Hydraulic cylinder shaft clearance to piston
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    Default Hydraulic cylinder shaft clearance to piston

    Is there any specifications chart on the shaft size to piston bore clearance. The piston bore has the triangular groove for an oring. I've been using h9 on the shafts. Reason I'm asking is because some of the shafts I get are more the h11 tolerance.
    I have attached a rough sketch.
    img_9251.jpg

    The parker handbook PG101 list the triangular chamfer, id say it would be the 3/32" CS oring size.
    PG89 list the diametral clearance for the static seal glands.
    https://www.parker.com/Literature/O-...ORD%205700.pdf

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    Every one I've worked on has been a close slip fit. At that size I'd probably shoot for whichever tolerance level gets you to .0005"-.001" clearance.

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    get as close as you can for a slip fit. most have an oring to seal it off anyways. id shoot for anything under 0.001"

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    .005 clearance nominal. 1.253.001 on the piston i.d. and 1.248.001 on the rod turndown. I would use a rectangular o-ring groove next to the piston rod shoulder. Easier to get the correct amount of squeeze on the o-ring. .06 radius where the rod turndown and shoulder meet. This is tried and true.

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    Quote Originally Posted by R. Dan View Post
    .005 clearance nominal. 1.253.001 on the piston i.d. and 1.248.001 on the rod turndown. I would use a rectangular o-ring groove next to the piston rod shoulder. Easier to get the correct amount of squeeze on the o-ring. .06 radius where the rod turndown and shoulder meet. This is tried and true.
    Plus one for that. ^^^^^

    Making the rod to piston tight can make a problem when the nut is tightened and burrs the piston enough to lock it to the rod. I have worked on hundreds of cyls and have seen some pistons that needed a large hammer and punch to remove, some times you can use the head as a slide hammer.

    Ed.

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    size on size , heat to install...Phil

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    Quote Originally Posted by R. Dan View Post
    .005 clearance nominal. 1.253.001 on the piston i.d. and 1.248.001 on the rod turndown. I would use a rectangular o-ring groove next to the piston rod shoulder. Easier to get the correct amount of squeeze on the o-ring. .06 radius where the rod turndown and shoulder meet. This is tried and true.
    I'd say your correct. The smaller pistons with a 1/2" shaft I'll make with less clearance.


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