The Evolution of the Crucible Dividers
Posted on 05 October 2017
Customers have asked why we call our dividers “improved pattern” dividers. In toolmaking lingo, “improved pattern” means the designer took a long-established tool and found a way to make it function better. That’s exactly what I think Raney did with our dividers, and the following is a small part of the tool’s story.It begins when my mom lived in New Mexico and ran a stall in an antique mall as a side business. Sometimes she’d visit the neighboring stalls and would pick up tools she thought I’d find interesting. She has a good eye. She used to collect wooden measuring tools, and some of those have been profoundly influential on my work.
Anyway, one Christmas she sent me a bundle of dividers she had picked up from other stalls and in the pile were the pair shown at the top of this entry. They were a bit large for furniture joinery, but I was struck by their sleekness and the way they felt like a seamless piece of smooth metal when closed. I thought their hinge looked a little small compared to the legs, but I otherwise liked them.
I loaned them to Raney along with a heap of other dividers I had been studying. He was drawn to the same sleek pair of Mom Dividers. That’s when the wheels started turning in his head.
Homemade but Clunky
One of the other dividers I had sent to Raney was similar in form but had a screw adjuster. While I liked the screw adjuster – it reminded me of my Starretts – it was too slow to be practical at the bench. Also, the way the dividers changed their shape from flat at the hinge to the roundish legs looked awkward to me.
The Klingon Pair
I like tools that are stripped to their bare essence. Raney sympathizes, but he also likes a little ornamentation. This version was an effort to take the original Mom Dividers and add a nice curve that actually might be functional.
This also is when we were still using a peened pin to keep the hinge in tension. It’s a common feature on blacksmith-made dividers. But it requires maintenance.
Can it Be Simpler?
One of my faults/gifts as a designer is to try to cut away anything unnecessary and find the beautiful skeleton below. Sometimes I go too far. As part of this exercise, I asked Raney to make a series of dividers with different tolerances and different numbers of leaves in the hinge.
It did. These two-leaf dividers were easy to make but they also loosed up too quickly. At this point Raney went deep into his lab and I didn’t hear from him for weeks, maybe two months.
The Working Prototype
When he emerged, he had synthesized all my comments and then taken a giant intellectual leap forward on his own. He designed the sex bolt that allows you to set the tension. He added the chamfers that I adore. And he created a tapered and curved shape that gives machinists fits to recreate, even on advanced CNC mills.
But we love it. The tools are incredibly difficult and expensive to make. The handwork to get the finish just right is grueling. But, as I’ve said before, they’re the best pair of dividers I’ve ever owned.
— Christopher Schwarz