donmarkey Posted January 8, 2006 Report Share Posted January 8, 2006 Anyone know what size it is, I thought it was a 8-40, but it doesn't go in all the way. -Don Link to comment Share on other sites More sharing options...
Clemson Posted January 8, 2006 Report Share Posted January 8, 2006 Anyone know what size it is, I thought it was a 8-40, but it doesn't go in all the way. -Don 9555[/snapback] I took one out to measure, and now I can't find the dadgummed pitch gauge! Sorry, Clemson Link to comment Share on other sites More sharing options...
donmarkey Posted January 8, 2006 Author Report Share Posted January 8, 2006 I found out what it isn't. I tried 8-32, 8-36, and 8-40. None work. 8-36 comes the closest. -Don Link to comment Share on other sites More sharing options...
Sailormilan2 Posted January 9, 2006 Report Share Posted January 9, 2006 It's metric. I am trying to read my Craftsman tap, but I believe it says 4mm-.75. Link to comment Share on other sites More sharing options...
Clemson Posted January 9, 2006 Report Share Posted January 9, 2006 I can almost guarantee that it won't be metric. The metric system was not used for machine threads when the Mauser rifles were first produced. All the threads are, suprisingly enough, English. This is a mistake that some of the gun writers propagated also. I have seen it in print before. Incidentally, I could not find my English thread guage, but I DID find my Metric thread guage. No joy! Clemson Link to comment Share on other sites More sharing options...
Sailormilan2 Posted January 9, 2006 Report Share Posted January 9, 2006 Well, I only said that cuz I ran my tap through 3 of the bolt stops to check it. If it isn't metric, then it is durn close to that size. The tightest fit was the Turk. I actually had to use a tap handle just to get it started, then it went easy. I am wondering if the they didn't use the 55* threads on those threads too, instead of the newer 60*? The tap I use says: CRAFTSMAN 4mm-.75 USA 9-52034 USE DRILL 1/8 vm But aren't the locking screws metric? Link to comment Share on other sites More sharing options...
carzngunz Posted January 11, 2006 Report Share Posted January 11, 2006 I am in need of several of these screws myself so I have been waiting for the definitive answer. Since no one has stepped up and said "I know for sure what size it is", I measured the last one I have thats not in a gun. Mine has some wear so the measurements aren't going to be exact and the thread diameter isn't a standard size so I still don't have a definite answer. It is either 5/32 diameter with 36 tpi or its 4mm-.7 pitch. I can tell you for sure that a standard 4mm-.7 machine screw turns right in the 4 ejector boxes I have in front of me, with a pretty good fit. When I make some of these I will probably use a 4mm split die to cut the threads. Thats a lot easier than trying to cut those fine threads, up to a shoulder, on a lathe. Link to comment Share on other sites More sharing options...
Sailormilan2 Posted January 11, 2006 Report Share Posted January 11, 2006 Well, I got a new unthreaded ejector box and used the 4mm-.75 on it, and it works fine. As I said, that tap screws in fine on almost every one I have tried it on. Sometime, it is a little snug at first. But I think it is just cleaning stuff out of the threads. Link to comment Share on other sites More sharing options...
donmarkey Posted January 11, 2006 Author Report Share Posted January 11, 2006 Thanks guys, I'll order some 4mm-.75 screws and give them a try. I need them fully threaded to install from underneath for a flush screwless look and didn't want to open the hole in the action up too much. -Don Link to comment Share on other sites More sharing options...
LongIsland Posted January 12, 2006 Report Share Posted January 12, 2006 Don, I picked up some metric button head screws a while ago that had an allen head drive. They were marked M4x20 but ran thru the 4mm-.75 die without a hitch. All I did was turn off the bottom 5/8" of thread to a point like the original and it worked fine. Looks good as a button top is rounded and the allen head is neat. I have a few left over and your welcome to try it if you like. Bob Link to comment Share on other sites More sharing options...
donmarkey Posted January 12, 2006 Author Report Share Posted January 12, 2006 Long Island, I'll keep you in mind. I couldn't find any .75 screws all I could find are .70. I tried fastenal and enco and the local shops with no luck. I was thinking of running a 8-40 tap thru them and seeing if that would work. I also could weld the top solid and tap only the bottom hole and use the existing screws if I could find a tap. -Don Link to comment Share on other sites More sharing options...
