Question on Grip Screws

sheepherder · 03-07-2011, 10:06 PM

I need to make a set of grip screws with a slightly larger head...I see from the Blueprint CD that they are a 3/16" Whitworth thread...but it doesn't say if coarse or fine...[24tpi vs 32 tpi]...

Does anyone know which they are??? I'm tempted to just chase the grip frame holes with a #10 SAE tap and make my screws Yankee...

John Sabato · 03-08-2011, 09:12 AM

Hugh Clark or Tom Heller or Ted Green should be able to answer this question for certain, but I believe that the "Nr. 30" in the description of the screw on the blueprint may actually mean 30 threads per inch...

I would suggest that you wait for one of the lugersmiths to answer before using your #10 SAE tap.

Of course it is your frame, and if you want to change the screw type Rich,

that is entirely up to you.

G.T. · 03-08-2011, 09:22 AM

Hi Rich, 10/32 is real close, but will bind up in just a few threads... 30 per inch works perfectly... I'm not for sure, but i believe the Luger used an old English thread size & pitch... No 1 rule of life, "nothing is ever as it seems!"

... Best to you, til...lat'r...GT

Mauser720 · 03-08-2011, 11:27 AM

Hi Rich -

I wonder if a person could make a cast of that thread using the bore casting material that is called "Ceros" or something like that? (I know you know what I mean.)

It's available from Brownells and melts at a low temperture so that you can take the interior dimensions of a chamber or barrel. When you do a barrel or chamber, you just plug the barrel or chamber with a rag and melt the stuff and pour it in. Then after it cools you just tap it out with a wooden dowel rod.

I'm wondering if you might be able to use that stuff to make a cast of the grip screw threads? However, instead of tapping it out, you would have to probably make some kind of mold or form so that you would have something to grasp and then unscrew it from the threads, etc.

Just a thought.

Ron

SIGP2101 · 03-08-2011, 01:21 PM

How about using a simple thread gauge to find out.
http://www.google.ca/images?hl=en&q=...w=1280&bih=862

Vlim · 03-08-2011, 05:02 PM

Quote:

I need to make a set of grip screws with a slightly larger head

How about using washers?

John Sabato · 03-08-2011, 05:37 PM

Heck, if they are going to be custom grips, make them out of brass or stainless steel and while you are at it, use allen-socket type heads, or twin steel pin holes like the adjustment screws on an Artillery model sights!

sheepherder · 03-08-2011, 06:18 PM

All right, let's not get frivolous here...This is serious business...

Quote:

Originally Posted by SIGP2101

How about using a simple thread gauge to find out.

Because there are only 3 threads on a grip screw, and the difference between 30 & 32 tpi won't show up until you get more threads to measure...

The blueprint clearly says Whitworth (pic below)...In 3/16" Whitworth, 24 tpi is coarse, 32 tpi is fine...There doesn't seem to be any 30tpi...as standard, anyway...

sheepherder · 03-08-2011, 07:16 PM

Here's the site I got my info from -

http://mdmetric.com/tech/thddat8.htm

Whitworth doesn't list 30tpi for *any* size screw thread...

Machine Tool · 03-08-2011, 08:31 PM

custom screws can be made

Lugerdoc · 03-09-2011, 11:02 AM

If you want larger headed grip screws to tighten up a set of loose grips, try the rubber O ring under your present screws. That usually works for me. Otherwise, I have NOS Mauser original grip screws available @$15 each or new repros @$5 or $8/set + $3 S&H. TH

SIGP2101 · 03-09-2011, 01:29 PM

Quote:

Originally Posted by postino

Whitworth doesn't list 30tpi for *any* size screw thread...

I see your problem, that is funny because i found this on the Inet.

Quote:

English threads are specified by how many peaks there are in one inch of the length. They are specified as "Threads per inch" written "TPI" The diameter is specified in "thousandths of an inch" The most popular English threads are: 48 TPI, 40, 36, 32, 30, and 24 TPI

Although English and Metric threads are not interchangeable, for the purposes of identification they correspond M-.5 : (48tpi) M-.75: 32TPI M-.9 (30tpi) M-1.0: 24tpi. (These are not necessarily the closest English equivalents but the closest commonly used English threads.) Metric bashers refer, for example, to an M6-1.25 as "A Metric Quarter-Twenty".

Than this

Quote:

The thread pitch can be gotten by using gauges or by using known screws as gauges (even if they are different diameters) Hold the known screw agains the one to be measured to see if it fits. A very slight mismatch means you are probably using the wrong measurement system. Metric instead of Enlish, or vice versa. It is a common suprise to find older items of European manufacture made to English specification for the American Market.

