Wanted – small pulley project and/or engine mounts..

[Ian Whittaker 3Participant @ianwhittaker3]

Hi guys, I have an old 1923 motorcycle and it needs a 7” pulley to fit onto my gearbox shaft. Alas parts going back 100 years are nigh impossible to find, so was wondering if anyone had the skills with a lathe to make me a new one?? Or could potentially recommend a company which might have something off the shelf.. Happy to pay for materials and of course time!!

Basic specs, 6 3/8” diameter pulley, pulley for 5/8” belt, inner bore 3/4” threaded (hole), etc.. more details to follow if my takers??

 

Another problem is I have some missing engine mounts, if I can make a model of what I need, has anyone got any ideas on how I can get them cast into metal etc??

 

Thanks Ian

Edited By Ian Whittaker 3 on 02/11/2021 16:04:16

[Ian Whittaker 3Participant @ianwhittaker3]

[Howard LewisParticipant @howardlewis46836]

You really need to provide much more detail of the parts that you seek.

For instance, where is the belt line relative to the shoulder or taper on which the pulley is mounted.

What sort of 5/8" wide belt? Flat, Vee? If so what section?

Otherwise no one is quite sure how long you want your piece of string!

Providing an accurate model of your engine mounts is a good idea.

But of what do you want them made? Rubber, (Any idea of the Shore hardness? ) Nylon? Steel? Aluminium?

A few answers might elicit a few responses.

Howard

[Tony Pratt 1Participant @tonypratt1]

Howard is right we need more details also where are you situated in the UK?

Tony

[noel shelleyParticipant @noelshelley55608]

Many of us may be able to help you but we need ALL the details ! Noel.

[Ian Whittaker 3Participant @ianwhittaker3]

Hi, Thanks for your interest and I've knocked up a simple drawing of dimensions etc.. I'm also located near Northampton, if that makes like easier??

Overall it's a V Pulley, 6 5/8" circular, with slight indentations either side to allow clearance of the gearbox cover. 1'4 Deep one side and 1/8" the other to allow for a bolt. I didn't it put on the diagram, but the centre indentations should be the same depth for 2" from the centre spot…

 

If anyone fancies a challenge, I would love to hear from you!! – Ian

Edited By Ian Whittaker 3 on 03/11/2021 13:47:06

[noel shelleyParticipant @noelshelley55608]

Cast iron ? What about re machining a polly V pulley ? There not dear and readily available. JUST A THOUGHT ! Noel.

[Ian Whittaker 3Participant @ianwhittaker3]

I am open to all suggestions, however the pulley is being used via a belt to power the rear wheels of a motorcycle, so as long as it’ll take 2-3 Horsepower without disintegrating?? So had originally thought of something in metal eg Aluminium etc?? I would love to get my hands on a lathe and probably would take 5 mins or less to make something, but alas I don’t have any space at mine to get one!!

[Tony Pratt 1Participant @tonypratt1]

5 mins

Tony

[Dave HalfordParticipant @davehalford22513]

That's an odd belt profile, do you have the belt or whats left of one?

[Howard LewisParticipant @howardlewis46836]

90 degrees is a very strange profile for a Vee belt.

The standard for many years has been 40 degrees.

And turning such a pulley will NOT be a 5 minute job, on a manually operated machine, by ANY stretch of the imagination . Possibly not even on a CNC machine programmed and tooled for high volume manufacture.

It will involve at least two set ups, and that is after making an arbor to carry it for machining. (Which will take a lot more than 5 minutes, for starters )

A commercial machine shop, if they took on the job, would probably charge you at least an hour for labour, plus overheads. So, being realistic, neither a quick, nor cheap, job.

How is the pulley located on the rear wheel hub?

Does it just rely on the friction created by clamping against a flange, or a keyway / splines? 2 -3 hp will need a fair clamping load to prevent slipping. And the material of the pulley will affect the clamp load required.

