Riddle me this...:confused:

[Kyle Stapleton]

I z-zero to the top of my board, and I have checked the zero many times and the just touches the board when I MZ0 and use the keypad to move.

But when I cut anything all my dado, pockets, profiles (anything) are all around.02" short of there programed depth.

EX: All on a ACX 4x8 sheet of plywood
programed dado .125 real dado .102
programed pocket .4 real pocket .378
programed profile .74 it barely cut through a .710 sheet of ply

[paul_z]

If you are measuring pocket depth from the top of the material (dial calipers?) and the material thickness was not set correctly, this could happen. Also, if you are cutting plywood, the thickness is likely to vary more than 0.020" across the sheet. In fact, I wish plywood was good to 0.020".

Second possible cause - the piece was not laying flat or your table. If you are using hold downs, put the bowed side down. If you are using a vacuum system, I'd put the bowed side up BUT understand that you may (are likely?) to get part of the sheet to rise up if you cut all the way through the sheet.


If you can scrap the piece, make a cut through the pocket with a saw and measure the pocket depth from the bottom.

Paul Z

[Kyle Stapleton]

Re mic'ed my sheet and it is about .701" and I told aspire that the sheet was .715".
I will try again Monday with mat thinken set at .7"

Hold down is a vac table but I do screw some in in the sheet in the corners and a few in the field (vac works well for not needing tabs but acx is not alway the flattest).

[coryatjohn]

A good rule of thumb I've found when zeroing to the material is to be sure to measure the thickness of the material in the same place that it is zeroed. That way, if there is a variation in the thickness (there usually is), the issue will be minimized.

[srwtlc]

Vac table surface could be off here and there too if it hasn't been surfaced in a while. Spring is sort of here and humidity is changing. Next week we'll have more snow. ;)

[Kyle Stapleton]

Table was just flatened and all my profile cuts just cut through the sheet.
Re mic'ed in some other places and got .695" (23/32 my butt):mad:

[gc3]

z zero from table

welcome to the jungle...

I always go 2mm deeper to avoid your error

"los errores questan"

[ssflyer]

I agree with Gene. Z-Zeroing to the table helps eliminate material variances, and you have precise control over how much material is left.

I can cut right down to my spoilboard on profile cutouts, and barely scuff the table - mostly from my downcut bit pushing chips into the kerf, which by the way works pretty well for holding pieces in place without tabs...

[dlcw]

I know it might be elementary and basic, but have you verified the thickness of your z-zero plate?

[supertigre]

If the Bot is "ALWAYS" 0.020" short in Z then just tell it that the Z-zero plate is 0.020" thicker than it is currently set to. Problem solved.

[srwtlc]

Like Gene and Ron stated, zeroing on the table surface will keep the thickness of what's left after the dado is cut consistent. Say you want a cabinet or box to be 12" wide so your top/bottom/fixed shelf would be 11.5" wide and the thickness of what's left after the dadoes would be 0.25. When put together it would be 12". The depth of the dado makes no difference then.

A tip for dealing with this in Aspire is entering the material thickness and then selecting the bottom for your Z zero when setting up a file. Then when toopathing the dadoes, in the depth of cut field, enter z-(what you want left over), say 0.25 and then hit =. This will set the depth of cut to what is needed to give you that 0.25" amount of material left, no matter the material thickness.

[scottp55]

Kyle, I'm with Don and Guy. Has anyone dropped/bent/dinged Z-plate? Had a warped Z-plate(about .02" -probably shipping on the Limestone machine). Asked the forum and people said press it down during Zeroing. Problem was if it WASN'T pressed down cuts were .02" light. Mentioned to Dianne at Shopbot and had a new(FLAT) one in 3 days N/C. Problem gone. Love Shopbots support. Just a thought. Thanks for shamrock hint.:)

[Kyle Stapleton]

It was me failing to set the right materiel thickness.
Thanks