Back ground is, we have a 2 tooth row sprocket this is 23.5mm tall with a D shaped center bore. The flat of the D shape is dimensioned as angularity 0.05mm -A- -B- -C-.

-A- is one of the flat ends

-B- is the cylindrical portion of the center bore

-C- is the center line of the timing tooth on one row

The part is sitting on a 6" square magnet for -A- and a plane is measured and leveled

6 linear open scans in bore that are then filtered for construction of a cylinder for -B-

2 center scans in the gap on each side of the tooth to construct a mid point for rotation of part to -B- -C-

Alignment is level Z axis to -A-

Rotate to Y axis -B- & -C-

Translate Z axis to -A-

Translate X&Y to -B-

The flat in the bore is measured with a patch scan of 6 rows and a filtered plane constructed.

Our problem is there is too much form error in the flat causing the angularity to be OOT, which is correct to ASME Y14.5 using exact measure.

I am trying to use a high point plane to establish a functional dimension without including the form error just the 3 points that the shaft will engage on.

Is there a way to easily extract the 3 points that the HP plane function uses?

Why is there flatness error in the constructed HP plane?

Why is my angularity dimension of the HP plane zero?

Our supplier is using V2019 and exact measure and is not seeing the form error as much as we do.

I've verified the form error on the surface plate with an indicator by leveling the flat surface and traming down the length of flat and seeing >0.04mm TIR

-A- is one of the flat ends

-B- is the cylindrical portion of the center bore

-C- is the center line of the timing tooth on one row

The part is sitting on a 6" square magnet for -A- and a plane is measured and leveled

6 linear open scans in bore that are then filtered for construction of a cylinder for -B-

2 center scans in the gap on each side of the tooth to construct a mid point for rotation of part to -B- -C-

Alignment is level Z axis to -A-

Rotate to Y axis -B- & -C-

Translate Z axis to -A-

Translate X&Y to -B-

The flat in the bore is measured with a patch scan of 6 rows and a filtered plane constructed.

Our problem is there is too much form error in the flat causing the angularity to be OOT, which is correct to ASME Y14.5 using exact measure.

I am trying to use a high point plane to establish a functional dimension without including the form error just the 3 points that the shaft will engage on.

Is there a way to easily extract the 3 points that the HP plane function uses?

Why is there flatness error in the constructed HP plane?

Why is my angularity dimension of the HP plane zero?

Our supplier is using V2019 and exact measure and is not seeing the form error as much as we do.

I've verified the form error on the surface plate with an indicator by leveling the flat surface and traming down the length of flat and seeing >0.04mm TIR

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