Skip to main content
Collection, Preservation and Display of Old Lawn Mowers

1995 Atco Commodore B20e Cylinder Removal

Enter a word or two to search the forum section and click the Search Forum button.

Hello there everybody,

I recently started working on a mower that I bought a few years ago and has been sat in storage since. It's in pretty good condition, little bit of surface rust here and there, I think it's from condensation. I wanted to remove the cylinder to repaint, as it would really make it look good. From looking at other posts it seems I have over dismantled, but none the less at this stage I have removed the back plate with the right hand bearing carrier attached. I have removed the two piece sprocket off the end of the cylinder spindle. At this point I thought I would be able to just pull the cylinder out of the left hand bearing carrier. I saw on other posts that the method was to unbolt the bearing carrier from the side plate, but I thought if it comes off in the end anyway I could leave it attached to the body. It's complicated by the fact that it looks like someone has had a go before on the hex cap bolts, and they are completely rounded off, allen key just spins inside. Do I really need to unbolt it? if so would I be best to dremel cut a slot across the bolt head for a slotted screwdriver or another method? I don't understand why I can't just pull it out, is there some kind of interference fit thing inside the bearing housing. I thought about using a drift to hammer it out, but I wanted to check first, incase this would be a bad thing to do and break something. any help would be much appreciated.

Forums

wristpin Mon, 22/02/2016

As you say, not the conventional way of of tackling the job but if I've understood you correctly the cutting cylinder should be free to pull out of the left hand bearing. That said, the shaft may well be more than a sliding fit and may need a bit of persuasion, but make sure that you protect the threads on the end of the shaft. Perhaps levers between the cutting cylinder and bearing carrier might be a safer first line of approach.

I don't remember any Commodore having cap screws with internal hexes but perhaps memory is playing tricks; can you not just grip them with "mole/vice grips"? However the hex head screws holding the bottom blade carrier to the bearing carriers can be pigs to undo and if you are unlucky the weldnuts within the carriers can come adrift and cause another headache!

That said I would suggest that when the cylinder and bottom blade have been sharpened / refaced it would be better to reassemble the cutter unit out of the chassis. A point to note is that the left hand bearing is positively anchored in its carrier by the combination of its seals, a wavy washer and a circlip but that the right hand bearing should be firmly assembled to the cylinder shaft and a tight sliding fit in its carrier so that everything lines up when the unit is replaced into the chassis.

An image or two might help explain the situation.

ajpmorgan Tue, 23/02/2016

Hi thanks for getting back to me.Yeah I'm quite a novice especially with cylinder mowers. I've done quite a lot of work on old hayter 48s and 56s but this is the first cylinder mower I've tackled. tried using mole grips on the cap nuts, but I was just chewing them up, and the domed shape encouraged the grips to loose their bite, why do those things always seem to be made of the softest metal? Anyway next I tried levering the cylinder out with a 4' 2x3, It just wouldn't budge. Reluctantly, having got this far, I used the outer sprocket as protection to get the spindle as far in as possible then a brass drift to get it through the bearing. It took a hell of a lot of force. And I guess you know what's coming next, Yes the threads are damaged on the spindle. I tried screwing the sprocket on and it didn't want to know. I think its just compressed a bit. So I'm guessing I need a left threaded die. Don't suppose you or anyone else knows what diameter and thread I need. I've been looking for a spec sheet or alike but so far can't find anything. I saw on the internet there are screw pitch gauges with multiple fold outs, is that my best bet? Anyway the good news is that finally the cylinder is out, and I've been prepping the carrier and other bits of body for re-spray. thanks again, Andrew

wristpin Wed, 24/02/2016

Oh********  or words to that effect !

What were you hitting ith your brass drift - the sprocket or the end of the shaft? If you had the sprocket  only just loosened and had the drift on the end of the shaft its possible that you've only "compressed" the last couple of threads and that you can clean them up with a modified hacksaw blade  - grind the "set" off the teeth into a V shape - or were you smiting it so hard that you've bent the shaft? Don't want to rub salt into the wound but had you dropped the cutter unit out in the conventional way you could have pulled the bearing carrier off the bearing and then the bearing off the shaft with a two or three legged puller. .

Easy to measure the diameter of the shaft and then the thread gauges will tell you the rest.  For the life of me I can't remember whether Atco had gone metric  when the introduced the Commodore or whether they were still on UNF. Although the Commodore was a new model name it was really just a beefed up version of the old Lightweight range so it's probable that the threads were Imperial, UNF.  The other hardware on the machine will give a clue but bear in mind that sometimes there would be a " carry over" from existing stock on things like cutting cylinders.

A good supplier of taps and dies, including left hand thread ( at a price!) is Tracy Tools  who have been in the business for many years and have a good web site.  www.tracytools.com

hortimech Wed, 24/02/2016

Cheaper and easier way to fix your 'mistake' would be to buy a thread file. If only the end is slightly mushroomed, clean it up with a normal file and finish off with the thread file, until the sprocket screws back on again, but what ever you do, don't force it on.