Atco Commodore 20" cut cylinder, I've no idea of age but...

Ii7My problem now is trying to understand what size are the three Allen headed screws holding the cylinder bearing assy. on that side? I've tried both metric and imperial, all near size are either too big or too small, a splined drive partially grips, but then screws are done up very tightly. I understand that they are very flat headed so as to miss the rotating cogs etc.

The normal UNF headed ones on the other side of frame came out very easily.

What's the secret Atco special tool number? Or do I grind an old Allen key to fit, which would probably soften it too much?

Not Torx by any chance?

EDIT.  Now been back through manuals from the introduction of the Commodore right through to its replacement by the Balmoral and the only reference is Socket Head Screw Exp, no dimensions or  other information. Not sure about the meaning of Exp but it appears after most references to hardware. By default, socket head usually refers to Allen or AF hex socket, so it remains unclear as to why neither your AF nor metric keys are a snug fit.

Over the years I’ve stripped down many Commodores and have no recollection any difficulty in finding the correct key for those screws and as far as I can remember Commodores  were always imperial  - all a bit strange.  As far as grinding and softening them goes, perhaps filing will  avoid that, or a very light and quick grind with frequent cold water dunking. I reserve some “ cheapo” ones for that sort of modification and my Unbrako sets that I’ve had since late 50s remain unmolested.

Thanks wristpin.

I did try to put my pic of the label on after forgetting, but then couldn't find this post at all.

I'll put it on now, perhaps you could give me an idea of the age, appreciated.

R suggests 1993 

Thanks for your input wristpin, it turned out that I was using a small, fold up,pocket type set of keys that didn't include the lesser used sizes.

A good cleaning up and some grease had the cylinder moving with ease.

I managed to clean off surface rust on bottom blade and give it a better edge with a file, cylinder is very thick steel and undamaged.

I managed to adjust the contact surfaces so it would cut thin card all the way along like a pair of scissors.

The main fault? Chap tells me now he lent the machine to a nice neighbour, who had no idea you couldn't cut three inch long grass with a cylinder machine! I give up on folk sometimes! Not again I hope...

All's well that ends well, I suppose.

Another mystery solved !

Never ceased to amaze me re the number of people who tried to hack off long grass with domestic cylinder mowers. Coincidentally I’ve just sold my Dad’s old Ransomes Twenty Four . The Twenty Four was a bit out of character build quality wise and was Ransomes “ semi domestic” machine to compete with the Atco And Webb 24” machines: no greasers on the cutting cylinder bearings and plastic differential gears etc. That said, a friend still in the trade was having a moan recently about a 2012 Marquis 50 that had just chewed up its PLASTIC diff gears.

Back to the matter in hand ; The Twenty Four was available with a high cut kit. Not just the removable front rollers, the whole cutter unit could be assembled an inch or so higher in the chassis and the kit included a shorter chain and shallower throw plate. I’ve never seen one in the metal but it’s in the operator’s manual and the parts are listed in the parts manual.  Only sold it a week ago or I could have taken an image of the vacant  mounting holes in the chassis plates. Not sure what sort of job it would have done in longer grass as the cutting cylinder is of relatively small diameter.