A part that fits in CAD can miss in several different ways after printing. Measure the outside, holes and diagonals separately before choosing a compensation setting.

Establish a stable baseline

Check the machine and material profile before compensating dimensions. Verify flow with a representative test and measure the cooled result. Mechanical slipping needs correction on the machine; changing flow to fix one hole can alter the rest of the part at the same time.

Record the slicer version and save the original profile. Setting names and conventions differ between slicers; values should not be copied by name alone.

Use the right shrinkage convention

The current OrcaSlicer material documentation[1] describes separate XY and Z shrinkage settings as the remaining dimension in percent. If a nominal 100 mm dimension measures 99.4 mm, that convention calls for 99.4%, not 0.6%.

For ordinary model scaling, the arithmetic is different: 100 / 99.4 = approximately 1.006036, or 100.6036% scale. Check which convention the specific control expects before entering anything.

Repeat the print at several sizes before assigning the mismatch to shrinkage. For a deliberately hypothetical comparison, a 20 mm feature measuring 19.8 mm and a 100 mm feature measuring 99.8 mm both miss by 0.2 mm; that is a different pattern from both features measuring 99.4% of their intended size. Treat the pattern as a clue about offset versus scale, not a diagnosis of the material. Keep the actual measurements and conditions beside the profile so the compensation has an error to explain.

Separate holes from external contours

OrcaSlicer documents X-Y hole and contour compensation[2] separately. Positive hole compensation enlarges holes; positive contour compensation enlarges external contours. Check the resulting hole and external contour sizes in the preview before printing.

Preview and print a small fit coupon containing the relevant hole sizes. OrcaSlicer’s own tolerance-calibration guide[3] names the Orca Tolerance Test and describes measuring the holes and tester before tuning hole and contour compensation. Use a coupon that represents the joint you need, and inspect both boundaries after a change: making a hole fit does not answer the outside-dimension question. Do not transfer a value to another slicer merely because the setting has a similar name.

Check squareness independently

Compare diagonals and side lengths on a suitable test. Klipper’s skew-correction procedure[4] recommends correcting significant mechanical skew first, then printing its calibration object with software skew correction disabled. Its measurement set uses the two diagonals and a specified side; an arbitrary square or guessed angle is not a substitute for that geometry. Follow the firmware’s procedure and reprint with correction enabled to assess the result. Klipper also warns that skew correction can move the tool beyond the X or Y boundary, so keep its placement and start-code cautions with the calibration.

Validate the actual joint

After each change, reprint the test and then a representative mating part. Check more than one dimension. Preserve intentional clearance and allowance in the design.

Apply compensation to the repeatable error you measured, then try the intended joint. Check its clearance as well as its overall dimensions: a better outside measurement does not tell you whether the mating parts fit. Keep the original measurements with the profile so a later mismatch gives you something concrete to investigate.