Bearing issue?

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curtis cutter
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Bearing issue?

Post by curtis cutter »

On my old Enco lathe I occasionally get what I refer to as a shift in something and it manifests itself as a stretch of cutting slightly deeper and a little rougher than the rest of the finish. This stretch is maybe 1/16th to perhaps 1/4" in duration and then the finish returns to the original desire. I took the cover off the gear box to check for anything out of the ordinary looking and all looked well. At least to my eye. Nothing in the bottom of the gear box.

I shifted the case into "neutral" and rotated the chuck and there was an obvious light clicking noise from the final ball bearing. No rumble at all. Nothing noticeable to the hand when rotating the chuck as well.

Is it possible that due to a bearing cage that is getting wear that the balls could possibly not be remaining in position causing the shaft to shift slightly? I cannot see the bearing.

Gregg
Gregg
Just let go of it, it will eventually unplug itself.
John Hasler
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Re: Bearing issue?

Post by John Hasler »

Do you see that with everything (topslide, compound, and cross-slide) locked down?
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Steggy
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Re: Bearing issue?

Post by Steggy »

curtis cutter wrote: Fri Oct 16, 2020 8:25 pmI shifted the case into "neutral" and rotated the chuck and there was an obvious light clicking noise from the final ball bearing. No rumble at all. Nothing noticeable to the hand when rotating the chuck as well.
First, what John asked. Is this happening with the carriage, cross-slide, etc. locked?

If it is, your description of the sound suggests that a bearing race is cracked or a ball in one of the bearings has brinelled and is no longer a perfect sphere.
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curtis cutter
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Re: Bearing issue?

Post by curtis cutter »

John Hasler wrote: Fri Oct 16, 2020 8:32 pm Do you see that with everything (topslide, compound, and cross-slide) locked down?
I do. As many as can be locked down. I thought due to a piston type QCTP I may have been shifting the tool but I held the tool holder with the tool in the lowest possible (for lack of better terms, tool down) and clamped down tight on the tool post. No change.
Gregg
Just let go of it, it will eventually unplug itself.
curtis cutter
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Re: Bearing issue?

Post by curtis cutter »

New SKF bearing is $61 so I think I will go there next.
Gregg
Just let go of it, it will eventually unplug itself.
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GlennW
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Re: Bearing issue?

Post by GlennW »

Sounds a bit like chip welding where a small chip welds itself to the cutting edge of the tool for a short duration and then breaks free.
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curtis cutter
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Re: Bearing issue?

Post by curtis cutter »

GlennW wrote: Fri Oct 16, 2020 9:19 pm Sounds a bit like chip welding where a small chip welds itself to the cutting edge of the tool for a short duration and then breaks free.
Had not considered that. If it were the case, oil should change this I would think. I have used oil often but not really paid that much attention. I believe I will give it a try before anything else. I use a lot of HSS bits I grind myself so we shall see.

Thanks Glenn.
Gregg
Just let go of it, it will eventually unplug itself.
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Harold_V
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Re: Bearing issue?

Post by Harold_V »

I'm late to the party, but if you've been machining mild steel dry, no lube at all, I'm on Glenn's side with this one. Mild steel is one of the worst possible materials to work with, because it loves to tear (generally the cause is chip welding). It mills well with the sides of an end mill, however, so it responds quite nicely to shearing action. All the better with lubrication, however.

If you have any at your disposal, try machining some leaded steel, to see if you get the same results. The lead in steel makes it machine beautifully.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
armscor 1
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Re: Bearing issue?

Post by armscor 1 »

Agree Harold.
My choice is 4140 or K 1035.
curtis cutter
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Re: Bearing issue?

Post by curtis cutter »

Harold_V wrote: Sat Oct 17, 2020 3:50 am I'm late to the party, but if you've been machining mild steel dry, no lube at all, I'm on Glenn's side with this one. Mild steel is one of the worst possible materials to work with, because it loves to tear (generally the cause is chip welding). It mills well with the sides of an end mill, however, so it responds quite nicely to shearing action. All the better with lubrication, however.

If you have any at your disposal, try machining some leaded steel, to see if you get the same results. The lead in steel makes it machine beautifully.

H
This does bring up the thought I had about the material being turned. At this point in my "career" :) of machining I am looking at technique and just learning the basics. Since I am turning what I find as scrap items, I toyed with the idea that an inclusion in the steel may cause things to change.

Before I waste a lot of time chasing physical problems that may or may not exist with my machine, I will look at the product I am working with as well as lubrication. Granted it is an old Enco and I did not pay much for it and I had to pull out the Romex it was wired with, this cutting issue would likely exist on even a very fine, expensive machine. It does what I need it to do on the farm.

The seasons have changed and I am repairing summer equipment and putting it away. Getting prepared for the spring cycle once more. Tractors, rototillers, mowers, rewelding pasture harrows and bush hogs, the list seems endless Harold. The hay mower and balers were gone through and put to bed in July so that chore is done. I have a whole process of changing gearbox greases and sharpening and looking for any issues with my old and new stuff. With the rain, I will be returning to the shop to tinker and work on skills.
Gregg
Just let go of it, it will eventually unplug itself.
Russ Hanscom
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Re: Bearing issue?

Post by Russ Hanscom »

Remember Occam's Razor; the simplest solution is usually the correct one.
curtis cutter
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Re: Bearing issue?

Post by curtis cutter »

Still a little bothered by the bearing noise though so maybe this winter I will change that out regardless as a PM item.
Gregg
Just let go of it, it will eventually unplug itself.
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