- #1
craigfperry
- 9
- 0
that uses a parachute type seal.
What is the correct grit hone for an air cylinder.
Click For Summary
Discussion Overview
The discussion revolves around determining the appropriate grit hone for an air cylinder that utilizes a parachute type seal, particularly in the context of airguns. Participants explore various aspects of honing, surface texture, and seal lubrication, with a focus on the implications for performance and wear.
Discussion Character
- Technical explanation
- Debate/contested
- Experimental/applied
Main Points Raised
- Some participants mention the use of a parachute seal and express uncertainty about the terminology.
- One participant suggests a 1200 grit hone, referencing a specific website for expert advice on honing.
- Another participant questions the appropriateness of 1200 grit, citing a lack of available information and discussing the importance of surface roughness for elastomeric seals, particularly in air applications.
- There is a recommendation to consult application engineers for tailored advice based on specific materials and conditions.
- One participant shares their experience with a 400 grit crosshatch, expressing dissatisfaction with seal wear and performance, and suggests that an 800 grit may yield better results.
- Concerns are raised about the durability of the crosshatch after use, with observations that the cylinder walls become polished over time.
- Participants discuss the quality of materials used in airguns, noting differences between manufacturers and potential impacts on performance.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the ideal grit for honing, with multiple competing views on the appropriate grit and its implications for seal performance and wear. The discussion remains unresolved regarding the best approach for honing in this specific application.
Contextual Notes
Participants mention various parameters related to surface texture, such as Ra, RMS, and the need for lubrication in the crosshatch, indicating that the discussion is nuanced and dependent on specific conditions and definitions.
- #2
FredGarvin
Science Advisor
- 5,097
- 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
- 2,461
- 446
- #5
FredGarvin
Science Advisor
- 5,097
- 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
- 2,461
- 446
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
- 3,181
- 57
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
- 5,097
- 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.