Author Topic: Good, good good......er...BAD vibrations. Lathe, that is.  (Read 910 times)

Offline propforward

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Re: Good, good good......er...BAD vibrations. Lathe, that is.
« Reply #15 on: December 21, 2021, 02:03:40 PM »
Belts are a definite. Jury is still out on the 3 phase motor upgrade - but it is not as expensive as I had at first thought so that idea has gained a lot of ground.

It does seem that with a relatively small amount of work I should be able to make this lathe a reasonable tool - I've turned some decent parts I just think I can make it a little better yet, which will be less expensive than buying a new machine. Oh sure, I'd like to have a new machine (new to me, not necessarily new new, although that would certainly be fun), but truth is I don't really NEED a new machine.

The problem with the place locally where I found the used lathe is that it is a used equipment dealer. Pros and cons to that, but they clean and paint all the machines they sell, thus hiding some clues of past life. There are other indicators of course. For now, since I have the DRO and the steel plates on hand, and one of the spindle bearings, I'm going to stay the course with the refurb. Maybe save up for a replacement machine for in a few years time in the meantime.

I'm about to enter a 3 week period of no shoppe activity for various reasons, so this is prime procurement time to have everything on hand for when I start.

All input thus far gratefully received! Great videos also.
« Last Edit: December 21, 2021, 03:32:41 PM by propforward »
Stuart

Forging ahead regardless.

Offline Jasonb

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Re: Good, good good......er...BAD vibrations. Lathe, that is.
« Reply #16 on: December 21, 2021, 02:57:59 PM »
If you notice my pound was balanced curve to curve on the circular bearing housing to make sure it got maximum vibration and if it moved it wouldn't roll around but fall off  ::) .

Jo

Sorry jo, no rounded parts on these machines, hence all the rough edges :ThumbsUp:

Offline Laurentic

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Re: Good, good good......er...BAD vibrations. Lathe, that is.
« Reply #17 on: December 21, 2021, 03:00:25 PM »
Stuart - I have a round column mill which originally suffered significant vibration. 

I changed the single phase motor for a 3 phase motor with inverter control, and also replaced the two vee belt drive arrangement for a single polyvee belt drive from motor to quill column thus missing out the intermediate pulley arrangement.

Result?  Vibration now negligibile, if this helps your decision making process at all.

Chris

Offline propforward

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Re: Good, good good......er...BAD vibrations. Lathe, that is.
« Reply #18 on: December 21, 2021, 03:29:19 PM »
Stuart - I have a round column mill which originally suffered significant vibration. 

I changed the single phase motor for a 3 phase motor with inverter control, and also replaced the two vee belt drive arrangement for a single polyvee belt drive from motor to quill column thus missing out the intermediate pulley arrangement.

Result?  Vibration now negligibile, if this helps your decision making process at all.

Chris

Great input, thank you. It has nudged the 3 phase motor plan further into the "must do" camp. I have found some very reasonably priced good quality motors so I think I'm going to procure one. If anyone has any recommendations on VFD's I'd love to hear those.

EDIT: One of the things that making using the VFD interesting is that you get to eliminate some intermediate shafting, and therefore some balancing acts. Not having to change belts to change speed will be a win.
Stuart

Forging ahead regardless.

Offline AVTUR

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Re: Good, good good......er...BAD vibrations. Lathe, that is.
« Reply #19 on: December 21, 2021, 03:50:49 PM »
Just adding my little bit.

About ten years ago I replaced my old Myford Super 7 (early model) with a new Big Bore Myford with all the bells on it. The old lathe motor was single phase and ordinary Vee belt drive. The new one was variable speed three phase, through an inverter, and Polly Vee belt drive. Over the ten years of good use, occasionally heavy, I have not had to adjust the belt while the three phase motor gives a very smooth start. I would expect it to run smoother under load but cannot actual see any difference. The variable speed is nice but not necessary.

My recent bought little lathe is like the old Super 7. I am happy with fixed speeds but smoother starting would be nice.

A comment, which has nothing to do with the subject, The little lathe does not have a DRO and I realise I do not need one.

AVTUR
There is no such thing as a stupid question.