PIMO counterbore

[stummel bum]

Just got the pimo line of drill bits so I can start drilling my own pipes. I'm confused about the combo mortise/shank square bit. The 5/16" bit part of it is fine, but the counterbore was advertised as being 7/8" which I thought meant that it would leave a 7/8" shank face. Turns out it only cuts a 1/2" shank face which tapers out to about 3/4". Am I doing something wrong, or does this mean that the largest stem I can use with this is 1/2" diameter?

Here's what the cut ends up looking like (pay no attention to the ugly mortise walls).



I would love to use the easy solution and square up with a forstner, then just chuck the mortise bit and drill the mortise. Here's the problem. I don't have either a drill press or a lathe, so I need a solution that ensures that the mortise goes in square, and I'm just not good enough to do it with a hand drill. I know a drill press is rather cheap, and I probably could afford one, but I have absolutely nowhere to put it.

Are there any other options, or do I just make skinny stems? And then there is the distinct possibility that I'm using the tool wrong

The bright side is that the 5/16" bit is just the right size for the delrin.

[NathanA]

I just used the same bit for the first time last weekend and have the exact same question. I hope someone out there has the answer.

[TRS]

When I first started I bought this bit and had the same revelation. The 'teeth' on the outer radius bevel off the face. My stems and shanks were very skinny so I invested in a larger counterbore bit.

[stummel bum]

Do they make a larger counterbore that will fit a 5/16" bit? All I've found has larger inner bits as you go up in the outer dimension.

[Philthy]

Don't know about the PIMO deal - would like to hear the answer as I am about to order from them or here http://www.jamestowndistributors.com/1/ ... bores.html
Cannot take credit for this link I think it was posted by someone else on here and I just saved it.

[SimeonTurner]

Yep. I used that bit for some time when starting out. It definitely limits what you can do because it bevels the outside edge of the shank.

[TRS]

These are what you're looking for;

http://www.jamestowndistributors.com/us ... do?pid=499

I bought an X85L from Vermont Freehand (Steve) and it works great. It's a 1 1/8" cutting surface with a 5/16" pilot. That allows you a lot of room to customize your shank size.

Edit; oop! just saw that Phil had posted the link.