3D model description
My last design for a binder clip spring scale left a lot to be desired. The improved design is more suitable for home use than outdoor/shop use, and the improvements focus on a few areas:
⢠The minimum measurable weight is lower. By putting the clips in parallel instead of series, the mass being measured has more mechanical advantage to bend the clips. Instead of a minimum weight of 6 lb., this scale can measure a weight as low as 25 oz (1.6 lb.).
⢠This design change also gives more displacement for the same weight, improving sensitivity. Tick marks can be placed every 2.5 oz instead of every pound. As before though, the units are customizable.
⢠The gauge mechanism has been simplified, which will also allow two scalesāfor instance, metric and SAE.
⢠This new design uses five printed parts instead of ten.
⢠The links have been more aggressively skeletonized, bringing the total filament demand from 181 g for the previous design down to 110 g.
⢠No additional hardware is needed besides the two binder clips and some paper and glue. The previous design needed four bearings, two bolts/nuts, and a few pieces of wire.
⢠The design is more compact in one direction, allowing the handles to fold against the central link. It easily fits into a pocket.
Most importantly, this design takes advantage of vase mode to speed up the prints and reduce seams. Vase mode relies on the part having one (and only one) contourā¦but that contour can be fairly long and complicated. So, by strategic placement of thin cuts, I tricked the slicer into treating the entire part as perimeter. Ben Eadieās video provided the initial idea of adding cuts to āforceā the model perimeter to protrude into what would have been infill volume. I just took that a step further and cut through 2-line-thick truss members to join all of them into a single perimeter. The cuts are thin enough to allow the melted plastic to still join itselfābut my slicer doesnāt know that. Using this technique, I made all three pieces of this design to be printed in vase mode.
3D printing settings
Overall dimensions are about the same as the last version, 8.5ā x 2ā x 2ā. Maximum measurable weight is 55 oz. The only materials needed are 110g of filament, a bit of paper and glue, and two 2ā binder clips. I got the clips I used here (Itās not an affiliate link. Just the most economical source of binder clips I could find when I bought them). I calibrated with around 20 weights, but you donāt really need that many.
Full instructions are in the guide document. There's also an assembly video.
https://youtu.be/ekHDj3zxUVY