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Grizzly G0602/G0752 Spindle replacement

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WarrenP

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So, the odyssey continues... I got the Bearings in put all gears etc back on. I was breaking the bearings in and I could hear slight clunking sound every once in a while. I took off the pulleys and all again then tapped in the left side bearing making sure it seemed all the way in and maybe a bit of preload on it. After putting it back together the noise had stopped so I assume the bearings just needed to be a little bit tighter. The spindle runout seems good, less than a half a thousands. I put a piece of 3/5 inch tool steel in the chuck and measured from one end to the other with my gauge on the carriage which showed me the head stock seems a bit off. Over about 8 inches it has a variance of about 4 thousands of an inch. So, it looks like im going to need to loosen the headstock and get that adjusted. sounds like it will be fun loosening the headstock to adjust. This was with my 3 jaw chuck so just to be sure, even though it will probably still be off, I am going to try the test with my 4 jaw chuck. After that gets adjusted I will need to adjust my tail stock too I presume. I will let you know how it all works out. Warren
 

WarrenP

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I have a question, hopefully someone can help me. I am not sure the test bar I am using is perfectly straight. I used tool steel and center drilled it and the steel is supposed to be within .0005 accurate, but I it seems like it may not be exactly straight. Can anyone tell me a way I can test it to see? Or maybe I should just order one from ebay that should be good within 1 micron. They seem to come from india, has anyone gotton any of these and know they are accurate? Thanks for your input. Warren
 

WarrenP

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Thank You Mitch, That is pretty much the way I am checking the spindle. It did give me a couple tips though. Actually my question though was about knowing if my test mandrel is straight or not. I think I am going to order one over Ebay to make sure. I want this as close as possible so there are no problems later when working with the lathe. Thanks, again. Warren
 
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If you search for Rollie's Dad's Method and apply it you will find that a straight bar is not mandatory for success.
 

Aukai

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If you are talking about seating the bearing race, do not use the bearing it's self to seat the race by tightening. I'm not sure my perception of what your doing is right. If it is the race you can use a brass, or steel punch, and hammer, and tap in a cross ways manner. Hit one side cross over, and go around in a circle like that until you hear the race seat. there will be a change in the note when its seated solid. I think that is what your doing.....
 
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WarrenP

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Aukai, Yes that is what I did for the race...Thank you. I was saying after it was all together I heard a little bearing noise when running the lathe. I tightened the pressure on the bearings a little and then the noise went away.
 

WarrenP

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OK, I am wanting to adjust the headstock on the G0752. Was wondering , has anyone done this on the G0752/G0602 ? I was able to loosen the 2 bolts in the front under the control panel but in the back I can only get to one bolt without having to take out all the electronics, etc that is in the back above the motor. Is this the way I have to do it? , and If so do I just loosen those 4 bolts and tap the headstock until I get the spindle straight? , will it be able to move then or is it non adjustable? If non adjustable how would I get the spindle aligned with the ways? I know some lathes have an adjusting screw but this doesnt have that. Thanks for any answers. Warren
 

WarrenP

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Well, since no one answered, (i assume no one has done this that read the question) my question about how to adjust the headstock on my G0752/G0602 lathe I emailed Grizzly about it so I thought I would quote them here for anyone that might wonder about it. Pretty simple procedure except for having to remove the electrical panel. Here is what they said in case someone is interested...

If the spindle taper has less than 0.0005” runout, install the test bar into the spindle taper. Now, with the test indicator attached to the cross slide, place the test indicator on the centerline of the workpiece at the front of the lathe, and test from headstock to tailstock to the end length of the test bar. Then, slightly loosen the fasteners holding the headstock in place and make your adjustments with light taps from a rubber dead blow mallet. Once you have reach the desired alignment, tighten the fasteners and retest the spindle alignment.

