The Old Lawnmower Club
Collection, Preservation and Display of Old Lawn Mowers
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Ransomes Ajax Mk5 Roller

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MAC Thu, 05/09/2013

I am a new member and have recently bought an Ajax Mk5. I decided to strip it down for a clean and service. All was going smoothly until I got to the nut that secures the main cog which is driven directly by the rear rollers. Can anyone tell me if this is a left hand thread? Please see picture. Thanks Ajax mk5 cog at end of roller shaft

Forums

Old Lawnmower … Sat, 07/09/2013

Yes, it is a lefthand thread.  Ivor Gregory.

MAC Sun, 08/09/2013

Ivor, Thank you for your reply.Great to have that confirmed before I take a spanner to it. Matt Clark

hillsider Sun, 08/09/2013

If you are ever unsure which direction a nut should be turned you can sometimes get a clue by looking carefully at the exposed portion of thread that often protrudes from the nut, you can then see which direction the nut needs to turn to wind it off of the thread.
Ray.

wristpin Sun, 08/09/2013

As Hillsider says, an exposed bit of thread will often give a clue but also it is worth considering what the part does . In the case of the Ajax illustrated the roller is driving the mechanism on the right hand side of the machine so "stand behind the machine" and take your left hand as being the roller and shaft and your right hand as being the nut and then rotate your  left hand in the direction of travel of the roller (clockwise) and see that it needs a counter-clockwise action of the nut (your right hand) to tighten it ie a left hand thread.

Just for the sake of argument imagine transposing the gears to the other (left) side of the mower and do the same manoeuvre but using your right hand as the roller and left as the nut and it will be a conventional "right hand thread" that is needed to tighten the nut.

That works for "driving" components but go to the other end of the gear train - the driven gear  - in this case the cylinder drive gear, turn this driven gear (right hand) in the direction of cut and it will be a right hand thread on the cylinder shaft for tightening the nut with this right hand located gear train but a left hand thread for our imaginary left hand gear train.

This hand waving exercise is probably best carried out in private  - less explaining to do!!