Barrel indexing

[William Reese]

Does anyone know if the front sight ramp and muzzle was shaped after installation of the barrel onto the receiver. If not, the threads would have to be indexed (both on the barrel and the receiver) so that the front sight would always come to rest straight up after tightening of the barrel. Any insight here? Thanks!!

[Hugh]

I am pretty sure the barrels were made in a seperate operation. I have replaced several Luger barrels, and 90% of the time a bbl from one gun would screw up right on another reciever without any extra fitting to be alaigned correctly.

[William Reese]

Thanks Hugh! William

[ViggoG]

My $.02 ;


The matter of indexing the barrels would seem to be a fairly simple problem .


The barrel (part 002) could be finished up to the point of milling the front sight post .


At this point it would be screwed into a "Holding Fixture" that has the exact thread dimensions as the "Standard Fork"(part 017) which positions it for the sight post machining secquences .( such fixture being mounted on a milling machine with the proper tooling to form the sight post ).


No magic involved and all barrels are precisely the same .


Perhaps it was done this way, or perhaps any one of several other ways. There are numerous possibilities ..


Just a thought to give some insight on the possibilities that may be involved .


ViggoG

[HÃ?Â¥kan Spuhr]

Viggo I do actually belive they have done the opposite.

First machined the frontsight band and dovetail out and thereafter indexed after that.

That would likely save some work with problematic setups and also be more uniform barrel after barrel.

I nclude a pic here on a barrel in the lathe, this barrel is not indexed but could easaly have been indexed with at tool against the spindle.


Just my opinion.


Regards HÃ?Â¥kan



http://www.vapensmedjan.com
http://boards.rennlist.com/upload/Barrelturning2.jpg

[Kyrie]

Hi William,


Pistols with barrels that screw into a barrel extension typically have the barrel installed in the barrel extension and then the chamber is finish reamed to correct headspace. A witness mark is then made to indicate how far into the barrel extension the barrel must be re-installed if it is ever removed for some purpose. Position of the front sight and threading of the barrel or barrel extension are non-issues.


OTOH, if the barrel or breech block are ever replaced headspace must again be inspected and set as necessary.


Hope this helps.


Best regards,


Kyrie

[Johnny Peppers]

Most military barrels that screw into a receiver are properly indexed at manufacture, but are normally short chambered. The headspace is then set by reaming to the proper depth.

During WWII Marlin had a contract for replacement barrels for the M1 Rifle. Due to some kind of slip up, the barrels were not indexed and most had to be discarded.

[HÃ?Â¥kan Spuhr]

I really doubht that the lugerbarrels was shortchamberd as the tolerances on the hole gun actually makes away the need of shortchambering.

But that is just my opinion, i don't know.


Regards HÃ?Â¥kan

[ViggoG]

Thanks for the great photo setup of how you produced the barrels for those great "9 mm Luger" Target Pistol that you so proudly display on your Web Page at http://www.vapensmedjan.com

Those are certainly very beautiful, High Quality Custom Firearms that you make .


However that picture demonstrates the most accepted method of custom fitting high quality firearm barrels . In small lot quanities .


But is a most time consuming method and not suited to the mass production of numerous firearms to the level of interchangability that was previously noted by "Hugh" , in having several barrels lock up at the same point of index .


Consider the problem of how to produce this mating of barrel and fork in quanities of say "One to Two Thousand Units" .


This presents a problem that demands a high level of fixturing and precise control of the accuracy of the final product . That is where the method that I have described provides a quite practical and workable solution .


As I said before , Just my idea of one of the possible ways to accomplish the task .


(Incidentally Where is the lathe dog that is needed to drive the Barrel ?)


Viggo G Dereng , CMfgE (Product Design for Manufacturing) N.A.S.A. RETIRED .

AKA ViggoG

[HÃ?Â¥kan Spuhr]

Viggo


You might be right but i doubht it.

As it would have been perfectly possilbe to machine the frontsightband first and then thread after it.

But I have no clue how they ahve done.


At the actual picture I didnt use any lathedog as I was just removing a few thousands of the shoulder in order to index the barrel.


Normally I am using a L shaped lathedog that indexexes the barrel after one of the chuck jaws.


By the way, I don't like to remove my chuck all the sime so instead of using a center in the spindle that sits in the morsecone I use a homemade center that I have to turn each time.

That works better in that particular machine.


Regards HÃ??kan



http://www.vapensmedjan.com