Just for the heck of it I rewatched all of my milling machine tapes (AGI) the past few days, and I was contemplating how difficult it would be to make a Blackburn type bottom metal on a manual Bridgeport J head Mill.

I think I can figure out most of it, but what I can't figure out is how one would machine in that round portion that sticks up for the front guard screw to go through (whatever its called).

I am thinking it would just be easier to machine that area flat and weld a tube of the proper circumference on it.

Otherwise, how would it be machined?

On a manual machine you could use a tool called a tree-panning tool.
It's designed to do just that type of operation, or you could make your own from a piece of tool steel and braze the carbide cutter onto it to provide the correct geometery you were after.
That's basically the method old Paul Mauser used back in the day.

Google it up and you'll see probably several different variations and sizes.

A rotary table would be a good item to have for that.

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I was contemplating how difficult it would be to make a Blackburn type bottom metal on a manual Bridgeport J head Mill.

Don't get me wrong here.....I'm cheering you on if you try this.....there is no intention to be pouring cold water on the idea.....

That said, I'd recommend a lot of patience and perseverence in this task because if it was easy there'd be a lot of folks doing it.

I'd highly recommend you try to find a used traveling wire EDM for the magazine boxes as I'd bet it's a lot easier to do this.

Set it up and let it burn all night and maybe in the morning you'd have a nice box.

The original mauser guards were milled on what today might be considered a drillpress. Using either of the two methods suggested by our residents smiths one could easily accomplish this task. I used to use a modified endmill that had a hollow in the center. Then I drilled the through hole. I only made a few, mostly for the short mexican 98's but back then, there were no off the shelf replacements available.

I have really been curious thru the years as to what is the advantage to having the box as part of the bottom metal rather than a seperate piece as on the Mdl 70. Seems it would be easier to manufacture different size boxes and a standard bottom metal would also be easier. Actually what advantage does the front guard screw 'boss' offer over a flat bottom at that point especially if you pillar bed. You don't have the 'boss' present for the rear screw. Seems you could modify the bottom metal with little or no sacrifice other that it would not be the 'original' to Mauser religion so must be bad.

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Originally posted by 22WRF:
I am thinking it would just be easier to machine that area flat and weld a tube of the proper circumference on it.

Otherwise, how would it be machined?

Just stick a boring head in your machine and put a small boring bar in with the sharp pokey side pointing towards the center instead of pointing out like when boring a hole.

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Just stick a boring head in your machine and put a small boring bar in with the sharp pokey side pointing towards the center instead of pointing out like when boring a hole.

Yep,
Just mill it square first and then use a boring head to essentially "turn" it round.
Of course if you want some fun chuck in a big lathe and turn it for real.

As one who was stupid enough to make over 300 guards this way from 1985 to 1992, some helpful facts.

Use 12L14 or C1215 steel, 1018 as a last option, this will save you a LOT of time in the machining part of it. Pacific Tool in Portland OR has 1 1/8" x 3" x 12 foot bars of 12L14 in inventory. You can alo get 3" sqaure stock and saw it down the middle.

Buy good end mills and keep the rpm and coolant where it should be.

Rough drill out as much as possible in the bow, and inside of the box, even a band saw to remove the big chunk behind and above the bow.

Use roughing end mills to hog off the excess, then come back with a finish end mill.

You can make a scrape cutter for the rear of the box and the hinge cut. Put these in your mill head in back gears. (make sure not to turn the machine on) and you can scrape these cuts out by using the quill handle by .002 to .004" at a time per pass. Then finsh the scraped surface with a file.

A Mauser unit will take you about 10 - 12 hours once you have figured everything out.

Once I bought the Hyd Profiler in 1992 then I was able to reduce the time per unit to about 8 - 9 hours each.

James Wisner
Custom Metalsmith

Jim

You had to do it to make a living, which is why it was a good thing you found a way to do it in a shorter amount of time.

I have to try to do it to find a way to spend the long winter months doing something other than wasting time watching TV. Even at 10-12 hours apiece, I shudder to think how many I could have made in my lifetime instead of wasting time watching TV.

