I have an idea...Jig for indexing a cylinder

[peckerwood]

I have had this idea for a while and got it purely by accident when looking at an antique revolver.

The idea involves the use of seamless steel tubing. Basically it uses a main tube that encompasses 7 smaller tubes each one's OD one third of the main tube's ID

So if the maintube has an ID of 1.5" then each inner tube should have a OD of 0.5". In this way all seven of the tubes will take up all the internal space of the main tube.

The outer jig tube is for indexing the steel rod to be drilled and for allowing the same thickness of the outer chamber walls as the inner chamber walls

Whaddya think?

 

[gunasauras]

Figure it would have to be a pretty low pressure cartridge based on the thickness of the tubing wall thickness?

 

[peckerwood]

Low pressure cartridges for antiques in medium grade steels...and other stainless steels for 38spl etc

But you can also get tubes from MetalSupermarket that will allow you to do whatever thickness you want depending upon how many outer tubes you decide to use

 

[peckerwood]

Here is where i got the idea:

Notice the last pic the cylinder is double thick between the chambers but the outer wall is half as thick...looks like a series of tubes were aligned and brazed together to form a single cylinder...then I got to thinking that such an apparatus would make a good jig for drilling a solid piece of barstock.

 

[gunasauras]

Interesting thought....

 

[Ripstop]

If this is a jig for drilling chambers in a cylinder, that seamless tubing is going to be too soft. You may get a couple of cylinders going and then the drill will have worn your jig to the point where it is too sloppy. You could put another seamless tube inside and first drill the chambers undersize then remove the jig and finish drilling/reaming. When the utmost inner tubes wear out you replace them. Also, if you drill the chambers undersize and then open them up to the correct size, you will not have any problems with the drill wandering when cutting through the cylinder. Most machine shop jigs use hardened steel bushings to guide the drill. Those jigs last a very long time.

Good luck with your project.

 

[art.h]

If it is to make a jig then it would be better to use headless drill bushings, they can be purchased thru any machine supply house. Your next thoughts should be towards how you are going to actuate the cylinder timing mech.

 

[peckerwood]

All good ideas...I am still putting together more correlative ideas together for such a project

 

[woodchopper]

Your next thoughts should be towards how you are going to actuate the cylinder timing mech.

mmmm... thats a good question.

I like the ideal for the jig for boring the cylinders, but why only 6 why not 5 or 7, an odd number might be better, a little more meat where your going to have to cut notches for the cylinder timing

 

[Rembo]

I don't get it...before you got this "jig" built any decent machinist with a drill press could have a cylinder drilled....ready to ream the chambers and cut the indexing notches and lock grooves...no real need for a jig for this job...unless you are planning to try it with the old Black & Decker...

 

[peckerwood]

That was the original idea...was more of a backyard garage approach to building something...I doubt that it would be perfect...but I was more geared towards the use of a small drill press for the initial holes and then ream from there.

Something less complicated and more expedient than the use of an 800lb milling machine

Right now it is just an idea and not really ready for any kind of task at the moment...just fishing for thoughts

 

[Rembo]

it would work in principal, but to get the tubes spaced and indexed properly would be as difficult and involve much the the same steps as setting up to drill the actual cylinder...so you may as well skip the jig and go directly to the cylinder IMHO.

 

[peckerwood]

ummm...1/2" tubes...1.5" internal diameter tubing.

Do the math...you can only get 7 tubes in there and the central 1/5" tubing will space the other 6 out against the inner wall of the 1.5"ID tube.

The 1.5"ID diameter would be evenly divided into three 1/2" sections...1/2" thick tubes would fill up the space. Therefore they index themselves.

Plus once the tubes are in there they can't torque out of position without stretching the main tubing jib...and there wont be enough pressure to do that

 

[Rembo]

maybe I'll draw it in MasterCam tomorrow....

 

[mooncoon]

A couple of thoughts --- many cylinders are tapered and would not snugly fit the jig. It would make more sense to put the indexing notches in a solid cylinder first, mount it on the gun and line the barrel with a snug sleeve while you drilled pilot holes for the individual chambers. drill the chambers first is going to be a bugger to then get the indexing notches in the correct place.

cheers mooncoon