Seed Spacer
An expanding ruler for sowing. Pull it out to the gap you want, lock it, and every mark sits the same distance apart. Lay it in the drill and sow at each mark.
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What it makes
A folding ruler made of crossed bars bolted together. Stretch it or squeeze it and the centre bolts always stay the same distance apart. Those bolts are your sowing marks.
A strap at one end has a scale in cm. Slide it to the gap you want and tighten the knob to lock it. The bolt heads underneath press a small dent in the soil at each mark.
One spacer, three ranges
Use every mark for close crops, every other mark for twice the gap, or every third mark for three times. The scale has a row for each, and the caps are marked 2 and 3 so you can see which marks to use.
The standard size covers carrots at 5 cm, onions at 10 cm, garlic at 15 cm, shallots at 20 cm and early potatoes at 30 cm. The crop buttons on the workbench show the setting for each.
Printing it
- Print the fit test first: two short bars and a cap.
- Stiff pivot: raise the pivot play by 0.1 mm. Wobbly: lower it.
- Print the bar as many times as the workbench says, plus the caps and the lock kit. All flat, no supports.
- PETG for outdoors. PLA is fine for a season.
Questions
How do I build it?
Lay the bars sloping one way on the bottom and the other way on top. Bolt them at the middle and the ends. The centre bolts go up through both bars with a nut pressed into a cap on top. The download notes list the order of the caps.
Which size should I make?
The standard 10 cm, 8 mark size covers most crops using every mark, every other or every third. Make the bulbs or wide size if you sow lots of garlic, shallots or broad beans and want every mark in use.