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Collection, Preservation and Display of Old Lawn Mowers

Ajax MK 3&5 main gear wheels

Hi, I’m in the process of rebuilding two ajax’s and both seem to have the same problem. The back of the main gears where the mills pins seat have worn and scored the gears. I can’t see any damage to the casings.I don’t think the pin was correct in the mk3 because it’s too loose and isn’t an interference fi and will cotter pins stand up to the job? Have the gears not been lined up onto the pins when the gears have been replaced? Does anyone have any spares for sale or know where they are available please. 

Thanks Nick.


Clive1997 Sat, 09/06/2018

Hello Nick

I'm just breaking some Ajax's, will see what the parts are like & should be able to help.




Brad Sat, 09/06/2018

MK3 has solid gears all the later ones have holes drilled into them, I assume to lighten them maybe.


NM Tue, 12/06/2018

Hi Clive 1997, thank you for your reply.  That sounds good, how do we arrange to sort out out the parts required and do you know what the cause of the damage is please.

Thanks Nick

NM Tue, 12/06/2018

Hi Brad how are you, thanks for the reply.  The differences I suppose are the result of development and they are very small changes. Were your gears damaged like mine when you took yours apart?

Cheers Nick


cwj123 Tue, 12/06/2018

It looks as though damage done by loose nut so not clamping pin.Over time wear on pin and alloy recess occurred.

Clive1997 Thu, 14/06/2018

Hi Nick 

I have one Ajax broken down & may well do another, need to know exactly what bits you need, assume you want the pin, image of the sprockets I have so far here, will email you direct to discuss further.




NM Sat, 16/06/2018

Hi cwj123,

Thanks for your reply. It does look like loose nut  but I can’t work out the reason for the indentations of the mills pin in the back of the gears. All I can do is replace and keep an eye on them.

Cheers Nick