Union Jubilee Clutch.

[pwdrive]

Hi Col, is the clutch idea to provide instant disengagement? If so, try a spring loaded levered idler, if i am missunderstanding then please ignore.

Lawrence.

[Retired]

Hi,

Many thanks for your idler suggestion Lawrence and this would possibly work if I could install one but apart from seeing the top of the belt the rest of the belt is fully enclosed and space around it is tight; this is why I opted for the harder option of tilting the motor. Just aligning the pulleys is difficult; this isn't the easiest of lathes to fit a clutch to but I'll stick with it.

You've got the right idea though Lawrence because all I want to do is to leave the motor running but stop the mandrel which sounds so easy to achieve; I could install flat pulleys and belt which is another option I haven't mentioned.

I'm surprised the lathe still drives whilst the belt is so slack; if I had clear access I could deflect the belt to see if there was a point where it wouldn't drive but I can't get at it to try.

I'm used to playing around with machinery so I hope I'm not encouraging anyone to take any risks by adding my story; I'm very much aware this motor could inflict serious injury if I made a silly mistake and I'm working with an open "T" box which should be fully lidded; a good earth is connected.

Kind regards, Col.

[pwdrive]

It's supprising how much a slack a flat belt will grip, the one on my old Dominion combination machine used to flap like the clappers, it drove via the gearbox the feed rollers in the 16 x 9 planer/thicknesser it pulled a 24 ft 12 x 6 Dougie Fir through it!

Lawrence.

[pwdrive]

Just a thought, if you want to disconnect the driven power to the mandrel why not just switch the motor off, with a job in place it will stop a lot faster connect to the motor than it would if left free spinning de clutched or am I way out here.

Lawrence.

[Retired]

Hi,

Thanks Lawrence for giving this some thought.

A few years ago I burnt out a very good 1.1KW single phase motor fitted to my Myford lathe whilst I was gear cutting; with a start/stop every minute for hours on end the motor expired in a cloud of smoke. I'm installing a 3 phase motor into the Jubilee and I want to keep this running through the VFD whilst being able to stop the mandrel; I could simply use the VFD but I want to remotely mount this as they are not happy being covered in dust.

When I bought this Jubilee last year it was fitted with a very old 1/4HP Hoover motor being started and stopped from the 13A socket. I've never attempted to fit a clutch to a lathe before so it's a project for me.

Kind regards, Col.

[pwdrive]

Ok, with you now Col.

Lawrence.

[pwdrive]

Ok, here's another, hows about a variable pulley, something along the lines of the old DAF Variomatc, you could arrange for the pulley faces to be moved further apart than the DAF so the belt drops on to a free running collar when the drive power needs to be disengaged, I am not too well up on variable pullies but you might be able to kill two birds with one stone ie, variable speed and de clutch all in one and in the available space.
Nut's or what...

Lawrence.

[Yorkie]

Ok, here's another, hows about a variable pulley, something along the lines of the old DAF Variomatc...
Lawrence.

That variomatic drive was a wonderful system. In the late 1960s I had a Raleigh 'Ultramatic' moped which I used to commute to the train station in Nottingham - about five miles each way. For a year, in 1968 I used to travel daily by train down to Northampton - about 100 miles. (£3.00 a day expenses, and a monthly season ticket was £11.00! The only thing that kept me sane was that to my ears, the train wheels didn't rhythmically go 'diddly dum, diddly dum', but 'three pounds a day, three pounds a day'!). I used to ride to the station, chain the moped to the railings, do the return train journey, then ride home on the moped. On Fridays, I left it chained to the railings over the weekend, drove my car down to Northampton and used it to drive around on business during the week, driving it back home on Friday afternoon. I guess that nowadays, some jobsworth or another would be down on me saying’ you can't leave that chained up there' or slapping a ticket on it.

The Ultramtic was a splendid steed. One kick on the pedals and it started right away. No clutch - just a throttle. It ticked over like a sewing machine and at tickover, the belt slipped so it was like being in 'neutral', but as soon as you opened the throttle, the two halves of the pulley came together by centrifugal force and were loaded with quite large metal balls which - as the speed increased - had the effect of pulling the halves of the pulley closer together so that the diameter of the pulley varied smoothly from minimum to maximum diameter as the belt rode up the pulley. The engine was mounted on springs to enable it to move as the belt pulled the engine backwards as the pulley grew infinitely larger towards maximum diameter. Never skipped a beat.

This was back in the days when mopeds weren't restricted and the 'Ultramatic' would top out at about 45MPH. It was a real joy to ride and I rather wished I'd kept it, but when the need for it no longer existed, it just became clutter so it had to go.

I'm rather surprised that more use isn't made of that system - no clutch no gearbox, smoothly variable speed - what's not to like?