Doble Troble Posted January 13, 2006 Report Share Posted January 13, 2006 This is great archival-grade info guys, thanks! Link to comment Share on other sites More sharing options...
carzngunz Posted January 13, 2006 Report Share Posted January 13, 2006 I have an update to the thread issue. Since my last post I have tried two different 4mm-.75 pitch screws in all of my bolt stops. Neither would screw all the way through the threaded portion. As I stated before, the 4mm-.7 pitch screws fit well. I think the problem is comming from trying to screw a tap through the threads. Taps are designed and made to cut metal. You really shouldn't use a tap to check thread fits. Unless it is the correct size you will almost always damage the threads. The smaller and finer that the threads are, the easier it is to damage them. As for this problem, if you run a 4mm-.75 tap through 4mm-.7 threads it will require very little effort and you may even be able to turn it by hand. The difference in pitch is only .05mm. That's less than .002". The threads are also very shallow. Add to this that you are only cutting across the threads that are already there and you can see how little effort would be required to cut the new thread pattern. Then you end up with two different thread pitches in one very small hole. The point I am trying to get across is that you shouldn't ever use a tap to check thread fits, use a regular machine screw of the proper size and if it doesn't fit,then there is less chance of causing any damage. Link to comment Share on other sites More sharing options...
donmarkey Posted January 14, 2006 Author Report Share Posted January 14, 2006 carznguns, thanks for the update I couldn't find .75 screws anyway only .70. I'll order some and post the results. -Don Link to comment Share on other sites More sharing options...
Sailormilan2 Posted January 14, 2006 Report Share Posted January 14, 2006 If I gave out bad info, I apologize. Link to comment Share on other sites More sharing options...
donmarkey Posted January 14, 2006 Author Report Share Posted January 14, 2006 When it comes to this stuff there in no such thing as bad info. Everyone does things differently and has different expectations. That's why you should always test and try thing for yourself before commiting money or actions on them. All ideas give you a little more insite on the situation. -Don Link to comment Share on other sites More sharing options...
carzngunz Posted January 15, 2006 Report Share Posted January 15, 2006 Sailormilan2, definitely no apologies necessary! I've been fooling with mechanical stuff just about my whole life and I still learn new things almost daily. I am not positive that the threads are 4mm-.7 but it does fit my parts. I am almost positive that with the closeness of the thread pitches, you could run the .75 pitch screw through the hole with a screwdriver. The parts wouldn't be happy but it can be done, afterall there are only 4 threads on the screw! My comments on using the tap to check threads comes from my personal experience over many years. I've messed up my share of threads, even when I knew better! donmarkey has some very good advice. If at all possible, check out the tips and advice you get from others before laying out your hard earned cash. I've learned a great deal from the people on this board and I think most would agree with his advice. My favorite situation is when a bunch of people chip in to solve a problem and the solution ends up being a combination of many suggestions. Link to comment Share on other sites More sharing options...
tinkerfive Posted January 17, 2006 Report Share Posted January 17, 2006 Guys, Guys,Guys! This thread is making me nuts! I can't believe that none of the truly knowlegable experts have chimed in yet. One thing I'm certian of is that nothing on a Mauser is metric. Paul designed his gun to be built on the worlds best machinery of his time, which was British. Therefore EVERYTHING is in "TPI". Phew!! Now I feel better! I guaged the thread at a 32tpi. I tried an 8-32, too tight; and a 6-32, too loose. The 8-32 started because the end had a slight taper. If you want to make replacements here is what I would reccomend.... Start with 8-32 screws. Get an 8-32 adjustable die. With the die you can reduce the diameter to fit. Make sure you get one that has a non tapered side so that you can get in tight under the head. Of course you will need to remove the threads from the lower portion, I'm guessing that a No. 8 will work out once you've removed the threads. Best of luck! I hope this works out, let us know. I could use a few new screws too. Tinker Link to comment Share on other sites More sharing options...
