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Ransomes Ajax Mk3 front roller

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Tom Fordyce Fri, 16/10/2015

Hi all, 

Newbie here! Just purchased my first old lawnmower this morning after much research on this site and auction sites, I set out for a Ransomes Ajax and came across a very nice example in need of some TLC, a Mark 3 with original grass box for £25. Overall, I am very happy with it as it is complete, and needs the refurb work that I am wanting to carry out over the winter months, ready for the growing season. 

On a very brief first inspection of it when I got it home today, I noticed that the front roller carriage is lose and being held to the side frame with what don't look to be original nuts and bolts, with no locking mechanism to stop any movement. Should these be 1-LK 165 and 1-LD 89? If so, what do the originals looks like and where can I get some? 

This also brings me to the question of what height the front roller should be set at? Is it at the point that the bottom blade just sits on the ground? 

Thank you for assistance in advance, I am sure it will be the first of many questions to come!

Forums

hortimech Fri, 16/10/2015

Don't know about the numbers you quoted (partnumbers??) but a picture may help.

 

As for what you set the height of cut to, well this all boils down to what you want your grass length to be. Most people cut their grass too short, I would advise leaving it about 3/4 inch long unless you are going to play bowls on it. Easiest way to set the height of cut on a hand machine, turn the machine over, place a straight edge across the front and rear roller at one side, measure the distance between the underside of the straight edge and the top surface of the bottom blade, repeat at the other end of bottom blade, adjust the front roller to get the required height of cut and the same measurement at both ends.

Tom Fordyce Fri, 16/10/2015

Thanks for the reply

It is the two points that the grass box hangs on, attached two the front roller. There is a nut and bolt each side. Will take a photo when I can. 

 

I presumed, possibly wrongly, that the height adjustment for the cut was done with the two screws either side of the cylinder blade on the top?

wristpin Fri, 16/10/2015

Those two screws set the "nip" between the moving and fixed blades which controls the quality of cut. If the blades are in good condition the moving cylinder  blades should just brush the fixed bottom blade. In an ideal situation they should just cut stiff paper such as 80gm copy paper.  

Set too wide and the grass will be bent or torn and the machine difficult to push. Set too tight. At the least the machine will be difficult to push and at the worst it will jam. Minor imperfections or dullness of the blades may be removed by back lapping with carborundum paste but anything more than that will require re-grinding of the cylinder and re- facing or replacing the fixed bottom blade. It must be emphasised that back lapping will only restore an edge to a straight and undamaged cylinder and is not a substitute for re- grinding rounded or damaged blades.

hortimech Sat, 17/10/2015

That is not strictly correct Wristpin, backlapping will not restore any edge, it will only maintain one.

If you are going to backlap, you need to do it on a regular basis, golf clubs tend to do it at least once a week on their greens machines.

If I said it once, I must have said it a thousand times, backlapping is not a repair, it is a maintenance procedure.

 

hillsider Sat, 17/10/2015

In wristpins defence he did qualify his advice by stating that backlapping was not a cure for a blunt or damaged cylinder. 

Re the question of bolt identity I am fairly certain that they are what is known as a cup square carriage bolt (domed head with a square forged on the shank of the bolt directly under the head) the thread is either a 1/4 or 5/16 Whitworth, I shall check the bolts on one of my machines tomorrow and post the result.

 

hillsider Mon, 19/10/2015

I can now confirm that the bolts that you seek are indeed Carriage bolts measuring 5/16 Whitworth X 1 inch (measured from under the head), you may struggle to find new bolts of this size unless you have a repair shop near you that keeps stocks of imperial fixings. 

If you are not too concerned about maintaining originality you could use the Metric equivalent that is M8 X 25 mm long.

The square section below the bolt head locates in the slot in roller bracket to prevent the bolt from turning

Tom Fordyce Mon, 26/10/2015

Thank you all, those are the ones - thank you for taking the time to locate and photograph. 

Thankfully, I have a contact at http://www.thunderbolts.co.uk/ and should be able to locate these. 

 

I have another question which has come up - The gear on the roller - I have removed the other gears no problems and the nut and washer on the roller gear, but can't seem to get the actual gear off. Is it threaded or is it just being stubborn? 

Stoko Mon, 26/10/2015

Hello Tom, I had the same problem as discussed in another topic!! The large pinion is not screwed on! The nut is left handed and I found that the thread had raised itself somehow and prevented the pinion from coming off! Carefully file round the thread or use some emery cloth to clean up the thread and the pinion should pull off.There is a cotter pin through the shaft behind the pinion that acts as a drive pin, the pinion just pulls away from this.

 Careful persistence will succeed!! I hope this helps you. Cheers, Colin.

wristpin Mon, 26/10/2015

There is a cotter pin through the shaft behind the pinion that acts as a drive pin, the pinion just pulls away from this.

Point of order!!!!! 

Its a mills pin not a cotter pin. Two different animals!

Tom Fordyce Tue, 27/10/2015

Thanks Colin, much appreciated. Managed to get it off based on your info. I hadn't wanted to force it off before I knew it wasn't on some sort of thread or held otherwise. 

 

Thanks as always!

sparkymike Thu, 05/11/2015

Hi Tom,

re. roller carriage bolts, the originals would have been zinc/cad plated. 

I used to work at RS & J  in the 60'sand spent a few weeks on the Ajax assembly line, and most of the other departments.. A very nice mower for a small lawn.

Mike.