Union Jubilee Clutch.

[pwdrive]

Hi,

I too had such a morticer many years ago Lawrence just as you describe; it was cast iron construction built like a battleship and weighed about the same; the long arm must have been around 4' or 5' in length with a very large round cast iron counterbalance which used to bash against the side of the machine; the cross slides were also substantial but it certainly punched holes into thick timber with little effort; the problem was that because of the long arm it needed a lot of space so in the end had to go. Mine was very similar to this;


Vintage morticing machine.

This slipping belt clutch is evading me; I've just come out of the workshop still without success; I rigged up a pair of belt deflecting fingers as shown in the pictures making these adjustable but the belt still drives having tried these fingers in many positions. With the motor tilted the belt is very slack and I can nudge it with a stick to stop it driving but as yet I'm unable to achieve this by simply tilting the motor. I've also just tried mounting a bearing on a bracket but this too has failed. I could enjoy this project but every time I visit the garage to do any work it's very cold but at least I've managed to leave the car out all day without the car getting a soaking.

I'll stick with it but the main problem is access to watch the belt otherwise I would have this job well sorted by now. What a life; the sun is now tormenting me by blinding me through the window. Each method I try is one method less and eventually I'll have tried all the unsuccessful methods first before I succeed?

Kind regards, Col.

Hi Col, yes that's the one, almost the same as the one I had.
Good luck with the clutch.

Lawrence.

[Retired]

Hi,

Thanks for your good wishes Lawrence; I hope to play around with the Jubilee again over the next few days.

Many thanks Joe for adding this link;

http://vdownloader.com/

I was keen to try it out but when I tried to download the program I received a "Dangerous Page" warning through Virgin Media security? After all my recent troubles with "Snap.do" I played it safe and didn't continue; how safe is this site Joe because I would love to copy some of the You Tube videos for future reference?

Kind regards, Col.

[Joe]

I installed it months ago and haven't had any problems.

- Joe

[Retired]

Hi,

Many thanks Joe; I've just installed it taking a lot of care not to download the extra tool bars etc which these sites tend to load a computer with. I'm very interested in downloading "You Tube" videos to disc as many of these are so useful especially the ones where Baz is showing how to lay veneer using hide glue.

Kind regards, Col.

[Retired]

Hi,

What fun I'm having with this Jubilee clutch job. I thought it would be very simple to get the belt to slip breaking the drive to the mandrel but it's so far proving impossible and over the last few days I've tried lots of ways.

Having the motor hinged gives lots of belt slack but it still drives even though I've tried to separate the belt from the motor pulley using metal rods as fingers; bearings and even strip metal guides all to no avail; to compound the problem I'm unable to gain easy access or to even see the belt in motion as it is enclosed in the head-stock pedestal. With the belt very slack I can't deflect the belt using wooden battens or screwdrivers talk about stubborn; these "V" belt drives are very efficient; had it been a flat belt drive it would easily stop driving with a slack belt. I've also tried to brake the mandrel whilst the motor was fully tilted but there was no stopping it.

   
Hinged motor mounting.

I've already gone to considerable trouble in making a decent job of hinging the motor and this worked perfectly giving at least an inch of lift. As an experiment I grasped a spare new "A" belt in my left hand engaging it into a pulley held in my right hand; all I needed to do was to move the pulley an eighth of an inch allowing the pulley to be turned by hand; moving the pulley an inch in the lathe doesn't stop it driving?

It's time I tried something different? Last night this problem kept me awake for hours in bed whilst I was thinking about all kinds of weird and wonderful solutions. I had considered a variable drive pulley and Lawrence also kindly suggested such a pulley in an earlier post but I dismissed the idea because I wanted to break the drive completely not to vary it.

I then started to think about a "split pulley" one that had a fixed cheek and a sliding cheek arranged in such a manner as to allow the cheeks to fully open thereby preventing them grabbing the belt as is currently happening; I believe the problem to be a wedging effect where the two cheeks are pulling the belt in rather than releasing the belt? If the cheeks could be made to open then the wedging effect would disappear or at least I hope it would allowing the belt to run free as it drops to the center of the pulley.

I've just spent a while browsing the web for split pulleys but found nothing so far I would consider suitable. I have however found a fascinating site showing pictures of how a steel "Split pulley" is manufactured ; this isn't the kind of split I had in mind as I wanted a two part pulley but nevertheless it is interesting;

http://www.scag.com/splitsteelpulleys.html

Being tight I tried to use the original stepped pulley but the unwanted steps kept getting in the way so I dug deep and bought a "Taper lock" insert for a cast iron pulley I had in stock. I was taking Bron to a craft shop in Batley so decided to do a detour in the opposite direction to visit Huddersfield Bearings on the outskirts of Huddersfield. I grabbed the pulley from the garage and bought the correct insert costing £5 (Minimum order) then visited the craft store.

In the afternoon I realized my mistake; I had got a pulley the correct diameter with correct insert but I now had a SPZ with the wrong belt size when in fact I needed an SPA; oh dear I need to slow down but nothing lost because I can still use this SPZ pulley on another project.

