The Cool Grips Project, Part 2

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In Part 1 of the Cool Grips Project, I discussed my first handmade prototype and the expense of having them made for public consumption.

At the end of 2013, I was looking for an alternative to an expensive injection mold to make plastic guards meant to seal the gun against dirt that might come through the holes in the grips.  I did a bunch of research on making my own mold, and, having discovered that injection molding services don’t want to work with your molds, on the price of used molding machines.  I have a friend who was able to advise me a bit, and the conclusion was: this is a bad idea.  It’s interesting to teach yourself how things work, but if the goal is to actually make products instead of playing with molds, it’s not the best route.

I chanced to meet someone at Club Workshop, Denver’s now-defunct makerspace, who suggested I look at silicone molding.  If I could get a hard mold master, either by cutting it out with a CNC mill or 3-D printing, I could pour silicone around it and have a flexible mold into which 2-part plastic or rubber could be poured.  It was a really good idea, albiet one that took a LOT of experimentation to implement.  But all that experimentation consumed several hundred dollars worth of silicone and and polyurethane, which was less than 5% of the price of a steel injection mold.

I had the final process worked out in early 2014, at which point I got somewhat sidetracked.  About that time I finished up work on my thermoformer, and began prototyping the Pocket-Safe hammer shroud. That whole process is detailed in my “Making Of” series, and you can see it took up a lot of time. Over the summer of 2014 I also started work on the Wall-Saver safety cylinder (as a safe way to demonstrate my hammer shrouds in gun stores and gun shows).  That, too took a lot of time (read all about it) and wasn’t really ready until Spring 2015.  Also in the summer of 2014, Club Workshop went bankrupt, requiring me to set up my own CNC mill, which didn’t happen overnight.

So for all this time I had a good way to make the plastic part of the grips, but I hadn’t been able to work on the metal part.  The suppliers willing to call me back were quoting over $12,000 for a set of dies.  I had worked on designing some square metal-cutting dies in early 2014 as a prelude to working on the grips, and I even bought parts to implement them, but didn’t have time with everything else going on.  But as with the injection mold, making your own is probably not the greatest idea. The level of effort required is huge, which is why the experts get to charge so much.

The biggest obstacle is the forming die design.  For short runs, the flat pattern can be cut out by waterjet (or even with an angle grinder).  Since I want a consistent look, the holes of the perf stainless can be used for alignment at all phases. But to form it accurately, you need to know how it springs back and design the die curvature accordingly.  You also need a good flat pattern that will have the right shape after stretching and bending in the die.

Cutting a bunch of steel dies to experiment is an expensive and time-consuming proposition.  Thankfully, a few months ago, I was flipping through a machinery catalog and saw something that might do the trick.


Part 1 | Part 3

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  1. […] Part 2 of “The Cool Grips Project” I explained that I figured out a way to make the plastic […]

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