Mandrel, etc.
 

I see how you did it, thanks! I have enough brass to make this type of jig. The barrel when screwed in angles upward slightly, enough to be noticeable....if your looking! It would be a problem though to accurately chamber it. I have to get a reamer, rent or buy, and preferably 'short chamber' the barrel, while off. As far as the tap, I ordered it off ebay, Merlin Tools, China.....of course. In my research, it appears 1/2-18 is used in some auto applications. Supposedly.....they say....a 1/4NPT is the same,those taps are tapered. I think I will wind up grinding the tap into a bottoming tap. the taper may have caused the problem to start with. I will mount the receiver on the lathe as you have. I've had various C96's since I was about 14.....could buy them then for $25....nobody wanted them. Top drawer Luger, $100! Thinking of the guns I've sold....I just hate myself!:mad:

Travers has all 3 taps in that size, @ ~$20 each...

4D and Elk Ridge both have the 30 Mauser reamer, IIRC. ~$35 to rent for 4 days or something like that...I was able to turn down a Craftsman 3/8" drive x 6" extension to fit inside the Mauser barrel extension...You can ream it with the new barrel in place...

Getting rid of that up-angle is a challenge...Please post how you do it! :thumbup:

Hopefully! Will do! Bill

Rich,

How did you figure the center on that brass insert? Do you have drawings of the bolt, or did you reverse engineer it? I was thinking about making a tight fitting insert, then turn a centering punch that fits snugly in the barrel and mark the hole from the inside. Once the hole is drilled, it would be easy to center and drill the taper for a live center. However, there could be a few sources of error (like a rough bore and a partially unsupported punch), so I don't know if that will be accurate enough.

Anywho, if you already have the dimensions, I'd be very interested.

Bill,

If I recall correctly, you don't have a mill. I can just as well make two inserts while I'm at it, it won't take much time to do this once everything is figured out and set up. It has been a while, so I'd be more than happy to trade it for a "gun and BS session", either here or at your house. ;)

That's one way. Here's another - use a 12" long 1/4" aircraft length drill instead of a punch. Make two small 30 cal barrel bushings with 1/4" holes, put them in the Mauser bore, and turn the drill just enough to make a dimple in the brass plug. Then take the brass plug out, center drill the inside end with the dimple, put it back in and drill it all the way through with the 1/4" x 12" aircraft drill. Then center drill the outside end. You'd hold the receiver clamped to an angle plate, with the brass plug secured with a clamp or a stop of some kind. Center drill the outside end would be done with a 4-jaw chuck holding the rectangular brass plug and using a 1/4" ground rod as a center. One idea.

My methods evolve as I get more tools, and if it was done some years ago I forget all the steps. :rolleyes:

And the methods are also limited to the tools you have at hand. :) I don't have that drill bit, so I think I'll have to try the center punch idea first. Then I can clamp the insert in the mill and use a center finder to get the hole in the right place. If I set the receiver in the lathe together with the insert, I can use a dial indicator on the barrel to see if the operation was successful. If not, just rinse and repeat, as usual...

Olle, sounds like a good excuse for a trip to Sparta! We're camping with the Grandkids, be home Thurs. I could bring my 'junk box'. Maybe between the two, we can figure out a solution! Bill

Bill,

Just give me a call when you get back, and we'll set up some play time. Got plenty of acreage and understanding neighbors, so you can bring whatever you need to test fire. I'll try and make some blanks for the inserts so I can experiment a bit, I don't think it will be too difficult to get them centered (famous last words... :D ).

Crude, but effective!
 

I ordered a special 1/2-18 tap from China......After a month +, it never came. Found a bottom tap on ebay and got it yesterday. cleaned up the threads and tried my barrel.....still crooked! Arghhh! Something ain't right here! Not to shock a Purist's sensibilities, but I resorted to a crude fix. I clamped the barrel and chamber portion only in the vise (protected of course). The 'flats' of the receiver and the barrel were dead on straight! The ejection port rearward were bent upward! How to straighten? Got the Mapp torch out and started heating at the ejection port area, got my big crescent wrench and put it on the square end and bent the rear portion downward! Voila! Not only did the whole thing come out straight, but, the fit on the frame is perfect. Somewhere along the way, the thing got bent. I have to know chamber the barrel, and put a front sight on......still studying that!

It's more than interesting, it's absolutely fascinating, thanks for sharing!

