View Full Version : Mauserr heat treat.

Harry Bonar
September 24, 2005, 08:00 PM
Dear Sir:
I do not know how to recieve personal messages, I can never get rid of them!
However, the answers to your message can be found on page 12 of the Smithy Forum posted for me by Hunter Customs under BILL Z on 2/2/05.
It covers the question you asked about re-heat-treating.
It also covers reworking Mauser (and other) actions in general.
Sorry I'm so stupid about attatchments and messages.
Harry B. Title of article: Turkish Mausers - As good as any 98.

September 25, 2005, 01:36 AM
You can email me at [email protected] to send me the info you mentioned. They guy I have been dealing with claims he only case hardens the bolt and receiver.

September 25, 2005, 02:22 AM
Harry, in that post on pg 12, you mentioned that you shouldn't have the rear lug bearing. From what I have been taught, you get better strength if you lap all three lugs. Let me go into further detail on it and maybe you can understand why that is. I was taught to lap the front lugs to a minimum of 95% bearing on the front lugs. During the lapping process, you may need to do some machining off the front lugs which will bring the rear safety lug further into contact in its recess. I was taught to achieve at minimum 25%contact with the rear lug when you get the front lugs lapped in so if for some reason you ever have a failure and the front lugs break off, you don't have a large jump which may give the bolt enough momentum to shear off the rear lug which is the last safety mechanism before the bolt will exit out the rear of the gun. From what I was taught, this makes a bolt safer.

My question is why do you say not to have the rear lug bearing when you lap the front lugs? I am just curious. I know no one man will ever have all the answers but I do try to find as many as I can. Whenever I find someone I feel knows a thing or two, I do my best to learn as much as I can from them which is why I would love to pick your brain for a while if you don't mind it.

Question 2 I have for you is if you use a tap to help straighten out the threads of the receiver or exactly how do you go about it. I have always used a tap myself, but I hear from a lot of folks that they think you have to to single point cut the threads to true them up. I have always used a tap using the tailstock to help keep it concentric.

Another question and I will let you rest for a while on this. I normally buy a short-chambered barrel and attach it and then chamber the barrel using a tap wrench and reamer through the back side. One thing I never thought much of until an article recently was that the barrels I have been using aren't a true 55 degree thread. I found out that they have been a 60 degree thread on the shanks. Do you know anything about this? I really never bother checking and just tightened the barrels up and never gave it much thought until I had a little trouble recently getting a barrel to thread up to the shoulder of the receiver. I asked about it and was told by a smithing buddy that the ones I was using were a 60 degree thread and not the 55 like what is on the Mauser receiver. I have been using the Adams&Bennett barrels a good bit lately and had only had this last one give me any problems. I got to researching it and found out that they do produce the 60 degree thread which is supposedly what the commercial Mauser receivers are now using. I have been running a lathe for several years now, but have never been taught how to cut the correct thread for the Mauser receiver. Do you have an exact name for the thread they use for the receivers? I have been told by several folks different names of the exact thread. Some have said it is a Whentworth thread and another guy says it is a varying thread of metric design but the old metric design changed so now no one knows exactly what pitch to use to cut it. As you can see, there are several ideas floating around on this. I plan to start using barrel blanks and cutting my own thread shanks to make sure I don't run into the same problem again. I now chamber using the lathe and a floating reamer holder and am still trying to learn as much as I can so any help will be greatly appreciated.

September 25, 2005, 02:43 AM
Harry, I messed up and deleted the PM you sent me and when I tried to email you, I got the email back saying it couldn't be delivered. Is your email address the same as it is posted under your profile?

Harry Bonar
September 25, 2005, 07:12 PM
My E-Mail is "[email protected]"

If I can help e-mail me.

Harry Bonar
September 25, 2005, 07:53 PM
Dear CNTRYBOY 1289
Ist. question - rear lug.
The third lug is simply a safety lug that was added to the 98 and was not on the 91-93-or 95. It IS NOT meant to touch. If you want to introduce innacuracy into a Mauser either have the third (safety) lug touching or the bolt handle touching the wood; also by fitting the third (safety) lug you are causing stress in the rear reciever which is fragile anyway due to the thumb cut on the left.
I NEVER "machine" the front lugs to get the rear to touch - whoever told you to do this is GROSSLY mistaken! Also, by machining the main lugs in front you are removing any carburizing there is!
Don't listen to so called experts - the Germans never wanted that third (safety) lug touching! I have NEVER found one touching on a 98.

