Per many Cat specs .001” is minimum and .0015”maximum per bore Ø typical Øs 2.5” to 6.5”. Installations via press-fits using the maximum should be considered mandatory, press fitting a last option versus cold shrinking (freezing) using dry ice or nitrogen and even heating the casting. Most bushings have a 32µ surface finish; typical as machined bores 80-120µ - peaks and valleys^^^^^^^^^^^^^. Pressing, the bush will shave off peaks and bend the peaks over into the valleys. Cold shrinking, slipping the bush into the bore after the bush warms up the peaks are spread-flatten out into the valleys via plastic deformation, provides a higher retaining force. Bore weld build up using wire with a bit of nickel alloy also increases the retaining force because the nickel alloy is tough resisting spreading-flattening into the valleys via plastic deformation, provides a higher retaining force.
