Member postings for Nigel Monk

Next step: bearings are bought and received, via eBay; Koyo R16's from henderson c.£14 ea and KSM R12's from bearingsrus c.£9 ea, lower and upper countershaft respectively.

I plan to split the inner races of one each of the old bearings to make well-fitting spacers for refitting, probably using an angle grinder. I think that will make them easily removable after fitting?

My question for today is what or whether to grease the shafts and/or pillow block rebates before pressing the bearings into place - any advice please? I think doing so will prevent rust creeping in, as well as reducing friction while fitting, but I've no idea whether to use copper slip, LM grease, hypoid oil, 2-stroke oil, Castrol M (yep, a very old tin, mostly goes into model diesel fuel), 3-in-1, sewing machine oil is the lightest I know of, WD 40 (just kidding) or simply rely on the light grease that is already on the bearings?

Also, I will cleanup the shaft and rebate fitting areas but presume I shouldn't use a degreaser at risk of pulling any lubrication out of the surfaces?

Or should it all be completely oil free and de-contaminated, including bearings?

Too much imagination, not enough practical experience!

Thanks, Nigel

Thanks each for your replies. I have an aversion to cheap 'n nasty, almost as strong as re-doing a job I've done in the past 60 years...

I haven't progressed to remounting the lathe back onto its base yet - stil lining the duck boards up. If the motor, layshaft and new V belts are anywhere near as quiet as Niels' set up, I shall be extremely pleased. I found I couldn't remove th emotor pulley in-situ so couldn't complete that test. Unfortunately, I will find out when I re-assemble.

I've just shortened a 5-drawer filing cabinet to 4-drawers so that it fits closer to the up and over garage door. I mainly wanted to keep the cabinet to block the view from the pavement of the lathe when the door is open. Not that I'm expecting anyone to come in and pinch the lathe, but it just gets people interested where they don't need to be.

That's made enough space to work around the base so I can get on with de-rusting and painting. Emptying the drawers of 15 yo paperwork, removing identifying names and addresses, took a while. The drawer space will allow stuff to be sorted off the floor and bench some more. Do you find things have to happen in a sequence to arrive at what you're actually trying to achieve? I will be organised one day!

Thanks again, Nigel

Edited By Nigel Monk on 02/02/2023 21:39:58

Hello again, back on the horse. Happy new year - I've been distracted. I think it started with making Xmas cakes x3 following my mother's recipe which we've had for 60 years - she's resigned from the responsibility now she's reached 90 (happy days ).

I managed to buy a VFD at a reasonable price, £115 iirc for a Mitsubishi FR-D720-070 which bizarrely I'm struggling to find a rating for, but I think it's 7A output so approx 1500W.

Both the replacement 1P and original 3P motors are 550W. The 1P is stiff to rotate and winds down after 4 turns from a good spin using the pulley. The 3P runs for 12 turns after a spin of the shaft. Hopefully a good 'un.

My question now - please advise if I should start a new thread - concerns the bearings for the intermediate / lay (?) shaft. These were also noisy and having stripped them from the shaft and pillow blocks, one rumbles while the other is gritty and scratchy.

The old bearings are shielded. Is that an old thing, because I can't think of a reason not to use fully sealed bearings? They will be somewhat stiff and may rob a small amount of power, presumably reducing as the grease warms and thins during use, but they should stay lubed and I can't foresee the need for a metal shield - what potential problem is that guarding against? Swarf? Appreciate any advice, thanks.

The bearings measure 2" x 1" x 0.5" and eb*y discovers 700,000 suggestions on an initial search! Can anyone suggest a reliable source for reasonable price and quality please? KOYO are supplied by Cromwell Tools and eBay at about £20 each. PGN read well but appear to be available only in the US. Had a quick look at Simply and Henderson, etc. Are the 'Budget Quality' bearings ok in practice? I thought stainless was typically quite soft so was surprised to find stainless bearings?

Thanks, Nigel

Thanks everyone for your suggestions, I can't keep up with them all!

Dave - I will take the pulley off and re-check the vibration. That would be a nice easy fix. Well, except I'd need a lathe to true things up lol.

Oldiron - did you bolt through the pads into the cabinet? Do you recall how tightly the bolts were pulled down onto the rubber pads please? The headstock flap had been riveted in place but my father had drilled these out. Perhaps the rivets were a safety measure in the school workshop? I will see if I can put some small allen screws in when I get to that stage.

Yes, I'm please to have found a definite source to work on. I can't think the motor left the factory with a vibration problem? In which case 'something has changed'. I have a vague memory the motor that's fitted is not overly powerful, but I need to check the plate to verify that. Another reason to ditch it if so. There wasn't much choice in the 1990's, at least not with the self-imposed constraints (local paper or Exchange and Mart and cheap!). In any case, the 3-ph plus VFD does sound attractive, just one more thing to look into. I'm so looking forward to being able to make something!

thanks again

Nigel

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

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

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

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

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