Chef's Slide Rule

Note: I accidentally had two ⅔ marks on the outer ring in the original model. That has since been corrected but I haven't had a chance to print out a replacement, so the pictures still have the typo

How to use

Pick a measurement disk with the appropriate units and slide it into the magnet base. Rotate the disk until the quantity called for in the recipe lines up with the 1 marker on the base. Once the disk is lined up, rotate the slider to the factor that you want to scale the recipe by. Any of the values in the slider window will give you the right quantity for the ingredient.

Example 1, basic scaling

1. The recipe calls for ½ tsp, so we line ½ on the disk up with the 1 marking on the outer ring
2. We want to make one and a half recipes, so rotate the slider over to the 1 ½ marking on the outer ring
3. The value inside the window is ¾ tsp, so this is what we'll need to use in the scaled recipe

Example 2, scaling with unit conversion

1. The recipe calls for 1 Tbsp, so we line that up with the 1 marking on the outer ring
2. We only need ⅔ of a recipe, so rotate the slider over to the ⅔ marking on the outer ring
3. There's no value on the Tbsp scale cleanly inside the slider window, so we check the other two scales to do a unit conversion. We can chose either 2 tsp or 10 ml, whichever one is easier to measure

Print settings

The make in the photos was printed on a mostly stock Ender 3 Pro with the following slicer settings:

• 0.4mm nozzle
• 15% gyroid infill
• 0.2mm layer height
• Top layer ironing. This isn't strictly necessary and takes more time, but it gives a cleaner surface finish
• Detect thin walls disabled for the top two layers of the disk. This increases the fidelity of the small text on the 0.4mm nozzle
• No supports necessary. The slider has a 60mm bridge, so depending on your printer's cooling capabilities and the material used you might need to add something to keep the bridge from sagging
• No multi material. The labels were colored after the print was done using a sharpie

Additional parts needed

The magnet base needs three 5mm rare earth magnets, one on each corner and one on the slider. Each measurement disk will need another three of the same type of magnets. The holes for the magnets are designed to be press-fit, but some small amount of glue might be required

Change Log

30 July 2022 - Fixed tolerances on 8 Tbsp disk and added blank disk for customization

Colophon

All parts were designed in Fusion 360. The font used for labels is Segoe UI black with 4.5mm height for the primary markings and 4.0mm height for the secondary markings. The sheet music shown being held up by the magnet is from Emperor Waltz by Johann Strauss