CamBam

Made by CamBam => Members Projects => Topic started by: lloydsp on November 21, 2019, 20:57:17 pm



Title: Can't (yet) find the drill I need.
Post by: lloydsp on November 21, 2019, 20:57:17 pm
I need a 0.5" x 118-degree standard 'twist drill' (for metal), short (2.5") would be nice though not absolutely necessary, AND with a 1/8" pilot point at least 0.040" long on its vertical sides.

All I've been able to find in pilot drills offer a FLAT full-diameter face, instead of the 118-degree tip.

Having one (and a source for more) would save me over 40 minutes - by eliminating a MOp - on a job I'll be doing repetitively over the next three years.

Thanks, all.

Lloyd


Title: Re: Can't (yet) find the drill I need.
Post by: EddyCurrent on November 21, 2019, 21:09:09 pm
Is this the kind of thing ? https://www.mcmaster.com/countersink-drill-bits


Title: Re: Can't (yet) find the drill I need.
Post by: lloydsp on November 21, 2019, 21:18:26 pm
Well, Eddy,

Yes, "like" those, but with a 1/8" diameter pilot, rather than 'screw or tap' sizes.  What I'm doing is drilling a 1/2" hole, then penetrating the bottom with an 1/8" drill in order to open a path to features milled on the bottom of the board.

But the major hole must be 1/2" with 118-degree tip, and the pilot must be 1/8" in diameter.

Thanks,
Lloyd


Title: Re: Can't (yet) find the drill I need.
Post by: kvom on November 22, 2019, 00:30:02 am
Take stub length 1/2" drill bit.  Mount in lathe and drill 1/8" through hole using carbide drill bit.  loctite desired length of 1/8" drill bit in the tip.   ???


Title: Re: Can't (yet) find the drill I need.
Post by: lloydsp on November 22, 2019, 00:58:39 am
Kvom,
Have YOU ever tried drilling a hole in the nose-end of a hardened 118-degree twist drill?  I mean, really.

I'd rather have one 'custom ground' than to try to modify a good-quality drill!

Lloyd


Title: Re: Can't (yet) find the drill I need.
Post by: dave benson on November 22, 2019, 01:56:25 am
Lloyd
search for pilot bore countersink's
Dave


Title: Re: Can't (yet) find the drill I need.
Post by: Bob La Londe on November 22, 2019, 01:57:49 am
Depending on what it is a shop ground D-bit might do the trick.  I have a few pieces of W2 laying around the shop for stuff like this.  


Title: Re: Can't (yet) find the drill I need.
Post by: Garyhlucas on November 22, 2019, 02:08:44 am
Lloyd,
The type of drill you want is called a subland drill. Look at 29475A81 at McMaster Carr. OD and angle are what you want but tip is oversize. You might be able to have one made as a special.  These are short too.


Title: Re: Can't (yet) find the drill I need.
Post by: lloydsp on November 22, 2019, 02:13:22 am
Yep, Gary.  I've already contacted a 'custom grinder' who will make such a bit for about $40 USD, onesies.

I'm betting they'd be closer to $30 USD each, if I bought five.  But FIRST, I'll test one on the job. <grin>

Lloyd


Title: Re: Can't (yet) find the drill I need.
Post by: dave benson on November 22, 2019, 02:24:28 am
Lloyd this is what I was thinking of.
This is a cheap one, but you can get them with a hollow shaft and used with a panel drill allows you to set the
Depth of the pilot drill, the ones I've used for metal working come in 120 deg which may be close enough and they are quite inexpensive.
Dave


Title: Re: Can't (yet) find the drill I need.
Post by: lloydsp on November 22, 2019, 11:44:54 am
Thanks, Dave.

Lloyd


Title: Re: Can't (yet) find the drill I need.
Post by: kvom on November 22, 2019, 13:46:46 pm
Kvom,
Have YOU ever tried drilling a hole in the nose-end of a hardened 118-degree twist drill?  I mean, really.

I'd rather have one 'custom ground' than to try to modify a good-quality drill!

Lloyd

I intended the drilling to start from the flat  end of the drill.  But since a custom grind is so cheap that's the way to go.


Title: Re: Can't (yet) find the drill I need.
Post by: Bob La Londe on November 22, 2019, 16:48:54 pm
That's pretty reasonable for a custom ground drill.  Often for me its one of those things where I need to do it NOW which is why I sometimes make tools instead of waiting for them. 


Title: Re: Can't (yet) find the drill I need.
Post by: Garyhlucas on November 22, 2019, 23:28:03 pm
$40 sounds like a deal if you save 40 minutes each time. I had a carbide router bit made for producing 20 degree angled flanges that mate with Ag ball valves and sanitary flanges too. One tool does 3 different operations in one pass each and no tool changes. Huge time saver and improved part quality at the same time.