I talked to Emanuel at Cattail Foundry this summer about getting lugs cast for a T45HW Shaw. He advised me that cast iron would break in this application and they would have to be cast steel to survive any work where they might hit a stone. Unfortunately, he does not do steel castings.
Thanks for the feedback. I haven't heard of Cattail Foundry before now, but after doing some research I see that they do some top quality work and are recommended by many. I would not question Emanuel's expertise, however would contest his comment to an extent, or perhaps need to clairify mine concerning the use of cast iron for the lugs. It looks like Cattail casts many parts that would be applicable for gray iron. I found an article where they casted a Case boiler stack. This part and those similar to it used on steam traction engines would of course not be cycle fatique loaded or receive impacts loads that a wheel lug would. The microstructure of gray iron is such that it cannot except these types of loads and would be susceptible to fractures, and this could be what Emanuel was referring to in his comment.
After discussing the pyramid lug application with my contact at the foundry I'm working with, he suspects that they were produced from malleable iron, which is a precursor to today's ductile irons. So for this project the current plan is to use ductile iron. This type of iron is also known as spheriodal graphite iron, describing its microstructure which is much more acceptable to reapeated cycle loading and impacts. The intent of this project is to have a source for a set of lugs which are representative of the original design where they would be suitable for the enthusiast that wants to replace their worn lugs when restoring and showing their tractor, for using it at a plow day, or a few times a year in the garden. I would expect the lugs to last a while without any issues for these applications, but without completing hours of testing under various soil conditions I wouldn't be able to guarantee a life target.
I hope this adds some clairity.
Edited by 1940Twin, December 26, 2017 - 06:15 PM.