Machine Tool · 03-09-2011, 01:34 PM

I believe they have used a bastard thread on purpose. I have found inch diameters matched with metric pitches in some european firearms. They knew exactly what they were doing!

Hugh · 03-25-2011, 03:18 PM

Actually there were two sizes, the early ones were 4.5mmx.8 TPI and the later ones were 3/16x32 TPI Whitworth.I don't remember when the change was made, but 90% of the ones I have encountered were the Whitworth threads. I have taps & dies for both.

Mark1 · 03-25-2011, 09:11 PM

From the 8 sample guns I have measured (all 1917 or earlier) , I would descibe this thread as 5mm diameter x 0.9mm pitch. The actual major thread dia. of the screws is 4.70-4.75mm which is a little smaller than the modern ISO M5 x 0.8mm (normally around 4.8-4.9mm).
It's known that prior to the ISO metric standard of 1963, Germany used the French SI sizes in 6mm-12mm only . Outside of these sizes the Germans used their own threads.
My measurements don't equate to any of the British Standard or British Association threads.

John Sabato · 03-28-2011, 10:36 AM

You can all postulate what the thread is "close to" but as mentioned above by the OP, The original German military blueprints CLEARLY state that the screw is Whitworth 3/16 English Nr. 30... The use of any CLOSE substitute is still going to bind when you tighten it, and will possibly mess up the frame threads if you force it...

I do not recommend subtituting this screw with something "close".

cirelaw · 03-28-2011, 12:51 PM

While on the subject, I need another grip screw for a 1913 Erfurt. This is the other that I am missing!

Hugh · 03-29-2011, 01:55 AM

This company has just about any size die & tap that you would want, some are a little expensive:

www.tapsndies.com

A.Mifsin · 03-29-2011, 05:49 AM

Quote:

Originally Posted by Hugh

This company has just about any size die & tap that you would want, some are a little expensive:

www.tapsndies.com

Is this the die we are looking for?

http://www.tapsndies.com/catalog/ite...10/6865208.htm

Alf.

sheepherder · 03-29-2011, 08:02 AM

Quote:

Originally Posted by Hugh

This company has just about any size die & tap that you would want, some are a little expensive:

www.tapsndies.com

...???...I don't see any reference to these being "Whitworth" anywhere on the site...

03-08-2011, 09:12 AM	#2
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,154 Thanks: 3,003 Thanked 2,306 Times in 1,097 Posts	Hugh Clark or Tom Heller or Ted Green should be able to answer this question for certain, but I believe that the "Nr. 30" in the description of the screw on the blueprint may actually mean 30 threads per inch... I would suggest that you wait for one of the lugersmiths to answer before using your #10 SAE tap. Of course it is your frame, and if you want to change the screw type Rich, that is entirely up to you. __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

03-08-2011, 09:22 AM	#3
G.T. Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: Chandler Arizona Posts: 3,507 Thanks: 1,318 Thanked 3,653 Times in 1,004 Posts	John is correct... Hi Rich, 10/32 is real close, but will bind up in just a few threads... 30 per inch works perfectly... I'm not for sure, but i believe the Luger used an old English thread size & pitch... No 1 rule of life, "nothing is ever as it seems!" ... Best to you, til...lat'r...GT

03-08-2011, 11:27 AM	#4
Mauser720 User Join Date: Aug 2007 Location: Kansas Posts: 535 Thanks: 18 Thanked 49 Times in 33 Posts	Hi Rich - I wonder if a person could make a cast of that thread using the bore casting material that is called "Ceros" or something like that? (I know you know what I mean.) It's available from Brownells and melts at a low temperture so that you can take the interior dimensions of a chamber or barrel. When you do a barrel or chamber, you just plug the barrel or chamber with a rag and melt the stuff and pour it in. Then after it cools you just tap it out with a wooden dowel rod. I'm wondering if you might be able to use that stuff to make a cast of the grip screw threads? However, instead of tapping it out, you would have to probably make some kind of mold or form so that you would have something to grasp and then unscrew it from the threads, etc. Just a thought. Ron __________________ Mauser720 - Ron "Those who do not know history are doomed to repeat it."

03-08-2011, 05:37 PM	#7
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,154 Thanks: 3,003 Thanked 2,306 Times in 1,097 Posts	Heck, if they are going to be custom grips, make them out of brass or stainless steel and while you are at it, use allen-socket type heads, or twin steel pin holes like the adjustment screws on an Artillery model sights! __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

03-08-2011, 07:16 PM	#9
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,183 Thanks: 1,400 Thanked 4,442 Times in 2,330 Posts	Here's the site I got my info from - http://mdmetric.com/tech/thddat8.htm Whitworth doesn't list 30tpi for any size screw thread... __________________ I like my coffee the way I like my women... ...Cold and bitter...

