Hi Everyone, post #1.

I've searched the Boxford threads and for 'vibration' but haven't found a suitable discussion but apologies if I've simply missed it. The question is probably not Boxford-specific so I hope here is a suitable place to ask.

My late father and I bought one of the legendary ex-school Boxford's complete with stand and 3-ph motor, probably about 25 years ago, from the school where we attended a night class, taking the opportunity when the school decided to replace it with a CNC laser cutter. £400 all in iirc.

I've finally moved the stand to my garage but have always thought the beast was unreasonably noisy. My garage is integral/attached to the house sidewall so I want to keep any vibrations out of the floorslab. I thought this was a good opportunity to set that up. I hope to lift the cabinet off the floor using anti-vibration pads of suitable material and geometry.

My request for help is basically asking for advice whether it's a good or bad idea? Does anyone do this? If it's not unreasonable, what material is recommended?

I've seen the yellow discs sold by Myford. They look like hockey pucks which are considerably cheaper but quite hard, perhaps too hard for low freuency absorption? I've found various thicknesses of rubber-encased, graded cork particles at Cromwell tools and unbranded versions on eB*y.

A concern is that the whole lathe/cabinet set up seems fairly top heavy – the cabinet pads are only 17" apart front to back. If I lift the base by 1/2" of rubber, I believe I need a hard pad to spread the sharp edge & pad loads so they can't 'dig in' and lose stability. I can use some very hard wood flooring between base and isolating material.

I also plan to re-assemble it progressively to discover if any particular part is causing the noise / vibration. I don't suppose it has been adequately oiled or greased over the years. I took off the cabinet door to the coolant pump area today to discover a loose plate that rattled in a suspiciously familar manner! That would be an easy fix!

So, I hope that more or less makes sense. Any advice or experiences would be much appreciated.

thanks and regards

Nigel M

Thanks, Noel. Sorry, posts crossed over. I will definitely have to experiment.

Thanks, everyone, fantastic advice. Apologies again I missed a couple of posts before my previous reply.

I don't remember it being particularly noisy when it was installed at the school, but there was plenty going on in the workshop. I think it was noisier than it should have been in my father's garage, which is why I wanted to try to isolate it from my garage floorslab from the outset. SWMBO sits watching telly just the other side of the wall dividing the spaces. No point creating problems if they're easy to avoid…

The garage floorslab is part of an attached extension, closer to the road. Late 1980's detached, normal footings, cavity wall, single glazing . I was under the impression that passing buses tend to shake the house, which I assumed came through the layer of roadstone which extends all around – the pile was temporarily here before the houses were built – but it might be airborne noise coming through the windows. I will focus on that (instead of trying to ignore it!), to see if I can tell which it is, but I hear your advice it's unlikely to be ground-borne, thanks.

My father re-wired the reversing switch and contactor (?) from 3-phase to single and fitted a suitable motor. I can't remember the power rating offhand but a torch and mirror should fix that. I remember him saying the contactor was tricky but I haven't found any circuit diagram he might have drawn, or maybe didn't reognise what it was for if I did see it, so he could have changed either or both item/s. Whatever, it's now stopped working! Hey ho, one thing at a time…

I wanted to address the feet first because once the lathe is back on the cabinet, I will struggle to raise the whole. I missed your second reference, Michael, I will read it thanks, but the nomograph in the first told me I would needed several inches of movement to be able to absorb 1500 rpm oscillations with high efficiency, if I understood it. I take your point that folk travelling this path end up with an air bed. I was still imagining modestly sized pads would help. I'm beginning to realise that's 'not so much'.

Yep, I said I plan to re-build progressively to try to identify any source/s, but I haven't been able to run the motor yet. The lists of potential problem areas are highly appreciated, thanks. Honestly, going from 'blindly trying it could be anything' to 'try a few of these' is a major step forwards. Also the advice that it's as likely to be panels shaking as rotating parts is useful – the base is a substantial thickness steel (.115" ) with welded dividers that produce 3 bays, all with a 2" lip at the bottom (four bolt-through pads beneath that), the top tray is almost .2" thick. Is that likely to oscillate? The doors seem to fit well but they are 1/16" and to be fair, tapping them produces noise similar to the general cacophany I remember, so I will focus some effort on those. Dedshete and isolate the door lip from the base if possible.

It does have one leather/rivetted chain belt and a v-belt that would have been installed back in the 1980's/90's when we got it, if not before. The chain came apart without too much of a struggle and I expected to reuse them but I will replace them instead in case, as suggested, they are transmitting vibrations onwards, thanks. Is there an improved alternative for the splittable belt? Sadly our local model engineering workshop in Derby, Des Gratton's, closed some years ago.

Think that's picked all your points. Softwood/hardwood point taken, Nick. Really thanks. I'd better go and do something! Apologies it has expanded from 'are rubber feet a good idea?' but it's covered my next few questions as well. Will report progress with photos.

regards

Nigel M

sorry, apparently double-quote close parentheses produces &quot

Edited By Nigel Monk on 04/10/2022 18:08:43

Hello Gavlar, thanks for taking the time to post. So far I've been tracing the electrical circuit so I can pin down where the electrical fault is. Wiring colours are basically what my father would have had to hand, so they are 'unhelpful'. His formative years were WW2 and post war era, so resources were scarce and he carried the 'make do' approach throughout his life. Laudable but slightly frustrating at times. Never had the internet…

I have so far noticed a couple of plates that are loose, the unnecessary material in the cooolant pump space plus the inspection plate (?) on top of the head stock that is normally riveted in place. Both easy to resolve.

Yesterday I managed to get the motor running. The contactor 'press to break' contacts were permanently separated. The contacts themselves looked fine but one of the multitude of small bits of paxolin board had become arranged to separate them and I couldn't see how that was intentional so I filed a bit off so they now make contact. It is a Benedikt and Jager K16 3-phase wired so that the 3 phases are in parallel and share the current.

Damn the thing is loud! The whole cabinet shakes and rattles. There is a fairly loud hum from the motor but overlaid by everything shaking. Not panels oscillating so much as the whole thing going. I could try to tighten the mounts and screw the cab to the floor, but I think I will try to find a properly balanced motor first. I have access to a couple as well as the original 3-ph it came with.

Looking on the positive side, this will hopefully mean the lathe itself is not the source of noise and everything is ok. Time will tell.

Nigel