Should I use anti-vibration mounts under Boxford AUD cabinet?

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

It all makes sense, Nigel … but [and there is always a but] if you really want proper vibration isolation, you will probably be looking for mounts that give less than 10Hz resonant frequency.

… and with those, I would probably want to put the Boxford cabinet on a plinth [pallet] or fit outriggers.

MichaelG.

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Edit: __ this might get you started on your adventure:

https://www.avproductsinc.com/technical/information.html

… and if you need more : skip lightly to section 9.10 of this 

https://www.cieffeerre.it/cdl/ing/lm.meccanica/insegnamenti/vibroacustica-del-veicolo-testing-e-simulazione/materiale-didattico/simulazione/e_rao_ch9/at_download/file

Edited By Michael Gilligan on 03/10/2022 19:58:03

**LINK**
this thread covered some uses of hockey pucks

Mike

Is your house and garage built on one single, combined slab? Or does the house have the more usual footings under the walls? If the footings are of the usual type with in-fill for the floors, vibrations should not be a particular problem wrt transfer from one flooring slab through to the other.

‘Vibrations’ are typically caused by large panels oscillating ‘in sympathy’ with the source. Bolting the base to 4 points but still allowing those vibrations seems, to me, to be the wrong way to go about preventing them - only reducing any transfer to the immediate flooring.

.

Agreed … That’s why I wrote what I did

MichaelG.

If your are worried about the top heavy aspect just bolt on a couple of bits of angle iron as outrigger feet. If a 3/4hp motor is making your whole house vibrate the foundations must be sitting on jelly. First identify the source of the vibration by taking off the belts and working through putting them back on.

Wondering what the source of the vibrations is. If it's the lathes motor, I suggest putting some sort of rubber insulation between the motor feet and the mounting plate on the lathe Iathe. I actually have a thick sheet of rubber under my motor, on the Myford. It was given to me by another club member who said it was a piece of conveyor belting. I was getting peculiar marks on turned work which stopped after fitting the rubber. That was with the original single phase motor but I have retained it under the 3 ph motor that I now have, controlled by VFD. Its a Newton-Teslar set-up which I am very pleased with. Can thoroughly recommend fitting one. I'm just a satisfied customer and wouldn't hesitate to purchase another if the need arose.

Can't think what's causing the vibrations if it's not the motor, unless there are loose components somewhere on the machine or its base.

John

Edited By DMB on 03/10/2022 21:22:00

Bolt the thing to the floor Then put deadening panels inside the cabinet, the cabinet is the most likely sorce of noise. Mount the motor on rubber exhaust mounts - go to a motor factor find the old boy in the place and ask for something like a mini cotton reel, only bigger, eg renault.. He'll know what you want. ! Noel.

Thanks, Michael and Mike. Good to see others have used pucks for similar purposes. I did notice some for sale on eB*y that claimed to meet the professional hockey association specification so hopefully they would not be cheap n nasty types. I have been using a generic puck on my trolley jack for a few years - it doesn't complain about being forced against a protruding nut and happily rebounds afterwards. I also recently noticed they are available with grooves and jack-cup shapes ready moulded in for the purpose.

10Hz is sub-audible? I can't imagine a material with that resonant frequency that would also take a substantial load. It makes me think of polystyrene foam, or blancmange/jello, or pretty thick rubber? I have a sample of the 12mm rubber/cork mat which gives quite a low frequency thud. The Cromwell site states the load capacity is 0.5MN/m2 (500kg/dm2 or 32kg/in2) so the 276kg Boxford would only load say four 4" square pads gently (about 10%) and thus not induce high damping, leaving it to work at its lowest frequency as well as possible. Maybe bigger pads at the heavy end. If only I had borrowed a 'bit more' before I left that work lol.

The bed will need something to lift it to accommodate the unevenness in the floor anyway. I'm still nervous about lifting the lathe 'even' further from the floor and might make the mounting deeper fore and aft an inch or so. I think the pucks would remove any harsh noises? Maybe a compromise using the rubber/cork at the light end.

I will continue to think - the electrics aren't working atm anyway lol... Any other experiences would be appreciated. The cabinet wasn't bolted down in my father's garage - could that make vibration noise worse?

thanks, Nigel

https://www.cromwell.co.uk/shop/power-tools/machine-mounts-and-materials/tp041560-machine-mounting-material-anti-vibration-pads-19mm-1-2m-x-100mm-1/p/TCO4527850K

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

.

