Spiral down cut drill bits

[dlcw]

Does anyone know of a company that makes spiral down cut drill bits (not router bits) that I can use in the ShopBot Air Drill? My shelf pin holes look rough with a standard or brad-point bit and I would like to make them look cleaner. I tried a spiral down cut router bit, but it's to short.

Thank you,

Don

[Gary Campbell]

Don...
I have drilled thousands of holes testing drill parameters.. Down plunge will usually plug and burn if the hole is over .15 deep.

What size are you drilling? What Depth? What RPM is the SB drill? What plunge speed? Material type?

Gary

[bleeth]

Don: We drill all our holes with the Centurian Tool 5mm down cutter. It works fine but I am using a spindle turning at 17-18k amd plunging at .5ips.
You can also chuck up a bit made for the line boring machines. They are commonly available from the likes of Amana and come in right and left hand twist.
I drill all my shelf and hinge holes around .42 deep (Exact number is at the shop-where I am not today)

[bill_lumley]

Don, I use a solid carbide 5mm line boring bit from Onsrud in my air drill plunging at .5ips and I get consistantly clean holes . Increasing the plunge speed increases the chipping I get on th edge of the hole .
Bill

[dlcw]

I am going to be ordering 1/4" and 5mm boring bits as per my conversation with Gary yesterday and adjust drill speed down to the .5ips suggested. I'll put a piece of scrap plywood on the machine and start drilling holes until I get things dialed in for my machine.

Thank you all very much!!!!

Don

[benchmench]

I've been using a 5mm brad point bit from Rockler ($2.99) at 5k RPM with a .5 ips plunge in melamine to .5 depth and the holes and rims come out fine - no chipping.

[nat_wheatley]

Don,

If you're turning the drill on an off between holes, I've found that I get cleaner holes when I turn the drill off as it exits the hole (material surface), rather than turning it off at the bottom of the hole. This may not make a difference in plywood, but does in melamine.

If you've got the same SB dril as me (most recent?) you should be able to get clean holes at 1 ips with the bradpoint boring bits. Through boring is a different story.

[dlcw]

Nat,

Yes, I purchased the SB drill about 3 weeks ago, so it's probably the same one you have.

I just installed your 2nd solenoid modification to control the plunge cylinder independent of the drill motor, so I will be doing the turn on-turn off routine as I drill (compressor limitations make this necessary).

Which Custom file do you put this turn-on turn-off code into and how is it coded? Do you have code you use that I could beg, borrow or steal..:-)?

Thanks,

Don

[nat_wheatley]

Don,

I've sent you an e-mail

Nat

[dlcw]

Nat,

The email didn't come through for some reason. Did you send it to: dlcw at povn dot com?

Thanks,

Don
www.diamondlakewoodworks.com (http://www.diamondlakewoodworks.com)

[nat_wheatley]

Don,

I did use that e-mail, but have just resent it, from Gmail rather than Outlook.

Let me know if it doesn't come through.

Nat