For lathe speed control they seem to have gone down the electronic route, often using inverters/3-phase motors. The lathe that we have at our woodturning club has the motor within the headstock and the drive shaft integral to the motor, the speed being varied electronically with a built-in inverter. It gets quite hot in use and if the motor or electronics fail, basically, the lathe would be a write-off. I'm just glad it isn't mine. I have the same make of lathe, but with a 1.5HP motor driving a eight-speed pulley. It only takes a couple of minutes to change the speed but would be much more convenient if it was variable. Often you need to turn at high speed - say 2000+ rpm, but then a much slower speed (say 300 RPM to sand an item or you risk cracking the wood through overheating it. I'm unlikely to ever need 1.5HP, though the headstock can be swung out and an outrigger used to enable larger diameter items up to 29" diam, (a spinning wheel for example or large platter) to be turned.

As I'm left-handed, it is handy to be able to swivel the head outwards from the bed when hollowing out bowls, but as it has a 16" capacity over the bed, for anyone right-handed, it would cope with most things most turners would want to turn. (The lathe model is '16-44', which means that it has a 16" swing over the bed, and can be extended to 44" between centres for spindle work). When I switch the motor off, I can slow the lathe to a halt with my hand as on the other end of the headstock shaft I have a hand-wheel. It takes ages to slow down to a halt if it has say a large bowl on it. 'Officially', the hand-wheel is meant for turning the shaft with the lathe switched off when using the indexing mechanism, but what the heck - everyone with a hand-wheel does it, (while they still have a hand to do it with!).

I don't want to take Colin's thread too far off topic, but I've attached a few pics of my lathe and motor/pulley arrangements. Think how much more convenient it would be if it had a simple 'variomatic' drive rather than an eight-stepped pulley or, an expensive and complicated invertor/3-phase motor arrangement such as on the Nova DVR-XP. None of which is of any help or relevance to Colin in his quest for a clutch arrangement for his Jubilee. Sorry about that!

[AlanBeckett]

Train Station? David, you heathen!

My Chipmaster has a 3hp motor and drives the Spindle via a Kopp Variator, a Matrix multi-plate Clutch and V Belts. The Clutch is surprisingly small. It runs up to 3000 rpm. It doesn't care what speed it's set at when you start it up, or what's in the Chuck. I bet Col's old Colchester was even more brutal.

Myford used slipping belts for many a long year, particularly on the Tri-leva, so it must be possible to get it to work. It's mainly the lack of space that's the problem I suspect.

Col, can't you mount the Inverter controls remotely? Most of the ones I've seen allow that. Essentially you just need a couple of Switches and a Pot in a box.

Alan

[Retired]

Hi,

No you are not nuts Lawrence unless I also am. Thanks for giving this project so much thought. Yes a variable pulley clutch would work and like you I considered such a pulley amongst my other options. Unfortunately adding such a clutch would be well outside the scope of the guy in a small home workshop; obtaining such a clutch could prove a major problem and possibly lead to a lot of extra cost. One thing I omitted to add is that this 3 phase motor only has a short shaft not even long enough to fully support the standard stepped pulley which I've reversed on the shaft to bring the 4" diameter pulley over the shaft; I could easily turn an extension bush but I wonder what length of shaft would be required to support a variable pulley? The further away from the motor the drive is the more the motor main bearing is loaded; adding an outboard bearing assembly is possible but given the space problem within the pedestal I would like to keep this Jubilee clutch as simple and cheap as possible. Good idea though Lawrence and we are thinking on the same lines.

Thanks David for adding the pictures of your lathe which is a beauty and I know it gives you much pleasure; Bron and I are happy to display items you have superbly turned on it. You are going back a bit David regarding the Raleigh Ultramatic moped; the only progress from those days has been to introduce gimmicky paint-jobs and lots of plastic; I can't think of anything new in motorcycles apart from electronics which hasn't already been tried and tested years ago. My late father used to own a Mobylette moped and one day he was not at all happy when I arrived home having just bought my Ariel 1.000cc Square Four.

All information is welcome David and is it possible to go "off topic" on this forum? Regarding the modern variable speed lathe burning out its motor or inverter due to heat build up this is very relevant with this Jubilee project and is why I'm wanting to install a mechanical clutch. Standard motors are happiest whilst running at full speed; this allows the motor to be cooled by the fan but once the speed drops but the motor is still giving full power due to fancy electronics you can guess how this affects heat build up? Lathes are constantly subjected to rapid start/stop cycles and although this is bad enough with a 3 phase motor on a single phase motor it can be catastrophic; it's very impressive to blow up a 1.5HP single phase motor due to repeated cycling but also highly expensive as I found out whilst gear cutting.

