curved graver

[Ian groves]

hi im having difficulty engraving inside some bike rims with clearence issuse and looking for some help on either raising the pitch off a normal graver or going about sharpening a home made curved

 

[AllenClapp]

You may need to increase the heel angle 10 to 15 degrees above normal. To engrave concave items, increase the heel angle to make it easier to keep the graver from digging in. To engrave convex items like rods and gun barrels, revolver recoil shields, etc., decrease the heel angle to make it easier to keep the graver from skipping out of the work. Often this will be all you need to do. With more extreme changes, you may also need to adjust the face angle to keep a reasonable cutting angle. Raising the heel increases the cutting angle. For example, if you start with a 50-degree face angle grind and add a 15-degree heel, the cutting angle will be 65 degrees. If you go to a 30 degree heel, the cutting angle will be 80 degrees, which is quite blunt. If the graver will not cut well at that cutting angle, you might want to decrease the initial face angle grind 5 or 10 degrees to bring the cutting angle back into a better cutting realm. Try a few changes to see what works best for you and record the changes for future reference.