carzngunz Posted January 17, 2006 Report Share Posted January 17, 2006 DON'T GO NUTS TINKER!! This is part of the fun! Do us a favor and check the threads with your guage again. I checked them and I gave the screw to two other machinists at separate times and asked them to tell me what size the threads were. I got the same look but also the same answer from both. I never have a simple problem. The O.D. of the threads measures 0.153" on one and 0.154" on another. Simple enough to measure but not real close to anything standard except that it is about 5/32". 5/32" being 0.156". A #8 machine screw has an O.D. of 0.164". Most screws will be a few .001's under nominal but not this much. 4mm is about 0.157". All three of us measured the threads at either 36 tpi or .7mm pitch. The pitch of 36 tpi is 0.0277". The inch measurement for .7mm pitch is 0.0276". The pitch of 32 tpi is 0.0313" or 0.794mm. This is further from either of our other "guesses". I learned a long time ago that you can make threads with any OD and pitch that you want. It doesn't necessarily have to be a "standard" size screw! I'm not saying that 'ole Paul made these screws metric but he couldn't have gotten much closer if he had tried! Let us know what you find. Link to comment Share on other sites More sharing options...
Clemson Posted January 17, 2006 Report Share Posted January 17, 2006 Well, I finally found my thread gauge -- in my toolbox where it should have been! I have a 98/22 in the cabinet that I just gauged the screw on. It is 0.1565 inches across the threads and 36 tpi. Don't let the numbers, #6 vs #8, throw you a curve. The ANSI standards had not been promulgated when Mauser designed his rifles either. That is probably why the guard screws are 1/4 x 22 instead of anything that we are accustomed to today. With a good, accurate lathe, you should be able to turn a screw that will fit. I think you would have to ask, "Why bother?" Replacements are probably less than a buck from Numrich. I have often wondered why the thing is so long and sharp. I can't see that it serves any useful purpose other than alignment, and it sure doesn't have to be a dagger for alignment. Clemson Link to comment Share on other sites More sharing options...
carzngunz Posted January 17, 2006 Report Share Posted January 17, 2006 Alright Clemson, now you've gone and started another one. I think that the screw is pointed so that it would originally push into the wooden stock to support that end of the screw since it is a pivot point for the bolt stop assembly and not really a fastener! Hows that for winging it with not one shred of proof? Link to comment Share on other sites More sharing options...
diggerdanh Posted January 17, 2006 Report Share Posted January 17, 2006 Hello gents. I was a regular contributor of the old boards, but stopped visiting about a year ago. Went looking for it a couple of months ago and luckily found my way here. I have been lurking for quite a while, but thought I would go ahead and throw my 2 cents in here: I think carzngunz is on to something, mostly because I've always thought the same thing. Any other military mauser that I have seen (I've seen not nearly as many as most of you guys!) always had that screw embedded into the stock quite a bit. I always assumed that it was supposed function as a pivot point for the bolt stop assy as well. Link to comment Share on other sites More sharing options...
LongIsland Posted January 18, 2006 Report Share Posted January 18, 2006 If you can get ahold of a Recknagel Feintechnik catalog( Brownells of Germany), they sell everything Mauser related from the actions to the individual screws. New England Custom Gun is the U.S.A. importer. Wish I could read German but can understand the photos. On pg. 85 is acessories for K98 with a drawing of the bolt stop screw, "SchloBhalteschraube" ,(Abmessungen) M 4 x 19 x6.5, (part #00000-1170). The TG screws are listed as 1/4-22x39x10, 1/4-22x26x10, 1/4x22x37x10, 1/4x22x19.6x10. Even the Tg locking screws are listed as M 3.5 x 5 x 7. hope this helps Bob Link to comment Share on other sites More sharing options...
Vladymere Posted January 18, 2006 Report Share Posted January 18, 2006 I wouldn't have believed that there where any screws that where metric on a Mauser. Two of the screws that Longisland listed from Recknagle are metric, those with the M prefix. Vlad Link to comment Share on other sites More sharing options...
carzngunz Posted January 18, 2006 Report Share Posted January 18, 2006 Here's something else to think about, an M3.5 screw, as mentioned above, has the same OD as a #6 machine screw. Link to comment Share on other sites More sharing options...
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