How to change Luger Main spring?

mrerick · 12-06-2018, 09:07 AM

The OP's Luger (assembled from two donor Lugers) may need some attention to hand fitting and lubrication.

There were a range of recoil mainsprings used on a variety of Lugers, and we have the table in the Luger FAQ PDF document available on this site. It lists them by wire size and coil count.

If there is any variation in the way the slide or toggle train movement cycles between sloppy loose feeling and tight binding, this could relate to fitting problems. Some detailed attention to how the action feels as it cycles without the spring in place might be useful. Also the tape test on the back of the frame to see how hard the toggle heel impact is on the frame.

I would address the hand grip and grip support first. Then start looking at the precision fitting of parts being smooth and properly close. Then perhaps the recoil spring.

The Luger has a precision balance in it's action operation, and many things can disrupt it.

sheepherder · 12-06-2018, 09:49 AM

Quote:

Originally Posted by mrerick

If there is any variation in the way the slide or toggle train movement cycles between sloppy loose feeling and tight binding, this could relate to fitting problems.

Some members who do a lot of barrel swapping have noticed that the sides of the barrel extension ['receiver'] can be misaligned, or twisted, or even bent in such a way that the extension drags on the frame, especially in the frame 'ears' area. This can be checked by a couple of spirit levels across the extension sides; careful measurement of the gap between the sides; and a ground parallel held to the extension sides, to see if there are any gaps when held to a light. A ground drill rod placed in the bore will also show up any misalignment when used in conjunction with the spirit levels.

Any small faults can usually be remedied with a combination of lapping compounds to get a smooth drag-free action. Severe misalignment calls for more drastic action, such as careful bending of affected parts.

As always, hope for the best and be prepared for the worst.

12-06-2018, 09:07 AM	#1
mrerick Super Moderator - Patron LugerForum Life Patron Join Date: Dec 2009 Location: Eastern North Carolina, USA Posts: 3,919 Thanks: 1,377 Thanked 3,135 Times in 1,518 Posts	The OP's Luger (assembled from two donor Lugers) may need some attention to hand fitting and lubrication. There were a range of recoil mainsprings used on a variety of Lugers, and we have the table in the Luger FAQ PDF document available on this site. It lists them by wire size and coil count. If there is any variation in the way the slide or toggle train movement cycles between sloppy loose feeling and tight binding, this could relate to fitting problems. Some detailed attention to how the action feels as it cycles without the spring in place might be useful. Also the tape test on the back of the frame to see how hard the toggle heel impact is on the frame. I would address the hand grip and grip support first. Then start looking at the precision fitting of parts being smooth and properly close. Then perhaps the recoil spring. The Luger has a precision balance in it's action operation, and many things can disrupt it. __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war.