OK I know I have one but I have torn my shop and boxes apart. So anyone have a link to where I can pick up a 3/4" counter bore. I need the type that will slip on and attach to my 5/16" LOOONNNGGG drill bit.

Try Enco.

I had looked there and the smallest I saw with a 5/16 bore was a 1"

northern precision

This almost looks like what you're describing:

http://www.mscdirect.com/product/09937376

If you're trying to bore the through bolt holes for stocks, what I do is use a spade bit, you can make a pilot to guide it in your pre-drilled bolt hole instead of the point. If you drill the hole in the lathe, you can even use the spade bit without a pilot, although it can grab and chatter until you get it in a half inch or so. The lathe lets you feed the stock into the rotating bit slow enough you can usually control it from grabbing.

dave

Actually, found exactly what you need here:

http://admiralshipsupply.com/cart/15/prod_348/


and here:

http://www.jamestowndistributo...=Type+B+Counterbores
dave

Dave,

Thanks, that is exactly what I was looking for. I must have went to 20 sites and didn't find it and you found three.

I'm sitting in CO my buddy with the lathe, torch, welder etc is in Houston. I bet the spade bit would work great if I had a way to install a pilot. So yes I'm redoing my jig to give me more control to drill the through bolts. Had one I had built using the drill press but had trouble with keeping everything aligned when I had to drop it to extend plus removing shaving was a royal pain.

So looking at a set up with a guide for the bit.

I have two or three different bits for different sized c'bores. I had then to the tool and cutter grinder who ground a pilot on the ends same size as the through bolt hole. No chatter and flat bottom.

I keep 4140 cutoff barrel ends to make up a counter bore. Turn to size and then use a hacksaw to make the cutting edges. It takes about 20 minutes to make and a set screw will hold it on the drill shank. The drill is the pilot after the hole is drilled. The counter bore is driven with a 1/2 in. slow speed drill so you can remove the tool and blow the dust out. I used a lathe most times to get the bolt hole drilled between a center and the headstock chuck holding the drill. You can make a jig of a couple of guide hole pieces and bolt to a flat surface to guide the drill bit.

You guys keep missing the "NO LATHE" or metal working equipment. Right now I'm a wood worker.