Why does nobody talk about touching off tools on scrap instead of the vise jaw

Last Thursday I had a run of 40 small 6061 brackets and on the last op I touched my 1/2 inch end mill off a scrap plate clamped next to the part instead of the jaw, and every single one came out within 0.002 on the height. I had been fighting a nagging 0.008 drift all morning from chips packed against the jaw face, and the scrap plate gave the cutter a clean flat spot the probe could actually trust. Do you folks touch off on a dedicated gauge block or just whatever loose plate is on the bench?

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umaf4423d ago

That nagging drift is almost always chips or coolant film sitting on the jaw face, so touching off a scrap plate that you stone flat before every run just kills that whole problem. If you mill a small flat pad on that plate first and keep it as your dedicated gauge, your probe or edge finder has the same surface every single time.

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