Anyone know why this is?

Seems to me that if you are starting with a blank that is large enough to
make the 1/2" tap, you might as well make the shank the same as the 3/8" but
the standard is significantly smaller.

1/2" taps have a 0.367" round and a 0.275" square

3/8" taps have a 0.286" round and a 0.381" square

What am I missing here?

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-HQ.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://www.facebook.com/AutoDrill

V8013-R

On 5/5/2011 12:08 PM, Joe AutoDrill wrote:
Anyone know why this is?

Seems to me that if you are starting with a blank that is large enough to
make the 1/2" tap, you might as well make the shank the same as the 3/8" but
the standard is significantly smaller.

1/2" taps have a 0.367" round and a 0.275" square

3/8" taps have a 0.286" round and a 0.381" square

What am I missing here?

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-HQ.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://www.facebook.com/AutoDrill

V8013-R




Dunno.

I myself wonder why "good" taps don't have the shank ground down to less
than the thread profile. That would allow you to thread a hole as deep
as the tap could reach, rather than only as deep as the threads are cut
on the tap. Even pulley taps usually have the shank as large as the
thread profile.

....And you're prolly thinking "well duh, it costs more", except that
most of the cheapest Chinese sets do it that way....

On May 5, 12:08*pm, "Joe AutoDrill" wrote:
Anyone know why this is?

Seems to me that if you are starting with a blank that is large enough to
make the 1/2" tap, you might as well make the shank the same as the 3/8" but
the standard is significantly smaller.

1/2" taps have a 0.367" round and a 0.275" square

3/8" taps have a 0.286" round and a 0.381" square

What am I missing here?

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills:http://www.AutoDrill.com
Multiple Spindle Drills:http://www.Multi-Drill.com
Production Tapping:http://Production-Tapping-Equipment.com/
Flagship Site:http://www.Drill-HQ.com
VIDEOS:http://www.youtube.com/user/AutoDrill
TWITTER:http://twitter.com/AutoDrill
FACEBOOK:http://www.facebook.com/AutoDrill

V8013-R

Look in the Machinery's Handbook. There are specs listed for taps,
including the shank diameter. 3/8" tap shanks are larger than 7/16" or
1/2" taps. No one knows why, or the history. But there is the
standard...

I have yet to get an answer for this..

On May 5, 10:08*am, "Joe AutoDrill" wrote:
Anyone know why this is?

Seems to me that if you are starting with a blank that is large enough to
make the 1/2" tap, you might as well make the shank the same as the 3/8" but
the standard is significantly smaller.

1/2" taps have a 0.367" round and a 0.275" square

3/8" taps have a 0.286" round and a 0.381" square

What am I missing here?

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills:http://www.AutoDrill.com
Multiple Spindle Drills:http://www.Multi-Drill.com
Production Tapping:http://Production-Tapping-Equipment.com/
Flagship Site:http://www.Drill-HQ.com
VIDEOS:http://www.youtube.com/user/AutoDrill
TWITTER:http://twitter.com/AutoDrill
FACEBOOK:http://www.facebook.com/AutoDrill

V8013-R

(It looks like you transposed your round and square dimensions for the
3/8 tap.)

I don't have an answer to your question, but one good result of having
different size shanks is that it keeps people in our shop from
grabbing the wrong size torque adapter.

DougC wrote:
Even pulley taps usually have the shank as large as the
thread profile.

The 1/4 - 20 pulley tap at school has a reduced shank I
know because I've used it to tap a very long deep hole
several times. I wish we had a 3/8 -16 one to match. :-)
...lew...

On Thu, 05 May 2011 21:32:27 -0600, Lewis Hartswick
wrote:

DougC wrote:
Even pulley taps usually have the shank as large as the
thread profile.

The 1/4 - 20 pulley tap at school has a reduced shank I
know because I've used it to tap a very long deep hole
several times. I wish we had a 3/8 -16 one to match. :-)
...lew...

Your 1/4-20 is a nut tap. The shank on pulley taps is the same
diameter as regular hand taps. The shank on nut taps is smaller than
the minor diameter of the thread.

--
Ned Simmons

(It looks like you transposed your round and square dimensions for the
3/8 tap.)

Yes. apparently I did. That and the typo in the subject line (now fixed)
makes me wonder how I ever passed a single class in school.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-HQ.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://www.facebook.com/AutoDrill

V8013-R