To access the headstock fasteners, you will need to remove the electrical panel from the machine. You will also need to remove the faceplate from the front of the lathe.
Thanks everyone.. Warren
 

The_Apprentice

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Well, since no one answered,
One problem, is finding people who have your exact model, and who also have bothered to take the same time and effort as you in order to get accuracy to the state you have is going to be a bit rare :p

But thanks for confirming what they told you. On my King I've had to remove a lot more than just the electrical panel to get under all the bolts from the head-stock.

I did see an unorthodox method a while ago, where some Brit (I think) drilled two holes into the ways next to the head-stock, and put in bolts, then jerry-rigged them so he could put threaded pressure agains the head-stock. One bolt for left side, one bolt to right side. Then he adjusted the tension to get concentricity...

I'm not so sure that's a good way to go about it though. If it was, I imagine lathe manufacturers would/should come with pre-drilled holes into the ways, as they could then call this a FEATURE. Sorta like, how hardened ways is a FEATURE by some sellers.
 

WarrenP

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Actually, yes I realize that probably anyone who read my post probably hasn't done this. That's why I mentioned that in my post. I wasn't trying to complain just stated a fact. And... I thought I could quote what Grizzly said so if anyone else was wondering about doing this there would be something for them to go to. I hope no one thinks I was complaining. Have a good day, Warren.
 

WarrenP

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Hello Everyone, I finally received my test bar from India. I didnt have much time last night but I checked it out a bit. I noticed while checking it that i can pull on the spindle and the dial indicator seems to move about 2 thousands of an inch back and forth. Is this normal? I was thinking that wouldnt be good for accuracy... Do you think I need to tighten the pressure on the bearings I just replaced to get rid of any movement shown on the indicator? Otherwise it seems good even though it looks like I will need to adjust the headstock. Thanks for anyones time on this.
 
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ddickey

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Can you post a link for the MT4 test bar?
Thanks
 

The_Apprentice

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> I noticed while checking it that i can pull on the spindle and the dial indicator seems to move about 2 thousands of an inch back and forth. Is this normal?
A few weeks ago I was examining the spindle on my King when changing chucks. I did indeed notice quite some play in it when I was attempting to jiggle it around my hands to test for play with the bearings, not too impress either.

However, keep in mind when in operation, the spindle only spins one way, (not back and forth like AC current), and has a constant load on one side only, not jiggled from all sides at once (lets ignore centripetal forces here). I think the effects are much more minimalized than one would think. At least this is my theory until some old-timer posts here and proves otherwise. Then I get to look like an idiot. :)
 

WarrenP

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Yes, that could be to a certain extent... But, I was thinking what about when you put pressure on your piece of work with your tool as your cutting it, wouldn't that push it a bit making it be "out" more than it really should be and not always the same amount? Doesn't sound to accurate to me... but if this is how all, or most lathe spindles are.. so be it. I guess it can be worked with in that case.
 

The_Apprentice

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Ok, if we really want to get technical here, your issue is even worse than stated. Reason being is there is a lot of flex going on, the cross slide itself has some give, even your toolbit itself has some flex (which often can impact your finish). In fact, even they ways themselves will flex and buckle during operation (you don't see it with your eyes).

The problem is rigidty, rigidity, rigidity. And is one of the reasons it is so dangerous to do a parting-off operation with a mini-lathe.

Each lathe has a different amount of flex when cutting, and even the same model will be out of tolerance to one another, simply due to difference in tightness of gib strips, length of toolbit, and other factors.

Here is the good news though, it doesn't matter too much once you've got the FIRST turning cut done. One thing all lathes have in common, is turning your dial 1/4'th of a mm for example, should advance the cut exactly that amount in comparison to the other cut previously. It doesn't matter how much give/flex there was previously. Each notch turn on the dial should be consistent in COMPARISON to the previous operation. This is because you are using the same machine and set-up.

Does this make more sense?
 

jwmelvin

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I noticed while checking it that i can pull on the spindle and the dial indicator seems to move about 2 thousands of an inch back and forth. Is this normal?
Are you talking about axial or radial motion? If axial, that seems to indicate a need for increased preload on the bearings, as the structure should be quite stiff in that direction.

