FWIW; brass should work ok, have you considered machining some from bronze bar, or sintered bronze bar where you could machine them then let them soak overnight in oil to absorb lubrication ?

George.

Rik,

I think that you are referring to the strap that goes around the eccentric sheave that is mounted on the crankshaft.

What is the sheave made of ?

What will the engine be used for light running or driving a real load|?

Brass / steel combination should be OK but as I suspect you know Bronze/ steel would be better giving a longer life.

If the sheave is cast iron you would be better off making the strap from steel.

Obviously make provision for adequate lubrication what ever metals you use.

Eric

When I rebuilt a rather battered Stuart Turner S9 I made the new eccentric strap from cast iron.

Ian S C

The strap casting for the Stuart 10 series engines is brass and there are one or two of those about that run OK with that combination of metals

Mechman48:

I would not recommend using sintered bar if you need to machine what will be the bearing surface, as the cutting action is likely to burnish the grain closed, so rather defeating the object. It is however possible to buy sintered-bronze bushes, and there may be a size available to suit (or so close you can modify the diameters without compromising the engine as a whole)..

In full-size, the eccentric sheaves and straps were usually both of cast-iron. Mild-steel and cast-iron and happy together too, with good lubrication: my old IXL lathe countershaft used this pairing, as does my little EW lathe headstock.

I've an idea mild-steel and phosphor-bronze are not so, with the steel wearing more.