2nd question
Lug laping; yes I lap the front lugs IF THERE IS very minimal set-back.
ALL rifles have some initial set-back of the lugs in high pressure cartridges. You check any rifle (brand new) and you will find that on 80% of them only ONE lug touches! If on a Mauser the upper recess has a SMALL shiny spot where there has been some set-back (the germans never really worried too much about headspace, I've seen numbered rifles with .025 headspace! So, when a military Mauser is fired the lugs are slammed back into their recesses and a very small amkount of laping will clear this up - if it is serious set-back scrap that action. (I had two "re-heat treated" and asked the "expert" what rockwell C they were and he gave me a number - I later at home tested the TOP reciever ring and there were soft and hard spots - I smashed the rings together on the block!). There were no Rockwell dimples on the action; this guy was trying to pull one over - in my opinion anyone who says to Re-heat treat ANY action is asking for a world of trouble. Douglas bbls Co. tests Rockwell and if 20 on C scale it's O.K. for 7X57 class cartridges, 40 on C is O.K. for CUP 50,000-55,000 jobs.
The more you lap the more case hardening you remove - be judicious - also a soft piece will lap a hard one!
3rd question.
This is simple- for years we've been using 60 degree threads but if this bothers you gring your threading tool using an old 98 bbl! That's what I did but either 55, or 60 works great! (TIP - on your last pass come in .001 with your CROSS FEED and polish those threads up)
The way I solve the thread problem is to fit to the front shoulder of the action (AFTER IT'S TRUED WITH A MANDREL ON THE LATHE.) this assures that the bbl is perfectly in line with the action reference! Don't worry about the inner bbl seat just stay close to it (.001-.003) however, if the inner shoulder is the same distance all around with the trued front action then fit to BOTH shoulders-any misalignment of threads is taken care of like this!

CNTRYBOY1289 - these are my opinions and, of course, I can be wrong - please don't feel I'm trying to correct you - I remember your post on using short chambered bbls and using a reamer with a tap wrench to fit the bbl - very fitting and great workk!
I probably should'nt give my E-mail on the forum but you would like it so there it is on my other post.


I sincerely hope this helps--- Harry B.

Harry Bonar
September 25, 2005, 08:02 PM
Please do not construe my remarks to say that the fine gentleman you're using is crazy - he may be a whole lot smarter than I. I wish him well.

My opinion, again!


We could go into heat treating in depth but it would take too long.
Thanks, both of you!
Harry B,. ;)

September 25, 2005, 08:42 PM
We had a detailed discussion of this on another forum. They did use a low carbon steel and carburized it .However ,especially during the war, the carburizing was not consistant .My '43 Oberdorf was very spotty, some areas hard and some soft. The answer is to carburize and heat treat ALL old Mausers .Find heat treating companies who are experienced doing this. The best way is to anneal ,do all machining and lapping then carburize and HT.We know enough about the composition and carburizing to do a proper job !!

September 25, 2005, 09:21 PM
Harry, I want to thank you for responding back to me on this. I and other folks hear so many different opinions on the matters we have been discussing and you get a different answer from just about everyone you talk to. One of the guys I learned from always told me to not machine the lugs since if you do, you do remove the carbuerization like you said. Another guy taught me to machine only if you have a lot of material to remove to get one lug to mate with the other one. This is why I have always HT the actions and bolts when I was finished with them if I had to do very much machining on either. Not all need a lot of machining and I don't HT all of them, just the ones I know I got down into the softer metal.

The guy I have been using to do my HT has proved to be a very good guy to deal with and his actions actually take a very good case hardening when he does his magic on them. I agree that the fact that they case hardened the receivers helped make them a lot stronger than folks give them credit for and that some folks that built them used different steels and did varying hardening jobs on the receivers. The guy I use claims that he does anneal like Mete said and then recase hardens the actions and receivers. I have always wondered exactly how they got the inside of the action hardened correctly, but never thought to ask about it.

Harry, do you think the reason the guy taught us to only lap 25% of the rear lug has anything to do with what you are referring to about inducing poor accuracy in the receiver. Some of the actions I have done I have never gotten close to getting them to bear on the third lug simply because the front lugs were bearing almost completely and evenly and the third lug was more than .100" away from bearing, but I have done a few that shot very well that had all three lugs bearing with the rear bearing around 25%. Who knows how much better they might have shot if the third lug should not actually be bearing.

