Thread: Orden TC grinder

How about you pull the other bearing halfway out and then use the head, 4 bolts, 4 spacers and a large center bolt as a pusher?
(or pull from the other end depending on what the shaft looks like?)

Someone else can work out what torque on what sized bolt = 2 tons

Stuart

Axial capacity of ball bearings is usually a small fraction of radial capacity... I think pulling the outer race will defintely stuff it.

Originally Posted by Stustoys

Would I be completely crazy to think that the dynamic load a bearing can take is higher than its static load.. so if you were going to pull on the outer race would it make any difference to make it such that the shaft turning?

(I have an excuse if this idea is sillier than my norm. I'm on the sick list lol)

Stuart

He would need to buy a bearing bigger than the one he is trying to remove to be able to apply more load with it. If he had spare bearings of a larger load rating handy and some sort of way to mount it, then it would work. Given most of us dont have huge bearings just lying around. Also, your assumption is that the bearing's fit on that shaft will require less force than its max dynamic load, which is unknown at this point.

Originally Posted by gallegos

Axial capacity of ball bearings is usually a small fraction of radial capacity... I think pulling the outer race will defintely stuff it.

Pretty well what I was thinking too. Unless there is a way to push the inner race only, its all over bar the shouting for that bearing unless it comes off with less than its rated max load.

Slight diversion here -
I bought a pair of SKF angular contact bearings last week because of the noises in my head - these were 206 size and cost $35 each. However, while picking them up I asked the bearing guys how to tell if an angular contact bearing is stuffed. The answer was basically you can't as once it is out of it's mount it is that sloppy that you don't know what is wear and what is normal clearance.

Gallegos, I'd agree with you for a deep groove bearing but for angular contact bearings I'm not so sure. If pulled in the direction that the preload is applied in I would have thought there should be enough metal there that they can cope with more than a DG. How much more is another question of course...

Michael

If the bearings are to be reused if possible cant you check the bearing on the shaft as is without needing to remove it?

Originally Posted by .RC.

hmmm would dipping the shaft end in dry ice help? If you can get dry ice that is... With a hair dryer on the bearing...

many years ago before they knew about the ozone hole we used to use refrigerant to freeze the shaft and mapgas on the bearing...but we were not re-using them

The 3 jaw puller did the job with a minimum of force. Which allowed me to mount the spindle between centres and clock the bearing journals for runout - which was the whole point of the exercise. And runout there is - about .035mm at worst. I tried to set the journals on V blocks and clock the tapers, but my setup was too crappy to get meaningful numbers. Will see what I can do about that, but it's probably academic as I'll need to either try to straighten it or make a new one. I've had modest success straightening slender shafts with a cheap press and patience, but this one is short and chunky. Not much to lose by having a crack I suppose.

The thing felt fine when assembled and greased - smooth & free, no detectable end float. And now I know the spindle is bent, I figure the bearings are innocent till proven guilty. OTOH you may ask, how could a blow sufficient to bend that spindle not damage bearings? My idea for further assessment was to assemble them clean and dry - or maybe lightly oiled - and see how they felt. Ideally with a true spindle.

Thanks for all the suggestions on bearing removal etc.

You did turn the headstock centre.

How true are the 2centres to each other

Originally Posted by pipeclay

You did turn the headstock centre.

How true are the 2centres to each other

No I didn't bother as both centres are stationary.

How then do you now that the headstock centre held in a chuck is true and not giving your runout.

Originally Posted by pipeclay

How then do you now that the headstock centre held in a chuck is true and not giving your runout.

Because it can't run out if it's not rotating. The lathe is off, I'm turning the shaft by hand.

Provided the centres do not rotate, they will define a fixed axis. The indicator is there to measure any radial difference. When the shaft rotates on the centres any movement of the indicator will show an eccentricity with regards to the axis and can be taken as the run out of the shaft.

Michael

I might be to intoxicated to think clearly, but if you put a centre in the chuck rather than the spindle taper and rotate a job around that centres axis isn't that the same as putting a drive dog on the spindle and rotating the spindle under power.

Also how have you checked the spindle centres to see if they are running true

Originally Posted by pipeclay

I might be to intoxicated to think clearly, but if you put a centre in the chuck rather than the spindle taper and rotate a job around that centres axis isn't that the same as putting a drive dog on the spindle and rotating the spindle under power.

Yes, and if you fed the indicator longitudinally you might think there was a taper when there was not or things were parallel when they were tapered. Here because the indicator is stationary that does not matter. All the indicator can do is show the relative distance between the surfaces passing under the foot.

Michael