Flying head!

Today I finished the laser head. It was my first time doing threads internally and I'm delighted with the results!(don't forget you can do a slide show by clicking on the images)

The beginnings of this piece can be seen in an earlier post, so this is the continuation.
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I'm going to test the ZNSE focal point with a red laser. I wonder if it is different from the focal point of the IR from the Co2 laser? Yes, I would say.
I think the images do a good job of explaining what i'm up to here so I'll keep this short.
The air assist fitting is 8mm tube diameter on a 1/8 bsp thread. Drilled and tapped.

Its difficult to see in this picture but the end of the middle tube is threaded externally at the end.

The thread I used is 24mm X 1mm. I learned how to thread off a video on youtube.(search "tublicain")
I decided to do air assist while I was at it.
I got a lovely 50.8mm focal lenght ZNSE lens off ebay. It is 20mm dia', so I cut a little sholder for it to sit on inside the nozzle.I'll put a thin washer/seal under it so as to protect the lens and seal the pressurised air from comming out the wrong place

The outlet for the air/laser is 2mm dia. I have no idea if this is too big or not. If anybody reading this has more information about what size it should be please leave a comment.