Looking for a special Drill bit....

[Jameel Abraham]

I want to drill a counterbore and a shank hole in one operation (one bit, one plunge) I'm thinking I need a basic countersinking pilot-hole combo bit so I can adjust the length of the pilot bit, but the counterbore needs to have a flat bottom, ala forstner bit. One other feature would be scoring rim or points (again, like a forstner) so the edge of the hole is cleanly cut, not like a standard twist drill. I need to drill for socket head cap screws and end up being flush, but I don't want to have to change bits. Any ideas?

[Cliff Rohrabacher]

I am going to suggest that it'd be best if you did it in two operations.
What you have drawn is a counterbored hole. In a machine shop it's done with a spotfacer or if the flatness of the large hole isn't an issue an end mill is often used.

The reason it's not done in one step is because the forces generated by the cutting of the larger hole will cause the part of the cutter in the smaller hole to drift causing the holes to be out of round.

I suspect that it's a sure thing that such forces would work that way in wood. Whether the drift would be noticeable is another question.

However, that said, if you had a custom tool made that drilled the first hole with a forstner type cutter (no edges on the sided of the drill) and made that body the pilot for the larger cutter you'd be golden - I think. But you are going to have to make or custom order such a cutter.

[Mike Cutler]

WL Fuller in Warwick RI has what you are looking for. It's a two part system that is basically a brad point drill bit inside of a larger brad point bit.
A picture appears on pg. 29 of their current catalog. They call them Adjustable Countersinks and Counterbores. It would appear that the stock # for your specified dimensions is, 5C03750125/ 503705125

I don't know if they sell direct, or use a retailer system. I can try to copy the page for you, if you would like, so that you can see the chart of sizes.
WL Fuller also makes custom bits.
PH# for WL Fuller is 401-467-2900. Nice people, family run business. They know their products also.

[David Epperson]

In wood, you could simply grind a 3/8" spade bit down to cut the profile you want.

[Bruce Page]

Jameel, what material are you drilling?
What size/type of SHCS are you using? The dimensions in your sketch are not standard for a SHCS Allen type screw.

[Bob Wingard]

I want to drill a counterbore and a shank hole in one operation (one bit, one plunge) I'm thinking I need a basic countersinking pilot-hole combo bit so I can adjust the length of the pilot bit, but the counterbore needs to have a flat bottom, ala forstner bit. One other feature would be scoring rim or points (again, like a forstner) so the edge of the hole is cleanly cut, not like a standard twist drill. I need to drill for socket head cap screws and end up being flush, but I don't want to have to change bits. Any ideas?

If those dimensions are correct, I believe a KREG pockethole bit (or one from another mfgr.) might be just the ticket.

[Mike K Wenzloff]

I use the kind at McMaster-Carr
http://www.mcmaster.com/
Type in this number into the find box and it will take you to the catalog page: 2426


They are also available from MSC/Enco. I purchase them with the hole for the pilot that my drill bit size is. Depending on the sizes you need, there may be a match. If not, consider the pilot drill bit as the guide for your eventual center drill, or have a bit made to fit the size piloted counterbore diameter you require.

These type are used industrially. They hold up wonderfully and cut perfect flat holes.

Take care, Mike

[Jameel Abraham]

WL Fuller in Warwick RI has what you are looking for. It's a two part system that is basically a brad point drill bit inside of a larger brad point bit.
A picture appears on pg. 29 of their current catalog. They call them Adjustable Countersinks and Counterbores. It would appear that the stock # for your specified dimensions is, 5C03750125/ 503705125

I don't know if they sell direct, or use a retailer system. I can try to copy the page for you, if you would like, so that you can see the chart of sizes.
WL Fuller also makes custom bits.
PH# for WL Fuller is 401-467-2900. Nice people, family run business. They know their products also.

Perfect Mike. Exactly what I was looking for. I guess I knew about Fuller, since I've bought their bits from various places. Never thought about looking them up though! I ordered the CR type (carbide). Should work perfectly. I actually ended up talking to one of the owners (Sandy Fuller). I love dealing with companies like this. God bless America!

[Mike Cutler]

Perfect Mike. Exactly what I was looking for. I guess I knew about Fuller, since I've bought their bits from various places. Never thought about looking them up though! I ordered the CR type (carbide). Should work perfectly. I actually ended up talking to one of the owners (Sandy Fuller). I love dealing with companies like this. God bless America!

They are nice folks. They're only 40 miles from me, and I forget about them as a resource also.
Hopefully you asked for a catalog. They have some really nice stuff.

From the work I've seen you post, I'm assuming that you need a bit like this because "good enough", won't be good enough for whatever it is you are doing.

[Cliff Rohrabacher]

WL Fuller in Warwick RI has .


Ohhh nice company thanks~!!

[Jameel Abraham]

From the work I've seen you post, I'm assuming that you need a bit like this because "good enough", won't be good enough for whatever it is you are doing.

Well, in this application I was more interested in getting something that would work in one operation instead of two, so laziness would be the motivating factor here! :D Precision would be a bonus. Thanks again for this contact. What a great company.

[glenn bradley]

You don't specify thickness but that looks a lot like a pocket hole bit:

http://www.mcfeelys.com/product/SPC-0052/38-Step-Drill-with-stop-collar

Unfortunately they are 3/8", a square shoulder and then an 11/64".

[Jameel Abraham]

You don't specify thickness but that looks a lot like a pocket hole bit:

http://www.mcfeelys.com/product/SPC-0052/38-Step-Drill-with-stop-collar

Unfortunately they are 3/8", a square shoulder and then an 11/64".

Thanks Glen. I've tried the kreg bit, and a Whiteside bit. Two problems, the pilot bit is too small, and there are no scoring tips to eliminate tear out. The Fuller catalog really has several options which fill the bill. We'll see how my choice fares next week.

[Steve Clardy]

Here ya go.
68468

I use this one on staircase railing.
Inner bit is depth adjustable.

Forest City Brand
Hickroy, NC.

I buy these from Ballew Saw and Tool in Springfield, MO.

Steve