Cylinder Liner Material

[GWRdriver]

I've returned to work on my 7.5"ga TICH and have been hacking away at the cylinders. I had these cast by a "friend of a friend" a few hundred miles away in what was supposed to be comon grey iron (G2) and while the castings are sound I've been very disappointed in the texture and machinability of the metal. Although it isn't hard (as in chilled) it is unusually brittle resulting in poor surface finish and edge chipping so among other things I may be required to use a valve face insert. The bores don't present a problem because I had planned to sleeve those anyway but thereby lies my question.

I had planned to use cast iron liners but it's occurred to me that perhaps I should also consider bronze. Here in the US bronze is rarely used for liners (or even cylinders) in any scale so there is no local history of experience to draw upon. So for cylinders of 1.625"ID using CI rings in CI pistons , what drawbacks might there be to bronze liners?

[albertsell]

Hello GWRdriver,
No problems with all cast iron providing the bores are good smooth finish( my 6 traction engines all have all cast iron cylinders ect.) but I would expect a bronze liner to pick up and score it self to bits in no time at all if using iron rings.
Bye Albert.

[steamjohn248]

In the UK you can buy "continuous Cast" cast iron which is fine grained, and, as it says on the tin "machines like butter" and you can get a mirror finish. It comes in various sections and is sawn off in lumps. We've had to fit valve face inserts into our cylinder castings because the lumps (all 35 lbs of them) arrived with the ports way out. With the size of bore you are talking about, if you cant get continuous cast tube or hollows, it would not be that much of a chore to chew them out of the solid, glue them in with the inside undersize then bore and machine in the normal way, a few passes with a hone and they finish a treat.
Live Steam Models or College metals are suppliers that I know of. in the UK.

John

[GWRdriver]

Thanks for the opinions guys . . . I already have the continuous cast iron bar on hand as I had picked up a stick of it anticipating the need for liner material. I wanted to hear opinions on the bronze. John, we have a continous cast product here called Dura-Bar which is available in several grades and is beautiful, but expensive, stuff.

I milled my horns from continuous cast flat material because while it was expensive, and it would take more time, it was locally available in small bits and an iron foundary wasn't. In retrospect I should have looked much harder for a foundary. One lives and learns.