Where I worked at Book Motors we supplied inverter rated motors and still do but we also supplied FVU's (Forced Vent Units). These units consisted of dedicated motor and fan built into an extend fan cover which directly replaced the original fan cover; this fan then gave correct cooling during low speeds but of course it wasn't a cheap option. also the extra length was added to the motor.

As you will probably know David having a lathe fitted with a remote potentiometer to control the lathe speed from zero to its maximum of around 3,000 revs only encourages knob twiddling; winding the speed up and down using the pot is obviously very convenient but it can also render the lathe scrap if the motor is a special built into the headstock also such a motor/inverter if they fail could cost more than the actual lathe to repair; they certainly are not cheap items.

Thanks Big Al. Your Colchester Chipmaster is a very capable lathe and I know you enjoy owning and using it; at 3HP it will do anything you ask of it and do it well without breaking a sweat. You are right about my Colchester Triumph though; this had a 5HP two speed main motor and even the suds pump motor was rated at 1/2HP. Like your Chipmaster Alan my triumph was also fitted with a multi-plate Matrix clutch; even with the power of the Triumph I once got the clutch smoking whilst turning a big lump of stainless. The drive was transmitted via three "V" belts and in low gear this was not a novices lathe as there was no stopping it.

http://www.lathes.co.uk/colchester/page8.html

I know flat belts can be made to easily slip but the "V" belt on my Jubilee refuses to do so and as access is so very limited I'm having difficulty trying to watch the action of the belt once the motor is tilted; you are right Alan in that these belts can be made to slip but the technique is so far evading me; yes lack of space within the pedestal is causing most of the trouble not only in mounting the motor and getting it to tilt enough but also the belt is enclosed; poking with a stick to see if there is a position where the belt can be made to slip whilst the lathe is under power isn't something I wish to experiment with; had the belt been open then yes I have no problems doing this kind of thing after all aged 15 in the pit I was poking very long flat belts in order to get them back on the pulley and tracking. Novices please do not attempt playing around with a motor under power or you will surely wish you hadn't whilst sitting in A&E.

As you say Alan I could easily obtain information where to attach a remote pot to control the VFD allowing the VFD to be remotely mounted and in part this is what I'm trying to achieve. I want to remotely mount the VFD but not add a pot to control the speed; David has already mentioned the problems of such an arrangement causing overheating; I would be OK with such an arrangement because I'm aware of the overheating problem so would not resort to twiddling the pot every few seconds. The idea is brilliant and it does work but eventually would the motor or inverter (VFD) fail?

One thing I hadn't given much thought to was to how the speed was adjusted on this Jubilee when it left the factory? The motor mounting is a fabricated heavy steel unit solidly mounted to the pedestal using two very big set screws and washers with the motor mounted directly to this making it one solid unit; the mandrel is obviously in a fixed position so how was the speed changed? Forcing the belt to jump steps in the pulley is sure to result in trapped fingers and many of these lathes went into schools?

I've not yet given up on this slipping belt clutch because as Alan says it must be able to be made to work so I need to find out how to do it? Simply lifting/tilting the motor fails as I've now found out but I believe the problem is the belt location once the motor is tilted; the belt must remain in such a position drive still continues even though the belt is very slack; it's highly possible the solution would be to arrange some kind of belt deflection removing the belt away from the revolving driving pulley? I added a video in an earlier post showing a lathe with a slipping "V" belt clutch but there is very little to give away how this has been achieved; I'm stubborn enough to carry on until I solve this because I'm now fully committed to installing a clutch whatever it takes and however long.

Had the weather not been so bad for most of the year I would have enjoyed scrambling around scrap yards in search of raw materials; I'm thinking on the lines of obtaining an assortment of timing pulleys from car engines; with a pair of these installed in the Jubilee I could order a flat timing belt of correct length but how about this for an idea; as the new timing belt will be toothed then why not turn the belt inside out to present the original outer flat section to the pulleys? As the belt will be flat against flat pulleys then surely it can easily be made to slip?

I've also given more thought to the limited amount of motor tilt; at the moment the "T" box fouls the pedestal but it won't if I remotely mount the box running the leads directly into the motor adding a suitable blanking plate? This would allow a lot more tilt but I believe the belt is slack enough even with the limited motor tilt so I need to experiment a bit; as I'm unable to experiment with the lathe this doesn't mean I can't experiment with a dummy set up on the bench using the motor but driving a spare pulley? OK Jubilee do your worst because I'm now on your case.

Out of interest; I keep complaining about my personal black cloud and how the weather dogs my activities; below is a picture of our sunset taken just now as it is setting at 5.30; we are in a black hole and it's been very cold here all day; this morning I took Bron over to Pudsey and it was lovely and sunny so why do I deserve this lousy weather year in year out? Our forecast for today was 10 degrees and sunny once the early fog cleared?

Kind regards, Col.