Best Size for tubing

[1Poet]

When setting up my diy pneumatic hand engraver, the hand piece I am modifying came with 3mm tubing and I don't know how to get it up-sized to fit my air supply. Can I drill out the 3mm tubing inlet on the hand piece without adversely affecting performance? What size can I use? 3/8" OD? Thanks for any help.

 

[Sinterklaas]

Maybe easier to find a coupling piece that will go from 3mm on one side to what ever diameter you need on the other.

something like this maybe:
https://www.aliexpress.com/item/32849597979.html?spm=2114.12010612.8148356.5.69c44958hhKine


Also, can you post a picture of your homemade device? I am very interested in it. I have the parts here my self. But never got around to building one. Since I use my Gravermax G8

 

[1Poet]

I will get some pics asap. Everything is working, it just won't cut. I think it may be the crappy graver part.