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Collection, Preservation and Display of Old Lawn Mowers

1968 ATCO B 23 mower

Greetings from Sydney Australia, I've recently acquired the above mower in reasonably good condition, replaced spark plug, broken fuel cock and gave it an oil change, ticks like a clock, quiet smooth etc.  Rotating blade is am little on the rough side so planning to do a little work on it using Valve lapping paste running the blades slowly in reverse.

Problem 1 - I've removed the chains hoping to be able to rotate the blade backwards but can't work out how to take the sprocket off. It's either on a spline or reverse thread, not sure which but if someone out there can advise me I'll be eternally grateful.

Would also be handy to have a service and workshop manual for it to help the cause, I'm trying to give it a full restoration, paintwork is reasonable but it would sure look so much better with a bare metal respray in 2 Pak paint. Amazing but the grass catcher doesn't even have a dent on it, I'll be looking for a photo of the original decals and transfers to apply when

Hope to hear from willing helpers.

Regards to all,


gtc Wed, 13/03/2019

Making duplicate posts is not considered good forum etiquette. We can all see new posts regardless of what section (forum) you put them in.

wristpin Wed, 13/03/2019

The sprocket is retained by a splined sleeve. Look down the recent posts for one by woollyhales asking a similar question and look at the images that I posted.

The process that you describe for cleaning up the blades is known as back lapping.  A lot has been written and debated on this forum and others and without opening up  another debate I will just make a couple of observations.

Valve grinding paste is oil based an it’s difficult to remove every trace - not desirable.

Back lapping paste is water based and easily washed off 

The process itself is a maintenance operation for blades that are in good condition, not a recovery operation for damaged or neglected blades.

Back lapping only works properly on blades that have previously been relief ground. That is that a small amount of metal has been ground off the back edge of the blade creating a space to hold the paste. Without that space the first reverse rotation of the cylinder tends to wipe all the past away from where it’s needed.

’nuff said!


olcadmin Wed, 13/03/2019

I have removed the original (duplicate) post before it attracted any answers.

hortimech Wed, 13/03/2019

Isn't the B23 what we used to call the deluxe and later became the commodore ?

If so, the cylinder sprocket is screwed on with a left hand thread.

As for backlapping, I agree with everything Wristpin said, if your cylinder is sharp it will keep it sharp, if it isn't sharp, then do not waste your time.


Gil Hassin Thu, 14/03/2019

Thanks for that info, I was confused as to which section in which to put my post, it was my first post on the site, my apologies.