Zeroing End Mill Question

[JC50]

When I do the X and Y zero on an end mil, do I center it up on the origin (0,0) or put it to the outside or my work, or the inside. Stupid question,I know, but I'm honestly not sure.

[ger21]

The center should be where you have 0,0 in your g-code.

[Cruiser]

Your X & Y zero should be set to a point of reference that can be proved easily. Whether it is the corner of the matr'l or the center of a hole is up to whoever draws up the plan. If programming to a print then you would most likely match your zero to that of the print. It is also common to use a hole or pin location within a fixture to set Zero. Where ever it is will be where ALL dimensions come from. The same is true for the Z, whether it is a top point or bottom point or something in between, it should be easily tested at any time to verify what you got.
What good would it be to set to the top of matr'l then cut off all of the matr'l and then not be able to reset easily when a problem arises. I like to keep it simpler so that I don't have to crunch a lot of math to re acquire an essential element.

[AssassinXCV]

What if the zero was at the very corner? how would you set the endmill in the corner?

[LeeWay]

I have a hole at a fixed point that I jog to.
Like X5 y3.
Then I lower Z to align the bit perfectly in the hole. Then I type into the DRO's the 5 and 3 hitting enter after each.
Then tell it to go to zero and it is fairly quick and accurate enough for me.
Better accuracy than I got from cheap switches I used initially.

[ger21]

I have locating fences at X0 and Y0. I just home the machine, place the part against the fences, and the part is at 0,0.

I should say that I actually route the fences at the zero positions after they're bolted in place. If I'm cutting the edges, I use spacers.

[AssassinXCV]

Could someone answer my question for where to position the endmill if the 0,0 is at the corner of the work piece?

[LeeWay]

It has been answered, but the cutter should be centered at 0,0 as well. You can have offsets instead. Then choose some other location for home. I like home to be at 0,0 though.

I do things differently on my mill than I do the router.
The mill is the center of travel for 0,0.
The router is 0,0 at the lower left corner of the cutting area.
In both cases, if I used a needle as a cutter, it's tip would be 0,0.

[AssassinXCV]

Originally Posted by LeeWay It has been answered, but the cutter should be centered at 0,0 as well. You can have offsets instead. Then choose some other location for home. I like home to be at 0,0 though. I do things differently on my mill than I do the router. The mill is the center of travel for 0,0. The router is 0,0 at the lower left corner of the cutting area. In both cases, if I used a needle as a cutter, it's tip would be 0,0.

Thank you for clarifying

[Helmuth]

Hello:

The zero or 0,0,0 position depends on the machine and the purpose. For instance, on our Bridgeport EZ Trak, once the machine references itself, we use either an electronic edge finder or a dial indicator to find or establish a work-piece reference point. On the other hand, our machining center has multiple 0,0,0 positions. It similarly has a machine home position but it is common, for instance, to have 6 different vises or work holding fixtures mounted to the table, each work position having its own set of X, Y, and Z reference points. Then our programming considers the machine it is going to be run on and we establish program reference positions accordingly. This is all drastically simplified and I would be happy to detail further but it would take several pages to explain and might be TMI.

Best regards: Helmuth

[Cruiser]

Originally Posted by AssassinXCV Could someone answer my question for where to position the endmill if the 0,0 is at the corner of the work piece?

An edge finder or probe would be ideal, but, using the end mill just touch the face of one side and the calculate and move so the center of tool is over the edge and then zero that axis.
Repeat for the other face / axis then zero it and you now have established the 0/0 proper.