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broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 10:49 am
by timsch
I've been using my '54 greenie for a number of projects and it's performed well in the few months I've had it. Light use overall, with short motor runs with breaks between. This week, however, I was using it to cut dado grooves in lengths of fiberboard trim with the unit running continuously. After about 15 minutes or so, the belt snapped and the quill stopped turning. I noted that the belt was in good shape otherwise, with no dry-rot or any other issue. I then noticed that the quill was hard to turn by hand, and was hot to the touch on the tail end. So, it appears the bearing failed, causing the belt to snap.

I'll replace the bearing (only one on this quill, IIRC) and get a new belt. Anything else that could have been impacted by this? What bearing is recommended, if other than OEM?

Prior to any use, I did tear it all down, clean & lube, and check everything out. I did not replace any bearings, but apparently should have.

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 12:25 pm
by chapmanruss
Depending on when it was made the first Mark 5 Greenies did not have a clutch in the Drive Sleeve Assembly. A clutched version soon became available as breaking belts became a problem. To see which one you have the first picture below is the Gilmer Drive Sleeve Assembly without a clutch.

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Drive Sleeve Assembly - Gilmer - no clutch.jpg
Drive Sleeve Assembly - Gilmer - no clutch.jpg (68.45 KiB) Viewed 757 times
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The set screw on this non-clutched Gilmer Drive Sleeve Assembly is in the teeth as seen above. Because it doesn't have a clutch there is no slippage allowed in case of a jam.

The picture below shows the location of the set screw, indicated by the arrow, on a clutched Drive Sleeve Assembly.

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Gilmer Clutch Type Drive Sleeve - arrow.jpg
Gilmer Clutch Type Drive Sleeve - arrow.jpg (53.35 KiB) Viewed 757 times
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Even with a clutched version the assembly may no longer slip helping to avoid a belt breaking as designed.

Since you have to remove the Drive Sleeve Assembly to replace the belt check the bearings on it to see if they are okay.

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 12:37 pm
by timsch
I recall cleaning the clutch plates & friction disks on mine. The blades didn't jam, so I'm not sure that the clutch would factor in here, but then I'm new to these shopsmiths

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 1:27 pm
by edma194
Hi timsch, sorry you ran into this problem. I will point out this is the point where you could upgrade the drive sleeve to use the Poly-V belt and upgrade to the 2 bearing quill as well. Those are expensive upgrades though, I've listed the parts below. You can find these parts used for some savings but it's still going to cost substantially more than just replacing a bearing.

Parts for a Poly V Belt uprade
  • 555088 - Quill Upgrade
  • 518145 - Drive Sleeve Assembly
  • 5041809 - Idler Shaft Sheave
  • 515616 - Eccentric Bushing
  • 521681 - Poly V Belt w/Instruction
If you don't go that route please provide pictures of the drive sleeve and quill you have. If you have to replace parts there are different versions to that have to match, and the possibility some parts have been upgraded already.

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 3:54 pm
by timsch
Thanks Ed, but I'll wait until this happens again before spending that kind of $$. I'll keep it in mind, though.

When I was in it before, I felt one of the bearings was borderline, but thought it would be fine with some TLC. I was right for a while, but I deserve this one. I'll go with new bearing(s) and a belt for now.

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 4:15 pm
by chapmanruss
timsch,

Did you figure out which Drive Sleeve Assembly you have, clutched or non-clutched? Although that doesn't matter if the clutch isn't working.

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 4:34 pm
by timsch
Russ, it is clutched. I recall cleaning the plates during the teardown. I didn't do anything to verify torque for slippage. I don't have time today to tear it down, so I hope this answers your question.

Re: broken drive belt, quill bearing semi-siezed

Posted: Fri May 06, 2022 5:38 pm
by DLB
timsch wrote: Fri May 06, 2022 10:49 am ...
I'll replace the bearing (only one on this quill, IIRC) and get a new belt. Anything else that could have been impacted by this? What bearing is recommended, if other than OEM?
...
Not long ago one could by the Belt Sander bearings from the MS, and IIUC they are the same as single bearing quill bearings. PN 502962 per the bearing document on Everett's Google Drive viewtopic.php?t=16113 But they seem to no longer be available from SS. Measure yours to confirm, but the size is 5/8" ID X 40 mm X 12 mm. I think this is a 6203-2RS-10. The -10 is important, differentiates the imperial measured ID from standard metric. The 2RS is also important, gets you sealed as opposed to shielded or worse. Shielded is okay, but I use sealed whenever possible on the Mark because it is a dirty/dusty environment.

Two bearing quills are more complicated due to varying designs that don't use the same bearings. Above is single bearing only. Which I've heard all use the same bearing but it's always best to measure twice and order once. Try to get a name brand bearing. Top companies are good about specifying and inspecting, so they get good bearings no matter where they are actually manufactured. I have good luck with Timken and stick with them, but I didn't see a listing for this bearing with the imperial ID, metric only.

Since you need a belt, you might ask SS CS about the bearing by PN. They can sometimes order things for you that you can't order yourself. But it is equally possible that they've stopped using 5/8" ID bearings in new Belt Sanders.

- David

Re: broken drive belt, quill bearing semi-siezed

Posted: Wed May 11, 2022 6:35 pm
by timsch
Turns out that it was not the bearing quill, but a drive sleeve bearing. I've tried to pull the drive sleeve out without success. I tried pushing it out by extending the quill to disengage it and then turning the quill extension handle backward, also w/o success. I've ordered a slide hammer - that should do the trick.

Re: broken drive belt, quill bearing semi-siezed

Posted: Wed May 11, 2022 9:50 pm
by DLB
timsch wrote: Wed May 11, 2022 6:35 pm Turns out that it was not the bearing quill, but a drive sleeve bearing. I've tried to pull the drive sleeve out without success. I tried pushing it out by extending the quill to disengage it and then turning the quill extension handle backward, also w/o success. I've ordered a slide hammer - that should do the trick.
Since you've had it out before you probably know this, but I feel compelled to remind you there is a retaining clip. Originally Spirolox style IIRC. Should not require a slide hammer.

40 or so years ago I broke my Greenie casting in that area. I just went to the shop and stared at it a few minutes to see if I could recall how. Which I can't. But the two reinforcing through-bolts and JB Weld are confirmation that I did in fact break it. Even without a slide hammer. ;) Perhaps that's what led my to buy a manual. Do be careful. I think the casting is fairly weak in that area.

- David