The day after I visited Huddersfield Bearings once again and this time simply asked for the SPA pulley and insert I needed the cost was very reasonable at just over £12. I had asked for a 75/80mm SPA pulley with a 19mm bore insert; the pulley supplied was 80mm.

For members unfamiliar with pulleys these taper lock pulleys are truly a delight to install. Insert the key into the motor shaft; slide on the pulley with the taper facing outwards; slide on the taper insert; align and install the two grub screws and tighten; job done. To remove the pulley removed the two grub screws and tap the pulley towards the motor to break the taper. I like these pulleys. Just for interest a couple of years ago I wanted a pair of Whale Tufnol head-stock bearings these being very basic with a single shoulder each; I sent details of the single main bearing to Tufnol and was quoted £150 plus VAT for this one bearing which I thought ridiculous ending up turning both bearings in my garage from a Tufnol blank for under £20; by comparison these taper lock pulleys are dirt cheap.

           
SPA & SPZ pulleys; SPA pulley installed.

I'm still practicing CAD and this morning used Emachineshop CAD to produce a basic drawing of a pulley I have in mind which I could machine in the garage. This pulley has a fixed cheek on a boss but the second cheek is designed to slide on the boss located with a shaft key to prevent it spinning on the boss; a thrust bearing is added and the fixed cheek is given a spacer allowing both cheeks to come together giving the correct belt spacing; I need to do more work on this but I'm thinking on the lines of a car clutch for activation using a forked lever to engage the thrust bearing?

   
My split pulley design.

I'm also considering turning two new flat pulleys because a flat belt can easily be made to slip so I still have options open to me. To add to the problems the motor shaft is very short but problems have solutions if I dig deep enough.

   
Short motor shaft.

All I want is to be comfortable to play in the garage but I believe snow is forecast; this climate spoils many of my projects taking a lot of the interest and enjoyment from them. I'll keep having a go at this project and I'm not in a hurry.

Kind regards, Col.

[Refugee]

I have have been a bit read only on this one, me not being an expert.
The clutch I have seen that may well do the job is the one on a rotavator.
I am not thinking of the domestic ones but the market garden ones with a three foot cut.
They have a cable operated combined clutch and brake that looks like it is screwed to the side of the engine.
I learned how to use one of these machines in a rural studies class at school and can vouch for the functionality of this component.
Disconnecting the drive alone will leave the 25KG of gearbox parts freewheeling.
The trick is to download a few manuals to look at the drawings.

[pwdrive]

Hi Col, in one of my earlier posts I was refering to a variable speed pulley which can also be set to neutral drive, ie one cheek fixed the other variable towards and away from the other pulley cheek to vary the speed, if you then pulled (by whatever means) the variable one back far enough then the gap between the two cheeks would be to wide for the belt to engage and the belt would drop down on the shaft, thus disconecting the drive, on the shaft in betwwen the two cheaks would be a free running sleave made from whatever, the belt would drop onto that in the "declutched position" and afford no grip.

Lawrence.

[Radio Fixer]

Looking at your drwg could you maybe have the pulley moving part always pulled to the open state by a stretched coil spring. The far end of the spring would be operated by a lever topside that would remove the tension to engage drive.

Later: Nope! don't think that would work. What closes it?

Hope I don't have a sleepless night

Gary

[Retired]

Hi,

Many thanks Lawrence for your explanation; I hadn't grasped that a variable pulley could be made to idle thinking it only covered a certain speed range. It's taken me a while to think about such a pulley in depth and as you rightly say a pulley with cheeks separated enough should not provide any drive to the mandrel; these cheeks will require the lower sections to be straight as in my drawing? If I can design and make such a pulley it should be a very neat solution but so far I've not seen it done even on Practical Machinist Forum; I thought adding a lot of belt slack would cause the belt to slip but I was proven wrong so I wonder what lays ahead should I tackle trying to make such a pulley and will it actually work?

Sleepless nights are OK Gary because I tend to get my best ideas in the early hours but it's good to see you giving my problem some thought. I'm pretty well advanced on the special pulley idea and believe the belt will separate the pulley cheeks; it would at first appear the belt will try to drive whilst in contact with both cheeks but having played around for many hours using a fixed or standard pulley I've reached the conclusion that if one of the pulley cheeks is allowed to move in a linear manner the belt will actually force the cheeks apart and as Lawrence says will eventually drop onto the boss thereby affording no drive? Pulling a lever though to apply pressure to the thrust bearing will force the pulley cheeks together allowing the belt to ride up to its correct operating position? It would be possible to spring load the release bearing making default in pulley closed position? I can foresee a lot of experimentation ahead of me which will prove most interesting. So far in browsing the web I haven't found a simple solution other than to use two flat pulleys with a flat belt which will definitely slip if the belt tension is released. This project is shaping up like many of my projects and is biting me.

