Good, good good......er...BAD vibrations. Lathe, that is.

[propforward]

I am about to embark on a bit of a project to see if I can stabilize my lathe a bit more. I have actually done reasonably well with it, and I would say I'm getting finishes as good as most get from basic imported eastern lathes and machines, so to speak.

But even so, I think it will be very interesting and perhaps yield some extra improvement if I put a small amount of dollars and some time into the machine I have. I can turn diameters to within a fraction of a thou reliably, so I think a little more work is justified.

My current plan is to remove the lathe from the cabinets it stands on (sheet metal mild steel cabinets that came with it), and modify them with 1" thick steel top plates. I plan to weld the plates on.

I also plan to replace the spindle bearings with brand new SKF bearings, and completely clean out the oil reservoirs for same. I may well replace some other bearings as well, and will look at fit of various items on shafts and make sure nothing is loose.

Also considering removing the motor ( a 2HP single phase item) from the lathe itself and mounting that on its own frame, to see if that removes any motor vibration. The motor will still be connected by a V belt of course, which I will also replace and properly tension.

While I have the thing apart I'll install a DRO too (already have that). As it goes back together I'll check all the cross slides and saddle for play and looseness, just kind of give it a health check.

Interested in any views people have of this work, or any tips, or anything others have encountered along the way that helped them eliminate or reduce machine vibration.

Or am I chasing my tail on a cheap import Grizzly lathe ( a 12 X 32 G9249 - which is now out of production after many years being sold by Grizzly, Jet, Enco and the like)?

Much as I would LOVE a brand new Clausing or LeBlond, just not a very realistic scenario. Might keep my eye out for used ones - but not sure I'm knowledgeable enough to spot a badly flawed one. Might be after this project though.

[ZebraDriver]

Some people have the opinion that a 3 phase motor produces a smoother power delivery than a single phase one. It may be worth doing some research to see if this is perhaps a worthwhile upgrade whilst you are embarking on your quest for a better finish.

Martin

[Sleddog]

Many years ago I had a Jet 12X36 lathe similar to yours. I chased “smoothness” like you’re about to do. At work we had Clausings, Monarchs & LeBlonds.
The one thing that helped tremendously was to install a twist-lock adjustable drive belt.

[propforward]

Some people have the opinion that a 3 phase motor produces a smoother power delivery than a single phase one. It may be worth doing some research to see if this is perhaps a worthwhile upgrade whilst you are embarking on your quest for a better finish.

Martin

Thanks, I had read that, which has me wondering about the single phase motor. I'm thinking going that far (cost of VFD and a new motor) is too far, but possibly just getting the motor off the machine on its own frame mount is worthwhile - relatively low $$'s involved in that. That said, changing to a 3 phase motor could be the icing on the cake if I can clean up some other factors as well.

[propforward]

Many years ago I had a Jet 12X36 lathe similar to yours. I chased “smoothness” like you’re about to do. At work we had Clausings, Monarchs & LeBlonds.
The one thing that helped tremendously was to install a twist-lock adjustable drive belt.

Excellent! That is good to know - I was looking at those as being easy to change but if that can help ease some of the shake that is an easy mod to make.

Thank you sir!

[internal_fire]

Some v-belts can create a lot of vibration. My Grizzly G4002 jumped a lot with the original junk belts. I replaced with good quality Gates belts and the extra motion went away.

I have the linked belts on my mill, and they also work well.

Gene

[tghs]

I've replaced the V-belts on almost all of machines that have them,, I use to have to run my table saw for ten minutes to take the "set" out of the belt for a  day of wood working.. the link belt ended all that..

[propforward]

Thanks for the input all - replacing the V belts is a certainty then. Also, I kind of dissed the 3 phase conversion, but based on some additional input I received and a bit of research, that's actually an intriguing modification. It would give me variable speed control, smoother drive and potentially more power / torque. Also the possibility of a few more rpms, although I mustn't go silly and put more motor on than the mechanics can really deal with - nevertheless I'm going to give that more consideration. Now is the time to do it - all at once while I have the machine apart and the room to work.

[Jasonb]

Going to Polly Vee or Polyflex belts would be a lot smoother than a standard V belt

[Jo]

What you need is a 50+ year old ex industrial lathe:

<a href="https://www.youtube.com/watch?v=d9BX_XBiliY" target="_blank">http://www.youtube.com/watch?v=d9BX_XBiliY</a>

This is what Jason terms a "Knackered old Lathe"

Jo

P.S. I tried thumping the tailstock with my elbow while taking the video but that did not work either 

[Twizseven]

Jo,

For a minute I thought you might have superglued the coin to the top of the lathe.   But then I saw how easy you picked the coin off.

Colin

PS
I knew you would not have cheated.

[propforward]

What you need is a 50+ year old ex industrial lathe:

<a href="https://www.youtube.com/watch?v=d9BX_XBiliY" target="_blank">http://www.youtube.com/watch?v=d9BX_XBiliY</a>

This is what Jason terms a "Knackered old Lathe"

Jo

P.S. I tried thumping the tailstock with my elbow while taking the video but that did not work either 

I agree. And such machines are around, for not too much money even. I’ve found what looks like a potentially decent Clausing locally - my fear is that I don’t assess it well and pick up one that really is knackered. But maybe I just take my DTI and give it a really good going over.

[Jo]

Look at the paint work: If it is original the wear gives you a good idea of how much it has been used. Look at the handles/levers/buttons see how worn they look.... Then feel/measure the wear.

With Mr Silky the paint was chipped but nothing showed any signs of wear... Eric just took one look at it (after we turned it on and checked the electrics) and said "you need it" and he was right 

Jo

[Jasonb]

There are many people who will tell you what they think you will need, at the end of the day it's what comes out of teh workshop ( or does not) that matters not what is standing idle inside it

I'll see your pound and raise you 2

<a href="https://www.youtube.com/watch?v=lIVell2vvdQ" target="_blank">http://www.youtube.com/watch?v=lIVell2vvdQ</a>

Not bad for one of those lightweight imported jobbies particularly considering its also running a cheap "reject" 5C chuck, imported collets, insert holder and inserts. 1/2" EN2 1mm DOC. Or could it be it has the OEM Gates Pollyflex belt fitted, certainly seems a lot more supple than some flat belts that have recently been shown hear going onto cleaned up old iron, hate to think what a stiff kinked belt will do to the finish on that machine

I have also read about those tailstocks possibly even on this forum where owners have had to modify the lathe to make them usable, no such problems with my machine. maybe my right arm is use dto working not stroking machines and fondling castings

[Jo]

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

[propforward]

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.

[Jasonb]

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

[Laurentic]

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

[propforward]

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.

[AVTUR]

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