Fixture plate has a few surfacing passes on it while trying to get tram dialed. Earlier iver the weekend I got it pretty close then used an SST tram squaring dial to bring it into within about .001 across 4.5 inches on X and within about .002 across 4.5 on Y. Have another gauge coming that sweeps 6 inches where I will really try to finalize it.
I clamped in a 3/8 plate to do some test passes on with the fly cutter and got some nice finishes with very little bit of edge that would roughly match what I was seeing on the tram tool dials, like .0005 of a step between passes which would roughly match the 2 inch step overs used with the fly cutter. I was able to measure a bit of an inconsistency thanks to the clamps bowing the 3/8 plate.
Now here is where it gets weird. Last night I wanted to use a thicker 1 inch chunk of aluminum which was gonna get surfaced on both sides. I wanted to see how parallel of a piece I could make.
Those with ESP can probably figure out that I wound up with a tapered part.
Running the dial indicator across my SMW jaws across the X axis I was getting around .001 per inch of rise.
Stripped all the clamps/pallets off and decided to test the entire plate.
This does not make sense as I would figure the gantry/spindle would make the fixture plate track in plane parallel to travel.
Lets call the corners where measurements were taken
Back left A is 0
Front left B is 15.5 in forward
Back right C 14.5 in to the right of A
Front Right D 15.5 in to front of C
Measurements are as follows.
A to B was run 15.5 inches and from a Zero Z at A I am low .003 inches at B
Running from B to D, I am .006 inches high at D from A
Running back to C from D, I am .009 inches high from A.
So what is interesting to me here is comparing left side to right side, the right is .009 inches higher across 14.5 inches.
Comparing front to back, the front is .003 inches lower than the back.
Dial indicator was mounted to the side of the spindle assembly so the dial is about 5 inches to the right of the true center bore of the Spindle. But if things were truly square the dial indicator should track as zero across the face of fixture plate.
Trying to figure this one out before final surfacing of the fixture plate.
Inchecked coplanar with dial indicator and the check gaige last night. I set it on top of the linear rails and I am between .001 and .0015 so there should not be enough there to cause the error.
I am fine with the .003 front to back slope across 15 inches, that does not bother me. But the nearly .010 across 14 inches is bothering me and given the spindle travels on the X gantry I am not seeing how a slope is introduced or revealed on the dial indicator.
Tonight I am going to tape out a pretty precise set of points for refrence edges put some 246 or 123 blocks down at a square refrence without having to dodge fixture plate holes. I am then going to touch off on all 4 corners with the dial indicator held in the collet of the spindle while testing zero and gathering data.
Maybe part of it is magnified by an off set of how I was testing before?
But the work piece I faced having a taper to it from a 180 degree rotation would seem to confirm there is indeed a taper.