G'day Vm,

Not sure if it's my pc or ODK but the image isn't viewable for me.

The Genuine Sanli Height Adjustment Knob (Part 50301) is a push-on fit, not threaded.

It is designed to be a very tight, friction-fit part that slides onto the flat metal lever of the height adjustment assembly. Because these knobs have to endure a lot of vibration and "yanking" during use, they are notorious for being a bit stubborn to install.

I wouldn't pay lawn mower tax for this part just go to Aliexpress and get one under $5 free post , I just searched for M8 threaded control knob

or maybe search (M4-M16 Black Red Round Ball Handle Ball Knobs Bakelite Lever Knob Grip Handles Of Furniture Or Machine Tool Replacement )
About $3. each free post ,just a heads up: don't use your first-purchase discount on something super cheap. AliExpress gives you a massive deal for your very first order, so use it on something a bit pricier to get the most money off!


Cheers
Max.