[Project_Hopeless]

I'm looking for recommendations for an inexpensive touch plate for setting the Z axis on my DIY CNC router.

In my searches I see a lot of hockey puck and plate style devices that don't seem to have any compliance or over travel capability. This can't be good.

I see some brass button styles starting at ~25$. Most of the comments say they have to be reworked due to poor continuity.

What would you recommend?

[TTalma]

I use a switch that is repeatable to 3 microns. this one

I purchased it on eBay for around $20 it moves about 1/8" before it triggers, then has 1/4" of travel after the trigger point.

In use, I rapid down to the switch, when it triggers I retract 1/4" then move down at 5 ipm, retract 1/4" then move down at 5 ipm again and take the average of the Z position both times. I exported the output the an excel spread sheet after doing it 100 times. I found the accuracy was repeatable within +-2 microns, and about 75% of the time it was the exact same value.

I like this method because I have an ATC and I can set depth as part of the change cycle, and don't have to worry about additional wires etc, to complete a circuit.

[DonKes]

Could you reveal the brand, supplier or Ebay seller of the product?

Don

[philba]

I don't think the one linked to is the one he bought for $20 on ebay... At least, not based on the listed price.

[TTalma]

The one I linked to is the one I use. The seller only had one, it was a lucky purchase. When I was researching doing this, I saw other using a hall effect sensor, but the issue with them is that the amount of metal at the end of the cutter could affect depth.

If you do a little googling you can find mechanical limit switches that are position repeatable. I believe most of them are just hall effect sensors in a nice package, where the mechanical switch trips the hall effect.

The biggest problem I have with mine is that once in a while a chip will land on it and goof up the depth, I plan to add blow off, but need more time!

[philba]

The one I linked to is the one I use. The seller only had one, it was a lucky purchase. When I was researching doing this, I saw other using a hall effect sensor, but the issue with them is that the amount of metal at the end of the cutter could affect depth.

If you do a little googling you can find mechanical limit switches that are position repeatable. I believe most of them are just hall effect sensors in a nice package, where the mechanical switch trips the hall effect.

The biggest problem I have with mine is that once in a while a chip will land on it and goof up the depth, I plan to add blow off, but need more time!

Fantastic score. You should buy some lottery tickets...