Setting up angular contact bearings

[calstar]

Setting up new lower spindle bearings on my 8530 Clausing mill. The info below is from the Clausing yahoo group file

http://members.core.com/~chessie/headrbld.html



The above pic above is of a matched set of angular contact bearings(DU), I bought mine not as a matched set but as twp single flush ground bearings(SU) and as such am planing to install them face to face with the inner races together as stated here:

"You could also mount them face to face with the inner races together and preload them with the retaining nut. They would take more misalignment (out of true) on the spindle, and have a lower capacity for momentary loads. In this case, I thought it was going to be easier to draw them together with the retaining nut."

Does this sound like an acceptable practice? This is my first go round with angular contacts and I want to get it right, not to mention the two bearings were $100 for the pair and I don't want to screw "em up.

thanks, Brian

 

[dracozny]

You may have to add some shimming material between the outer races to give the inners more room for preloading https://www.youtube.com/watch?v=RBbaSsxCzI8

 

[4GSR]

Mount them back to back just as it is in the picture. Don't put any shims in between the bearings! Should be just enough preload built in flush ground bearings that shims are not needed.

 

[kd4gij]

Mount them back to back just as it is in the picture. Don't put any shims in between the bearings! Should be just enough preload built in flush ground bearings that shims are not needed.

The flush ground bearings are ground as the name sujest. The inner and outer races are ground flush so you would have no preload. Where as matched sets are ground for optamume preload.

 

[kd4gij]

Setting up new lower spindle bearings on my 8530 Clausing mill. The info below is from the Clausing yahoo group file

http://members.core.com/~chessie/headrbld.html



The above pic above is of a matched set of angular contact bearings(DU), I bought mine not as a matched set but as twp single flush ground bearings(SU) and as such am planing to install them face to face with the inner races together as stated here:

"You could also mount them face to face with the inner races together and preload them with the retaining nut. They would take more misalignment (out of true) on the spindle, and have a lower capacity for momentary loads. In this case, I thought it was going to be easier to draw them together with the retaining nut."

Does this sound like an acceptable practice? This is my first go round with angular contacts and I want to get it right, not to mention the two bearings were $100 for the pair and I don't want to screw "em up.

thanks, Brian

That isn't true With them face to face when you draw the spindle up with the top nut, you will decrease the preload on the one bearing and increase it on the second bearing. I would need to see the drawing of the spindle to see what the best way to use the bearings you have. You realy need match sets to get the full benefit of AC bearings.

 

[calstar]

. You realy need match sets to get the full benefit of AC bearings.

While that is true matched sets are at least $400 so thats not going to happen for me. Clausing no longer sells matched set bearings for these mills, only the individual flush ground ones as a set of two(which btw were $130 each + shipping, around 3x what I paid for the exact same Fafnir bearings on the bay), that implies Clausing thinks its OK to use unmatched sets and I'm I'm a hobbyist, not a NASA machinist, so unmatched it is. The bearings I removed(not the oem) were just standard single row bearings that the previous owner put in, I looked them up and they are around $12 each, measured .0003 tir on the spindle with those in place. Hell, maybe I didn't even need the flush ground ones!

I talked to Clausing regarding the use of an unmatched bearing set, they sent me instructions(see below, take a look and let me know how you interpret them) but they look to me like the same instructions for a matched set, confusing right? So I'm still stuck on how to install them, hoping for more info.

thanks, Brian

steps 1,2 and 3 apply to the lower spindle bearings in questions, other steps do not apply

 

[kd4gij]

Mount them per Clausing instruction. And check your end play. If it is good run them that way.

 

[calstar]

As I mentioned earlier the mounting method circled in the instructions must be using the matched bearings(DU), if no shim is used with this method the flush ground unmatched bearings could not be preloaded. The second figure seems like the more reasonable to attain any degree of preload, either that or use a shim as was shown in the video link above.

Hey guys I really don't mean to be beating the proverbial "dead horse" here, just trying to understand something I have no experience with to get the best results.

thanks, Brian

 

[kd4gij]

If the bearings are true flush ground you won't get preload eather way. The way the spindle goes together. I would use the DB mounting and shim as necessary. That would give the best results. you can mic the inner and outer raceses. and see how close thay are.

 

[chips&more]

I have had very good luck procuring plain old AC bearings that have no bearing race contact specs at all. I get them cheap that way. With a little effort on my part and my little Sanford surface grinder. I have successfully ground the faces on AC bearings for a preload condition. Mostly on Levin high speed accessory spindles and head stocks. All with good results and a big savings in $’s…Good Luck, Dave.