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Spindle problem with cincinnati tool and cutter grinder 2 spindle
PekkaNF:
Yesh and sometimes a little of discretion can ruin the whole thing....you think you have the exactly right pressure plate and all and then something is skewed and then it's easily too much force on wrong place and when bearing just jerks, instead seating right....cold sweat breaks.
These are small and relatively cheap bearings and I have suspicion on all work I do. I don't think I will cause irreversible damage, just lost work/dignity, some lost time and cash. That's all.
Tried shortly to google good method and DIY-fixture or contraption to measure bearing inner clearance (radial/axial) and to measure "high spot" on IR/OR that is bearing inner/outer ring coaxiality in relation of raceway....my English her is pretty sketchy, because I find only chinese videos :lol:
This looks nice, but I don't get how that frictionless and differential measurement works:
http://www.prattandwhitney.com/Content/LabMaster_Universal_Bearing_Measurement_Instrument_.asp
Click those pictures bigger at the bottom of the page.
Thinking of using V-block and that sort of stuff at home and have bearing resting over a surface plate, but I'm probably going to measure more my weebly-woble than bearing on my first try.
Any advice?
Pekka
PekkaNF:
I soaked the bearings overnight on IPA and got all grease and most of gunk out.
Self-aligning ball bearing 2305 seem to clean up completely and is charming himself with clear iternal clearance as it should.
The ball bearings are bit more troublesome. The ball retaining ring (cage) seems to be shedding some stuff. Part of that is something like flakes or something, bit like grud you get when put wrong type of oil on sychro gear box....and when viewed 20x magnification shows some metallic grit on surface. The cage sheds that stuff in 2 minutes on ultrasound wash (heated, about 70W) that first I though I ruined it, balls would not turn easy, but when rinsed in IPA it pretty much comes out.
So, the plan is to find replacement.
PekkaNF:
Armed with 0,002 mm/div lever dial indicator and some hardware tried to measure concentricity of inner ring to ball races, barely could measure outer ring, inner ring was easier.
I need a fixture or setup, this size bearing is too small to measure on surfavce plate. Hard not to move the bearing while it is rotated.
Hopeless to measure internal clerance, indication is clear enough, but too many moving parts.
Pekka
PekkaNF:
Did some cleaning, belt pulley had almost lost crown and had some wear. Quick mounting on lathe a bit spin restored it good enough, very little material was removed, more like smoothing than anything else.
Secon thing as to check all threads and clean them. All went well. i notices that fixed bearing end bearing outer ring retainer had some resin left in the thread, looks like it was glued with a thread locker, cleaned i up and planning to use weakest thread locker I have (blue in color).
Then I check the fit on shaft and shell. I used very little layer of micrometer blue to see if there are any problems, There were some little abrasion marks on the other end, i used plastic abrasive pad, just one quick round and they seem to disapear most of it. Shaft measured out 24,995 mm ant six places and on one 25,994 mm. Nominal is 25,000 mm and that size bearing should have inner ring about -10 µm tolerance. Looks fine to me.
Shell to bearin outer ring was firm sliding fit...did not quite drop of it's own, but when straightened with a press (by rotaing sheel/outer ring just when arbour kisses the outer ring seating bushing) it bottoms with "swoosh" with a slight manual effort.
Shaft to inner ring as an easy press fit, basically all has to be straight, can't push it manually, but press has no eferrot at all.
Both fits were that perfect that no dye was left on mating surfaces, pretty much all color was pushed ahead of the bearing.
PekkaNF:
Now the interesting part: Trying to figure out how to replace matched ball bearing set.
I tried to measure axial play of one bearing....not really a standard way because inner ring tilts too easy on this measurement, got about 0,14 mm axial play, think that axial play is average about 8,5-10,0 times of radial play....
6205 has a 25 mm bore the C3 has a radial clearance range of 13 – 28 microns (µm).
Shaft was measured 24,995 mm and 6205 has an inner ring diameter tolerance of -10 µm, leaving the true average around 24.995 mm...and outer ring is not affected (could not measure any compression when mouned), therefore we have straight C3 tolerance to play with - I think.
So, that seems to confirm that C3/P5 ball bearings should be my starting point. What do you think?
If I get good quality C3/P5 I should be able to shim that set close to original set.
Pekka
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