Assembly checks

Correct a printed template scale

Use a measured calibration bar to calculate the next print percentage, then verify with a second print.

A template can look right while being a few percent too small because a viewer fitted it to the printable area. This worksheet uses an explicitly dimensioned calibration line to calculate a correction. It works only for uniform scaling. It cannot correct a photographed drawing, a warped image, or a printer that scales horizontal and vertical directions differently.

How to use the result

1. Print a calibration line with known intended length using the same viewer, paper and settings as the template. Measure between its marked endpoints.
2. Enter the actual print percentage used for that attempt. If the viewer substituted fit-to-page, first make a controlled print at an explicit percentage.
3. Apply the suggested percentage and print again. Measure a horizontal and a vertical reference before transferring any cut or hole positions.

Worked example

A 100 mm reference printed at 100% measures 97 mm. Its observed size is 97%, and the correction factor is 100 divided by 97, about 1.031. The next trial is about 103.093%. If the original setting was 95%, the corrected setting would instead be about 97.938%.

Before making

• Use the written dimensions as the authority whenever a template and a ruler disagree.
• Check page seams and overlapping registration marks on tiled prints; scaling alone cannot align badly assembled tiles.
• A second measured print is required. The suggested percentage is an arithmetic correction, not printer calibration evidence.

Continue your plan

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