Metal combinations for a plain bearing

to add to the mix; how about miniature split bearings that could be tightened as required? could be as simple as a V and a plate?

Tapered axle and bearing like on a shaper's clapper box.

You push the axle further in as wear becomes an issue.

How about a ceramic ball bearing? You can get them pretty small, like 4x9x2.5. A bit more expensive but unless the PTFE cages wear out, you'd imagine the balls and races would laugh at clay particles and appreciate the lubrication offered.

Murray

How about using two brass cup nosed grub screws in the legs of the forks. The wheel could then be dimpled in the centre at either side. A small single ball bearing at each side could be held between the two grub screws and the wheel to act as the bearing. Wear should be minimal but a little lubrication would help minimise this. The grub screws can be adjusted inwards to deal with any wear that appears.

How about IGUS bearings - **LINK**

Fantastic things, we used to use them under railway carriages for brakegear with no lubrication. Have a range for all sorts of environments. I notice RS sell them - **LINK**

Their M250 Range goes down to 1mm shaft size - https://www.igus.co.uk/product/5 and is good for general dirty environments.

Edited By David Murray 1 on 07/06/2018 12:09:15

In view of the abrasive environment, would it be possible to fit small 2RS ball races, to have low friction and reasonable protection from the abrasive slurry? MIght even be worth modifying the holder for this?

Howard

This question has attracted a lot of creative responses - thanks to all for suggestions, I can't try everything, so I just have to go with gut feeling - the MKIII is going to be cone and cup as in the toy gyroscopes. I think this gives me the best chance for the user to adjust for wear.

I'll post a pic of article when done - thanks again for all the ideas, much appreciated.

Robin.