Fixture building comprises a lot of a manufacturer's time, regardless of the scale of the operation. For small shops, designing fixtures that can be used repeatedly for different customers is extremely useful. I faced this challenge a number of times when I was working on bikes, and spent a lot of time setting up fixtures that helped my productivity a lot.

In 2010, I built the brake boss mitering jig below. It mounts to a tiny little rotary table that I bought for my Benchmaster, itself the tiniest horizontal mill that I owned and still one of my favorite tools.

This chart maps XYZ coordinates for a toolpath that will cut a pocket in a piece of Mic6 tooling plate. It's machine code.

The pocket is finished, and will now be drilled for mounting holes. I believe I was tapping right in the machine spindle too, though not under power.

I made a variety of split blocks to hold various tube sizes to be mitered. In the center, you can see a drill bushing that I installed to allow a hole to be drilled right in the middle of the tube; it would generally receive a threaded boss.

The jig, mounted to my little Benchmaster, on a messy day in the shop.

It seems quaint, but little productivity tools like this are how shit gets done in even big production style factories around the world. I kid you not - little manual mills, drill presses and lathes are in operation as I write this, performing some little repeatable operation on high precision parts for demanding customers.

Eventually a lot of these things are likely to be sold for scrap and passed down the line to developing economies. I've been to a few tooling auctions, and have seen 75 year old punch and foot presses that weigh (literally) a ton being sold for under $100. I understood that they would be loaded into a container and shipped to Asia, and it's likely that they got a new life there making good parts for another decade or so at least.

I generally think that that lifecycle is a healthy one, though it does have the strange effect that nowadays, even the most industrious kids are likely to end up knowing additive manufacturing in lieu of conventional (mostly subtractive) methods. Schools around the country are buying up MakerBots by the truckloads, and with good cause - to fail to do so would be an offense on par with teaching me cursive in 1992, when what I should have been learning was C or HTML. But all those 3D printers have got to go somewhere, and I suspect [citation needed] that they're supplanting Heavy Tens and J-Heads, which anyway don't get too much use as it is.

While I'm reasonably unromantic about that transition, it does strike me that subtractive methods are likely to remain, for the long time, significantly more efficient and effective for making certain types of products. Just as CNC machining hasn't replaced casting, forging, and sheet fabrication, additive manufacturing won't totally replace those methods either. All of these tools will, instead, complement each other - and the institutional knowledge pertaining to traditional manufacturing will, I hope, be not supplanted but enriched by newer paradigms of manufacturing philosophy.