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able to reduce the time per unit to about 8 - 9 hours each.

Man you need a piece of modern equipment....

When I was younger (and even stupider) I tooled up to make bottom metal. Bottom line was that I needed about $700.00 apiece when Blackburn and Jim Wisner were selling for around $250.00...great way to lose about $500.00 on each unit...but then again, maybe make it up in volume? If you compare labor intensity to a pipe wrench, this custom bottom metal should be sellng at about $1200.00

I wonder if it could be effectively cast?

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Originally posted by 22WRF:
I wonder if it could be effectively cast?

Your best chance would be to invest cast the part.

I'd bet you could die cast it if one poured aluminum or possibly magnesium or zinc.....

You have a company in your back yard called invest-cast. Ask them but I'd wager the walls are too thin to permit decent material flow (assuming steel)

I can assure you that there's a reason most are stamped from sheet metal and attached by "integral fit" or welding of some nature.

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I can assure you that there's a reason most are stamped from sheet metal and attached by "integral fit" or welding of some nature.

Nice bottom metal is not that hard to make if the box is permitted to be a separate piece that is attached by a quality process. Otherwise you can continue to pay an extra $200 to $400 extra just for the integral magazine box that is not easily adjusted for the application.

The minimum cast wall thickness used to be .080 for aluminum investment castings. I never worked with think walled steel castings. They would look like crap without a good bit of hand finishing. I would prefer to machine the bottom features and attach a sheet metal magazine box.
The deluxe attachment would be Electron Beam welding. But TIG stitch welding could be made to look nice. the right design could even use small rivets for those that think it needs to look like it is built like a tank.

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the right design could even use small rivets for those that think it needs to look like it is built like a tank.

like the 1917 enfields.....and they didn't look bad at all.

well, who cares what they look like underneath the wood. Heck, couldn't a guy just make the box from some sheet metal like Winchester used to and inlet in into the wood to the right depth. the main thing is the bottom metal, i.e. the triggerguard with the pivoting floorplate.

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Originally posted by 22WRF:
well, who cares what they look like underneath the wood. Heck, couldn't a guy just make the box from some sheet metal like Winchester used to and inlet in into the wood to the right depth. the main thing is the bottom metal, i.e. the triggerguard with the pivoting floorplate.

I agree with that and Williams Firearms already makes Remington and Winchester bottom metal minus the box. It would be easy to produce the Mauser dimensions less the magazine box. Then everyone could have Mauser Oberndorf bottom metal on any Mauser this side of the 1891 Argentine.

Ireload

you sound like you have some machinery available to you. How about if I buy some steel and you do some machining.

If I owned the equipment I would be making knock offs of the Oberndorf Square bridge actions just for fun.
I was just dropping a hint to Williams to think about making a 98 Mauser with a sheet metal box.
It is easy to tool up for and would sell like crazy. I have an FN98 by Firearms International with the aluminum bottom metal that has to go.

I once had a Mark X magnum Mauser action that had bottom metal without the integral box. I still have the original box made from sheet metal. I replaced it with a long action Remington mag box. It was chambered for the 300 WBY. Never had a lick of trouble with it. Do they still use them on the Mark X. If the Charles Daily replaced the Mark X action, is it an integral box or is it sheet metal like the Mark X action?

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Originally posted by ireload2:
If I owned the equipment I would be making knock offs of the Oberndorf Square bridge actions just for fun.
I was just dropping a hint to Williams to think about making a 98 Mauser with a sheet metal box.
It is easy to tool up for and would sell like crazy. I have an FN98 by Firearms International with the aluminum bottom metal that has to go.

Sounds like a fine plan to me! Intermediate (7X57) and full length (30-06)
boxes could be made, not to mention better boxes suited for the magnums. (300 Winchester)

There has already been a guy here on AR that has proven that you can do mausers with a separate box. That guy is Gunmaker, who made (makes) some truly gorgeous bottom metal for those little Mark X Mausers. The triggerguard looks just like a Blackburn, but he uses a separate box for the cartridges. You can see it in this thread.
https://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/247101837