Shop Fox M1098

May 16, 2011 27 Replies

My reference was to people doing CNC retrofits, not big commercial machines. Whe we replaced ball screws on the big machines the new ball screws came with a pitch error table to enter into the control.

Also, measuring an inch at a time does not "localize" errors, you map continuously from one end to the other and unless you are quite sloppy, you introduce no cumulative error into that mapping.

Yep, the ball screws for real machines are laser mapped. You can probably buy your ball screws mapped with a pitch error table included for an extra charge.

I worked on some very high quality machines back when I did CNC service, and *all* of them did screw mapping. Replacement ball screws came with pitch error tables to enter into the (Fanuc) controls.

I would expect that with the drive for higher and higher accuracy on the high end stuff, that would trickle down to the lower end stuff as well.

Using screw mapping compensation makes any screw more precise.

i

Cool. Is that built into Mach3?

What do you think of this package for a CNC router: Gecko G540, 3 Nema23 8-wire Steppers 620 oz/in, 3 D9 connectors and shells, latching E-stop switch, 3 homing buttons, 3 current set resistors, a licensed copy of Mach3, and a licensed copy of Bobcad Express V21 for $659 + $25.22 delivery? (modelshopcnc vendor on eBay)

-- It could probably be shown by facts and figures that there is no distinctively native American criminal class except Congress. -- Mark Twain

Hmm, that's right. You'd need some sort of feedback (DRO?) to do the mapping, wooncha?

-- It could probably be shown by facts and figures that there is no distinctively native American criminal class except Congress. -- Mark Twain

Larry Jaques fired this volley in news: snipped-for-privacy@4ax.com:

Yeah, and the new lathe doesn't come with a DRO, which would run me roughly $700. I'll bet I can wheedle someone qualified to do it for half that.

The question, then, is would precision, pre-machined-ends screws cost me in differential cost even less than that. I'm betting yes, but haven't nailed it down. The precision-ground screw crowd doesn't seem to list their prices on-line (which could be BADDD!)

LLoyd

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