Heavy Duty Rock Guard Supports

[klpauba]

My rock guard supports were pretty shot when I bought our TM early this year. I suspect it contributed to the rock guards developing cracks since each of them had one support that wouldn't lock. Perhaps the wind would shake the free end around enough to develop stress cracking.

After repairing both rock guards I built some heavy duty supports to replace the old ones.

I picked up some "Standard Miter T-Bar" from Peachtree Woodworking. This aluminum is very well made and the two mating pieces slide very smoothly.

The first picture shows one of the assembled supports. The red knobs I picked up somewhere online. A 1/4-20 nut is dropped inside and is permanently retained by screwing it onto a bolt.

The second picture shows the components that make up the support. You'll notice that I had to grind the outer piece into a quarter-circle for clearance in order for it to open smoothly. The threaded components are all 1/4-20 stainless steel and the nuts have nylon inserts to prevent them from working loose.

The third picture shows the construction of the lock. The hole closest to the end of the slider has a slight countersink. The second hole serves to relieve the stress concentration at the end of the slot. It will (hopefully) prevent the aluminum from cracking further. The bolt shown has a taper that matches the counter sunk hole. As the bolt is tightened, it spreads the slider inside the miter track causing it to hold very tightly. You could probably use an ordinary flat-head machine screw. My son wanted to practice turning on the lathe so he made me four of them. Since the were originally bolts, he left a little bit of the head intact so that it wouldn't rotate while the knob is tightened.

The forth picture shows the knob threaded on to the locking bolt.

The final image shows the new heavy-duty supports in action (rather, in inaction!). It doesn't take much to lock the sliders in place and they hold much better than those in place before. They also move as smooth as silk.

It's not particularly cheap -- I probably spent between $60-$75. One 48" Standard Miter T-Bar makes about 3 3/4 supports that were identical in length of the originals. If you are willing to accept slightly shorter supports, you can get all four made from one 48" length.