Making pinch rods

Start with an appropriate section of mild steel square tubing, I have bought a 1 meter long square tube with an outside dimension of 20mm and a wall thickness of about 1.3mm. I also got a small bag of 20mm M8 bolts.

Cut two 1" pieces off the tube with a hacksaw and drill a hole of the correct size for the bolt you have (6.5 or 6.8 work for M8). Tap that hole.

Let's check that the bolt fits, it does...

Now find a piece of wood with straight grain and plane it until it's about 20mm by 20mm. Resaw it and check the fit in the metal parts.

The stick was originally longer, but it snapped at a knot when I cleaned up the saw marks.

Here's the almost finished pinch rod... all in, less than 30 minutes work. I still need to taper the sliding ends.