I and another member make steel cross slide and compound slide gibs for the Atlas and Craftsman 6", 10" and 12", all models made from 1934 through 1981. We originally did ones for the 6" primarily to replace the plastic ones introduced with the MK2. Then I discovered that sometime in the mid 1970's, Clausing changed to plastic ones for the 12" Commercial models, and for all replacements in older models. The compound slide gib also fits the 9" made by Atlas and sold by them and by Sears. If someone ever needed a replacement gib for an Atlas or Craftsman 9", we could probably make one of those the next time that we run a batch. I would have to get a copy of the factory drawing from Clausing, as according to the part number, the 10" and later used a different gib (10-56) from the 9" and we don't at present know what the difference is.
The cross slide gib also fits the vertical slide on the 6" and the 10"/12" milling attachment as they used the 6" or 10" and early 12" cross slide on those.
The carriage gib we haven't made as that part remained steel. If anyone ever does need one, call Clausing first. A few months ago, I bought a replacement for my 3996 (late 12") from Clausing and they had 3 or 4 more on the shelf. I didn't ask about the other sizes.. Looking at the parts lists, there is one for the late 12", one for the 10F, one for the 10D and 10E, and I don't know for the original 10" and the 9" but think that those are both the same.
Anyway, the compound and cross slide gibs are $18 each for any one piece or $30 for a pair, either 6" or 10"/12". Plus $3.50 First Class postage for CONUS, AK, HI & US Territories. That'll go up a little in January. For the rest of the world, send me a PM or email.