Lathe Vibration

Hi all,

I have finally got around to powering up my Myford M Longbed, using the solar powered motor. My lathe table is a big aluminium catering table frame, with 1 1/2" scaffold boards over the top and also down the sides/back. The lathe is bolted down to a single board and the back bolts also go through the aluminium frame. The counter shaft is also made from scaffold timber and bolted down to the table. The motor is under the table top (inside the cabinet) and the v belt comes through.

All seems well and it seems to work well, but at a certain speed there is a bit of vibration coming through. I'm really surprised by this, the whole cabinet weighs a metaphorical ton.

Any thoughts? Is this likely to be a problem?

James

This is a nice description of 'sympathetic vibration'.....Lots of stuff on the planet vibrates including ALL machines regardless of size, even the bigest. When a machine vibrates at a particular frequency any nearby resonator which has a receptive resonance will start to vibrate as well...ie., in sympathy. The only thing you can do usually is to change the sensitivity of the resonator by adding weight or otherwise changing the vibration frequency, but you can never remove vibration only change it to a more aceptable rate....when it's less of a problem. You could try running the machine with a couple of bags of sand on the bed and see what sort of change this produces......and then adapt things accoirdingly.

.....It might be a good start to unbolt the machine from the table and see how things are as you carefully retighten....hoping for a 'sweetspot'

My Craftsman lathe is no light weight and is bolted to the floor,runs well at all speeds except one of the high speeds,at which it is subject to some vibration,which I cannot account for. It,s not really a problem since I seldom use that speed,just odd !

Drive belt alignment and too much belt tension can cause some vibration, worth a check in those areas. Mike.

Whats it like when its off that cabinet?

Have seen and experienced a few times mills suffering same problems bolted to seemingly unbreakable robust wood. One the bench was made from railways sleepers and the tops. Never heard anything so loud in all my life.

Hi all,

Thanks so much for the advice and feedback. I'm going to have a fiddle about over the next couple of days and will feedback.

Kind regards,

James

Hi all,

I have fiddled about and managed to reduce it quite a little, took some initial cuts today and I cannot see that the vibration is causing any issue. Which is good news.

Rather excited as I took the first cuts, with the sun beating down - using the free power!

James

Hello James

How do you propose to run it over the winter, and/or in the evenings after dark? Battery storage?

It is likely that the vibration results from an out of balance in the drive to the spindle. At higher speeds, my hefty, 300 Kg, BL12-24 (BH600 / Craftsman lookalike) vibrates, slightly. The pin in the Bull Gear to engage backgear is the most likely culprit. So, the same device on your Myford M may well be source.

Probably, lots of us suffer the same problem, for the same reason. As long as the vibration is not excessive (If it makes the machine walk about, or gives you double vision; it is) but does not cause problems with producing the required standard of cut, I should live with it.

Howard

I ran the lathe yesterday, most of the day playing around and didn't really notice the vibration causing a problem. I was struggling to get a fine finish, but I think that's me needing to get a proper grinding set up so my finishing tools are less of a point and generally sharper. Plus the Myford/Drummond has a minimum fine feed of around 6 thou, which I have always found leaves ridges.

Yes, we have a battery bank, which gives us capacity once the sun goes down, but being my place of work I'm mainly there during the day. Yesterday, which was reasonably sunny, although late autumn low sun, the lathe was using 160w to tick over at 800rpm and 240w to take 10 thou cuts in 1/2 to 3/8" mild steel at the 6 tho feed at around 800/900 rpm. Using a die to cut a 3/8" BSW thread with the backgear required around 80w. The solar panels, were producing around 300w at the time I looked, so running the lathe and still charging the batteries. They have a theoretical power when new (they are ex-solar farm) of around 750w on the perfect spring day, at the perfect angle etc etc.

Link belts, with their high inherent losses, are good at damping vibration. Belt drives can vibrate horribly. Brammer or Powertwist belts make the primary drive on Myford Super 7s much sweeter, in my (and others' experience.

Ordinary V belts can sometimes take a set and that can cause vibration, this can be helped by letting off the belt tension when not in use.

To get a better finish on the lathe on auto feed, put a bigger radius on the point.

Ian S C

Hey! Who defaced my post with a vile, smirking emoticon(?). I typed a closing bracket. What's going on?

I've noted comments on here that if you add a space between the last character and the closing bracket then the dreaded emoji will not strike !
DaveD

.

The single most irritating feature of this forum ... The software is set to "autocorrect" some sequences of characters.

We have been whinging about it for years.

MichaelG.

Hi James J 1,

I'm going to send you a PM within the next 24 hours.

regards,

Sam

If you don't want that ********* emoticon, just leave a space before the the closing bracket. Took me a long time to find that; still waiting for the blood pressure to fall back to normal!

Howard