Need A Little Help With Drill I.D.

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: Harold_V, websterz, GlennW

McKay59AB
Posts: 7
Joined: Sat Mar 22, 2014 9:52 am
Location: Omak,Wa.

Need A Little Help With Drill I.D.

Post by McKay59AB » Fri Dec 18, 2015 2:46 pm

I have had these drills for years and have worked great in aluminum. I want to purchase a few more with a larger size (+.750), but I have cruised some tool catalogs and cannot seem to locate any. Could somebody shed some light on the kind of drill this is? Can these be sharpened in my home shop,or do they have to be sent out? Here is a picture. Thanks for any and all help.
Attachments
P1030479.JPG

User avatar
ctwo
Posts: 2731
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: Need A Little Help With Drill I.D.

Post by ctwo » Fri Dec 18, 2015 3:08 pm

looks like a counterbore
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

User avatar
mklotz
Posts: 354
Joined: Thu Jan 09, 2003 11:35 am
Location: Los Angeles, CA, USA
Contact:

Re: Need A Little Help With Drill I.D.

Post by mklotz » Fri Dec 18, 2015 3:27 pm

I know them as "bullet point" or "pilot point" drill bits. Googling on those terms produces lots of hits. However, I've never seen one larger than 1/2".
Regards, Marv

Home Shop Freeware
http://www.myvirtualnetwork.com/mklotz

sch
Posts: 276
Joined: Wed Jan 15, 2003 7:51 pm

Re: Need A Little Help With Drill I.D.

Post by sch » Fri Dec 18, 2015 5:49 pm

Counter bores are generally shorter, designed to sink a SHCS head below or at surface level. The narrow part fits in the hole to be threaded as a
pilot (or drills the shank hole) and the larger part makes a slightly oversized hole for the SHCS head. The OP drills look like aluminum helixed
pilot point drills. Counter bores are sized for specific SHCS sizes.

User avatar
10KPete
Posts: 390
Joined: Wed Sep 30, 2015 5:29 pm
Location: Nordland, WA, USA

Re: Need A Little Help With Drill I.D.

Post by 10KPete » Fri Dec 18, 2015 7:01 pm

Looking closely, there is no flute relief on the pilots and at least one has a diametric relief where the pilot joins the drill portion.
The pilots are ground as cylinders with no relief.
Most definitely pilot drills intended for enlarging an existing hole, or part of a hole anyway.

Never intended for drilling new holes!

Pete
Just tryin'

McKay59AB
Posts: 7
Joined: Sat Mar 22, 2014 9:52 am
Location: Omak,Wa.

Re: Need A Little Help With Drill I.D.

Post by McKay59AB » Fri Dec 18, 2015 9:20 pm

That is correct Pete, I never use these drills without first drilling the correct pilot. I just finished drilling 24 holes .7049 in aluminum and the drill struggled. I think the drill was made at Precision Twist Drill. The I.D. on one of them is "PTD HS USA L#775". It looks as if they are out of business? Are there any attachments made that will fit in a lathe to sharpen this kind of drill?

User avatar
10KPete
Posts: 390
Joined: Wed Sep 30, 2015 5:29 pm
Location: Nordland, WA, USA

Re: Need A Little Help With Drill I.D.

Post by 10KPete » Fri Dec 18, 2015 9:46 pm

To my knowledge PTD is still in business. I haven't checked. Sharpening those drills can't be done on your normal
Drill Doctor type as you know. It takes a cutter grinder to get to the ends of the flutes behind the pilot. Any tool
and cutter grinding shop, that does end mills, c'sinks, and the like should be able to do those and be able to make
any size pilot you want on new drills. I've never seen them just sold as stock, but have had dozens made for me
over the years.

Cheers,
Pete
Just tryin'

User avatar
GlennW
Posts: 6735
Joined: Sun Apr 15, 2007 9:23 am
Location: Florida

Re: Need A Little Help With Drill I.D.

Post by GlennW » Fri Dec 18, 2015 10:48 pm

NAS937 drills are similar to the ones being discussed.

http://www.panamericantool.com/piloted- ... s-937.html

I have a bunch of them just like the ones being discussed, and will look tomorrow to see if there are and manufacturers names on them.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

Russ Hanscom
Posts: 1556
Joined: Wed Mar 15, 2006 11:10 pm
Location: Farmington, NM

Re: Need A Little Help With Drill I.D.

Post by Russ Hanscom » Fri Dec 18, 2015 11:15 pm

These would be treated as specialty drills, and priced accordingly. I have a large bunch that were purchased from Boeing Surplus in Seattle while they were still open to the public. Probably purchased to special requirements and not standard catalog items. Really nice to use when they fit a requirement I have.

Sharpening the step requires special equipment not normally found in the home shop; since I got mine for cents on the dollar and have many, I make no effort to sharpen them.

User avatar
reggie_obe
Posts: 250
Joined: Sat Jul 24, 2004 6:16 pm
Location: New Jersey

Re: Need A Little Help With Drill I.D.

Post by reggie_obe » Fri Dec 18, 2015 11:37 pm

Those are subland sometimes called step drills.

curtis cutter
Posts: 389
Joined: Fri May 18, 2012 11:46 pm
Location: Curtis, WA

Re: Need A Little Help With Drill I.D.

Post by curtis cutter » Sat Dec 19, 2015 1:19 am

Russ Hanscom wrote:These would be treated as specialty drills, and priced accordingly. I have a large bunch that were purchased from Boeing Surplus in Seattle while they were still open to the public. Probably purchased to special requirements and not standard catalog items. Really nice to use when they fit a requirement I have.

Sharpening the step requires special equipment not normally found in the home shop; since I got mine for cents on the dollar and have many, I make no effort to sharpen them.
That takes me back. I used to go to Boeing Surplus in Kent probably once a week. Good stuff by the pound.
Gregg
Just let go of it, it will eventually unplug itself.

earlgo
Posts: 1425
Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: Need A Little Help With Drill I.D.

Post by earlgo » Sat Dec 19, 2015 10:09 am

Re: sharpening.
IF you have a Dumore or similar die grinder and a means to attach it to your lathe compound/tool post you could possibly sharpen the cutting edges of the drills. I don't think a Dremel would have enough horse-power.
You would need to index the drill properly and that can be done by measuring the OD of your chuck cutting a strip of (paper) marking off 3, 4, or whatever spaces and taping it to the chuck. A pointer attached somewhere would be the index finger.
Enough setup and fooling around should get you where you want to be.

Before I bought the Delta Toolmaker, I made a counter-bore and sharpened it in this manner.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.

Post Reply