Gallery, Projects and General > The Design Shop
lathe milling spindle?
bertie_bassett:
iv used double row bearings so think they are already preloaded?? however the spindle iv got is hollow so I may tap the end and add some preload via a bolt or if I cant tap the shaft I could use a draw bar type arrangement.
in regard to the motor, I struggled to find one in stock anywhere but eventually found one with a different name but the exact same specs, ( and same name on the order form?)
if iv done this right heres a quick vid of a test run : try again :
mattinker:
Double row angular contact bearings should be preloaded. My "spindle is not hardened, I was thinking about a left hand thread on the outside. My problem is finding a suitable amount of preload using something like belleville washers.
Regards, Matthew
bertie_bassett:
being as double row AC bearings are essentially a matched pair and they must already have a set preload, I don't think youll need to worry too much about and actual value for any extra you add.
using 2 x double rows isn't a normal application for these bearings as normally one end would be in a normal ball race and allowed to float, the way these are set up isn't 100% ideal but I think perfectly fine for my use.
iv managed to tap a short 6mm thread in the end of mine so can use a bolt and washer to add a little pre-load against the end of the bell housing, that should give the motor bearings some pre load to stop them skidding. I may add a small fan to the end as well to aid cooling
ran it for bout an hour this morning, was nice and smooth and only got warm to touch so I think its good to go as is. just need to finish up the z axis screw and fabricate the actual body.
drawings will take a while as my autocad 2002 cd refuses to install properly on this new laptop, will have to dig out the old one which has got the original drawings on anyway
also measured the run out and appear to be only getting 2 thou run out ( this was measured on the internal taper ) which im quite pleased with.
mattinker:
Ok, I asked because I intend using two single row angular contact bearings! I would suggest Locktiteing the 6mm tensioning screw as it will have a tendency to unscrew if it's not a left-hand thread.
Regards, Matthew
bertie_bassett:
ahh single row bearings will need a different approach, easiest way would be to machine a spacer tube to go over the shaft between the inner races. pre load would change slightly with temp changes, but should be ok.
or you could put both bearings the same way round, and use a nut/bolt to add tension from the end, only problem with that is youll be adding lots of preload to the motor bearings
is there a reason your not using double row bearings? mine are only 30x14mm so would fit in most designs
yes ill remember to locktight the bolt in once im happy with everything.
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