OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Need Measurements for SB Mod 40 drive clutch

Hi Guy's,

Looking for someone to take some measurements of there drive clutch (on the engine crankshaft) so I can hopefully make a CAD drawing and then make one on the CNC machine at work. This is the only thing stopping me from making my 40 from running. I could do some measurements myself on the space available and dimensions of shaft etc. but I would rather look at copying the original.

Cheers

Glenn

Hello Kearnsie,

Welcome to these forums!
There are members who could benefit from this post.

Could you confirm you are after the rubber drive dimensions?
That is the OD of the rubber ring?



Cheers
------------------------
JACK.

Hi Jack,

I would love both of there dimensions.

Length of slug (metal part that sits on the crankshaft)
diameter of slug

OD of rubber wheel
width of mating surface.

if you have any other pictures, that would be great too.

Cheers

Glenn

Hello Kearnsie, ODK members & Guests

This rubber drive is the Achilles' Heel of the Model 40.
It's not that the design wasn't good; it's now the unavailability of spare parts!
If this problem - of the rubber drive - could be solved, many machines would be
saved from the scrap heap.

I have no dimensions myself, but I hope a member will be able to help here!

Thanks again Jack,

Just a thought (haven't come across this before) but what if I machine a round stock with say 30mm clearance at point of engagement and attach a strip of old tyre tread (something that is readily available) to the stock? I know the rotating mass will make the engine slightly less responsive under load but it makes the unit serviceable at the end of the contact surfaces life.

regards

Glenn

Hello Glenn

This is unknown territory for me.
We are lucky to have top-quality people on this site.
I hope folks can offer some advice here.

Hope this helps.
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JACK.