What drillbit to use for this job?

[Steve Knight]

Ok here is what I am doing and I do a lot of it. A ½" hole 2.5" deep in tropicals like purpleheart and cocobolo ebony ipe and such. I need a clean entrance and long life. Something that does not clog up too bad. Carbide will be a must I think. So do I go for a ½" carbide tipped jobber bit I can sharpen myself? Carbide tipped forstner bit that really needs to be longer then the standard. Or a carbide tipped bradpoint like lee valley sells. I know I changed from them to a regular bit for some reason years ago. Not sure why though I just can't remember. I liked the sawtooth bigger bits I got from lee valley but they don't go down to that size.

[Lew Hodgett]

Have you ever considered a four (4) flute, flat bottom, end mill from a milling machine?

Might have to play with the speed and feed, but should provide a clean hole and the mill is self clearing like a twist drill.

HTH

Lew

[Patriarch]

Steve Knight wrote in news: [e-mail]:

Do you have a local saw/blade/bit/tooling supplier/sharpener that you trust? Here in the SF Bay Area, I'd call Bay Area Carbide, and ask the owner what he'd recommend, given your recurring work load.

Patriarch

[CW]

[arw01]

Steve:

Bike over to a local machinist supply shop and pick up a solid carbide spiral endmill. You would be able to us it both in your drill press and a router if so inclined. They are available both in upcut and downcut. The upcut would be best in this application if you are NOT going all the way through quickly. But the bits are reasonably cheap, can be resharpened..

Only concern I could see is the initial plunge might try to lift some edge fibers, perhaps use a hand countersink would precent the chip out in a couple seconds around the hole.

Alan

[max]

Make sure it is a center drilling one or you will have to drill a pilot. Does any one know the diameter of the hole? I don't understand the symbol he uses. max

[Larry Jaques]

On Sat, 12 Mar 2005 22:19:51 -0800, the inscrutable Steve Knight spake:

Lee Valley's carbide-tipped brad points? (I haven't tried them.)

-- Life's a Frisbee: When you die, your soul goes up on the roof. ---- Comprehensive Website Development

[Larry Jaques]

On Sun, 13 Mar 2005 06:45:12 GMT, the inscrutable Lew Hodgett spake:

I'm pretty sure those don't have nearly the length he needs.

-- Life's a Frisbee: When you die, your soul goes up on the roof. ----

Comprehensive Website Development

[CW]

Sure do. Come in various lengths.

[Steve Knight]

they work ok if there is little slop in the drill press. but a 1/2" one would be a problem.

[Steve Knight]

remember right are wider then the shaft. so when I used a drill bushing it was a problem. but I did forget that the piece will be ran through the planer so a super clean entrance hole is not a big deal. so the carbide jobber bit would be the way to go since I can sharpen it and that will save big bucks in the long run.

[Steve Knight]

I use them in my router all of the time. they are for drilling holes in a drill press. but I need a 5" or so long one. plus a 1/2" one would wander I think.

[toolguy]

Hi Steve. To me, this is a no brainer. Carbide tipped brad point is the way to go. Lasts long between sharpenings and makes a lovely hole. :>)

Neil

[gandalf]

----------------- I've never drilled into such exotic stuff but, I think something like this may do the job. It's a drill that you buy to accompany the BeadLock system. It's 12.7mm, plenty long enough for what you want, and mega sharp. As a plus it's designed to be used with drill guides. It is virtually self clearing and makes a perfectly clean cut.

You can see it here:

and the part number of the drill bit only is: BL/DRILL/127

If you weren't so far away I'd lend you mine to try.

[max]

They make high helix (for rapid chip removal). I would not use a router to spin the bit because you would just burn the wood and the bit would overheat. I would use a TIN coated high helix bit and get some stick lube to keep the bit from clogging. I once had to drill 2000 or so holes and that is how I did it. max

[Teamcasa]

If you drill the hole before final planning, then use a high helix, deep flute drill, (Bosch makes them) sharpened with a center point. As long as you are drilling with a good drillpress and able to eject the chips, this will work fine.

Dave

Posted Via Usenet.com Premium Usenet Newsgroup Services

---------------------------------------------------------- ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **

----------------------------------------------------------

[bridger]

look at his length requirement.

[Leon]

IMHO if you are drilling at a 90 degree angle to the surface of the wood a carbide tipped brad point bit should work well and keep the chips cleared out. If you are drilling at much of an angle at all a Forsner bit is going to be a better bet but will not remove the chips as efficiently.

[Anonymous]

2.5" is not a particularly deep hole for an end mill to make. He'll find a wide variety of end mills long enough for this purpose in either the J & L catalog or the Production Tool catalog. If he's concerned about wander (probably an unrealistic fear) then all he needs do is make a starter hole about 75% or so the finished size with whatever tool is handiest.

End mills tend to make a relatively accurate hole if you can hold them and the work rigidly. Likely all the run out he measures will be in the bearings of the drill press and the variations in the grain. There isn't a cutting tool made that can compensate for bad bearings in the spindle and even slow passes with a boring bar are still somewhat vulnerable to alternating soft and hard spots in the material. A 2.5" deep hole simply calls for a longer end mill shank.

Bill

[CW]

What about it?