03-07-2011, 10:06 PM	#1
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,183 Thanks: 1,400 Thanked 4,442 Times in 2,330 Posts	Question on Grip Screws I need to make a set of grip screws with a slightly larger head...I see from the Blueprint CD that they are a 3/16" Whitworth thread...but it doesn't say if coarse or fine...[24tpi vs 32 tpi]... Does anyone know which they are??? I'm tempted to just chase the grip frame holes with a #10 SAE tap and make my screws Yankee... __________________ I like my coffee the way I like my women... ...Cold and bitter...

03-08-2011, 01:21 PM	#5
SIGP2101 User Join Date: Sep 2006 Location: Canada Posts: 256 Thanks: 74 Thanked 67 Times in 32 Posts	How about using a simple thread gauge to find out. http://www.google.ca/images?hl=en&q=...w=1280&bih=862

03-08-2011, 08:31 PM	#10
Machine Tool User Join Date: Mar 2010 Location: Tennessee Posts: 16 Thanks: 3 Thanked 5 Times in 1 Post	custom screws can be made

03-09-2011, 11:02 AM	#11
Lugerdoc Patron LugerForum Patron Join Date: Jun 2002 Location: POB 398 St.Charles,MO. 63302 Posts: 5,089 Thanks: 6 Thanked 736 Times in 483 Posts	If you want larger headed grip screws to tighten up a set of loose grips, try the rubber O ring under your present screws. That usually works for me. Otherwise, I have NOS Mauser original grip screws available @$15 each or new repros @$5 or $8/set + $3 S&H. TH __________________ Tom Heller POB 398 ST.Charles, MO. 63302 Tel 636-447-3006 lugerdoc@charter.net

03-09-2011, 01:34 PM	#13
Machine Tool User Join Date: Mar 2010 Location: Tennessee Posts: 16 Thanks: 3 Thanked 5 Times in 1 Post	I believe they have used a bastard thread on purpose. I have found inch diameters matched with metric pitches in some european firearms. They knew exactly what they were doing!

03-25-2011, 03:18 PM	#14
Hugh RIP Join Date: Jun 2002 Location: Southeast Texas Swamp Posts: 2,460 Thanks: 2 Thanked 165 Times in 64 Posts	Actually there were two sizes, the early ones were 4.5mmx.8 TPI and the later ones were 3/16x32 TPI Whitworth.I don't remember when the change was made, but 90% of the ones I have encountered were the Whitworth threads. I have taps & dies for both. __________________ *TRUMP FOR PREZ IN '20!*

03-25-2011, 09:11 PM	#15
Mark1 User Join Date: May 2008 Location: New Zealand Posts: 72 Thanks: 332 Thanked 74 Times in 25 Posts	From the 8 sample guns I have measured (all 1917 or earlier) , I would descibe this thread as 5mm diameter x 0.9mm pitch. The actual major thread dia. of the screws is 4.70-4.75mm which is a little smaller than the modern ISO M5 x 0.8mm (normally around 4.8-4.9mm). It's known that prior to the ISO metric standard of 1963, Germany used the French SI sizes in 6mm-12mm only . Outside of these sizes the Germans used their own threads. My measurements don't equate to any of the British Standard or British Association threads.

03-28-2011, 10:36 AM	#16
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,154 Thanks: 3,003 Thanked 2,306 Times in 1,097 Posts	You can all postulate what the thread is "close to" but as mentioned above by the OP, The original German military blueprints CLEARLY state that the screw is Whitworth 3/16 English Nr. 30... The use of any CLOSE substitute is still going to bind when you tighten it, and will possibly mess up the frame threads if you force it... I do not recommend subtituting this screw with something "close". __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

03-28-2011, 12:51 PM	#17
cirelaw Lifer Lifetime Forum Patron Join Date: Dec 2003 Location: PORT ST LUCIE, FLORIDA Posts: 12,216 Thanks: 6,209 Thanked 4,133 Times in 2,173 Posts	While on the subject, I need another grip screw for a 1913 Erfurt. This is the other that I am missing! Attached Thumbnails

03-29-2011, 01:55 AM	#18
Hugh RIP Join Date: Jun 2002 Location: Southeast Texas Swamp Posts: 2,460 Thanks: 2 Thanked 165 Times in 64 Posts	This company has just about any size die & tap that you would want, some are a little expensive: www.tapsndies.com __________________ *TRUMP FOR PREZ IN '20!*