Precision Tolerance Tester

thingiverse

Overview: A precise tolerance test designed for simplicity and efficiency is attempted here. This tolerance tester will measure print tolerances that are "printed-out-of-place" with just two parts. Design: The end of the measuring bolt is exactly 9.5mm in diameter, while the base is precisely 10mm. The measuring tube has a constant 10mm inside diameter and is 50mm long. This gives a tolerance testing range between 0.5mm and technically zero. The ratio of the measured gap to the tolerance result is exactly 100:1. In practice, a remaining gap of 30mm would mean your printing tolerance is 0.3mm, an 18mm gap means 0.18mm tolerance, and so on. There are cogs on the bolt used as indicators of 5mm intervals in height (the smallest being a half interval at 2.5mm), and also for increasing the difficulty of tighter tolerances, as more cogs are introduced as the tolerance shrinks. How to Test: Slide the bolt down the top of the tube without pushing on the ends of the tube or bolt. Measure the gap with calipers or a good ruler between the bolt and tube in mm and divide by 100, or simply move the decimal left 2 places. Use the cogs as a guide if you want a simpler measurement, and round up to the next cog for your tolerance safety margin. The amount of tolerance resistance is up to you, whether you want a freely spinning part, or something that will fit in a hole nice and snug, and still be able to be removed. Reference: In terms of a reference example, my pretty well-tuned Ender 5 produced a resistance-free gap of about 14mm, or a tolerance of 0.14mm, and a snug tolerance of nearly zero (I can insert the bolt completely and remove it without using tools). In practice these results correlate pretty well as I design with a 0.15mm tolerance for freely moving joints, and 0.01mm tolerance for removable press-fit parts.