Is there hysteresis in the motion? As in, does the resting position depend on the direction of the last-applied force? That would indicate a gap instead of just compliance, and would support a need for increasing preload.
 

WarrenP

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Apprentice, thanks for the response, I do understand about the lathe needing to be very rigid , etc for perfectly accurate cuts. Thing is if the whole lathe did not flex at all ( I know they all do some :) ) then with the spindle moving side to side, or top to bottom you wouldnt get accurate cuts because it would move with the pressure of the tool against the work seems it would make a taper cut... furthermore it would move differently with different pressure. I can work with the material flexing when the tool is puttng pressure on it, that seems workable but seems if the spindle changes just by pulling or pushing a bit on it that would be hard to compensate for. Anyway, just trying to find out if all spindles do this or if trying to preload the bearings more might make it less of a movement of the spindle..

Jwmelvin, Thanks for your response also, it seems to move sideways back and forth and probably up and down too if you push or pull on the spindle a bit. Dont really have to push hard but it seems to be no more than 2 thousands of movement. Was thinking of trying more preload only I didnt want to put to much either. I will need to check and see if after pushing or pulling the spindle it stays there or moves back to the original position.

Maybe im worrying about something I shouldnt, guess I will experiment some. Thanks.
 

WarrenP

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After setting up the headstock alignment, and tailstock I started doing some cutting with the lathe. I am noticing the lathe making a lot of noise when I am cutting the outer end of a 1 1/4 " rod furthest away from the chuck and it seems to be chopping the metal abit also. I am thinking it has to do with being able to move the spindle back and forth by that .002 or a bit more. If anyone has the time I was wondering if you might put a indicator on your spindle and see if it moves or how much it moves if you put some hand pressure on it back and forth, side to side (push towards the opposite side your on then pull towards you) and let mw know how much your spindle moves. I will probably see about tightening the load on the bearings to see if it helps but your input would help. I don't want to put to much preload on them if I can help it. Thanks in advance.
 

Mitch Alsup

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I can tell you of an event with my G4003G where one of the DI5 clamps was not tight.
Bad surface finish,
weird noises,
fast tool wear,
That all went away instantly when I found the loose clamp.
 

WarrenP

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I can tell you of an event with my G4003G where one of the DI5 clamps was not tight.
Bad surface finish,
weird noises,
fast tool wear,
That all went away instantly when I found the loose clamp.
What does your DI5 clamp do? Never heard of it and didn't see it on the grizzly parts page just wondering. It seems my problem is more with the spindle maybe being loose but am curious about your clamp.
 

Mitch Alsup

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DI is a system whereby chucks are held on spindles with 1/4 turn fasteners holding 1/2 moon studs in the chuck.
5 is the size (there are many), and 5 in particular has 6 studs and 1/4 turn holders.
See page 663 of 2018 catalog.
 

WarrenP

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DI is a system whereby chucks are held on spindles with 1/4 turn fasteners holding 1/2 moon studs in the chuck.
5 is the size (there are many), and 5 in particular has 6 studs and 1/4 turn holders.
See page 663 of 2018 catalog.
Oh I see Mitch, that would make sense on why yours did what it did.

Has anyone had a chance to put a dial indicator up to their spindle and try to move the spindle by hand to see how much movement there is? Hopefully someone can help me out on this.
 

xman_charl

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Crowbar used to attempt to move spindle back and forth.

Results, are zero on the indicators.

Have you ever greased wheel bearings like on a auto?

Those require a pre-load on the bearings...

A person can put an indicator on the spindle, or chuck, tighten
the retaining nut on the end of spindle, watch indicator needle move.

One turn of that nut will result in say .050, indicator movement.

So when nut is tight, another turn will result in .050 bearing load.

Another method used, get nut tight, then tighten nut 1/6 turn, which
is just eyeball that flat on the nut, move it 1/6 turn.

