How do you machine cast bronze elbows?

[Metal Butcher]

I occasionally use 90 degree 3/16 cast bronze elbows on my builds. I buy the inexpensive trees available from PM Research

I like the way they look and they are a good alternative to bent tubing that needs to be epoxied or soldered in place.

I end up marring them with my vise. Getting both ends drilled and tapped on center and at a true 90 degrees, has been a hit- miss proposition.

Does anyone have any ideas, or a good set up that gets accurate results?

-MB

 

[Tin Falcon]

One of the guys on another board made a neat and simple jig out of aluminum to hold them. I think I have a photo somewhere. It is a set o blocks with a cross milled into them with a ball mill so it will hold a cross, a Tee an L or a coupling.IIRC You can use it in a milling vise or a 4 jaw in the lathe.
Tin

 

[Mike N]

First of all I buy the threaded ones. If you clamp the blank between 2 blocks of wood to do the first end then screw them onto a threaded stud clamped level in your vise the 90 degree angle will come out perfect!

 

[bearcar1]

Mike, I made one of these adapters and chuck it in the lathe to drill and thread those fittings. I have several sets for the different sizes of model pipe.

Jim B.

 

[Mike N]

Mike, I made one of these adapters and chuck it in the lathe to drill and thread those fittings. I have several sets for the different sizes of model pipe.

Jim B.

Awesum idea! I need to make a set of these.

 

[Metal Butcher]

Mike, I made one of these adapters and chuck it in the lathe to drill and thread those fittings. I have several sets for the different sizes of model pipe.

Jim B.

Thanks to all for your help and the quick response to my question.

Thanks Jim B. for the photo, the fixture makes it all very clear now. The idea of a fixture crossed my mind but I just couldn't visualize it.

I guess that the fittings would be cut off with a hack saw first, and then clamped in the fixture for facing on all sides before drilling and tapping

Is there a step and is it necessary, on 2 sides of the fixture?

-MB