G3103 spindle bearings

On my Rockwell there was a snap ring above the top bearing that had to be removed. Then you tap the top of the spindle and it should drop out the bottom of the quill, with lower bearings attached. Do not use a steel hammer directly or you will deform things. Use either lead or copper hammer or put a block of wood in between. Depending on the fit this may cause some further harm to the current bearings. You can also potentially use threaded rod and bushings/pipe/spacers (maybe PVC drain pipe?) to accomplish this, or use a hydraulic press. Try not to be too rough and see how willing it is to come apart.

If the bearings feel rough you really need to consider replacements. Fresh grease will not fix them.

That was my thinking recently as well. I'll measure the bearings when I remove the spindle before ordering.

I'll clean everything then check for any type of retainer when I get home.
 
I removed the spindle @machPete99, there were no retainers or anything. A couple mild blows with a brass hammer dropped the spindle from the quill with no damage to the splines of the spindle.

I cleaned the bearings and concluded that the two lower bearings are going to be replaced. The bearing that remained in the quill is perfectly fine. Now what is the easiest/safest way to remove these from the spindle, without damaging the spindle? The rubber seal from the top bearing reads "6007RS" the lower bigger bearing has "7207AC" etched on the outer diameter.

I've included a picture to show the bearings on the spindle. 20180418_180818.jpg
 
Wow, that configuration differs from the parts diagram, in that there is no retaining nut holding the bearings on the spindle, so they must be pressed on pretty tight, and/or loctited on there. Likely a cost reduction on the spindle fab. The bearing numbers do seem to match up with the parts list, as listed in my earlier post.

You probably want to punch out the collet guide pin before playing with the bearings, in case it gets in the way.

You will need a short length of pipe (maybe 4" or so) that fits over the spindle nose, but contacts the lower bearing. Then ideally stand it up in a press and push the spindle down through the bearings. Its probably only a press fit for the last inch or so on the spindle. If you don't have a press find the biggest piece of all-thread that will go through the spindle, and put plates and nuts on each end to apply the force, using the pipe over the spindle nose against the lower bearing. McMaster-Carr has some nice high strength all-thread if the hardware store stuff does not cut it. The forces here will likely damage both bearings, you will not be able to reuse them.

If the bearings do not budge there could be loctite holding them, which might require heating with a torch to get in the 450-500F range, at which point it should break down.

To install new bearings you will need a pipe that slips over the top portion of the spindle and contacts the inner race only of the bearing. (Can also use a combination of pipe and a turned bushing). Look at black iron or galvanized pipe sizes. Once again use a press or all-thread to bring them home. It would probably be best to press each bearing on separately, using the same procedure. (If the outer races touch and you did them both at once there could be some adverse forces on the races that might damage them). If the new bearings do not fit tight you may want to use loctite sleeve retainer on the inside surfaces.
 
Last edited:
Wow, that configuration differs from the parts diagram, in that there is no retaining nut holding the bearings on the spindle, so they must be pressed on pretty tight, and/or loctited on there. Likely a cost reduction on the spindle fab. The bearing numbers do seem to match up with the parts list, as listed in my earlier post.

You probably want to punch out the collet guide pin before playing with the bearings, in case it gets in the way.

You will need a short length of pipe (maybe 4" or so) that fits over the spindle nose, but contacts the lower bearing. Then ideally stand it up in a press and push the spindle down through the bearings. Its probably only a press fit for the last inch or so on the spindle. If you don't have a press find the biggest piece of all-thread that will go through the spindle, and put plates and nuts on each end to apply the force, using the pipe over the spindle nose against the lower bearing. McMaster-Carr has some nice high strength all-thread if the hardware store stuff does not cut it. The forces here will likely damage both bearings, you will not be able to reuse them.

If the bearings do not budge there could be loctite holding them, which might require heating with a torch to get in the 450-500F range, at which point it should break down.

To install new bearings you will need a pipe that slips over the top portion of the spindle and contacts the inner race only of the bearing. (Can also use a combination of pipe and a turned bushing). Look at black iron or galvanized pipe sizes. Once again use a press or all-thread to bring them home. It would probably be best to press each bearing on separately, using the same procedure. (If the outer races touch and you did them both at once there could be some adverse forces on the races that might damage them). If the new bearings do not fit tight you may want to use loctite sleeve retainer on the inside surfaces.

Thank you for the help and the tips! I don't have access to a press big enough, but I do have various lengths of all kinds of pipe on hand.

I'll make the bearing puller/pusher you described tomorrow and have a go at removing them. I also sent you a private message regarding a specific bearing.

Thanks again!!!!
 
Pack the spindle in dry ice and you probably won't even need the all thread. If you do use it, coat the threads with some anti-seize. Mike
 
Pack the spindle in dry ice and you probably won't even need the all thread. If you do use it, coat the threads with some anti-seize. Mike

Might be a stupid question, but I'm going to ask anyways. Dropping the temperature of the spindle to shrink it with dry ice won't cause any type of warping when it comes back to ambient temp?

I know that metal can be warped if heated too much, didn't know if that applied to cold temps.
 
Not a stupid question at all. Should be no issue, as high accuracy parts are routinely submerged in liquid nitrogen for strengthening. I would try to make sure that it is cooled as evenly as possible, but I don't beleive it's really that critical. You might even get by just putting it in the freezer overnight, and measure the difference in size from room temp to fully cooled, and compare to your bearing id. Just install your bearings quickly. You could also preheat your bearings to around 200-250 degrees (rubber seals), but I think you will find the cooling adequate. Mike
 
Not a stupid question at all. Should be no issue, as high accuracy parts are routinely submerged in liquid nitrogen for strengthening. I would try to make sure that it is cooled as evenly as possible, but I don't beleive it's really that critical. You might even get by just putting it in the freezer overnight, and measure the difference in size from room temp to fully cooled, and compare to your bearing id. Just install your bearings quickly. You could also preheat your bearings to around 200-250 degrees (rubber seals), but I think you will find the cooling adequate. Mike
I've done that very thing to install beading in small engines (atv and motorcylce). Freeze the bearings and warm the cases. Bearings dropped right it most of the time, then were nice and tight when the metals settled at room temp.

I plan on doing the same thing with the spindle. Freeze it over night then lightly warm the bearings hoping they fall right into place. Now I'm considering your idea of using dry ice to shrink the spindle for bearing removal.
 
Well the bearings came off the spindle with some persuasion. I had a pipe that fit the outer race of the lower bearing. I stood the pipe up on the bench with padding in it. Placed the nose of the spindle in the pipe, aligning it with the bearing. About 7 decent whacks with my brass sledge with a 1" aluminum between the spindle splines and hammer and the spindle dropped.

Both bearings came off with no damage to anything. I already ordered new bearings, they should be here Monday.
 
Got the new bearings in today. Gave them a good cleaning then put in new grease. I did not fully pack them as I was told not to. Instead, they are packed about 20-30%.

I got the new bearings pressed on the spindle, which I put in the freezer over night. The new bearings went in with a little effort, nothing went wrong. Got the spindle in the quill, all thats left to do is put it back in the mill and everything else with it.

I must say, just hand spinning the spindle in the quill and I can feel that it's way better.
 
Back
Top