Spindle play

[Garagedweller]

Hi everybody.
I`m new here and a total beginner on just about all matters of lathe and millwork.
I have an old Sieg C3 lathe/milling combo machine.
Recently I replaced the bearings on the millspindle. I read on arceurotrades site that the angular contact bearings are better than non angular ones. So I bought those. Now I can`t get rid of the play on the spindle. I loosened the nut completely, no difference. Hand tight, small difference. Tightened with wrench, small difference. Today I ordered 2 SKF non angular bearings. I`ll put those in and see if the play goes away.
Am I doing something wrong, or rather, what am I doing wrong?
View attachment BA252AF3-C7B0-4A82-99CC-CAF3A002240A.MP4

 

[RJSakowski]

Have you installed the bearings correctly? Angular contact bearings have to be installed so they are opposing one another (the angles face in opposite directions).

 

[Garagedweller]

Yes I did, there`s a wider side on each bearing that is supposed to face outwards if I remember correctly. Anyway I put them in right.

 

[tkalxx]

That amount of play looks like the angular contact bearings are not getting any preload as you tighten the preload nut. For angular contact bearings to be properly installed, the nut has to make contact with the thicker inner race and preload it against the outer race on the opposite side. Do you have a sketch or picture of the bearing arrangement in your spindle?

I wouldn't even bother trying the SKF "non-angular" contact bearings that you ordered. I assume they're just normal radial ball bearings? The reason nearly every single machine tool uses some kind of angular bearing with adjustable preload is because they can resist both axial and radial loading. A normal radial ball bearing will only resist radial loading. In addition, if you end up preloading the radial bearings to eliminate axial play as shown in your video, you risk elastically deforming the rolling elements and damaging the raceways.

 

[homebrewed]

Did you look at the article on ArcEurotrade's web site that describes the procedure used to install angular contact bearings? The author does mention some excess play that developed because the bearings weren't completely seated.

 

[tkalxx]

Did you look at the article on ArcEurotrade's web site that describes the procedure used to install angular contact bearings? The author does mention some excess play that developed because the bearings weren't completely seated.

If the bearings don't seat completely, it's likely because the thickness of the angular contact bearings are thinner than whatever was originally in the spindle. In that case, some spacers would need to be made to account for this. It is common practice when converting from tapered roller bearings to angular contacts.

 

[Lo-Fi]

Angular contact bearings are often sold in matched pairs, having been ground to give the correct preload when the inner and outer spacers between them are equal length. If your mill uses this arrangement it will be impossible to get the correct preload with standard bearings. A sketch of your spindle configuration would be really helpful for narrowing down the problem for sure, though.

 

[pdentrem]

Need a spacer to take up the excess space.
Pierre

 

[hman]

I would suggest a small diameter spacer (about the size of the inner diameter of the bearings) between the bearings, and a large diameter spacer (about the size of the outer diameter) above or below the paired bearings.

 

[Garagedweller]

Wow! What a respons! Thanks guys I think you`re on to something there. Spacers. Never thought of that. Bought the bearings from arc and assumed they would be like the original ones concerning measurments. I also replaced the plastic gears with metal ones. Have to rip it apart and take a closer look at everything. See if I can get it done or at least begin today. In the middle of making burnwood for next winter. No rest for the wicked. I`ll be back. Thanks again.