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Trouble with setting tool length/height.


Nov 18, 2021
Hi, first ever post here.

I started working on a machine that is new to me, it's an old Matsuura RA-3F with a Yasnac I80 controller, CNC mill.
My past experience was working mostly on Haas machines and the occasional Fanuc controller machines.

Anyways, I've been reading through the manual for the RA-3F, as well as the "handy-man operation manual" for the I80 system, but things are not going quite as smoothly as I'd hoped.

I somehow managed to magically set my G54 settings properly for all 3 axes (took a while), and it seems that at least one of my tools (a 12mm end mill) is set properly in terms of height. Or at least I hope so.

I tried a few things for setting the tool length, such as touching off of a flat surface on the vise and using the controller's TLM/measurement setting; tried both adding in the "bias" for the height of the vise from the table and seeing how that looks like, and also doing the same but with no bias and touching directly on the top of my part.

Doing the latter seemed(?) to work, but when I call other tools and try to set their height the same way, they seem to be off by different amounts.

This controller feels familiar (as it's Fanuc based as far as I understood), but so different at the same time.
FYI, the tool height offsets show as negative numbers - a former employee who worked on it had the same 12mm end mill height offset set to a positive number, but I really don't know how/what he was doing to set it that way.

Any help/tips would be greatly appreciated.


Cast Iron
Oct 27, 2006
New Hampshire
The bias under that page should be the Z machine coordinate of you spindle face to your reference surface. This could be a 123 block on the table. When you use the TLM button with your bias set correctly you will get positive tool lengths. If you do this, your Workoffset Z values will be distance from spindle face at Z home to the top of your part or fixture etc. HTH