Well I don't know if this has been shown before on this site but this is my fix for a hold down system that is both flexible (and Cheap!) ;). Don't get me wrong I do like T-Slot clamping systems but the only drawback I see to them is that if you want alot of different clamping positions you have to add alot more T-Slot. The keyhole system I'm using is spaced about 2" apart covering my entire table, so if I want to clamp down a part that is say 3"X 3" on all four sides I need only to locate it between 4 Keyholes pretty much anywhere on the table! If I were to have used T-Slot odds are if I didn't space the Slot 2" apart all the way across the table I would only be able to clamp the part on 2 sides.
Here's a shot of the keyholes along with the Gcode I used to make them.

I made up some quick clamps using pine, the ideal material would be a hard wood but I was in a hurry and i'll make some better ones when I have more time. This one is a simple leveraged hold down, the block on the back of the clamp should idealy be slightly taller than the material being clamped this creates downward pressure on your work piece. If the block were shorter the clamping pressure would want to squeeze your work piece out of it. I used a 1/4" bolt with a wing nut for quick fastening, look at how easy it is to insert!:)

This is another clamp based on a cam design I made up to handle items where I need the surface free of clamps. It uses another 1/4" bolt to attach it to the table then you would twist the cam to wedge the clamping block tight to your work piece.

Great Idea! thanks for sharing

Andy

Nice work ! I am definately going to use that idea :)

Thanks.

Russell.