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Collection, Preservation and Display of Old Lawn Mowers

Ajax MK3

Hi, I have purchased a MK3 to bring back to life and it needs a bit of work. I was wondering if anyone can supply a grinding in pin for Ajax mowers or supply size of thread. I have tried to thread bolts on the machine into thread but nothing seems to fit.  Is this a left-hand thread? 

There are no wooden handles or bolts to hold them on and the gear casing is worn through. 

The oil nipples are missing on the land rolls but present on cylinder bearings and gear case, they are a bit different to the others I have seen. 

Here’s a few piccies. (Hopefully)









Brad Sun, 03/06/2018

Alright NH, I've a MK3, 4 and 5 and the grease nipples are the same push in fitting on all the models I've in the shed.

Unless you have removed it you appear to be missing your thrower plate also.

As for the pin/handle to turn the flywheel so you can lap the blade in on the mower while stationary I've not seem one, but I would guess it was bsf not metric or unf.

I removed my cylinder and bottom blade to get them sharpened rather than do it myself, I've not even started to paint or reassemble yet though.

The only difference I noticed on the mk3 to the others were the cylinder adjuster, rollers, the main body where the handles attached and the gear wheels are solid disks but he later ones are drilled.  

NM Sun, 03/06/2018

Hi Brad, thanks for your reply.  There was a thrower plate of sorts, a very flimsy bit of ally that I have put in the recycling. It also came with a MK5 grassbox. Are your bottom blade carriers the same because this one has an ally one that isn’t solid but has webbing for strength.

I have disassembled it and started cleaning all the solidified grease and gunk but now realise the roller spindle bearings are very worn and need replacing. 

Brad Sun, 03/06/2018

Both sound wrong to me, the bottom blade on all the mks I have are the same, pretty heavy duty bit of metal, as for the thrower plate the three I have has a tiny bump in it to keep it in place unlike the later ones.

Where are you in the country?, up north wasn't it or that might be someone else doing a resto, I can give you both a bottom bade, carrier and thrower plate.

NM Sun, 03/06/2018

Hi Brad thank you for your generosity. I’ll post a picture when it comes out of soaking in diesel to hopefully unsieze the screws. I’m in Bedfordshire so I suppose I am ‘up north’ if you live on the south coast. How do we go about shipping items.

Thanks Nick.

Brad Sun, 03/06/2018

No worries Nick, I can post them to you if you want to cover the postage, send it to me as a paypal gift.

I will wrap them both up and tell you how much it comes to from Royal Mail.

I'll put in a bottom blade on carrier and a thrower plate.

I'll PM you once I have done it.

If your trying to remove the blade from the carrier I wouldn't bother to be honest, mine took me ages and I ended up using an impact driver after soaking as it still didn't want to come off, once I had got it off machine shop said it had to be on to sharpen it as it will mounted anyway!. so was a waste of my time. My second one I left on, cleaned it up, painted it and then sharpened.

NM Sun, 03/06/2018

Cheers Brad, PayPal gift new to me and pm, is pm an email?

Here’s a couple of photos of blade carrier.

Brad Sun, 03/06/2018

OK there is nothing wrong with the bottom blade or carrier as that is exactly the same as what I would have been posting to you.

When you said mesh, I thought ?, but that looks correct to me.

In regards to the thrower, my MK3 has a smooth plate, the later ones all have fullers in them, I have a spare later one I can send you but I don't have an early one. If you want it let me know.



NM Tue, 05/06/2018

Hi Brad, thanks for your reply. Thanks for the offer of a thrower plate but I have a donor MK3 now and it has the correct thrower and the wooden handles and bolts that were missing on the original. Also the gear casing is in better condition so hopefully I’ll end-up with one half-decent lawnmower.

Thanks again, Nick

Nigel Wed, 06/06/2018

Re a pin for turning the gear for the sharpening process, according to the manual it's one of the wooden handles. I've just tried it on my Mk3 and it works. It's not left hand thread; I've no idea how to "describe" a thread, but I could post a picture and a couple of measurements if you could identify it from that.

hillsider Wed, 06/06/2018

The Ajax MKs 1&2 parts list shows the Handle bolts as having a 3\8" Whitworth thread so it is safe to assume that it is the same size as the threaded hole in the gear wheel. It should be noted that the later style handles are not removable but the parts listing for these mowers shows a part number for a back lapping pin but no mention of the thread size but I see no reason to think that it would be different. 

NM Sat, 09/06/2018

Thank you Hillsider for your reply, the mower I have came with no handles so more items to go on the list. I have a MK5 to do  as well so all info appreciated.

Thanks Nick

NM Sat, 09/06/2018

Thanks Nigel, you’re right, the bolts are listed in the manual. I’ll try and track down some bolts, although cup sq. 6” bolts in whitworth could be hard to find.

Cheers Nick

wristpin Sat, 09/06/2018

Thanks Nigel, you’re right, the bolts are listed in the manual. I’ll try and track down some bolts, although cup sq. 6” bolts in whitworth could be hard to find.

As you say but a workaround could be UNC studding (threaded bar) and nuts. For most diameters, UNC is compatible with BSW and is readily available.

Harvey Sat, 09/06/2018

I do have a backlapping pin but sometimes ( when I couldn't remember where I had put the pin ) I used a 1/2" drive socket and 'wheelbrace' on the gear retaining nut.

Works ok.


NM Tue, 12/06/2018

Hi Nigel, thanks for your helpful reply. That is ingenious. If you have just tried it have you just found out that the handle doubles up as as grinding in pin?  The trouble with my mk3 is it didn’t have any handles and as six inch whitworth coach bolts are probably hard to find at least I can probably source the correct bolts to make one.

Thanks Nick

Nigel Wed, 20/06/2018

Here's a few pictures of the "multi-tasking" handle.

(...and I haven't got the hang of dealing with pictures yet!)

Clive1997 Wed, 20/06/2018

Hi Nick

Will add handles to your list as I should have some bolts & possibly some serviceable wooden handles, have emailed you direct.

NM Thu, 28/06/2018

Thanks Nigel for posting pictures, Ransomes maybe saved themselves a few shillings by not having to provide a pin like they did on later MK3’s and the 4 & 5’s. Pictures are a bit of kerfaffle, especially moving cursor to position of picture.

Cheers Nick