Better Strength Material
Looking for a better material then delrin. Have been searching but I’m not to good with all the technical data. PEEK seems better but machining is a problem. Has to be annealed before machining. At $65.00 a foot I need to know if it wil work. Need to make a breech for .25. Having problems with heavy hammer spring and cocking. Aluminum works fine on .22 with stockish size spring. .25 worked good until I went really big on spring and now I have a problem. I guess I can use brass but I think I want to go back to plastic because it slides better. Thanks
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Thanks. I was trying not to make a 2 piece breech. Where the problem is going to be is the bigbore breech. Has to have .500″ hole tru a .960″ OD so not much room left for doing anything. Bigbore is going to take big hammer spring and that’s what make the problem when cocking it. I will make a breech and put some of the bearing nylon I use for my barrel guided hammers in between the o rings.
If it’s just the ability to contain pressure that concerns you, perhaps consider a composite breech cover? Minimal increase in mass of the part.
Metal sleeve with the rest being delrin.
6061 T6 and 304 are things I have on hand and don’t mind working with.
6061 T6 has a slightly higher yield strength than 304 stainless, it’s relatively light. Both are easily machined.
Will crunch some numbers for you if you’re interested. Would need a measurement for the id of the breech cover.
Al
Thanks but I still don’t know with one would work best for pressure and it has to be machinable.
This what you’re looking for? 🙂
http://www.plasticsintl.com/sortable_materials.php?display=mechanical
Al
Looking for something stronger. Don’t want any breech problems when I’m trying to make stupid power.
what is the problem with the delrin one?
i think that your breech knob is comming out of the delrin…
if so a custom double scwrewed breech knob might be your awnser
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Yup…not a lot of room.
If you chose to make the sleeve from 6061 T6, a thickness of .125″ over the o-ring groove would leave enough room for a thin bushing on the od.
The sleeve would have a working pressure of 4700psi with a 3x safety factor at yield.
Based on .875″ od x .500″ id, 35000psi yield strength, 1/16″ cross section o-ring.
Al