machinest crew: slide tolerance?

[STANG KILLA SS]

say ive got a machined shaft thats 2.000" OD.
i need a sleeve/collar to slide over it(say .25" in "length"). a nice slide fit, not press, and not sloppy. ie good enough to keep the shaft and sleeve centerlines parrallel and not let the sleeve/collar turn sideways and wedge.

what should the ID of the sleeve be. ie a slide fit tolerance?

 

[maslin]

I'm no machinist, but these links seem to have a lot of answers.

Running and sliding fits,ANSI Limits And Fits,Limits and fits,ANSI Hole and Shaft tolerance,

Shaft - Hole Tolerance Data and Chart Information - Engineers Edge

Looks to be around .001 to .003 for a looser fit, .0002 to .0021 fit a tighter, but still slip fit.

 

[wings_of_fire]

2 inch = 50.8mm

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Precision Slide fit = Locational clearance fit provides snug fit for locating stationary parts; but can be freely assembled and disassembled.
Symbol of Fit = H7/h6

Maximum hole size = 50.830 mm
Minimum hole size = 50.800 mm

Maximum shaft size = 50.800 mm
Minimum shaft size = 50.781 mm

Note there is a possibility of having no clearance in this type of fit. That means no air gap between the shaft and sleeve if shaft OD is machined to 50.8mm and the hole bore also comes to 50.8mm. However depending on the final machined size there can be some air gap.

Maximum clearance = (50.830 - 50.781)
= 0.049 = 49 micron
That means there can be a maximum air gap of 24.5 micron between the shaft and the sleeve.

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Close running fit = Sliding fit not intended to run freely, but to move and turn freely and locate accurately.
Symbol of fit = H7/g6

Maximum hole size = 50.830 mm
Minimum hole size = 50.800 mm

Maximum shaft size = 50.790 mm
Minimum shaft size = 50.771 mm

Note the holes smallest diameter (50.800 mm )and the shafts maximum diameter (50.790 mm).
Clearance = 50.800 - 50.790 mm
= 0.010 mm = 10 micron
That means there will atlest be an air gap of 5 microns between the hole and shaft.

Maximum clearance = (50.830 - 50.771)
= 0.590 mm = 59 micron
Hence the maximum air gap can be 29.5 micron after machining.

 

[HoosierClod]

I work in a tool and die shop and deal with slip-fits and press-fits every day. For your application, I would suggest between .0005"-.001" clearance. With your sleeve being only .25" long, any more clearance would allow it to rock quite a bit.

 

[STANG KILLA SS]

thanks hoosier!

I increased the sleeve length to .4" to help alignment. what could I increase the clearance too?
and is that calculated per side? or is that total difference in diameter

 

[HoosierClod]

You may get away with a little more clearance but I wouldn't go over .002". That is total clearance (2.000" shaft OD/ 2.002" sleave ID)

 

[STANG KILLA SS]

thanks!