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Boxford AUD motor drive wheel plus reverse switch issue

Drive wheel keyway slipping.. And.. Reverse switch malfunction

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SillyOldDuffer31/05/2020 09:53:22
5798 forum posts
1235 photos

Is it worth asking a different question? Rather than assuming the belt twists and wears because the pulley wanders due to a loose key, ask why the belt is moving the pulley at all?

The displacement implies a sideways force on the pulley. Although sideways movement might be worsened by a damaged belt - change it - another question is what damaged the belt in the first place? Misalignment is a possibility. Have a good look at the two shafts: they need to be parallel, and then the pulleys need to be aligned vertically on them.

As motor mounts are usually adjustable maybe the motor isn't parallel with the lathe? May have shifted over time or been left wonky after maintenance. Less likely that the driven shaft is wrong but worn bearings that side could also cause the problem, especially if they've been stressed by a misaligned belt for years.

Whatever the reason, a misaligned pulley will lever against one side of the belt, causing wear while tending to slide the pulley sideways. Worth checking motor alignment and, with the belt off, any sign of play in the motor shaft and/or the bearings on the lathe's driven shaft.

Dave

Simon Williams 331/05/2020 09:53:52
509 forum posts
80 photos

Posted by Fergus Davidson on 30/05/2020 21:41:09:
The grub screw is about 20° anticlockwise from the key...

That's mighty fishy!

If, as I understand it, it is a plain key I would sensibly expect that the grub screw would bear on the top of the key, which says to me that the pulley bore has slipped and is somewhat chewed. Trying to tighten the grubscrew to compensate means that the screw is trying to take the drive torque, as the key isn't helping. That in turn chews the motor shaft.

'Fraid you're going to have to dismantle enough at least to get the pulley off the motor and see what the problem is.

As others have said beware of the second grubscrew in the same hole below the first, also another screw (or screws) at 90 deg to the obvious one.

Good luck, and do keep is posted

HTH Simon

Fergus Davidson02/06/2020 17:24:30
29 forum posts
19 photos

Another question. I'm going to order bearings for all spindles including the motor. How much should I be spending with their prices ranging from £3 to £80.

Should I be mindful of the rpm and sealed units? The current ones on the motor spindle are deep groove and unsealed.

I've cleaned everything up and have the new v belts, so just the bearings to go.

I drilled a hole for a 5mm grub screw to hold the key in position so even with the new bearings and also lining the pulley up exactly with the one above, there is no chance of the key slipping again. The pulley grub screw is the only one and at 90° round from the keyslot but the flat it should locate onto was about 97° from the keyslot so that's one reason the pulley was slipping. I ground a small concave round into the spindle for the pulley grub screw to settle in so that also will now not move.

Photos to follow

Fergus Davidson02/06/2020 17:25:56
29 forum posts
19 photos

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Fergus Davidson02/06/2020 17:26:54
29 forum posts
19 photos

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Fergus Davidson02/06/2020 17:27:29
29 forum posts
19 photos

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Fergus Davidson02/06/2020 17:27:49
29 forum posts
19 photos

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Fergus Davidson02/06/2020 17:30:12
29 forum posts
19 photos

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John Baron02/06/2020 17:49:22
avatar
301 forum posts
122 photos
Posted by Fergus Davidson on 02/06/2020 17:25:56:

img_20200531_151341.jpg

Hi Furgus, I would have drilled and tapped the pulley directly over the key. That would stop any movement of both the key and the pulley.

Having said that I've also seen a screw put into a shaft to stop a pulley moving. In the old days a tapered key would have been used and hammered in. You might have seen them on old machinery, they had a raised section on the end so they could be extracted.

Hollowpoint02/06/2020 19:49:20
331 forum posts
31 photos

Looks like you are sorted now but I converted my AUD to a inverter/VFD a few years ago. Probably the single best upgrade ive made to the boxford. It runs so much more smoothly and is a lot more convenient to use now. I would highly recommend it. A project for the future perhaps.

On the bearings, don't cheap out! Its not worth the hassle. Try to get decent branded ones. (FAG, Timken, Koyo, SKF)

Brian Morehen02/06/2020 20:07:01
avatar
85 forum posts
6 photos

Bearings is really a matter of choice sealed or not they are normaly grease packed for life,, Prices depends on the dealer if this is a large concern they are normally cheaper , Trade prices can be as much as 80% discount,

Good luck

Brian m

Fergus Davidson02/06/2020 23:19:52
29 forum posts
19 photos

Thanks, believe it or not I've got a Jaguar CUB inverter on order from Pete Moss at Transwave. I just need more control. I really need the best I can get but also have to keep my head during this lock down. Crazy timing I guess, not just for me.

Regarding the bearings, I've been looking at SKF at Simply Bearings. Quite a price range. I could pay £90 for one but I think that's out of my league and perhaps overkill. Maybe they're for marine use or the auto industry? Anyway I have to get 6 in 3 sizes so I'll try and get the best I can for around £30 a pop. They'll probably last as long as I use the lathe and maybe I'll be in a better place to buy higher end once they wear.

I'll update once everything arrives and I reassemble the lathe. It's at least comforting to know it's spotless inside now... for a while anyway.

Fergus Davidson11/06/2020 21:17:59
29 forum posts
19 photos

Finally everything arrived after the 3rd attempt at ordering a sealed bearing and getting an unsealed one through the post.

The inverter has taken the lathe into another realm. Quiet and hopefully more efficient. It's at the very least good to know everything is clean and functional.

Thanks for all the suggestions. Here are three photos .

Fergus Davidson11/06/2020 21:18:27
29 forum posts
19 photos

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Fergus Davidson11/06/2020 21:18:47
29 forum posts
19 photos

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Fergus Davidson11/06/2020 21:19:23
29 forum posts
19 photos

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Brian Morehen12/06/2020 10:13:19
avatar
85 forum posts
6 photos

Well done sounds good bet you are pleased with your work, Just keep a watchfull eye on all you have done any noise that you are not used to have a look and find sometimes saves a lot of work later.

Nice to hear a success story.Regards Brian.

Mike Poole12/06/2020 10:43:27
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2578 forum posts
60 photos

A bit late to join in on this one but in some of the early photos it looked as if the pulleys were misaligned, if you use a straight edge on the side of the pulleys you can check that the pulleys are in the correct position along the shaft and that they are parallel with each other. Make sure you allow for any difference in the thickness of the pulleys. It is surprising how misaligned pulleys will try to walk along the shaft. You may have found that the motor had moved and was generating your original problem. Glad you have it running sweetly now but could still be worth an alignment check.

Mike

Mike Poole12/06/2020 10:45:11
avatar
2578 forum posts
60 photos

Double post

Edited By Mike Poole on 12/06/2020 10:45:44

Fergus Davidson12/06/2020 11:20:20
29 forum posts
19 photos

Will do. Thanks again one and all! I'm not going to miss anything any more if I can help it.

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