I only had the one shoulder that wouldn't tighten up all the way and had to remove some of the back of the barrel to get it to fit correctly. I then had to deepen the chamber to get the correct headspace. I have heard from several different smiths about mating both the shoulder of the barrel and the back of the barrel against the shoulder of the receiver, the answers have varied on this subject as well. I have done it both ways and haven't seen enough difference to say either way works better than another except on a few where the barrel was crush fitted. These sometimes could be made to shoot better when the back of the barrel was relieved slightly so I have always made sure to not crush fit the barrels.

When I bought my new lathe back early this past summer, I started using it to chamber my barrels. I haven't noticed a lot of difference in the accuracy of them so far. If you use a good receiver, barrel, and stock and either way is done correctly, it will give you a very good shooting rifle. I know alot of folks will argue otherwise, but none of the rifles I have built have ever left my shop not shooting very well. Who knows, when I become more proficient with this lathe, maybe I will notice a bigger difference one day. I chamber using a JGS floating reamer holder now using the tailstock to provide the drive for the reamer I have read where others do this and that to get theirs chambers perfect but, I have never wasted the time to acheive perfection myself. A half thousandths is as close as I ever try to achieve and I think the rfiles shoot rather well myself.

Harry, I always use the compound rest to cut the threads until the last two passes of a thou or so using the cross feed and this has always helped me achieve a class 3 thread fit. With the barrel that gave me trouble, it was a short chambered, pre-threaded barrel that I believe ended up being threaded just slightly too long, but even with the rear turned down, I had to slightly relieve some of the front of the thread to get it to tighten up correctly.

Thanks again, for giving me your answers. I agree that no one knows it all and if we don't talk amongst ourselves we will be limited in our knowledge. Harry, if you feel like it you can go back and delete your email address out of the post. I have it now. Last night the one that was on your profile bounced on me was why I was asking for it. Take care.

September 26, 2005, 10:00 AM
The Mausers should be cut to contact both shoulders and the threads cut to give a snug fit .This ,and good bedding with fiberglass ,is done to give maximum rigidity. Max rigidity gives you accuracy. :)

September 26, 2005, 03:22 PM
I would love to sit down with the fellows like you and Harry and just pic your brains for a very long time, but today I would like to ask a question if you don't mind, Mete. What is your opinion on mating all three lugs on the Mauser? Do you feel it is not the right thing do or would you try to mate the safety lug? I have been using the folks out of Salt Lake City to handle my HT, do you know of any one else to consider for this?

September 26, 2005, 07:00 PM
Can't help you with a heat treater as I'm not gunsmithing these days . When I was in Gunsmithing school I can't remember any comments on mating the safety lug. When you've done everything else ,machined or lapped lugs and carburized and heat treated properly the safety lug is just that ,it's for when the forward lugs let go.This is a very rare even if you've done the rest...I'll see if I can find a HTer....Blanchard Metals Processing Salt Lake City I thought there was one on the west coast but couldn't find it.....In school they suggested receiver hardnes s of .030-.040" case and 36-40Rc and 40-44Rc for the bolt. I agree.

Harry Bonar
September 26, 2005, 07:40 PM
Dear Shooters:
I operated on a Belgian FN Mauser today; am fitting new bbl from blank.

There is discussion, now, not on heat-treating, but on bbl fitting!

Years ago I noticed that on military Masusers when fitting to the inner shoulder only (the way some pretty savy firms were doing) the barrels would cant to the right of the center line. This is because of the cut-out for the extractor, (Yes, I know the Mark 10s, and FN's, had both sides cut out for ease of manufacture - a good idea) and since there was no support it caused the bbls to go to the right and created problems.
Now, men, let's get straight and honest about this! How are Mod. 70, and 700 Remingtons fit? Now, you men explain to this old boy what the difference is in fitting Mausers (when necessary) that way? I say this for one very good reason; When you true the action front face (the belgian was .010 out!) and then measure down to the inner shoulder, IF it isnt the same distance from the trued face Then, and then only, fit the bbl inner shank to just touch the highest place on the inner shoulder. If you insist on screwing it into an out of line inner shoulder, not only are you doing very poor work, you are setting up a strain between a 90 degree outer action face and an inner shoulder which is out of line!
I want to state right here that VERY FEW Mausers after truing action faces will HAVE A CROOESPONDING INNER SHOULDER THE SAME DISTANCE FROM THE FACE! If it is O.K., fit it to both shoulders the inner shoulder is good design, it helps feed mil-spec cartridges into the chamber!

