The folks at Thrustmaster were gracious enough to give the T.1600M FCS system a pair of M6 bolts on the bottom of their HOTAS joystick and throttle combination. This is a big step up from the HOTAS X which was decent but had no way to attach it to anything.
This thing is a simple pair of mounts for attaching the joystick and throttle to your own 1.5" schedule 40 PVC frame. The small model (orange) is for the joystick, the large model (green) is for the throttle. The secondary arms on the joystick could probably be a little bigger, but it is very stable once attached to the PVC so I'm not sure there is any benefit. I've not modified the OpenSCAD file from the design I printed and photographed.
You will need2x M6-1.0 bolts per piece (4 total) which are available at Lowes. The joystick can take up to 30mm length, and the throttle can take up to 20mm length, but I used M6x16mm hex head non-hardened bolts (92 cents for a pack of 4).
The design can be adapted to other PVC diameters just by changing the OD measurements pvc_od_a and pvc_od_b to the proper taper.
The author marked this model as their own original creation.