Thread: movement during heat treat

Not sure if this is the correct place to post this so please move if needed.

I was given a 1 x 4.75 x 9.00" block that has 4 dowel holes that were machined in the mill. They want me to set it up in the edm and fix it. The dowels are 2.25" and 6.25" apart on the x & y axis. 2 of the 4 are off location by .016" and .010" in the same direction because they say it moved during heat treat. I understand things can move a little and what not but do these numbers seem a little excessive? Looks to me like someone messed up in the mill. Is there a rule of thumb on how much stuff can move based on the steel size? And, if things do move, how were things done before edm so locations were maintained? Thanks.

how were things done before edm so locations were maintained?

Jig grinder excels.

Nothing ever moved that much in heat treat if it were that size. (Caused by operator, not heat treat department)

What material was used? What kind of heat treatment and quench was used? Does the block appear to have warped faces? Was the part machined in a manual mill?

Can you split the error among all the holes, instead of picking one at random as your zero datum?

L-6 is about as bad as anything for movement. It grows by about 0.001"/inch.
Somebody missed some hole locations.

We didn't have a jig grinder. Used a sinker EDM with a 3R orbitor.
JR

Originally Posted by johnoder

Nothing ever moved that much in heat treat if it were that size. (Caused by operator, not heat treat department)

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