- #1
craigfperry
- 9
- 0
that uses a parachute type seal.
What is the correct grit hone for an air cylinder.
Click For Summary
SUMMARY
The correct grit hone for an air cylinder using a parachute-type seal is crucial for optimal performance. Discussions indicate that while 1200 grit is mentioned, experts recommend a maximum of 800 grit for effective surface roughness, particularly for elastomeric seals in air applications. The manufacturer of the seals, Jim Maccari, is noted for producing seals for pellet guns, and it is essential to maintain lubrication in the crosshatch for proper seal function. Users have reported that a 400 grit crosshatch leads to rapid polishing of the cylinder walls, suggesting that higher grit options may yield better longevity and performance.
PREREQUISITES- Understanding of surface roughness parameters such as Ra, RMS, and Rt.
- Familiarity with honing tools, specifically Sunnen hones.
- Knowledge of elastomeric seals and their lubrication requirements.
- Experience with air cylinder maintenance and repair, particularly in airguns.
- Research the impact of surface roughness on elastomeric seal performance.
- Learn about the specifications and applications of Sunnen honing tools.
- Investigate the differences between various grit sizes and their effects on cylinder walls.
- Explore the maintenance and repair techniques for airguns, focusing on seal replacement and lubrication methods.
This discussion is beneficial for airgun enthusiasts, repair technicians, and engineers involved in pneumatic systems, particularly those working with elastomeric seals and honing processes.
- #2
FredGarvin
Science Advisor
- 5,093
- 10
Hi Craig,
I must admit, I can not say I am familiar with the term "parachute seal." Perhaps I know it by a different term? Once I know that I'm sure we can track down the right info.
I must admit, I can not say I am familiar with the term "parachute seal." Perhaps I know it by a different term? Once I know that I'm sure we can track down the right info.
- #3
- #4
Ranger Mike
Science Advisor
- 2,453
- 442
- #5
FredGarvin
Science Advisor
- 5,093
- 10
I would double check that number. It sounds awfully high. I haven't been able to find anything as of yet other than this reference from flex hone.
http://www.flexhone.com/flexhone%20for%20cylinders.htm
They don't even go up to a 1200 grit hone and they're talking about an 800 grit being an Ra = 3-10. Many elastomeric seals require some surface roughness to operate correctly, especially with liquids. Since this is an air application the question arises do these seals need oil entrained in the air for seal lubrication (they are dynamic seals).
Do you know the manufacturer of the seals or the actuators?
http://www.flexhone.com/flexhone%20for%20cylinders.htm
They don't even go up to a 1200 grit hone and they're talking about an 800 grit being an Ra = 3-10. Many elastomeric seals require some surface roughness to operate correctly, especially with liquids. Since this is an air application the question arises do these seals need oil entrained in the air for seal lubrication (they are dynamic seals).
Do you know the manufacturer of the seals or the actuators?
Last edited by a moderator:
- #6
Ranger Mike
Science Advisor
- 2,453
- 442
correct
thats why i recommend he contact theweb site and talk to appliactins engineers who deal with this..i can spend a lot of time discussing surface texture and various parameters Ra, RMS, Rt RV Peak Count etc..but he needs to tel the A.E. the type steel and coating if any and fluid for more help
they do make 1200 grit..
might fine
thats why i recommend he contact theweb site and talk to appliactins engineers who deal with this..i can spend a lot of time discussing surface texture and various parameters Ra, RMS, Rt RV Peak Count etc..but he needs to tel the A.E. the type steel and coating if any and fluid for more help
they do make 1200 grit..
might fine
- #7
craigfperry
- 9
- 0
thanks for the links this gives me a place to start.
i do know that i do need some lube to remain in the crosshatch to lube the seal.
these seals are for a pellet gun, the maker is Jim Maccari.
i do know that i do need some lube to remain in the crosshatch to lube the seal.
these seals are for a pellet gun, the maker is Jim Maccari.
Last edited:
- #8
turbo
Gold Member
- 3,154
- 56
He is out of commission with a severe back injury. Are you going to do the repairs yourself?craigfperry said:
- #9
craigfperry
- 9
- 0
yes i have rebuilt a few of the airguns i have.
but the best info i can get is a crosshatch of 400 grit which i am not happy with those results as far as seal wear and overall preformance.
it seems to me an 800 grit may be better.
the other thing that puzzles me is with the 400 grit crosshatch after a few hundred rounds thru the gun the crosshatch is gone and the cylinder walls are polished to a mirror finish.
but the best info i can get is a crosshatch of 400 grit which i am not happy with those results as far as seal wear and overall preformance.
it seems to me an 800 grit may be better.
the other thing that puzzles me is with the 400 grit crosshatch after a few hundred rounds thru the gun the crosshatch is gone and the cylinder walls are polished to a mirror finish.
Last edited:
- #10
FredGarvin
Science Advisor
- 5,093
- 10
What is the barrel made out of? It seems like the surface hardness of the bore is too low.craigfperry said:
- #11
craigfperry
- 9
- 0
i would say not high quality, i don't know enough to guess.
the guns this happened to were made by Crosman with parts made in china.
i am about to try a reseal on a spanish made gun and from what i have seen they seem to be made better.
the guns this happened to were made by Crosman with parts made in china.
i am about to try a reseal on a spanish made gun and from what i have seen they seem to be made better.