Dynamometer From Scrap

I had some nice, longh-ish, springs around. I thought I could build a small dynamometer, especially because it’s been some time since I’ve wanted to calibrate my torque wrench but I had no way of doing so. Therefore, in the next posts you’ll probably see me checking if my torque wrench is precise enough, using this handmade dynamometer.

Steps

First things first, I grabbed a wooden slab and a bolt to attach the spring at the top.

Next, I cut a shape from a piece of brass that I could bolt to the other end of the spring. This piece will point at the notches on the wood that I’ll mark at each kilogram of weight:

I only had two weights of 1 kg and one of 2 kg around, so I marked the first four weights by hand, and interpolated the rest. From the chart you can probably see that the spring is far from ideal, as it does not have a constant factor (the weights I used were intead very precise).

As a finishing touch, I used the pyrograph to mark all the notches. I left the interpolated ones without the number to remind myself that those are not real measures but interpolated ones.