Now, to the Belgian commerciat Mauser I have: Boys, the rear lug DOES NOT TOUCH! Dag-nab it, IT'S NOT SUPPOSED TO!

Now, as to my article on set-back being in all rifles that generate more than 45,000 CUP!
This Belgian had to have a carbide tool to square the action face - that's hard ! Yet in the inner top bolt lug area you could seer that little indent in between the top inner lug showing very small set-back! Judicial laping took this out! Argue all you want to about milling on that bolt etc, till doomsday the safety lug is NOT to TOUCH! The Germans didn't do it, the Belgians don't do it, the Turks, don't do it - NOBODY DOES IT!
Don't let anybody do it!
Now, let's get to headspace: set your headspace with the brand of ammo you'll use (oh! yes! by all means use that headspace gauge, we would'nt want to forget that or members will come down on me like Zuess), and set it so YOU FEEL THE BOLT CLOSE ON IT!!!!! :mad: This can eliminate set-back to a large degree because the undersize cartridge using the go/no-go gauges can not seat the case all the way up in the chamber! When it goes bang! the case doesn't slam into the bolt that .006 like a factory headspaced weapon can! And, if you set your dies like the instructions tell you, within a few sizings with a max chamber you'll begin to get incipient case head stretch and separation.
May I respectfull say, I do not agree with milling the bolt, cae hardening or any other metalurgical alteration! Yes, it would be great if we found the German and Czech specs! WE DON'T HAVE them! IF YOUR ACTION IS SOFT - DO NOT USE IT!

I'm sorry to be so blunt but this has been learned over 50 years of reading, working looking at others (and mine too) mistakes; it is good advice and sound gunsmithing and I cannot for the life of me understand why these modifications are done --IF THE ACTION IS SOFT - DO NOT USE IT!

Harry B.

September 26, 2005, 09:39 PM
I agree 100% about the ill effect that crush fitting does. I have tried my best to get the barrels to fit to the inner shoulder, but like you said, most aren't machined square across and I will come across one or two that is more than a thousandth out of square. I cannot see torqueing up to a shoulder that is out of square. Of all the folks I have ever watched or heard talk about it, none have ever went in and machined the shoulder square for obvious reasons so I have not either. I was getting them to tighten against the inner shoulder, but I have done few without touching the inner shoulder and have done a experiment that someone in class did one time myself and it worked fine. What I did was assemble the rifle and fire ten three shot groups. All were within a 1 1/2" group. I then removed the barrel and then reassmbled the barrel hand tight only. Shot a three shot group, remove the barrel and reassemble it and fire the next three shot group and do the same thing all over again. I did this for a total of ten groups and none were larger than a 1 1/2" group. I then torqued the barrel up tight with a crush fit and refired the groups and none were larger than a 2" group. To me it hurt when I crush fit the barrel, but one might say I had shot more than I might have needed to before giving it a rest, but I do shoot several hundred at a time sometimes without problems.

Harry, not sure exactly how I feel about the case hardening since the ones I have had done seem to work well. The folks have been doing this a long time and they deal with it on a daily basis. I have never had one come back so far and I know for a fact that I have broke through the case on atleast two that I cleaned up. I don't fool with a soft reciever myself. All I mostly deal with is the VZ24's. If I don't do a lot of machining on them, I don't fool with sending it off to begin with. I wish I had the gumption to machine the inner shoulder square and then have it sent off and HT to be able to say if it would hold or not, but I guess maybe I don't trust it as much as I thought I did. I guess that is why I do the work with the Remingtons and Winchesters as much as I do I suppose.

BTW Harry, I have gotten into the habit of HS off the cases from anyone that reloads. You don't shoot HS gauges and no one die set is going to be the same for every one. If a guy shoots factory ammo, I do use the Go and No-Go gauge just to be safe, but I always ask if a guy usually shoots reloads, if he does and wants me to, I use a few of his cases to get a good average so I get a good feel when the bolt closes so there is no HS at all. To me and you and a lot of other folks, it makes very good sense. I always warn the guy though that if he sells the rifle or ever needs to use factory ammo, it may not close so if he sells the rifle to sell the dies with it. Thanks again Harry and Mete.

Harry Bonar
September 27, 2005, 08:01 PM
We've had fun with this one and it has made me think! I appreciate that; we'll all learn from this one!
Harry B.

September 28, 2005, 02:35 AM
That's why this place is here is for us to discuss things such as this. I really appreciate it myself. Thanks Harry.