Please have a look at my second reference, Nigel

[and also study the nomograph in my first]

If you genuinely want isolation, the resonant frequency of the suspension system needs to be significantly below the frequencies you are isolating.

Optical tables, for example, are often 4Hz or lower !!

MichaelG.

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Edit: __ with all that said, I agree with the other contributors … the problem is more likely panel vibration, and much more easily suppressed.

Edited By Michael Gilligan on 03/10/2022 22:12:30

Dedshete self adhesive bituminous pads are used for anti drum sound deadening in automotive and other applications.

Mike

Hi Nigel, I have a CUD with a single phase 1HP motor and don't get any real vibration issues, and it just stands on a couple of slats from a pallet. I haven't experienced any tendency of it wanting to topple one way or the other, even when turning a fairly heavy piece, which was slightly out of balance. I wouldn't use hardwood and I suspect that would just transfer any vibrations easier. Pallet wood will allow a machine base to mould into itself much better and will probably absorb vibrations much more.

Regards Nick.

Edited By Nicholas Farr on 04/10/2022 08:39:31

Have you got old belts on it? If so new belts should be fitted to see if they are the source of any vibration. Usually 3 phase motors are close to silent when running. If you run the motor without any connection to the drive train is it quiet? If you drive the spindle but not any gearing is it quiet? You need to find the source of the noise and try to reduce it at source before tackling the symptoms. The only time my lathe makes significant noise is when doing interrupted cuts and they are soon gone.

Martin C

+1 - that's the proper engineering approach.

Starting right at the beginning can we assume that the lathe still has a 3-phase motor? If so, and you don't have a 3-phase supply, how is the motor being driven?

Andrew

As a side note, my experience with the yellow levelling feet is that they are crap. They are only good if you like the idea of introducing instability and wobble to your machine. 👎👎

++1

At the moment the evidence doesn't pin down whether this is:

• A normally noisy AUD that it's hoped can be made more quiet, or
• An AUD that's excessively noisy due to one or more faults that need to be fixed

I've never seen or heard a Boxford AUD in action, but they don't have a reputation for being unusually noisy; I expect the opposite. Of course lathes of this size do make a racket, but it would be good to know if this one is unusually bad, i.e. faulty.

As a benchmark, the two cooling fans on my Chinese WM280 are about as loud as my workshop radio (so I can't listen to it), and the noise roughly doubles or triples when the machine is cutting. I can talk to someone at my side when the lathe is cutting, but have to raise my voice if they're more than a metre away. The lathe is only ear-defender loud if I allow a cut to chatter - operator-error - carbide on overextended steel etc. It doesn't create much low frequency vibration - the racket is mostly audible noise that wouldn't be reduced much by rubber feet.

Excessive noise - a few suggestions in no particular order:

• Loose, misaligned or faulty motor
• Loose, dented or bent panels
• Hardened belt causing bumping as it rotates
• Failed bearing(s)
• Change gears set too tight. (Allow gap about the thickness of a sheet of A4)
• Adjacent change gears rubbing. (check spacing between facing gears)
• Broken teeth (change gears or in the fixed gearbox)
• Bent shafts, pulleys, or gearwheels (any suspicion the lathe has ever been dropped?)

If it were mine I'd try to isolate the source(s). For example, if the noise persists after disengaging the banjo so the motor is only turning the spindle, it suggests the problem is in the headstock bearings, belt drive, or motor. Also, with the machine unplugged, try:

• heaving on the chuck horizontally, vertically, and in-out: it shouldn't move.
• turning the lathe over by spinning the chuck by hand. It may be possible to feel rough spots, tightnesses etc that point to a particular faulty part.

Sound sources can be a pig to pin down. A stethoscope or wooden rod used as a stethoscope helps.

Dave

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 "

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

Hi Nigel, you can replace your old-style link belt with a modern type, often referred as twist link Fenner V belts They are available from various suppliers and there are various different makes, price and quality also varies. My lathe still has the old type, but that doesn't make any significant noise or vibrations, as the rivets should not actually make any contact with the V pulleys. If the rivets are making contact, then either your belt is the wrong size, or the belt or pulleys are very badly worn.

Regards Nick.

Edited By Nicholas Farr on 04/10/2022 19:11:34