If I may offer some advice on making a file guide. TEMPER IT TEMPER IT TEMPER IT. Did I say that out loud? All joking aside, please temper it!!! The other day I made myself a guide out of W2, thinking I would leave it as quenched. .25" thick x .5" x 3.75" Drilled the holes for boths halves. Tapped the threads on the bottom half. Brought it up to 1500 and quenched in water. Did a file skate test and the file ran away with it's tang tucked between it's legs. Chased the threads again to make sure. Assembled file guide on knife blade to be ground. You need to torque down on those screws so the guide doesn't walk on you during work. I tightened the first bolt down...tightened the second bolt.....and.....snap. It cracked right into one of the threaded holes. If I would have done a quick temper at just 300F or so, I doubt I would have to make another file guide! I hope this helps you and others down the road. The only way I see getting away with not tempering it is if the two holes are close together, so there is less chance of bending the bar and it snapping, but then you're limited to certain blade height.