Need to drill a flat bottomed 29/64" hole in wood 1/8" deep.

[SmokeWalker]

And I want to avoid buying a $40 end mill just for this one task.
Any ideas? I have a 7/16" end mill that seems to cut about .003" (dia.) oversized for 29/64.
I need to make many of these.

Oh, and I had an anger breakdown yesterday trying to sharpen my 29/64 machine screw drill bit. I am no good at sharpening bits. For lack of a better word, I felt like a tool.

I'm thinking I could use a 3/8" end mill to get the right depth, and then fashion my own brad point-ish bit at 29/64 (w/o the point) to get the right diameter.

Thoughts?

 

[JimDawson]

The cost of the $40 end mill amortized over the number of parts that you need to build might be a reasonable cost per unit. If 0.003 oversize is acceptable then use the 7/16 end mill. Another option would be to have an end mill re-sharpened to your specs.

I used to have trouble sharpening drill bits until I grabbed a large drill bit one day, and with the grinder turned off, I followed the face of the drill bit until I got the motion down correctly. The secret is: Don't rotate the bit while sharpening.

I'm not a wood worker, but I'm pretty sure I have seen bits designed for drilling holes to insert plugs, that might be what you are looking for. Another option might be a 29/64 router bit if you can find one.

 

[pdentrem]

Unfortunately I did not find a 29/64 Forster bit. The Forster would do the job and not tear out.
Pierre

 

[AlanR]

Can you find a 15/32" spade bit that has spurs on the outer corners?

Several times I've taken spade bits and filed the edges down on the sides to drill a smaller hole. The metal is not real hard so it can be filed.

You can also take a larger spade bit even without the spurs, file it to size on the sides and cut spurs into the end, done that too.

 

[Bill C.]

And I want to avoid buying a $40 end mill just for this one task.
Any ideas? I have a 7/16" end mill that seems to cut about .003" (dia.) oversized for 29/64.
I need to make many of these.

Oh, and I had an anger breakdown yesterday trying to sharpen my 29/64 machine screw drill bit. I am no good at sharpening bits. For lack of a better word, I felt like a tool.

I'm thinking I could use a 3/8" end mill to get the right depth, and then fashion my own brad point-ish bit at 29/64 (w/o the point) to get the right diameter.

Thoughts?

Small drills under a 1/2" take a lot of practice hand sharpening. The lips have to right on. I always had trouble doing it.

If you are making enough holes to justify the $40 investment do it. Not sure how much they charge to sharpen a end mill.

 

[AlanR]

11.5mm end mills can be found for less, I just checked. With an ER collet (if you have ER) you probably have a size that will hold it.

 

[Ebel440]

If you have the drill you messed up and another good one you can drill the hole to depth with the good drill. Then take the drill you messed up and grind the tip off so its flat. Then use that to go back into the hole and square it up. It won't have any relief but will work.

 

[Jimsehr]

If you have the drill you messed up and another good one you can drill the hole to depth with the good drill. Then take the drill you messed up and grind the tip off so its flat. Then use that to go back into the hole and square it up. It won't have any relief but will work.

I just went out to shop and hand ground a flat bottomed drill and cut a piece of steel with it. I grabbed the next size bigger drill by mistake so it cut bigger then you want. But if you PM me your address I'll make you one and ship it to you for $15.
jimsehr

 

[hgk]

FWIW I see a 29/64 forstner bit on ebay today.

 

[nmasi]

any Forsters close to 29/64? a little over could be made smaller in the lathe.