How do I take this apart?

How do I take apart this GMN TSI 60 x 250 left-handed spindle?



The spindle came with some other things that I got recently. The tool interface taper on the left is damaged (crash?) so I was about to throw it away when I noticed that in the box next to it was a brand new shaft. So I'd like to try and disassemble it, and move the bearings to the new shaft. How do I take it apart? I can easily remove the two rings on the right hand side of the diagram above (both are a right hand thread). This
exposes the right-hand bearing above. What's next?

(I realize that spindle bearings need great care and will try hard to apply forces in ways that don't put stress on the bearing balls or races. But the alternative is to throw it in the trash now, so I don't have a great deal to lose. I did successfully remove, clean, regrease and re-install the spindle bearings on my Logan lathe some years ago.)

Looks like it would go forward and then carefully use a hook slide hammer or a leaded cold roll shaft about one 1" OD and lightly tap out the bearings if the stick. Many times the OD is a light press compared to the ID. Don't use a BFH though. If you have a arbor or hyd press...after your remove the caps...LOL Be sure to have a bath towel or rubber topped table, take lots of pictures and one very important thing is to scribe a line on the location of the caps before you remove them. Also like we talked about in the class mark where the * TIR marks are mounted on the bearings relationship to the spindle and housing. And Be (get) Smart about it and not be Primitive Pete....

Be sure to cover the press with a towel too to catch the springs if they should fall out. Rich

Also measure the new bearings and check to be sure the springs are all the same length.

You cannot possibly disassemble without putting stress on the bearings. You might have to sacrifice them. Whack axially on the spindle taper with a plastic hammer or with a steel one and a piece of hard wood between, at first only lightly. On reassembly you need a tube for pressing down the new bearings over both rings. Note you have special spindle bearings there.

Go to you tube and search SKF GET SMART and you will see the good way and the bad way of disassembling. Why do you want to dismantle it?

Mechanola said:

You cannot possibly disassemble without putting stress on the bearings. You might have to sacrifice them.

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OK

Whack axially on the spindle taper with a plastic hammer or with a steel one and a piece of hard wood between, at first only lightly.

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I assume that you mean on the taper shown on the right hand side of the diagram? In this case, the tapping just compresses the springs supporting the two right hand bearings. Is this what you intended?

On reassembly you need a tube for pressing down the new bearings over both rings.

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Understood.

Note you have special spindle bearings there.

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Yes, I known. These are not C3 motor bearings.

Cheers,
Bruce

Hi Richard,

I hope the second week is going well.

Richard King said:

Looks like it would go forward

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Does "forward" mean shaft to the left in the diagram above? Or to the right?

and then carefully use a hook slide hammer or a leaded cold roll shaft about one 1" OD and lightly tap out the bearings if the stick.

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The slide hammer/leaded cold roll shaft is for AFTER the spindle shaft has been removed, correct?

Many times the OD is a light press compared to the ID. Don't use a BFH though.

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Understood

If you have a arbor or hyd press...after your remove the caps...LOL

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By "caps" you mean the threaded covers on the right side, correct? Those come out easily by screwing. I am not sure how to remove the caps on the left hand side. The outer one appears to be pressed onto the shaft, not threaded. I can try to press the shaft off of it, but don't have a good way to hold it. Will post a photo later.

Be sure to have a bath towel or rubber topped table, take lots of pictures and one very important thing is to scribe a line on the location of the caps before you remove them.

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By "caps" do you mean the outer bearing races?

Also like we talked about in the class mark where the * TIR marks are mounted on the bearings relationship to the spindle and housing. And Be (get) Smart about it and not be Primitive Pete....

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Yeah.

Be sure to cover the press with a towel too to catch the springs if they should fall out.

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I'm still not sure WHERE I need to press...

Also measure the new bearings and check to be sure the springs are all the same length.

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I don't have any new bearings, am hoping to save/reuse these ones. Please see my first post for the reason why I am doing this.

Richard King said:

Why do you want to dismantle it?

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See the first post in this thread, please.

ballen said:

I assume that you mean on the taper shown on the right hand side of the diagram? In this case, the tapping just compresses the springs supporting the two right hand bearings.

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Yes, I mean the taper on the RH side of the diagram.

No, you will drive out the two bearings on either side because the spindle sits behind them. I proposed to hammer on the taper side since you have more room to go. The other end seems to be less important, though.

The purpose of the springs is to prestress the bearings axially. Not quite clear from the diagram but as much as I can see they’re not in contact with the spindle. The spring packs touch both rings of one bearing, a bizarre design. Also, there’s a step on the spindle within the outer bearing, something I’d like to know what it’s about. Eine Stufe in der Zeichnung, diese Durchmesserlinie . . .

