Bike Scruler - screw measuring device for M3-M10

NOTE: An improved version of this is available for purchase on my Etsy store. While you can download and print your own here, purchasing from my store gives you additional benefits:

• The M3, M4, M5 and M6 threads are pressed-in aluminum inserts for more precision and durability.
• All of the printed-in threads are chased with taps so they work better for judging a thread pitch match. This isn't a trivial amount of work.
• Two 8mm magnets are pressed and glued into place
• Multi-color printing for the top and back text as well as the background of the ruler portion, more than just a simple M600 layer change.
• Availability in colors you might not have on hand.
• Supporting my work creating printable tools and parts.

For buyers in Australia, you can skip international shipping and buy directly from the amazing Beaut Bike.

Bike screw ruler - aka “Scruler” - for quickly sorting and measuring screws in the sizes most commonly found on bicycles. Simple OD gauge on the side, length in the slot down the front, and reference printed-in threads in the back.

Thanks to Sneaks for his original design that I remixed back in the day that also served as the direct inspiration for this!

Printing instructions

Use at least PrusaSlicer 2.5.0 which has the Arachne perimeter generation, or Cura for the same reason. The text is noticably improved, especially the top text.

I recommend 0.2mm layer heights, I wasn't happy with how it looked at 0.3mm. You can print it at a finer layer height but you're mostly giving up print speed for not much in the way of improved appearance. 2-3 shells, and infill can be light, 20% is usually plenty. Insert M600 gcode at the appropriate places for multi-color printing. When I was selling this version on the store I'd do a layer of contrasting color at the top of the back text, then just before the measuring slot started, and finally change at the start of the top text.

PLA works fine as long as you're not going to leave it on the dash of a car in the sun on a hot summer day. In that case it will warp and shrink and the measurements will all be off. I've got a PLA version in my toolbox that stays in the car and even through this summer it never got hot enough in the toolbox (which stays in the shade inside the car) for the PLA to be a problem. Or, take the safer route which I've done for everything on the store and use PETG instead.

Please note that you will very likely have to chase the threads on the back manually for the best results, which takes some time but is really worth it. If you don't, the threads will likely fit tight and it will be hard to quickly judge if the screw is the right pitch. If you just use the quick diameter check and the length check, however, the printed threads won't be an issue. In that case, you might wish to speed the print up by downloading the version without the threads in the back. I recommend having the threads for confirmation as there are many SAE screw sizes that are close in diameter, and the thread check will quickly confirm if it's metric or SAE.