Tuesday, December 9, 2008

Making Saw Blades

I posted this as a tutorial on Woodnet forums a while ago. This is how I make my particular style of saw blade with a laminated, epoxied, and screwed back.

I start with blue-tempered spring steel (usually .018" thick) and brass bar that's 1/8"x3/4". These blades are 8" long, and roughly 2 1/4" wide for a small DT saw. Each blade has been cut such that it will fit into the kerf of its handle. I've cut two pieces of brass for each blade & taped them together for drilling.






Each bundle of brass is drilled (three holes) on my cheap, tiny, benchtop drill press. I use a set of transfer punches to transfer the locations of the holes to each respective blade (the brass & steel parts are each labeled to keep track of things throughout this process).

I use an inexpensive hand punch to punch holes in the steel plate. While I'm at it, I punch the holes for the screws that I'll use to attach the handle (I transfer the locations using the transfer punches again). At this point, a few minutes of sanding with a couple of grits removes the bluing (I used to use citric acid, but they must've changed something about the steel, because the citric acid has absolutely no effect on the last few rolls I've gotten). The sanding also removes the small burrs left by the hand punch.




I clamp the brass pieces to each side of the blade to prepare for tapping the holes for screws. Tapping the brass without the steel in place would throw everything off, and the threads wouldn't line up when I assemble everything later. It looks kind of complicated and there migt be an easier, more elegant way to do this, but I'm able to clamp everything up & chuck it all into my vice this way.





A little more cleanup, and I epoxy the whole thing together, using bits of threaded rod to screw it together. An added bonus of using the screws is that I don't need to use a lot of clamps to hold everything in place while the epoxy cures, and I don't have to worry about overclamping things.

Once everything has cured, I'll clean off the excess epoxy & clean up the brass with some sanding.

That's about it! I'm just left with shaping the handles, cutting mortices for the backs, sanding & finishing everything, cutting, filing, & setting the teeth, and putting it all together, & I'll end up with something like this:




8" dovetail saw with cocobolo handle, 15ppi, rip.




1 comment:

Unknown said...

Those are nice looking saws! I found your post on the Creek and made one recently. I found that Evaporust removed the bluing rather handily.