Homing switch repeatability

Is it safe to assume when my machine finishes the homing process that it will consistently set up the same?

Or should I ask, how consistent are the switches? Will they trip at the same point in travel, or is there a bit of bounce/variability?

I want to avoid the process of resetting home each time I put work onto the machine. I want to set up a reference fence, measure the distance to the ‘home’ origin, and then set up my work accordingly.

But this will only work if the machine ‘homes’ to the exact same location each time.

The switches used are:

http://www.digikey.com/product-detail/en/omron-electronics-inc-emc-div/D2QW-C003H/SW1221-ND/2698560

Datasheet: http://www.omron.com/ecb/products/pdf/en-d2qw.pdf

They should be consistent. Further information:

https://www.ia.omron.com/support/guide/29/further_information.html

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Those switches look awfully tiny.

I attached an indicator to the spindle mount and homed the machine about a dozen times. It was spot on the same place every time.

I am very happy.

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They are tiny, but they are sealed, so that’s nice for keeping the inevitable gunk out of them. Keeping the rails clean is probably a bigger problem.

It looks like the data sheet says +- 0.3mm, but it does not specify if that is variation between switches vs variation within one switch over time.

I think that would generally be from switch to switch. A given switch may change slowly over time, but click to click they should be a lot closer to that.

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I don’t have the stock switches but had a few issues with repeatability. I’m just about to swap mine out for magnetic reed switches.