How To Make A Mauser Bolt Turning Fixture

In most gunsmithing shops, thrift is key. We all know our tools (at least the good ones) are expensive and our profession doesn’t always provide the means to purchase the myriad specialty tools we need.

Even though I’m the owner/operator of a gunsmithing shop (HCP Gunsmithing, hcpgunsmithing.com) and sometimes feel the need to purchase a specialty tool for almost every model of gun that comes through the shop, there is a constant balancing act between new tools needed and whether or not they will pay for themselves. With that attitude in mind, I approached a specific need in my shop for a certain fixture. I have a Mauser 98 action in my shop that I am building a hunting rifle from.

Military Mausers are classic rifles but they almost always need a little TLC before they are ready to build from. One of the operations most needed are truing the locking lugs and cleaning up the bolt face. Volumes have been written on converting Mauser actions by masters far more skilled than Iso I won’t go into the details of the particular work except to say it involves turning the bolt on the lathe. But how to turn it? There is a female thread on the back that the bolt shroud screws into.

The 0.528"-13, 60 degree buttress thread is a weird, angled thread that is difficult to turn; it is at least more difficult than is necessary when other options are available. There used to be a false center tool available that is basically a shaft that fits in the chuck of a lathe and has the male bolt shroud threads on the other end. I couldn’t find it on my last search but I found another solution.

While scratching my head trying to figure out how to turn those darn threads it occurred to me that the hole in the bolt shroud that the firing pin goes through has flats on two sides. Why not use those flats to turn the bolt in combination with the steady rest? I foundapiece of scrap 1-inch round steel a little over 3 inches long in the shop and set to work.

I measured the internal diameter of the bolt shroud where the cocking piece is inserted and then took an outside diameter measurement of the firing pin where it goes through the bolt shroud. They measured 0.560" and 0.330" respectively. The side-toside flats of the firing pin measured just about 0.250" but the inside of the shroud was 0.290" so there was some wiggle room there. Putting the round stock in my lathe, I turned a shoulder on the back so it would butt up against the chuck.

Then I flipped the piece around, faced it off and turned about 1.635" of it to a little under 0.560" diameter. The length was an arbitrary number and it just ended up that way. I found that the bolt shroud would not fit over it but I figured I could tweak it later if needed. I then turned about 0.950" of the end down to 0.325" diameter. I drilled and tapped a hole for a 10-32 machine screw in the end. This is what will hold the bolt shroud tight up against the fixture. Now for the real work.

Remember those special tools I was talking about not being able to afford? Well, in my shop, a mill is one of them. If I had a mill, creating the flats

on the sides of the piece would be a snap. Unfortunately, I don’t. One of the positive side affects of not having a mill is that I have gotten pretty good at hand filing. I even do dovetails by hand! I’m sure the ghosts of 19th century craftsmen are smiling at me while I sweat away at the vise, but I digress. I kept the piece in the lathe and put a cloth down over the ways to catch the filings. Filings will always find away to get into and ruin the most expensive part of your lathe!

I The rollers on the rest ride on the extractor collar of the bolt. filed down each end until the flats measured 0.265" and they fit neatly in the shroud. This part is easy to mess up so I went slow and checked my work often. The distance from the rear of the bolt shroud to the end of the firing pin hole in the shroud was about 0.665" long. I wanted to make the shaft a little longer so I could use it on different bolt shrouds of different dimensions.

The length ended up being 0.685" and I turned the diameter to 0.552" so it slips into the shroud. Now I had my fixture and it works great. I put the bolt shroud over the end and installed the machine screw with some washers to hold it tight. Then I screwed the bolt on to the shroud and installed the steady rest in the lathe so it would support the bolt at the extractor collar. Using the rollers on the steady rest I was able to indicate the bolt body until it was running true.

Using a tool I ground in the shop, I was able to clean up the bolt face and remove any old pits and dings. Fortunately, the bolt face looked pretty good so I didn’t have to go too deep. I imagine if the damage was too deep this fixture would be helpful when installing a firing pin bushing as well. I also trued up the lugs on the back. Whenever I get to do a project like this I feel like I’ve put knowledge and experience I’ve gained over the years to use and have a great deal of pride and a sense of accomplishment.

When it works as well as this fixture does, it’s even better. AG