On a small spindle that can be hand held our bearing man would set a chunk of 4x4 (wood) on end on a stout table with the 4x4 on end (not on the side) set directly over the table leg for more solid support. then he would hold the spindle vertical with two hand so it very straight. Then with both end caps off he would give it a solid [but not crazy] end smack to the 4x4.
He said that was to see what way it wanted to go most easy. Such a smack wont hurt bearings as the 4x4 gives some and so the whack is often less than a work load..
Many high speed bearing fits in the tube are often not a hard press because that can stress a bearing tighter than it/they need be. some times the fit to the shaft is tighter. Some are hard or harder press on the shaft,but ti be able to pre-load they cant be super tight.

He said many spindle hacks would blow a bearing to make it spin during cleaning and that a bearing should never be fast spun when not under load. Clean in fresh new solvent and dip in spindle oil so it might not rust with washed hands in a clean room not in a dirty shop where that even the air is full of bad stuff. ,then set between two fresh towels over night to drain.

I have an old plane bearing grinding spindle that I took off a Brown & Sharpe 13 grinder while it was still working fine..the shaft will push one way with a hard hand push (perhaps 10 pounds push) but is solid retained pushing the other way. It feels that it might have springs but I have never had it apart.

Bruce what is the but end like for how you intend to drive it?

I like to mark the position of the threaded end caps and note how far they are to the tube..then when apart run the end cap threads past the mark to see they can run deeper by hand or with the wrench with same resistance..this makes setting per-load easier because you don't run into resistance in the thread. I like to tighten to make end play out then turn a little more to give load to bearings. you can use the thread pitch as a micrometer so a 1/8th turn equals so many thousandths or MMs.

Say if a 20 thread per inch so one full turn is .050 / a half turn .025/ quarter .012 and so on so you can figure a .001 take-up easy.

With all play just out then with running expansion a spindle may be tight enough..or a little tighter than all play out. Having a little temp rise running at highest speed for 10 minuets or so.

yes you run tighter to seat the bearings to the shoulder then back away to get the pre-load feel..

michiganbuck said:

On a small spindle that can be hand held our bearing man would set a chunk of 4x4 (wood) on end on a stout table with the 4x4 on end (not on the side) set directly over the table leg for more solid support. then he would hold the spindle vertical with two hand so it very straight. Then with both end caps off he would give it a solid [but not crazy] end smack to the 4x4.

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The good news: that worked perfectly.

The bad news: I found out that the "replacement shaft" has different dimensions than the one that I just removed. So looks like this will all go on Ebay as "spare parts".

Bruce,
Couldn't you fix the damage to the taper with your cylindrical grinder?

Paolo

Paolo_MD said:

Bruce,
Couldn't you fix the damage to the taper with your cylindrical grinder?

Paolo

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QT:So looks like this will all go on Ebay as "spare parts".

Or consider perhaps put it back together then grind the nose to fit a small precision 4 jaw chuck. then make a 24 index to fit the but end. With that it can be set in a V block or to the side of an angle plate to be used on many machines for holding odd jobs that may need index..perhaps even used for slash grinding cutting tools. That would be good as a drill and reamer sharpening holder to be used on your surface grinder with working off index or normal work and spinning a certain a diameter to .0002 close to needed size and back it off(add clearance) with a simple riding finger with such a chucked easy spin spindle with it set on a surface grinder.

Slash grinding is facet grinding so the primary and secondary cutting edges are just simple grinds, not a radial or cam grind. Slash grind is almost as good as a radial grind with just having a little shorter tool life/ the secondary or even the primary clearance can be rolled off the first or second grind to male a very nice looking sharpening.

Axial cutting cutters should have clearance angle being a minimum of perhaps 8* and maximum what ever the material being machined likes best. (figure some of the cutting edge clearance is taken up by the feed rate so at a high feed rate the end may act like it has no clearance at all)

or make the working end a face plate so an adjust true 3jaw might place there, as well as a L-bar so a diamond can be attached to make concave and convex radius to a grinding wheel.

L-bar: perhaps 3/8 or 1/2" bar stock shaped like an L having Bolt holes on the short leg and bolt holes on the long leg , with also having a diamond holding hole with set screw hole on both long and short leg. It being high precision ground on all sides so to be also use as a holding fixture. Yes this set to the face plate when the chuck is taken off. (CRS is fine/OK for a L bar)

Paolo_MD said:

Couldn't you fix the damage to the taper with your cylindrical grinder?

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No, the taper is cracked from a crash. The shaft is hardened so might be quite brittle. Remarkably the bearings seem undamaged.

michiganbuck said:

Or consider perhaps put it back together then grind the nose to fit a ...

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Good ideas! I'm not sure there is enough left of the nose for this, but I'll take a close look. Nothing left to lose in any case!

OT:

Another idea is to make a bar with a center point. It being clamped to a V block or angle plate can end stabilize the out-end of a part perhaps when the part is held by the other end a distance away.

Such a bar can also have V slash going across the width so a bushing might be clamped there to stabilize an out end off the part OD.

Not a bad idea for a bushing Jig is to have pre made and centered bushing blanks so one might be drilled, bored or reamed to a needed size ,perhaps with using the cutter itself needing holding.