taper lock pulley advice needed

[finyuk2005]

So i am trying to upgrade an older Logic flail mower (MF120) for behind the quad bike, trying to convert it from a single Vee belt and centrifugal clutch, to a double vee pulley and an idler to tension the belts.
The newer mowers use 3 belt pulleys and a tensioner as they figured out that centrifugal clutches are rubbish for this application!
I was hoping to use the bottom pulley from the slightly newer mower (MGF120) but its discontinued.

this gives you a good idea of what im looking at
https://uploads-ssl.webflow.com/5f7...9528d308d1518_logic-parts-manual-nov-2019.pdf (page 47)

My question is how would you get a pulley to grip the splines of the shaft?
I think i could just about squeeze the whole rotor in my lathe if it would only be possible to make a pulley of some kind fit by turning the splines off.

any ideas?

cheers!

 

[Agroshield]

Clean it to surgical standard. Fill the splines with something (bronze, JB Weld, cast aluminium around the shaft), turn back to OD of splines. Use a suitable taper lock pully on shaft.

Alternative: make a close-fitting soft aluminium sleeve of reasonable wall thickness and poke inside a hydraulic hose crimper to squeeze the aluminium into the splines. Turn to suitable OD.

Alternative2: shrink fit a steel sleeve and fill the gaps with JB Weld (using a syringe).

The first thing to do would be to find out what standard sizes are available in taper lock pulleys as that will dictate the diameter you need to be.

 

[gaz1]

you can make both the pulleys and also spline the device by just using your lathe

as the lathe can also do splines as well

but to spline it you would need to use your tailstock or a homemade device on your cross slide

 

[finyuk2005]

Clean it to surgical standard. Fill the splines with something (bronze, JB Weld, cast aluminium around the shaft), turn back to OD of splines. Use a suitable taper lock pully on shaft.

Alternative: make a close-fitting soft aluminium sleeve of reasonable wall thickness and poke inside a hydraulic hose crimper to squeeze the aluminium into the splines. Turn to suitable OD.

Alternative2: shrink fit a steel sleeve and fill the gaps with JB Weld (using a syringe).

The first thing to do would be to find out what standard sizes are available in taper lock pulleys as that will dictate the diameter you need to be.

I forgot about jb weld and the like, thats a good idea! cheers

 

[Brad93]

Personally i'd either turn the splines off or fill the splines with belzona 1111 (using a compressive mould and release agent)

 

[Hopefuldave]

you can make both the pulleys and also spline the device by just using your lathe

as the lathe can also do splines as well

but to spline it you would need to use your tailstock or a homemade device on your cross slide

A parting blade or similar ground to the right profile and laid on its side in the toolpost works OK-ish for cutting splines, advance cut a few thou" at a time with the cross-slide and rack back and forth with the carriage handwheel, the hard bit is indexing accurately enough to get all the splines to line up, one way is to make a plug for the back end of the spindle and add a disc with the needed graduations - there'll be no rotating load on the spindle so just a pointer should be enough. takes bloody ages, though. For external splines either drill holes for the cut to drop into at end of travel or cut a groove, internal (assuming not all the way through) cut an internal groove to end up in.

 

[m_c]

The chances are it'll be a fairly standard involute spline, so I'd start by counting the splines, measuring the diameter, and seeing if there's an off the shelf coupling available.

 

[GG1]

Not sure if I completely follow - but if you have a splined drive pulley that came off it, could you turn that down to a splined plug then bore out the new pulley to fit and braze it in?

 

[finyuk2005]

Not sure if I completely follow - but if you have a splined drive pulley that came off it, could you turn that down to a splined plug then bore out the new pulley to fit and braze it in?

also not a bad idea!
I think its cast, but would likely be cast steel? so possibly weldable or brazable?

or could i turn it down so a taper lock could fit it?
That would be a very good option!

 

[GG1]

Or shrink on an interference fit if you're feeling brave?

 

[Agroshield]

I think it's cast, but would likely be cast steel? so possibly weldable or brazable?

You could loctite backed up with a mechanical connection. Glue the two parts together, drill three holes spanning the joint and loctite in some pins. Or thread the holes and loctite in grub screws. I think it is called a Dutch key.

 

[8ob]

Turn the hub you have down to make a flange/register and bolt a pulley to it.

Bob

 

[Brad93]

You could loctite backed up with a mechanical connection. Glue the two parts together, drill three holes spanning the joint and loctite in some pins. Or thread the holes and loctite in grub screws. I think it is called a Dutch key.

Exactly that, a dutch key

 

[finyuk2005]

Exactly that, a dutch key

i think i can picture that right enough!
Im sure most of these options would fairly easily hold 10hp no problem!
plenty of ideas to mull over

thanks yet again folks! bloody wealth of knowledge on this forum!!

 

[Brad93]

Hmm 10hp, might be better off with a power lock

 

[finyuk2005]

Got the pulley off to have a closer look, and im not sure i could make that idea work anyway,
Looks like the hubs on the un-bored aluminium pulleys wont have enough meat on them to fit over the original pulley hub if it was turned down.
Im not too sure if i would even have enough length of shaft to work a double belt setup, only 30mm of the splined shaft.

Any one know if you can calculate how much power 1 B section belt can handle? (roughly 90mm pulley pitch diameter on both pulleys)
The belt shredded in pretty short order after trying the replacement clutched pulley, but i think that was mainly to do with the heat from the centrifugal clutch burning up!!

 

[Brad93]

Rough guide but sheave size makes a difference to transferable torque.

 

[finyuk2005]

https://calcdevice.com/v-belt-drive-id124.html

I tried that calculator, and at 7.5kw (10hp) it was saying 3 belts would be needed! ha ha!
Mind you, this is 10 chinese horse powers from a single cylinder yanmar diesel clone, so it will be more like 8 hp or 6kw ish!

I might see if i can cobble together a single belt setup without the centrifugal clutch and see how long a belt will last!

 

[finyuk2005]

The pulley diameter is pretty small (90mm) so probably isn't helping matters, it does have a good 180 degree belt wrap though

 

[jenki]

Can you increase the pulley diameter? possibly try a polyvee belt they drive a lot of equipment on cars now however the use a pulley tensioner system might not suit.