Probing ability on LongMill / gSender?

So, something I have seen proposed in another Facebook group, (GSENDER related, but definitely would require some kind of probe.)

I am not sure if I can explain it properly, so I will attempt to use the example that was proposed.

The Short version, It would be nice if the Longmill could be used to “find the work”

One of the groups I belong too, is for Cutting boards, people will make them up, glue up, sand and then seal.

A few individuals, have started to put Bevels, “Drip Trays” , Logo or Inlay’s into the work. but struggle with lining them up. and after 30-40 hours of making a cutting board, the last thing you want is to make a mistake on the CnC

I would like to be able to have the longmill, do a kind of Find, and have it define the actual workpiece, then based on the results, it sets the XYZ 0 at the center of the work. (as well as report out the Work dimensions.)

Then I know the Center of the Work is true center. I could put a Bevel on the block of wood, because I know EXACTLY the mm to the detail

Truth be told, with this kind of information, you could tell if your project is skewed as well ,
Because a X1Y1 - X1Y550 and X500Y500 - X500Y450 reports the block is not centered properly.

Probes available from Ebay

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@Menglor As I’m sure that you know, Stephen, it’s simple to do this now without the expense of a probe. I have set up my Mill and I believe that @Heyward43 has, too, to be able to make repetitive carves accurately and simply. Like you, I carve cutting boards. I also carve picture frames that I have assembled off the Mill. I use the Mill to carve intricate details into the frame. If I’m out at all, I’ve wasted a lot of time. I’ll be interested to see if gSender will do this in the future. Until then,you may want to pass along to your friends on other Facebook pages that it can be done now.

I see what you’re describing here Stephen, though I’ve never heard it being applied to finding work exactly in the way you describe. Interesting.

I can say that as of now there is a easy-ish way of accomplishing the same final result as this without a probing sensor which is to cut out a pocket in a piece of sacrificial material - it doesn’t have to be very deep at all - which matches the outer dimensions or contour of your item. Then, with the origin point of that cutout already known you’d be able to place the item within the pocket, hold it in place, and perform the engraving, drip tray, etc. exactly lined up. This would also automatically take care of ensuring the item top is parallel and squared up to the mechanics of the CNC.

I’m sure you’ve already heard of this method but I figured I’d mention it for completeness :+1:

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@chrismakesstuff This is a similar process to mine - but somewhat different. :grinning:

I have drilled a series of 1/4" diameter holes in my spoilboard along both the X and Y axes of the Mill, using the Mill to drill them. I believe that @Heyward43 has done something similar. When I want to engrave a picture frame, for example, I place 1/4" dowel pins into these holes. I snug the frame up to the pins and clamp/tape/glue the frame down. Now, I know that the frame is perfectly aligned and square to the Mill’s X and Y movement.
I set the X0Y0 to the front left corner of the frame, using the touch plate and probe function in gSender. Obviously, I cannot set them to centre as there is no centre. However, even if there were, as in the case of a cutting board, I would still set to the front left corner for the sake of precision.
This method has worked perfectly for me for several cutting boards and more than a dozen picture frames. It’s not my “invention” as many others both here and on other sites have adopted the same process. It seems to have withstood the test of time.
In terms of non-square/rectangular items, I have used your method, Chris. I did two oval picture frames. I cut a pocket into a waste piece of MDF that precisely matched the outside dimension of the frame. Without moving the MDF, I placed the frame into the pocket, then carved the graphic onto the frame. It worked perfectly.