Lawn Mower Wheel Drive slipping?

[Burnerman]

Many thanks for the pics!
I can only assume that the small grub screw is meant to tighten down onto a key, but this design isn’t common.
No matter, congrats on what you have done and happy mowing, if there’s such a thing!
Regards John

 

[Hysteresis]

Many thanks for the pics!
I can only assume that the small grub screw is meant to tighten down onto a key, but this design isn’t common.
No matter, congrats on what you have done and happy mowing, if there’s such a thing!
Regards John

The Grub screw is diametrically opposite to the Keyway cut into the Boss, so it isn't for tightening down on the key although that would have been an excellent design feature. No Idea what it is meant to do, but I think whoever assembled the mower in the factory seemed to have used the Grub screw to secure the Boss to the Drive shaft.
Just after I bought this machine about 3 years ago I had to return it to MowDirect as the timing Mechanism had slipped when I caught a tree stump. The supplier was MowDirect and I suspect their workshop mechanic failed to replace the Key on reassembly and returned it to me. I cant prove that or take it up with MowDirect as they are now out of business (I think). Not to worry though, all is operating now, thanks for your help and interest.
I suspect the Key will fall out soon as there is a lot of Vibration in that area of the machine. If it does, I am a lot more knowledgeable about this cheap and nasty little machine, so I will know how to get to the problem and devise maybe a better key or some method to keep in in place.
Maybe a Grub Screw will do the trick!!!!!, only needs a tapped hole on the opposite side of the Boss to the present one to achieve it.
You have come up with a great Idea for a modification.
Thanks again.
Ian

 

[Old Salt]

Loctite on the grub screw will help

 

[Burnerman]

I think you are absolutely right, the grub screw just locates the boss onto the crankshaft and maybe takes up any clearance between the two parts.
For sure, this isn't common procedure.
Hopefully the blade holding boss will prevent the key from escaping!
Blades usually have two locating holes which engage with two pegs on the boss, other designs have a domed (i.e sprung washer) to hold the blade firmly.
Regards
John

 

[Hysteresis]

I think you are absolutely right, the grub screw just locates the boss onto the crankshaft and maybe takes up any clearance between the two parts.
For sure, this isn't common procedure.
Hopefully the blade holding boss will prevent the key from escaping.
Blades usually have two locating holes which engage with two pegs on the boss, other designs have a domed (i.e sprung washer) to hold the blade firmly.
Regards
John

Spot on. The Blade boss is quite a clever arrangement using a couple of blade locating pegs. These pegs are eccentric and are such that the blade cannot be replaced upside down.
Ian