On Mon, 21 Jul 2014 13:13:23 -0700 (PDT), rangerssuck
wrote:

I need to make (or have made) a custom router bit. The groove I need to make is a truncated V 15/16" wide at the top, 3/8" wide at the bottom and 1/4" deep. The dimensions aren't super critical, but closer is better.

I do NOT have a real tool grinder, and HF seems to have discontinued theirs. I also don't (as will become apparent) have more than a very little bit of experience grinding tool bits. I DO have 1x30 and 4x36 belt sanders, a set of 5C collets and a square collet block.

I'm thinking that I could lay out the shape on a blank, hold it in the collet block, set the fence on the sander to 41 1/2° (to form the V angle), tilt its table to 20° or so (to form the cutting edge and then grind to the line. Then grind the flat end and its cutting edges.

Question 1:
Does the above sound reasonable?

I have found a source for HS blanks http://goo.gl/13G1cD but a) they're not at all cheap and b) they have a half-inch shank and I have a 1/4" router. I'm not opposed to a new router, but only if I really need it.

Question 2:
Is there any reason I couldn't start out with a 15/16" spade bit as my blank? Even the most expensive spade bit is going to be less expensive than that router bit blank. Is there something about a spade bit that would make it totally unsuitable for this?

Question 3:
should I just job this out? If so, is there anyone here who would want to do it? How much should I expect to pay?

Thanks for the input.
Do you have a milling machine or a milling attachment for your lathe?
If so, then get some drill rod, turn the profile you want, transfer
the part to your collet block, then mill the teeth in the part. Heat
treat with a torch and then stone the teeth after the cutter has been
hardened and tempered. If you can get by with just one cutting edge
then mount your cutter blank in the lathe eccentrically. This can be
done just by using a shim between one jaw and the blank in a three jaw
chuck. Or use a 4 jaw chuck. Then mill the blank to get the one
cutting edge. Then when the tool gets dull you only need to sharpen
the top of the one tooth. The eccentricity of the tool will provide
constant relief. You cound even make a one tooth cutter with the lathe
and a bench grinder. Just use the grinder instead of the mill. I have
made many custom cutters this way. Using the mill though, not the
bench grinder. I have sharpened my custom cutters on the bench grinder
though. It is pretty easy to make your own cutter this way and you can
even cut steel if you harden the cutter properly. Just about two
months ago I whipped out a special single flute cutter just the way I
described above because the special one I ordered hadn't arrived yet
and I needed to get the parts out the door.
Eric