The jig we made to miter the chain stays to the bottom bracket needed to be adjustable and accurate. Conceptually it was simple, but in order to get the cuts to work for all of the variables we have planned on throwing at it, things became a little complicated.
But it was nothing a little math coupled with some careful and well thought out machining couldn’t overcome.
Jamie worked day and night to get things right. The jig’s structure is essentially a flat plate with a couple of raised bridges that hold down the stay blocks and hold the jigs adjustment as it supports the stays during mitering.
We had to make special blocks to support the stays securely and close to the cutter. The more stable the tube is while it is being cut, the better the chances for a perfect cut.
Loose tubes could potentially slip, causing damage to the tube, the jig or even us. Tube security equals safety on many levels, and we like that.
As the jig comes together, the fit up of the tubes and the registration of the slot (made on the slotter jig) are checked over and over until we are sure that the fit and adjustability is spot on.
Above is the slot produced with the slotter from the previous post interfacing with the chain stay mitering jig.
Now it is time to use the jig to cut some stays…