DIY Clamps #7: Wing knob refinement


This is part 7 in a 7 part series: DIY Clamps

  1. Introduction
  1. Custom T-bolts and knobs
  2. Wing knob refinement

The wing knobs and T-bolts from the last post were working well for the cam clamps, but one thing I thought would make them better is if I could install and remove them without having to slide them down and off the end of the track.  There are special nuts for aluminum extrusion track that can be dropped-in and twisted 90 degrees to engage the underside of the track.    As Splinter mentioned, they can be expensive unless you get them on Amazon and with metric sizing.  So, I got a bag of 50 with M6 threads.  Sorry 1/4-20, we had a good run. 

I remembered that I had a scrap of roughly 3/8" plywood in the garage that came from a Lumber Liquidators pallet.  It was not quality plywood, but it would work for knobs.  The knobs needed M6 threads too, and I thought that the rectangular track nuts would actually be ideal since there would be no chance of cam-out like there would be with a hex nut.   I created a recess in both the knob and the 1/8" plywood disc standoff to capture the nut, leaving the square center "chimney" of the nut flush with the outer surface.

I cannibalized an M6 by cutting off its head.  It became a T-bolt with one of the new T-nuts threaded to one end (which will be permanent as soon as I can track down my threadlock).

Then it can be dropped-in anywhere along the track.

Turning the knob rotates the nut which locks in place as the knob it tightened fully.

With the prototype done, I setup to cut 30 knobs.  Eight of them disintegrated while being cut because some of the plies were not glued.  But 22 knobs ought to be enough for a little while.  Check out the edges of that plywood.  Definitely not cabinet grade!  Knob grade?  Yep.

After assembly and glue-up, I wicked some low-viscosity CA glue into the edges of the plywood, hoping that would help anchor any loose plies.

I've got some M6 threaded rod on order so I can make a set of T-bolts to outfit my current set of clamps.  
Some great ideas Ross, looks like it is working out. Thanks for sharing.

Main Street to the Mountains

Those "cam lock" nuts are a good solution. I've marveled at the evolution of surface clamping for woodworking. Early on was the really cool adaptation of T-track slots as used in large metal machining tools. Just slide in the nut from the end of the track and you can lock down anywhere along the track. Then enough people got tired of feeding the nuts from the end and the popularity of the drop-in styles took hold.

Only thing I can think of that is "better" are vacuums or magnetics but it really all depends on the properties of the material being secured (and the budget)