What metal are the small sliderest gibs made from?

[cazclocker]

It's been a LONG time since I've posted here!
Question: as the title says, I'd like to know more about the material the gibs are made from - specifically for the Rivett line of watchmaker's lathes. They appear to be just some kind of high-quality steel, precision-ground and bevelled. But...they might be made from something different.
Anyone have any idea? I'm sure it's hard to know the specific manufacturing specifications from a long-defunct company, but physics is physics, and Edward Rivett would have chosen his materials for good reasons.
Thanks in advance,
Doug (cazclocker)
(now I'm in Mulvane, Kansas!)

 

[ddillman]

I thought they used cast iron as a general rule.

 

[jwmay]

I don’t know. But I’ve been under the impression that gibs are just made of a decent spring steel. I’ve seen to many bent wonky to imagine they were cast iron. Will cast iron bend? I didn’t think it had very much yield. Also, I read somewhere long ago that dissimilar metals were chosen for gibs due to friction advantages. Allegedly cast on cast would be a stickier action than cast iron on brass, or cold rolled, or delrin. So these are all just some random (alleged facts) my brain has held on to through the years. Maybe it helps. Or maybe it’s just faulty wiring.

 

[cazclocker]

Thanks guys. I did a bit of reading on a couple of other machining forums and the consensus seems to be that the gibs in the upper & lower slides of a typical sliderest is mild steel. I don't have any experience with overhauling any other sliderests besides the ones made by Rivett for their watchmaker's lathes, so I don't know how pervasive that "rule" is. But, according to what I've read, mild steel is chosen so that the gibs will receive the brunt of wear instead of the scraped dovetails. Makes sense to me, but that's only what I've read.
Reason I'm asking is that I'm almost finished writing a tutorial explaining how to disassemble & reassemble a Rivett compound sliderest. The project got me curious as to what those gibs are made from!

 

[sdelivery]

The cast iron would wear before the mild steel gib.
Cast iron has been the go to for Gibs for machine tools for decades, now if you look at a facing boring head, I have found some of those will have a steel gib but it seems that it is against a steel surface.
The porosity of cast iron helps to hold an oil film.
Regardless of the materials ALL are designed with the idea that there would be a film of oil between the sliding surfaces.

 

[SouthernChap]

I’ve seen to many bent wonky to imagine they were cast iron.

Maybe not bent but warped during manufacture? Perhaps in the hardening process.

 

[woodchucker]

For a little watch makers lathe, wouldn't brass be a good choice. Let the brass wear and replace it, over the castings.

 

[SouthernChap]

For a little watch makers lathe, wouldn't brass be a good choice. Let the brass wear and replace it, over the castings.

Bearing or phosphor bronze would be even better but kinda expensive.

 

[jwmay]

Maybe not bent but warped during manufacture? Perhaps in the hardening process.

I sure don’t think so. I don’t really think they’re hardened either. A few whacks with a hammer usually straightens ‘em right out. Which is another reason I don’t think they’re cast iron.

Cold rolled seems the most likely.

Another valid concern regarding what I think I know. It’s based entirely around the four Atlas lathe compounds I’ve worked on. Lol. Probably not a representative sample for the whole machining world! Haha!

 

[Forty Niner]

I have 3 watchmakers lathe cross slides for 8mm lathes. Two are Levin and one is Boley. All have steel gibs. They are finely finished and fitted. I don't know if they are hardened, but suspect not.