Suspension Bushing Material: Red Lurethane.

Below is a pic of 1.25" (31mm) rod material, it is available in all shapes and sizes, as well as three different hardness grades, it is ideal to use wherever cushioning or isolation bushing is required, every suspension, shock, sway bar, diff bush in my elan has been done with lurethane, it is an excellent material. In Australia & NZ it is available from Ludoplas plastics. Complete Aust contact details are at:
elantrikbits.com/links.html I am not sure whether they have OS branches. The material can be easily machined in a lathe, but there are a few little tricks involved to get a good finish.
Col


Would you like to share your " tricks" for machining this material

Hi All.
Yes, I can share the “how to” tricks for machining Red lurethane.
First thing you should attend to is the spindle speed of the lathe, set it at the highest speed. (1240 RPM is ideal). Bear in mind that old style lathes may not provide high spindle speeds. Next is the type of tool needed for a good finish,
the “V” point used in general turning is not really any good. The best type of tool form is shown above, a kind of knife point edge gives good results, but this is only general advice, you cant beat experimentation with your own equipment. These are the tricks you learn by doing.
Col.

I made suspension bushes for my Griffith from polyurethane bar. Hallam polymers I think is where I got the raw material from, about ?50 per foot as I recall.

It turns ok on a lathe but as you would expect of it’s ‘rubbery’ nature it’s different to say turning a bit of ally.

Keep it cool before working - in the freezer is good as it will deflect less when your cutting tool makes contact. After each cut you’ll find it’s oversize to what you thought it might be, so don’t get too hung up on working to the nearest thousandeth of an inch etc - just the nature of the material as it deflects when the tool cut’s it. Also don’t have too much sticking out from the chuck, only enough to do one bush is best. And I found it was best to cut the whole ‘top hat’ bush section with a parting tool, important to keep it very sharp. I found a parting tool gave the best quality cut. You won’t get a finish like on a moulded polyurethane bush but that’s not really important.

I didn’t use a maximum speed that one might use to get a top finish on say steel or aluminium, used an equivalent speed to general metal cutting of aluminum of the same diameter. And no coolant used either.

Probably take you a day to make a set of bushes but you can make them bespoke for your own car. Elan is next up !!

To all,

In another life I made moulds to manufacture urethane bushes for my Ford Customline, you used to be able to buy the raw liquid material and mix it, then pour it into the mould, worked a treat. It was a bit like mixing fibre glass resin.

OK if you want to make a whole bunch of them.

Tony W

Yes, and you can still do that, the smallest pouring kit is 1.5KG, and cost about $100 here in OZ.
Col.