Layout marks

Mark an evenly spaced row of holes

Place the first and last hole at equal end margins and calculate all intermediate centres from a single reference end.

Five holes have four spaces between their centres. Dividing by the hole count is a common way to put the final hole in the wrong place. This worksheet fixes the first and last centres at the specified margins, then divides the remaining distance between them. It is a marking aid for a straight line, not a hardware compatibility chart.

How to use the result

1. Choose a sound reference end and measure the full length along the intended line of centres. Establish the sideways offset separately.
2. Set the margin from each end to the centre of the first or last hole. A centre margin is different from the clear distance to the hole edge.
3. Mark each returned position from the original reference end. Do not repeatedly step off a rounded pitch; that compounds the rounding error.

Worked example

On a 500 mm reference length, five holes with 30 mm centre margins span 440 mm over four intervals. Pitch is 110 mm. Mark at 30, 140, 250, 360 and 470 mm. Six holes with the same end positions would use five intervals of 88 mm.

Before making

• The final centre plus the end margin should equal the full reference length.
• Check hole diameter and the remaining edge material against the actual hardware instructions.
• Printouts must be calibrated before transferring marks; a ruler and a single datum avoid print-scale errors.

Continue your plan

• print scale
• divider spacing