G0602 lathe.JPG









Charl
 

WarrenP

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Hi xman...Thank you very much. Wow, no movement at all, with a crowbar? I must have a problem there. I can easily make mine move a couple thousands by hand. In the above posts, as I have said I replaced the spindle bearings with timkin bearings. Since, replaced and this problem showed I have tightened the nut on the end of the spindle very tight to see if it would make a difference, I wouldn't want to tighten anymore it seems, I still have the problem. Grizzly says not to put grease in the spindle bearings that to just oil everytime you use the lathe. I suppose it really shouldn't hurt if greased them, I was trying to follow grizzlys instructions. Im also wondering if the bearings I got just aren't suited well for the lathe. Maybe I should order the grizzly bearings and see what happens then. One thing I think of is on the G0752 it has the bearing then the spacer(washer) then it has a plastic insert that tells the vfd display the rpm's, then a plastic gear and then the spools and 2 nuts. Im wondering how good the preload is on the bearings with all that plastic between the bearings and the nuts to tighten, although it is the way they designed it and worked before. I also wonder if the problem is the left bearing (on the side of the gears) is pretty tight on the spindle and hard to get a preload on the bearing. Im thinking my best bet would be to get the grizzly bearings and see how they might work. Any input is appreciated.
 
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WarrenP

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For anyone interested.... Finally got back to repairing my lathe. The wife had a total shoulder replacement and I was held up with taking her to Dr's, tests, etc. now she is done with the surgery and rehab hospital so I came back to the lathe. I replaced the spindle bearings again with the grizzly bearings. These seem better for the lathe than the timken ones I got. The timken ones I had seemed to have more play in them than the grizzly did and the grizzly bearing so far seem to be working well. not so much movement in the spindle now and the cuts so far are good. Not sure if timken may have some heavier duty ones than the ones I received but mine seemed to give problems. I wouldn't recommend the same ones I got from timken. Still need to test the performance a bit more but so far seems to be back to good cuts, etc. Hopefully wont have to go through this exercise again for some time.
 

fitterman1

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Hello Warren, getting back to you over this bearings issue.
Seems like you're having a hard time.
Upon reassembly of your spindle you should've tightened the first of the locknuts till you thought everything was seated.
I would then have rotated the spindle by hand whilst tapping one end with a soft face hammer.
This seats the races in the headstock housing recesses. Repeat for other end.
Then check for endplay with a dial indicator by trying to manoeuvre the spindle axially to show a reading.
You will have to adjust the locknut to a point where there is no axial float as indicated.
You're now at a point nearing completion.
Assemble your drive gear and run the lathe slowly for say 10 minutes.
Then shutdown and do an axial endfloat check.
Adjust lock nut if required.
Power up again and run it faster and listen for abnormal noises. If it sounds good, power down and adjust your locknut 1/16th of a turn tighter. This will induce some preload in to the spindle/bearing assembly cause once everything warms up to operating temperature the spindle will elongate and preload will reduce. Achieving this " running efficiency " is the holy grail of tapered bearing adjustment.
At this point i would run the bearings in.
Then shutdown and let everything cool down at which time I'd do another endfloat test.
Next would be the headstock alignment.
Next would be some test cuts under power feed to gauge finishes.
After some serious playtime using your lathe , i would come back and check alignment and endfloat again in the cold state.
Adjust if necessary, bearing in mind there must be some form of preload on the bearings to achieve serious accuracy.
Excessive preload will cause excessive temperatures and shorten the life of your bearings.
Insufficient preload will cause terrible finishes and inaccuracies during setup also.
Reading your post told me you were almost there with your timkens, you just needed more adjustment for the bearings to be seated properly.
I don't know what brand bearings grizzly source, but if they don't have a quality name stamped on them, i won't buy them.
Hope this helps
Regards Alby
 
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WarrenP

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Hi fitterman1, Thanks for the reply. Actually It seems I got it done. Have had together for a few months now and it seems to be working well for me now. I appreciate the thought...
 

fitterman1

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No worries Warren, glad to hear you've got it sorted
 
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