It is a frequent requirement in many manufacturing workshops to put away random drill bits that have been used in various projects. Annoyingly, it is not always clear what size the drill bit is. I often found myself measuring a bunch of drill bits with vernier calipers to confirm their size before putting them away in the correct spot.
Often, it is something that can be done by eye. Common sizes like 1/8″, 3mm & 4mm are easily identified when those are the only sizes used, but an issue arises for me when incremental drill bits are used. For example, 3.2, 3.3mm, 4.2mm etc. My confidence in estimating by eye is reduced somewhat and I end up reaching for the calipers. Annoyingly, calipers are useful for many tasks so they are not necessarily where the drills go and often end up going walkabout. Frustrating.
So, a gauge of some sort to make the process quicker is one 3d printing project I had in mind for a while. It went through some iterations in my head until I decided to go with the super simple solution of using a thin block with slotted holes. It’s not very accurate but it is sufficient for the job. There is no real need to be more accurate than a tenth of a millimetre.
I did a few iterations which involved minor changes to markers and dimensions. I tied it to be piece of string to keep it in the correct location and have been using it successfully for a month or so now. It has been perfect for what I need. For the first few uses, I needed to confirm to myself that it worked as well as it does by checking against the verniers. Spot on every time.
It is faster than using calipers or the usual method of trying to put the drill bits into the holes in drill bit cases. Accuracy is low but adequate. As far as improvements go, I think it could handle more sizes and have clearer markings but it does what I need perfectly at present so I am leaving that version as is.
I uploaded the model to ‘printables.com‘ at: printables.com/model/428869-metric-drill-bit-diameter-gauge-for-2-to-5mm