3D probe for plywood

[Davo]

So when i vcarve plywood it's never the same thickness size in all locations so cutting a border on it ends up jacked up majority of the time

My idea was to take the 3D probe and have it touch every 5+/- inches so it doesn't take but 10min or so , then project the toolpath into that 3D model of it

Does this work in theory?

[steve_g]

Sounds very much like my problem…

http://www.talkshopbot.com/forum/showthread.php?22704-Is-there-a-practical-method-of-“scanning”-a-large-surface

SG

[Davo]

After looking at that link it looks like the probe is what I'm after

I don't have much elevation difference, just need an average every 5" or so of probing would work for me

Also I remember someone posting a disc for zeroing that's a lot quicker than the plate and clip... I need to find that also

[coryatjohn]

Have you thought about just leveling the sheet in the same way that the spoil board is leveled?

[Davo]

Can't, it's multi layer plywood with a thin top

[dlcw]

Another option, used extensively in cutting cabinet parts and mortise and tenon joinery for those parts, from plywood is to zero from the top of the table, not the top of the sheet. Take a few micrometer thickness readings of the plywood to .001" and it should work. With cabinet parts, mortise and tenon joints are cut to .007" thickness tolerance so you get a good fit with a tiny bit of room for the glue.

Plywood is so crappy today that zeroing to the top of the sheet just doesn't work anymore. The most consistent thickness in plywood I've seen is Armorcore plywood. This has a thin layer, 1/8", of MDF under the outside veneer. The thickness of the MDF can be controlled much better giving a better consistency in thickness.