any benefits to tapering of the blade.  I can see how it could have benefits if the set was minimal, though - and it is a sign of the care for quality the sawmakers put into their product.  In the end, I think that is the most important thing about a tapered saw blade.

What to look for when buying an old saw

Many old saws are rusted, but this isn't always a deal breaker.  Look for heavy pitting, and avoid those where it is too heavy...  Rust can be removed if it hasn't gone too deep.

Look for a handle free of cracks or breaks, that has all of it's nuts.  Make sure the handle fits tightly on the saw and doesn't let the saw move in the handle.  

Avoid saws that are bent or kinked.  You might be able to straighten them out, but then again - you may not.  If you don't have to, it's best not to have to worry about it.

Look to see there is plenty of blade left, and that it has been sharpened properly.  There should be no curve to the cutting edge, either convex or concave.  

If you are unsure on whether you should purchase that antique saw, or even use it - research it!  There are tons of places on the web dedicated to old tools to check, or internet forums where you can find help.  Don't forget auction sites and antique dealers, both in person and on the web!  Google is your friend!

That should cover some of the basics of the basics... Like I said, there are literally hundreds of different types of saws - I hope this at least covered the need-to-know aspects of hand saws commonly found in cabinet shops.