Sergio

Rich,

I made a receiver insert today, and after some measuring and test fitting I found that .540" x .540 was a snug fit. I figured that the firing pin is most likely centered, so I drilled a hole and chucked it up in the lathe (barrel band in the 3-jaw chuck and with a live center in the insert). With an indicator at the rear end of the taper (right before it rounds over), I read a .006" TIR side to side. Top to bottom was only .002" TIR, which is not too bad considering that the barrel has some slight pitting. I turned the insert 180 degrees and tried again, and got the same result. The low reading was on the same side regardless of how I turned the insert, so it seems like the bore for the bolt is off center. The point I measured is about 1/3 from the muzzle, which means that the rear of the receiver is off by .009".

Have you tried to measure the runout on an intact barrel/receiver, or do you know what a normal runout would be?

If you mean is the original C96/M30 barrel OD concentric with the bore, I'm not sure...I could chuck my C96 barrel extension up and dial indicate it, but I'd bet it's at least a bit off-center as to the OD...

Here's my setup - the first pic is some of my ground drill rod blanks that I use for bore measuring...And by clamping my 7.6mm rod in the chuck and turning the C96 barrel extansion (not the chuck) by hand, I got the indicated runouts...

When I was done with that, I chucked my C96 barrel extension between a center in the chuck and my brass insert and got exactly the same results...Yeah, I was surprised too... :D

Rich,

I tried the setup in your third pic, but with a turned brass rod instead of a straight rod. I got the same side-to-side runout as when chucking it by the barrel band, but the up/down runout was now about .015. Seems like the bore is off center by maybe .007-.008 at the muzzle.

Anyway, the runout in your second picture is close to what I got in the very same location, so I guess these guns are not as precisely machined as I thought they were. That could make it iffy to get a new barrel centered, as you won't have any reliable index points. On the other hand: It won't be difficult to stay within Mauser's tolerances, a tape measure will probably do just fine... :p

BTW: For operations like this, I prefer to turn a rod and leave it chucked until I'm done. My Emco 3-jaw chucks usually stays within .001" TIR, but turning the rod right there and then will eliminate any possible runout caused by the chuck. I use a brass rod, and turn about 1/4" to a diameter that slips into the bore. Then I back off .001", turn another 1/8", back off etc so I get a stepped taper. This will usually get me dead center in the bore.

I have done that in the past, but then I started marking my chuck center and mating it with a corresponding mark on the 3-jaw chuck. I also tighten the same jaw each time. Seems to work...

tell you what - that barreled extension up in the last post is an original C96 Mauser. Bore is a bit worn, but good rifling. Let me get my last re-barrel out and measure the runout on that...Stay tuned...

Ooowww...I'm not as good as the boyz at Mauserwerke... :(

Amazing work! Especially the way to make the front sight. Is this the "standard" way to make front sight on screwed-on barrel?

I don't think so - at least not for production work. I'd be willing to bet that making a fixture to mill the threads after machining the front sight would be much quicker, easier, and cheaper for large numbers of barrel extensions.

But for only occasional, small numbers, this is more efficient. IMO. :)

Edit: Indexing the tapping of the extension for the new barrel would be difficult. C96 is not like Luger which already has indexed extension, always in same position. I am not even sure as to how to index C96 extension so every one will be in same position relative to threaded replacement barrel...

Well this is my first post on Luger Forum, in fact its my first post on any firearms forum.

I must say that I am struck by the sheer beauty and balance of the Luger P08, so much so that it I have dedicated 2015 to replicating this piece. I have all the machinery necessary to perform the task, and access to any special steels and tooling that I may require to finish my project.

The firearm will probably never be fired, but we will see.

I have truly enjoyed the contribution that "sheepherder" has made, many questions that I may have had have already been answered by reading this forum.

I hope to make a contribution along the way.

I do have a rather poor copy of the P08 blue prints, so my question is this: is there a clean copy of the original 1900 P08 blue prints available?

Regards,
engineer.

There certainly is! A CD with all the parts in the original German, in an insanely large format! :D

Right here on this forum! For a paltry sum, you too can be the owner of Pistole 08 blueprints! ;)

Just follow the instructions in this thread...

http://forum.lugerforum.com/showthread.php?t=11286

BTW: The "1900 Luger" and the "P08" are two different versions of the "Luger". If you are hell-bent on "1900" blueprints, the Sturgess & Gortz DVD have many of them in DVD format.

Sheepherder,

Please excuse my ignorance, if I may ask what material do you use for your replacement barrel? do you heat treat before and or after machining.

Regards,