cnc barrel rifling machine

[MacCustom]

Might be a crazy question,but I can't help myself.
I am thinking I could build a cnc gun barrel rifling machine using the Acorn control.
Any input on this Idea?

[martyscncgarage]

Might be a crazy question,but I can't help myself.
I am thinking I could build a cnc gun barrel rifling machine using the Acorn control.
Any input on this Idea?

That's a vague question.
Sure you can do it....
What do you want details on how?
You need to state how you envision it....

[Rob Carnell]

Would not be much help for a button rifling machine, as the hydraulic ram does all the work.

But for a cut rifling setup you could. This is just basically cutting a multi-groove thread inside a tube. The tricky part is indexing the barrel between cuts as these are done with multiple cuts of around .002" per pass.

There are a few videos on the web of old sine bar Pratt & Whitney machines that do the indexing mechanically.

Rob.

[mick41zxr]

Could this be done with the spindle indexed with an encoder & cut in a similar fashion to a single point internal thread?
Just a matter of generating G code for the rifling pitch.

[Rob Carnell]

Two ways to do it, with a single encoder or multiple.

Here is a video of how they do it at Bartlein with cnc equipment:

So, I guess you could do it with Acorn and a single encoder but you would need specialized software.

Here is a video of the mechanical variety from Pratt & Whitney. It is a very old machine, but you will get the idea of how it works. The barrel indexes after each pass instead of the cutter:

If you had 2 encoders you could use another of the Centroid boards to do something like this. This is the way I considered doing it.

Rob.

[MacCustom]

Great input guys. I'm thinking of indexing the tool rather than the barrel. Since the Acorn has encoder input for spindle position it would be a very solution. Some of the hybrid barrels have varible pitch twist that must be cut rather than formed.