Restore the safety detent plunger

Mods and Fixes by P-64 users...
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sbj
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Joined: November 5th, 2016, 6:13 pm

Restore the safety detent plunger

Post by sbj » November 5th, 2016, 6:49 pm

Earlier today I found my new P64's safety lever dropping from the FIRE position down toward the SAFE position during firing. Sometimes it took a couple shots to move it far enough to block further firing, other times the recoil of the first round of the magazine would knock it down enough to stop the second shot.

As I drove home from the range I decided it was likely that the detent plunger or the notches in the safety catch lever's "barrel" (into which the detent plunger fits) might be excessively worn. This could be allowing the safety to bounce out of the firing position. When I got home I field stripped the pistol to reveal the underside of the slide, then depressed and held the firing pin in the extended position using locking forceps (like hemostat). This allowed the safety catch lever to be removed from the side of the slide.

Inspection revealed the notches in the safety catch "barrel" were a bit worn at the edges, but the detent plunger was rounded off almost flat! This was keeping the detent plunger from getting down into the notches to any extent, making it pretty easy for the safety to rotate out of the fire or safe positions. Since I didn't have a spare I found a way to restore the plunger and so far it seems to be working: I chucked the detent plunger into the collet of my Dremel Moto-tool (it fit perfectly into the middle-size collet) and turned the motor on at the slowest speed. I then used a small file to reform a cone shape on the rotating end of the detent plunger - I created a poor man's miniature lathe I guess. See the attached sketch for my comparison of the worn vs restored detent plunger shapes.

I reassembled the pistol and found the safety catch lever still rotated fairly easily but the fire and safe positions clicked in with a much more positive action. This restoration shortened the detent plunger a bit but the spring behind it seemed to still have enough power to press it firmly against the safety catch and push it down into the notches. If the detent spring were weaker this approach might not work as well but so far after about 30 more rounds the problem has not recurred.
DetentPlungerSketch.jpg

chestertnted
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Re: Restore the safety detent plunger

Post by chestertnted » November 5th, 2016, 6:58 pm

Fantastic. Congrats

TED
"For the Founders, the right of the citizen to be armed-they never imagined a world in which they would be disarmed for the supposed benefit of preventing access to weapons by madmen."

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Curly1
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Re: Restore the safety detent plunger

Post by Curly1 » November 6th, 2016, 12:57 pm

Welcome to the forum, nice write up.
Laugh Hard and Often.

Gary

big54r
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Re: Restore the safety detent plunger

Post by big54r » November 10th, 2016, 9:17 pm

nice work..and welcome to the forum!

sbj
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Joined: November 5th, 2016, 6:13 pm

Re: Restore the safety detent plunger

Post by sbj » November 14th, 2016, 10:52 pm

Thanks guys... I shot 50 more rounds today with the P64 - no trouble at all with the safety.

I love it when a plan comes together...

tpelle
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Joined: November 22nd, 2016, 8:20 pm

Re: Restore the safety detent plunger

Post by tpelle » November 22nd, 2016, 8:37 pm

Good job, but you might not be finished yet. If that plunger wore down that it much from normal use, then it might need hardening. You may want to buy something like Kasenit powder, and do a case hardening job on the plunger.

sbj
Posts: 3
Joined: November 5th, 2016, 6:13 pm

Re: Restore the safety detent plunger

Post by sbj » December 13th, 2016, 3:21 pm

That's a good point, tpelle. The plunger seemed reasonably hard when I shaped it back into a cone, but maybe it is not as hardened as it should be. I tried to do the re-shaping more slowly than I might have in hopes of not weakening the temper through heating. Definitely if I were going to do a lot of shooting with this pistol then hardening the plunger would be wise.

Why was this one so worn? My guess is that a previous user had this pistol in a belt holster for many years and had a habit of flicking the safety on and off absentmindedly while resting their hand on the pistol. I suppose I'm glad the plunger was not as hard as the safety detents so that the wear was mostly on the plunger.

sbj

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