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Walther LGR "coin slot" screws?

Posted: Wed Apr 20, 2011 2:08 pm
by azmule
Finally got around to ordering a replacement piston seal, but...

Those 2 flat head screws with the radius-bottom slot that hold the piston lever assembly in the rear of the receiver - is there a special driver available somewhere for those things?

Also, are replacement screws available for those of us that tried to kludge our way through with a standard flat blade gun screwdriver first?

Posted: Thu Apr 21, 2011 8:44 am
by JSBmatch
Most screw drivers have tapered blades, but the gunsmiths screw drivers usually have a parallel blade. This is so the screw driver does not 'CAM' out of the screw slot.
Check the Net for gunsmiths screw drivers.

Re: Walther LGR "coin slot" screws?

Posted: Thu Apr 21, 2011 11:26 am
by azmule
Yes, I've got and use a set of those, but these screws are not flat in the bottom of the slot, they are cut to a radius that does not extend to the full width of the head. The result - as I unfortunately discovered - is that standard gunsmith screwdrivers, cut flat on the bottom and not to a matching radius, will not go full depth into the slot. In fact the proper width driver barely extends into the slot at all because of this feature, I have to use a too-small one to get any significant depth of contact.

I tried hand-grinding one to a matching radius (about R0.218 as near as I can measure) but doing so must have destroyed the blade temper, because combined with the damage I've already done to the top of the slot, the modified driver just twisted at the corners and slipped out anyway.

I would just drill it out and replace it, but I've never seen one of these screws before (sort of a combination flat-head/shoulder-screw) and have no idea if replacements are even available.

Thanks,

Scott

Posted: Thu Apr 21, 2011 12:13 pm
by JSBmatch
Thats a bummer, I think it must be a special type screw driver, try E Mailing Walther.

JSB

Posted: Thu Apr 21, 2011 10:16 pm
by justadude
It has been 20+ years since I have had my hands on an LGR so my memory of these exact screws is faded. There are a number of screws on some of the older rifles where the slot made an amazing fit with either a 1DeutschMark or 2 DeutschMark coin. Both those coins, and the 5DM if I recall correctly had a pretty square shoulder. The one thing I will say, is that most often the screws with the radiused depth slot were those meant to be loosened often for adjustment and it does not sound like these screws were meant to be touched all that often.

Not very helpful I am afraid but perhaps some insight to the problem.

'Dude

Posted: Fri Apr 22, 2011 3:48 am
by RobinC
I don't think these screws should be mega tight but they may be loctited in and need a little subtle heat applied very carefully to not damage the blue. Before you do any more I suggest a call in to Bill Welch (Bill's Walther Spares and Repairs) in England. He is very highly respected by Walther and does some of their repairs on classics. He will know what to do and there may be a little trick required which may help. I'll PM you his details as I'm not sure if he would want them put out on a web.
Best regards
Robin

Posted: Sat Apr 23, 2011 3:27 pm
by sandy22
justadude wrote:It has been 20+ years since I have had my hands on an LGR so my memory of these exact screws is faded. There are a number of screws on some of the older rifles where the slot made an amazing fit with either a 1DeutschMark or 2 DeutschMark coin. Both those coins, and the 5DM if I recall correctly had a pretty square shoulder. The one thing I will say, is that most often the screws with the radiused depth slot were those meant to be loosened often for adjustment and it does not sound like these screws were meant to be touched all that often.

Not very helpful I am afraid but perhaps some insight to the problem.

'Dude
Unfortunately the DM was replaced by the Euro in 2002

Posted: Mon Apr 25, 2011 5:18 pm
by azmule
Thanks everybody! I just wound up machining (and properly hardening) a special bit to use with an impact screwdriver to remove the old screws - one slot is left a little chewed up, but I'll just make a replacement set to take a hex key so I don't have this issue next time. I was hoping to avoid the trouble if OTS replacements were easily available, but it was starting to look like tracking those down would take more time than just spending an hour or two in the metal shop.

Posted: Wed Apr 27, 2011 9:03 am
by azmule
I take that back... heard back from Bill Welch, looks like he has those screws in stock!

Thanks RobinC!