Spindle bearing replacement

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Wolfgang
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Spindle bearing replacement

Post by Wolfgang »

Mine is a two-lathe shop, an Emco-Maier V10P and a Bergeron watchmaker's lathe.:-))

The V10P needs new bearings; I've been putting it off for years but recently I turned a friend's identical lathe by hand and was amazed by how smooth and slick it turned: Build was the same year and his was used professionally all those years. Recently I tuned up a pair of valves for a little hit n miss engine I'm building, using 17-4 PH 900 rod I had. The finish turning showed chatter marks which I think came from the bearings.:((

The replacement bearings are 32006 xc /P6 and 32007 xc /P6. I am not sure what the xc signifies. I was quoted about $100 Canadian for genuine SKF bearings. Could still be made in China, mind you, as a recent wheel bearing replacement has shown.

I was also quoted $500 or so for a pair of FAG bearings, quality P5, with the inner race run-out less than 1/2 of that of the P6 bearings.

I like to use collets for small work and I was wondering if the extra expense is worthwhile.

The lathe is mounted on a really rigid steel frame bench, with cross bracing, all 2" HSS construction.

I would like to see the opinions of those experienced in these things, and thanks for sharing those opinions!

ON P5 quality bearings, are the high spots of the eccentricities marked so that they may be installed with the markings in-line? w
John Hasler
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Re: Spindle bearing replacement

Post by John Hasler »

What is the specified runout for the P5 bearings? What runout do you actually need?
Wolfgang
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Re: Spindle bearing replacement

Post by Wolfgang »

John Hasler wrote: Fri May 31, 2019 2:52 pm What is the specified runout for the P5 bearings? What runout do you actually need?
The run-out of the inner races is .00015" and .0002" respectively, for P5 tolerance class.

For P6 tolerance class the run-out is twice as much ie. .0003" and .0004" which is close to half a thou. (I thought it was more than that, but I was mistaken).

As to what I need is somewhat elastic. I am used to collets running within .0002". Even my old Atlas 6 achieved this using M2 collets. I know this because I checked every collet in that spindle with dowel pins and a .0001" reading dial indicator, when I got the collets.

On my V10P all collets run out about .0005" last time I checked, and it irritates me, perhaps unreasonably so. w
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Bill Shields
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Re: Spindle bearing replacement

Post by Bill Shields »

I would take the old bearings out before I did anything....assuming you can afford the down-time.

it might NOT be a bearing problem...
Too many things going on to bother listing them.
Wolfgang
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Re: Spindle bearing replacement

Post by Wolfgang »

Bill Shields wrote: Sat Jun 01, 2019 6:45 am I would take the old bearings out before I did anything....assuming you can afford the down-time.

That is indeed my game plan. Don't want to lay out $500+ without knowing for sure the problem. It is approaching summer time and the machinery can have a rest. Just a thought here, I have done a lot of interrupted turning of steel and aluminum. Wonder if that beat the heck out of the bearings?

it might NOT be a bearing problem...
Hmmm, the voice of experience? What might I expect to find, other than rough bearings 1976 vintage? Thanks. w
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Bill Shields
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Re: Spindle bearing replacement

Post by Bill Shields »

never know....

just because a bearing is old does not mean it is necessarily bad...

might find the bearing loose on the spindle from a bad initial manufacturing...
Too many things going on to bother listing them.
jcfx
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Re: Spindle bearing replacement

Post by jcfx »

Interesting thread since I'm also a V10P owner.
I think you should rule out everything else before you suspect the spindle bearings,
it's also a 40 plus year old machine parts get scarce, bearings go out of style.
Unless you bought the V10P new there's not telling what the past usage was like.
If you can afford a new set of bearing I'd go for them as insurance.

I get a little chatter that seems to be coming from my compound, if I lock the compound gib it
it lessens .

In the eventuality that the problem does lead to the spindle bearings, you do know that they can be adjusted ?
Wolfgang
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Re: Spindle bearing replacement

Post by Wolfgang »

I've checked the spindle for play, and there is none.

In my original post I stated that the spindle on my friend's lathe turned smoothly and slick; what I did not explicitly state is that I compared it to my spindle which feels rough when I turn it by hand.

Other than that the lathe is tight and accurate.

The spindle bearings are tapered roller bearings which are easily adjusted if any play develops. At the tail end of the spindle is a threaded collar with a set screw. Loosen this screw and turn the collar with an appropriate wrench or slip-joint pliers until all play is removed. Then re-tighten that set screw.

I purchased this lathe over 25 years ago from the estate of a clock maker who turned clock cases of wood and brass on it. It saw quite light usage judging from the condition of the paint at the left hand side of the cross slide. That paint disappeared within a month of my usage.

jcfx: Do you have collets for your lathe that fit into the spindle, ie. original equiment? If so, what is the run-out of these? Thanks.

The question remains: Should I spend $100 CDN or $500 CDN for new bearings??? w
Rwilliams
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Re: Spindle bearing replacement

Post by Rwilliams »

Bearings can always be interesting as they slowly wear out. Long ago a friend had a well used lathe that had developed a slight chatter in the turned finish of parts. He tried all possible methods to resolve the chatter and decided that the spindle bearings were suspect. He purchased new spindle bearings and once installed, the chatter problem was eliminated.

Another friend was experiencing the same problem and decided it was in the spindle bearings. Upon taking the headstock apart, it was discovered that the expensive tapered roller bearing was slightly loose. A slight adjustment to tighten up the bearing solved the problem and saved him almost $1,500.00.

More recently I was using a ball bearing live center that was of considerable age and some abuse . It showed not way of lubrication for the bearing and at higher spindle speeds, the live center imparted a slight vibration to the lathe that could be felt with the fingers. A new live center resolved the vibration and improved the finishes what had been going downhill ever so slowly that it was hard to notice.
jcfx
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Re: Spindle bearing replacement

Post by jcfx »

Wolfgang,
I have two sets of L20 collets that came with my V10P and Maximat 7, both sets are Schaublin that American Edelstaal
offered as an accessory for the Emco lathes.
The Maximat 7's were in near mint condition in a fitted Edelstaal wood box, unfortunately the V10P set came
loose in a cardboard box. I have never checked them for runout since I don't have a set of gauge pins.

I just spun my V10P's spindle and when I'm in gear I feel the gears in the headstock meshing ever so slightly
so it feels "rough" if I diddle with the gear shift paddles till the gears don't mesh the spindle is smooth as silk.
Could it be that you're feeling the gears ? Perhaps your friends V10P has a heavier weight oil in the headstock
versus the OEM recommended 10 wt and it's "smoothing out" the gears meshing ?

It's worth a look inside, as you might know the shift forks in Emco lathes are Zamak, some batches are prone to cracking,
my Maximat 7 is out of service because of a cracked shift fork ( I caught it in time during an oil change ).
armscor 1
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Re: Spindle bearing replacement

Post by armscor 1 »

Watched a video on YouTube, The World Turns on Colchester Lathes, shows the precision that goes into making the Gamet spindle bearings and the tight tolerances on spindle runout.
Going to check my lathes to see how much out of round I have on test pieces.
I gave my Emco V10 to my brother, spindle bearings are still sound.
I could never part off on mine, simply not rigid enough.
Forget about heavy interrupted cuts, the fibre gears are not up to it.
armscor 1
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Re: Spindle bearing replacement

Post by armscor 1 »

Test cut 6061 aluminium at 900 rpm, measured out of round 0.00005 thou on my 12" lathe, good enough for what I do.
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