I've given this clutch project so much thought that I'm now seeing what I want to see and I refer to the video I added in post #16. I watched this video many times and even jogged it to freeze frames; I had seen the guy pull the lever thus slackening the drive belt and stopping the lathe? I was so convinced by this I thought a "V" belt could be made to slip so I then spent many hours trying to get my belt to slip but without success. Why can't I get me belt to slip because it looks so easy in the video; the guy simply releases belt tension and the lathe stops turning?

Eyes can deceive as mine have in this case; this afternoon I spent more time watching this video and sure enough it certainly would appear the guy is stopping the lathe by pulling the lever but he isn't doing this at all; put yourself in the guy's position at the lathe and very; very carefully watch what you do with your left hand; this is so quick it's very easy to miss; the left hand switches off the motor whilst the right hand pulls the lever so what is happening? The guy is simply changing pulley speeds and nothing else; pulling the lever is not stopping the lathe but even after watching this video many times I missed the action of his left hand time and time again?

I could not understand why my lathe would not stop even with lots of belt slack; I thought if the guy in the video could stop his lathe so easily by pulling the lever then surely I could rig my lathe to do the same; I seldom take things on face value but I got badly caught out in this instance. I still have plenty of ideas to play around with but I need some decent weather as I'm sick of playing around in the cold.

I've completely removed the hinged motor platform returning the motor mounting back to standard; I sure can weld though.

Kind regards, Col.

[Retired]

Hi,

With the workshop and garage out of bounds due to dire weather I decided to stop moaning and occupy myself.

I'm still very much a novice at CAD but I am making steady progress and over the last couple of days I've been refining my pulley clutch drawing in post #55.

After spending many hours and failing dismally to get the belt to slip I'm now trying a totally different approach as I like to experiment. I've browsed the web and looked at many variable speed clutches but haven't found one to suit my application; I'm not bothered about the clutch providing variable speed as I merely want it to drive/not drive but in the no drive mode I was worried about the "V" belt grabbing and possibly causing me injury whilst I worked at the lathe? It would be highly dangerous for a 1.5HP motor to suddenly apply power so I've been awake at night thinking about the problems involved; I come up with my best ideas in the middle of the night.

   
Jubilee prototype clutch.

This clutch has grabbed my interest and I'm now like a dog with a bone unable to settle until I sort it out. The drawing above is now updated and hopefully the clutch once made will work as expected? This clutch looks quite bulky but in fact the overall size is only around 75mm diameter and 50mm long.

The material is cast iron and I have suitable blank in stock. The bearings are standard deep groove types readily and cheaply available from "Simply bearings" or cheaper through eBay.

One half of the pulley is securely attached to the motor shaft being keyed and a grub screw will be added making it fixed. The other half is arranged to slide allowing the two halves to open and close. In the closed position the belt will drive arranged so that the top of the belt aligns with the outer pulley diameter.

In order to ensure no drive can take place in the "no drive" position I've incorporated a bearing between both halves of the pulley; as the pulley is opened the belt will be released but my fear was that the belt could still operate as a flat belt if allowed to simply move to the center boss? In order to prevent the belt driving it will ride the bearing ; now lets see if it will drive? I've not seen this tried so can only give it a go but hopefully my theory will be proved correct; the sides of the belt cannot drive because the wedging effect will be lost and the bearing won't afford any drive either; a neat idea but only if it works.

A lot of consideration went into choosing the bearing sizes; the belt bearing especially; rather than having the belt flapping around in no drive mode only limited amount of slack is allowed; enough to release belt tension but still allowing the belt to be very quickly engaged with the pulley; this arrangement also simplifies clutch activation as little movement will be needed. The belt is shown riding the bearing in "no drive" mode.

Two keys are added; one locates the clutch to the motor shaft the other key ensures both halve of the pulley rotate together. Collars and circlips (snap rings) are used wherever possible for simplicity.

To operate the clutch a simple lever coupled to rod or cable linkage will be attached; pulling the lever will apply pressure to the spring in turn applying pressure to the thrust bearing; the outer half of the thrust bearing is arranged to rotate it being secured into the end of the sliding half of the clutch; this will force the two pulley halves together; in order to separate the two pulley halves it will be seen pressure is applied to the other side of the thrust bearing. The lever will be supplied with an "indent" this being either ball bearing or plunger but whichever is chosen it will be spring loaded.

So far I've failed to get the belt to slip and once I can get into the garage in comfort I'll spend a lot of time playing around with this project which I'm finding most interesting. At the moment this is only an idea but I hope to turn the idea into a working clutch.

It's most frustrating that when I want to be tinkering around on my projects in the garage I'm shoveling snow and blasting snow from the car using a pressure washer before I can put the car away. Never mind I can laugh at a huge joke shortly; we put our clocks forward and call it BRITISH SUMMER TIME?

In the meantime I'm enjoying playing around with EMS CAD; it's amazing how much time converting my clutch idea into a drawing has so far taken but it's better than being idle.

Kind regards, Col.