Quote:
Originally Posted by 6point6
LaSalle 1144 is sold under the trade name "stressproof". It is "notch sensitive", grainy and splits easily. In my opinion, poor choice for a tounge and groove drive system. Manufactures like it because its easy to machine, stays straight and they dont have to heat treat it but its not always a good choice. I designed with and machined a lot it in my career with good and bad results. Most of the guys I worked with considered it cheap junk.
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Thanks for this. To me, "notch sensitive" is more about impact loading than just overstress. No info here suggesting impact loading but hard to know. Being cold-drawn and not really "solutionized", your comments about "grainy" make sense. The web site talks about allowable "seams", which sound like artifacts from hot or cold forming...and can't be good. Maybe what you describe as splits easy?
As to being cheap junk, it is pretty strong without needing heat treatment, so that might be a little harsh, but definitely not going to be the same quality, strength, nor toughness as a quenched and tempered alloy that costs much more.
Personally I think the original slotted design is pretty bad. To your point, GM probably made these parts out of something better but could have at least reinforced the slot or increased the shaft diameter.