Circular saw shoe flattening

[zzdodge]

Perhaps someone else has a better idea.

I have a cordless DeWalt circular saw. The intended use was as a cordless saw in general, and also as a trim saw.

When the saw was first acquired, several cuts were made of a 2x4, and the blade and angle index pointer were set to zero based upon measurement of the squareness of the 2x4 crosscuts. It turns out that this may have been a mistake.

Recently when using the same saw for trimwork, several cuts were not square, or at the needed 45 or 30 degree angle. Upon examination, and test cut, some test pieces were at the correct angle, and others were not. Some cuts were crosscuts and some were rips. Generally, the rips were off.

Upon further scrutiny, it was found that the shoe (base, sole or whatever it is correctly called) of the saw was not flat. It is a steel stamping, and is reasonably rigid, but bows up in the middle longitudinal portion of the shoe, and when thinner pieces are ripped, the angle shifts because of this.

To fix this, the thought is to remove the shoe, and incrementally press on the center of the sole, to bend it to a flat position. It will have to move a little less than a tenth of an inch (haven't taken the blade off to measure). A hydraulic press would be used, and the changes would be intended to be small, realizing that it will be necessary to push beyond flat, and then rely on inelastic deformation to provide the desired sole changing.

Has anyone done this? Is there a better way? One concern is that going though this process, particularly if there was an overbending (and stretching) and the shoe had to be bent back the other way, might result in a warp of the rest of the shoe.

We are not talking a high end saw here, with a cast magnesium, rather the shoe is made of a mile steel formed sheet steel.

Thanks again.

 

[mkepke]

Some thoughts:

1) apply an overlay of 1/8" plate steel. You can fill the low spot in your current shoe e.g. with epoxy or Bondo before applying the overlay.

2) you don't need a hydraulic press to try pressing the shoe flat. Use some angle iron and a heavy bolt tapped through a hole in the angle iron. Securely C-clamp the ends of the angle iron and tighten the bolt..the bolt presses against the convex hump in the shoe. Use a steel shim under the bolt-end, e.g. a washer, to spread the force.

Check progress frequently.

Very controllable even in tiny increments.

3) If you only need to remove a small amount of material, you might have the option of belt-sanding the shoe-flat (assuming you have something with a large platen like a 6x48 sander).

-Mark

 

[KenOfCary]

How old is it - under warranty? Take it back for a replacement.

 

[KenOfCary]

BTW, I have one also. Only use it for mending fences - where I need to cut a few inches off of a fence rail to make it fit when replacing one that the horses have cribbed or broken. Usually way too far from the house or barn for an extension cord and lugging around a gas generator is a PITA.

I would not consider it precise enough to use for anything else, but then that's just me.

 

[zzdodge]

Thanks for the comments. A 1/8 " steel plate would double the weight of the saw!
A belt sander or the steel plate would give me a surface that would be prone to rust. Since I have a hydraulic press I already use for pressing bearings, front end parts, etc. using the press is faster and less messy then using something like epoxy. Nevertheless, the leveling with epoxy is a good idea.

Fences? That's what recip saws are for... No fences here, the volunteer yard birds wander in and wander out. My wife likes the peacock. He and his brother showed up last spring. She likes guys with good looks and raisin sized brains.

 

[Endless Pursuit]

Take the sole off and identify the center of the lowest spot and, if possible, draw an outline of the depression. Using MAP Gas or an Oxy/Cet torch, heat the sole starting at the perimeter and following the outline, work you way toward the center. You will need to get it hot enough to severely discolor it, almost red hot. More heat in the middle that the perimeter. Something that thin won't take too long.

That's how fabricators put the mild arch, called camber, in bridge girders. I've taken waves out of a distorted car fender this way.

If it doesn't work, you always have your press.

 

[zzdodge]

The press won't destroy the plating on the saw; the torch will. Plating keeps the saw from getting rusty, and takes a light coat of wax every now and then to help it slide.

How do I assure flatness when using the torch? With the press, I can make small incremental changes, each time verifying how close to flat I am. Checking with the torch requires a cool down cycle, because the sole will dimensionally change with temperature as it cools.

 

[Endless Pursuit]

Start the presses!

 

[chris_goris]

I dare say its the wrong tool for the job, its like using a chainsaw to do framing. Circular saws were never intended for trim (fine cutting) applications. Sounds like you need a miter saw and a jobsite tablesaw.

 

[zzdodge]

I took the shoe off the saw today, and flattened it out. The base appeared to be rather flexible, and I just adjusted it in the shop, using a piece of 10mm drill rod chucked into a drill press. I laid scraps of MDF underneath the shoe to help me define the area I would be bending.

It is no flat, took very little time, and hopefully stays that way. If I don't drop it or something stupid like that. Test cuts show squareness within the limits of my ability to test, after a couple of tweaks. I also aligned the pointer. I am happy!