Best method for internal hone over short length
|Mark C||25/03/2014 22:15:59|
|707 forum posts|
I have a small cylindrical bearing that needs altering to C3 clearance, I was going to have it done out but at £20 for the race I thought I might give it a go in the workshop. I know a lot of people do bores with hones but the race is 26.5 mm diameter and 10 mm wide making it short compared to an engine cyl.
I was wondering if anyone has any experience of honing such a short diameter and how they went about it? For information, I need to add 0.007 mm (roughly 2 or 3 tenths) to the diameter.
|Michael Gilligan||25/03/2014 22:33:08|
14135 forum posts
Not much experience, I'm afraid
... I sold my Delapena because it wasn't being used.
Biggest problem will be avoiding "bell-mouthing", so it's probably not a freehand job [which is all the Delapena was intented for]
... Here is an article that may help.
|jason udall||25/03/2014 22:43:54|
|2011 forum posts|
|How did you intend to immobilise/drive the inner race to hone it?|
Once done why not machine a stack..with first/last as sacrificial..to the gods of bellmouth
|jonathan heppel||26/03/2014 07:35:57|
|99 forum posts|
Why the C3 clearance? If you're just following factory recommendations I wouldn't bother. Such a tiny amount would make very little difference to the service life of the bearing, if that's your concern. Doesn't C3 refer to the clearance between inner and outer race? That would be a tricky job indeed, and well worth £20.
|Mark C||26/03/2014 09:26:42|
|707 forum posts|
Sorry, the cost of the bearing assembly is £20, having it altered was more like £50.... I reckon for that I would have a go and still take a chance on a second standard bearing if it goes to pot!
The idea is to alter the outer race to give extra running clearance and the bearing is "n" type with detachable outer race. the reason for trying is not just replacing like for like, it is a very tight fit in the housing and as it is on the business end of an armature, it gets quite a large temperature difference across the bearing, hence the increased running clearance.
Michael, thanks, I did not think about holding the race before (I planned on sticking it in the 3 jaw!). I will probably make a housing that it can sit in, just clear so the diameter is free and nip it in with a retaining flange (should that be convex or concave   I will then make a lap (again, I thought they were the same thing hone=lap interchangeable but you live and learn - and I am supposed to be qualified....) along the lines of a tube with longitudinal slots in a soft material like aluminium and put it on an support such that I can compress it progressively to increase the diameter. I have never tried anything like this so I was curious how much material comes off and what sort of fit the lap needs to be in the bore to start with. I figured the speed would be very slow - 50-100 rpm
|519 forum posts|
Why not adjust the mating part & keep the standard bearing standard ? Modify the bearing & next time you replace it you will have to modify the replacement - modify the mating part now & next time a standard bearing will fit straight in.
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