No, that's not at all what I was saying. Better temper no doubt helps machinability and I believe I said that immediately after your post about using wheels as a metal source but achieving T6 temper can certainly be in doubt. In Jeff's thread that you reference, it was stated in post #67 they were brought to T6 in Michael's oven (which is a pretty nice oven BTW and similar to mine at work), but there was no mention of how that was verified other than treatment schedule.....so T6 may or may not have been achieved. There is a significant improvement in mechanical properties from T5 to T6. I was just responding to your post about CoreyM's casting apparently machining better than yours and you remarked about yours being a little gummy. I don't know how to measure or quantify "a little gummy" but temper is measurable. Many rims are 356 but many are not, and it's quite common for rims that appear to be cast to actually be forged and though forged rims also seem to be decent casting stock, they are a different alloy thus my comment about how subtle differences in alloy can produce very different results for a given post treatment regimen. Whether he post treated his castings or not, Corey had certainty in his alloy because it was sourced from known A356 castings. Best, Kelly
