Question on Grip Screws

Machine Tool · 03-09-2011, 12:34 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, 02:18 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, 08:11 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.

03-25-2011, 02:18 PM	#2
Hugh RIP Join Date: Jun 2002 Location: Southeast Texas Swamp Posts: 2,460 Thanks: 2 Thanked 166 Times in 65 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!*

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode

03-09-2011, 12:34 PM	#1
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, 08:11 PM	#3
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.