And a piece of steel or cast iron (Assuming those would be the most suitable materials ) is going to be 170 mm diameter as raw material And a 16 mm slice is going to be literally cutting it fine to clean up.

You need to carefully check the driving pulley profile, and ensure that the belt line will be correct, Otherwise you are spend a lot of time renewing belts, and possibly even bearings!

Howard

[not done it yetParticipant @notdoneityet]

In addition to the above, I expect you would need a twin-sheave pulley to transmit 3 HP, particularly if the belt is a long one. Thought that a tension pulley/device may be required?

[Pete.Participant @pete-2]

If it only takes 5 minutes I'm sure you can find the time to learn metal turning, that should take you all of 10 minutes.

[Howard LewisParticipant @howardlewis46836]

A B section belt would have a top width of 17 mm, which is almost 0.050" wider than 5/8", and be 40 degree cross section, so may be what you need.

So that is the first amendment to your drawing..

How close a fit do want the bore to be? Drilled, or reamed / bored?

3/4 is open limit so could be + / – 0.015", which would be a sloppy, and unrealistic, fit for a pulley intended to transmit power.

I think that some more research and thought is needed before quoting dimensions, let alone targets for production times.

Howard

[EmgeeParticipant @emgee]

Ian

Check your INBOX on the top menu bar.

Emgee

[Ian Whittaker 3Participant @ianwhittaker3]

Hi, thanks for the info and Emgee thanks for the email. As you may appreciate what I need cannot be bought off the shelf, as the gearbox itself is nearly 100 years old. I have seen photos of the missing part, but alas not in sufficient detail to get accurate measurements. I suspect it’s going to be a trial and error approach in trying to get this right. Apologies if I have offended by saying 5 mins to make, but how hard is it to take a circular blank and perform 4 basic machine operations on it?? As I am keen to learn and the pitfalls / problems in doing so??

Ian

[Howard LewisParticipant @howardlewis46836]

The more detail that you can provide, the less will be the trial and error. involved.

Making steel or cast iron items of that diameter, and then scrapping them because they do not do what is required will be an expensive hobby.

At least, you need to define the groove more precisely, and the tolerance on the bore.

Incorrect or vague details will only result in some kind soul making an item that is at best, not fit for purpose..

A B section belt with a 40 degree angle won't function well in a 90 degree groove

An open limit, possibly drilled 3/4, bore will be a loose fit on a shaft that is 0.750 + / – O.001", and will wobble or run eccentric, neither of which will be good for the belt of the bearings at each end of the drive train.

You need to measure the shaft diameter accurately, not with a tape measure or 6" rule.

As in "four basic machine operations" I would take six, or seven, plus making an arbor, if you want reasonable accuracy.

Do the photographs of the original show any fixing or lightening holes? If so, more operations required !

I may be wrong in that, but over 40 years in manufacturing industry makes me think that way.

Hopefully, some kind soul will take pity, and close enough to you that you can watch and find out what is entailed in making your pulley; when it becomes clear exactly what is required.

Face to face to contact and accurate measurements are what is needed, before cutting metal.

Based on the information provided so far, it can be made, but you will probably not be satisfied with what you get.

I certainly wouldn't be!

Would you like me to set out the machining operations, and the order in which I would do them, for you?

That would give you a better understanding of what is involved. If so PM me.

Howard

[BazParticipant @baz89810]

Many years ago my brother in law told me that machining couldn’t be that difficult because we all done metalwork at school and it was only a case of turning a few handles. I won’t repeat my reply but he got the message load and clear.

[Pete.Participant @pete-2]

If you want an idea on what's involved machining a belt pulley, this 3 part I think it was, series of videos will give you an idea, bear in mind the guy doing the machining is also very experienced, you only have to browse this forum to find out many people can't do 'simple' operations like parting off.

machining a belt pulley youtube

Edited By Pete. on 04/11/2021 00:23:21

Edited By Pete. on 04/11/2021 00:24:26

[Howard LewisParticipant @howardlewis46836]

Ian

Go to your IN box, you have a PM.

Howard

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