They are actually pretty easy once you get a couple done. I just use 1/16 orings various sizes. Many guys on here have built them, all a little differently but same results. Steve, Ihbuilder makes his with thread on caps, I like that idea but yet to jump into internal threads on the lathe.
. Look up his dozer build. The hardest ones I've done yet were the double acting telescopic ones for haul truck.
http://www.rctruckandconstruction.co...t=9048&page=87
It's a conglomerate of pics/ideas , on/off topics but possibly some useful info in there. My hard part is getting the internal oring groove. Trial n errors on the right depth of cut. Nothing out there for proper compression dimensions for our small stuff. Basically I found out if you can't move it in n out with very little force from fingers it's too tight. And it doesn't take much to seal (compression of oring wise). Clean, honed, polished cylinder and rod , straight too!! If you are getting tube get smooth walled stuff. Otherwise it may be welded tube and rough on inside. Look up on web basic cylinder design and pretty much just retain rod/piston and cylinder cap/seal. Fine to use alum for piston but not for cylinders as it gauls and contaminates easily.
Just ask whatever you need along way. There is no right or wrong way!! And they leak or they don't!!! Lol!!