Questions and answers: straightening a bent circular saw.

Vern Burke, SwiftWater Edge Tool Works

I’m going to take a minute in this post to answer a question I saw come in to the saw sharpening blog today via Google.

Q. Can you straighten a bent circular saw blade?

A. In almost every case, don’t try it.

How do circular saw blades get bent? Other than the time honored practice of throwing skil saws round in the backs of trucks, the most common way to bend or warp a blade is to catch something metal in the wood you’re cutting, such as a nail, a spike, or other obstruction the tree may have grown around.

Hitting a metal obstruction can result in lost or broken carbides, broken teeth, or a totally warped saw plate. A broken tooth is an automatic scrap. Carbides can be replaced but it’s certainly not economical on most blades.

The problem with warped saw plates is that, aside from wrecking the balance of the blade, this actually stretches the steel in places, messing up the tensioning of the blade. Screw up the blade tensioning and you’re left with a potential structural failure, a spinning hand grenade.

I do know Forrest claims to be able to straighten saw plates. I don’t think I’d trust one from anyone much less than that level.

Tales from the saw shop: jointing saws, changing tooth profiles, and snaggletooth..

Vern Burke, SwiftWater Edge Tool Works

Today was a day of challenges in the saw shop.

The first thing brought to me today by a local cabinet maker was a small vintage Disston dovetail backsaw. Other than being phenomenally dirty (hey, look, there’s a nice Disston etch under all that crud!) and wrong handle screws (nope, a vintage Disston backsaw handle should not have a medallion, much less an HK Porter era “Disson USA” steel medallion.), the little backsaw’s biggest problem was a severe case of snaggletooth.

Snaggletooth on a handsaw is usually the result of bad amateur filing attempts. The teeth come out far from even and the tooth heights are up and down all over the place. Not the thing for the smooth cut a cabinet maker is looking for!

The cure for snaggletooth is file, joint, and then refile. The first filing is a fairly aggressive filing that starts to clean up the tooth shapes and gives as much definition to the teeth as possible so they don’t disappear when jointed.

After the first filing, the teeth are jointed using a saw jointer and a flat file to knock the teeth down to the same height. On a handsaw with this much snaggletooth, I don’t try to get the teeth all perfectly even the first time. This would cost major filing time and waste irreplaceable steel from the blade. Get the teeth jointed to where the saw will work and then improve it more the next time it needs sharpening. The final step is another filing to get the tooth profiles tuned up and sharp and set the teeth. The end result is a sweet little saw that even a finicky cabinet maker could love .

The second saw, from the same cabinet maker, was a German made straight handle dovetail saw, filed in a repulsive “combination” pattern. Combination saw teeth stand the points straight up with no rake. This pattern is intended to both rip and crosscut but is inferior (in my opinion) to a real rip filed or crosscut saw.

The request for this saw was to file it true rip, not a particularly difficult request, since the blade filed fairly easy. Since I was reshaping the teeth anyways and since I knew the customer also used Japanese saws (which cut on the pull stroke), I gave him the option of filing this one to cut on pull as well. I filed an excellent true rip pattern raked toward the handle and the saw cut my test yellow birch just fine.

I have no idea if I managed to beat the fancy pants Japanese saws, but this was a great way to save a couple of nice old saws and give the customer exactly what he needed.

Tales from the saw sharpening shop: Inverters, bent backsaw blades, and more!

Vern Burke SwiftWater Edge Tool Works

Here are a few questions I’ve seen show up in search engine hits on the blog and web site and the answers to them.

1. What type of inverter do I need for mobile sharpening?

The real question is not type (most inverter types will run small sharpening equipment just fine) but size. Remember, there’s a LOT of inertia in large grinding stones and it takes a LOT of current to get the machine started.

On my small machine that I use for knives, plane irons, planer knives, etc, I had to remove the coarser aluminum oxide wheel and just leave the wet horizontal fine wheel because I couldn’t start the machine consistently without overloading the biggest inverter I could get, due to the inertia.

2. How do you straighten a backsaw blade?

It takes a special talent to bend a backsaw blade, since the spine holds them super rigid. The only credible sources I’ve seen recommend removing and reinstalling the spine after straightening but I think this is liable to produce sub-optimal results. I straighten a lot of handsaws here, but I wouldn’t attempt a backsaw.

3. How can I tell if a handsaw is combination tooth?

Combination teeth have the same slope on the front and back rather than being raked toward the front like a normal crosscut or rip specific handsaw. If you find one of these monstrosities, which crosscut and rip but do both poorly, I recommend running over it a number of times with heavy equipment so that nobody else makes the mistake of attempting to use it.

4. How do I sharpen sickle bar mower knives?

The best tool I know of for sharpening mowing machine knives is the same on the old timers always used, the hand cranked or foot treadle cut stone grinding wheel.

Tales from the saw sharpening shop: The Pawn Stars Effect

Vern Burke SwiftWater Edge Tool Works

In this post, I’m going to talk about an evil trend in old tools that I used to curse Antiques Roadshow for. Now, as entertaining as shows like Pawn Stars and American Pickers are, they’ve made this even worse.

I can’t begin to count the number of times I’ve been out with my refurbed old planes and handsaws on display and had person after person stroll by and comment “Oh, so that’s what my old tools are worth”. Well, in short, NO. These shows convince everyone their old junk is worth a fortune and, after listening to the crowing about how much money the pawn boys and the pickers expect to make, anyone buying this stuff is just trying to take them to the cleaners.

So, here’s a list of why your tools probably aren’t worth what mine are:

1. Mean and unclean. You’re not going to get top prices from anyone for a dirty tool. Rust, pitch, paint splatters, handles painted with house paint and a brush, I think I’ve seen nearly everything that you could coat a plane or a handsaw with. There’s a reason your tools don’t look like mine. It takes time, effort, care, and skill to recover a filthy tool.

2. Amateur cleaning. Vintage blades with a bright polish, etches polished off the blades, tools derusted with naval jelly, sandblasted tools, I think I’ve seen nearly every awful thing someone could do to a tool in the name of making it look pretty. Damage your tool by destroying a delicate etch or original label and that’s what you have, a damaged tool.

3. Amateur refinishing. Covering the tool with a coat of varnish, painting a handle with latex paint (usually with a brush), stripping and repainting a perfectly good japanned surface. Yeek.

4. Amateur repairs. Bad welding or brazing repairs, handles repaired with household glue and almost every kind of fastener not made for the job that the local hardware store stocks, vintage fasteners replaced with obviously different modern ones, bent blades damaged by misguided attempts to straighten them, as Red Green says, duct tape, the handyman’s secret weapon.

5. Dull blades and amateur sharpening jobs. Nobody wants a tool to use that has a dull blade. Mess up the edge on a plane iron or misfile or misset a handsaw and, even if you can sucker someone into buying it, they’re going to be seriously unhappy campers.

A beautifully restored vintage tool, cleaned, sharpened, and refinished appropriately, is a joy to look at and use, but they don’t come into the shop that way and there’s no magic to get them from nightmare to sweet dream.

Questions for the saw sharpening shop: Files for axes, sharpening shiney blades

Vern Burke SwiftWater Edge Tool Works

In this post, I’m going to answer a couple of more questions that I’ve seen come through regarding the right file to sharpening an ax and sharpening “shiney” blades.

1. Double or single cut file for sharpening an ax?

An ax is the ONLY tool I’d ever consider using a double cut file on and then only if I couldn’t get a single cut file. If the ax bit is so bad (severely dull, nicks, missing chunks) that you think you need the more aggressive double cut file, use a 6″ bench grinder instead.

My normal routine for sharpening axes is to restore the shape of the edge and remove nicks or missing chunks with the bench grinder, being extra careful not to burn the metal of course. After that, I smooth the bevel flat with a single cut mill file which leaves almost a perfectly sharp edge. I finish by running a medium stone across the edge lengthwise a couple of times on each side to remove the wire edge. The end result is an ax that you DON’T want to be testing with your thumb. Forget the double cut files.

2. Sharpening “shiney” blades.

The cutting irons in late model Craftsman planes are a good example of the evil “shiney” blade. These irons apparently contain a fair amount of chromium, making them effectively stainless but lousy to sharpen (a file will skid right across them). These types of blades really need to be machine sharpened and then I feel they produce a substandard edge. Best to throw these for standard high carbon irons. They might take a little more care but you’ll be a LOT happier with the results.

Tales from the saw sharpening shop: Announcing new weekly sharpening services in Topsham and Brunswick Maine!

Vern Burke, SwiftWater Edge Tool Works

SwiftWater Edge Tool Works announces new weekly sharpening services covering Topsham and Brunswick Maine!

We will be at the former Champion Glass location on Rt 201 in Topsham every Tuesday from 8am to 3pm with the mobile sharpening rig and vintage restored tools such as wood planes and saws available! From downtown Topsham, just take Rt 201 north towards Bowdoin, cross over I-295, and we’re just on the right!

Our mobile sharpening service offers almost all of our services, including kitchen knives, scissors and hair shears, and almost all woodworking tools, including carbide saw blades. Need lawn and garden or farm tools put into shape? Just drop by and drop off! Most blades are returned same day or even while you wait! For blades that cannot be done same day, we offer a one week turn around with the blades being returned the next Tuesday.

Come visit us on site tomorrow and bring your dull blades!