Question (WOODWEB Member) :
Like everyone else, I have been using pipe clamps, long bar clamps, etc. for years/decades to position, hold, and glue frame or box products, and currently, shutters – principally rail and stile frames. As an efficiency method it would be beneficial to build a simplified form of a clamping table such as sold by Kreg, using pneumatic clamping air cylinders instead of loose clamps with limited-travel hand cranking, etc. Interest is in two rails clamped between two side stiles – just two clamps applying pressure on the two sides.
In looking at cylinders, I see incrementally increasing diameters, references to flow controllers, foot switches of several varieties – forward backward, continuous, non-continuous…
What about working air volume requirements? Control of speed of piston advance? I would like ability to slowly advance piston making sure that tenons/dowels are properly positioned before smashing them; what about determination of final pressure?
What options are desirable, and what is the best source? I prefer a low profile, less-than pretty, commercial source versus store front retailer with consumer marketing and equally fancy markups.
I am looking for guidance in proper sizing – avoiding the simplistic bigger is better syndrome. I particularly invite the mechanical engineer-types among us to spring forth with advice on part selection for such a simple, small table setup.
(Architectural Woodworking Forum)
From contributor D:
You need diameter for pressure. That said, my case clamp only uses 2 3" diameter cylinders per joint. With the regulator set at 40psi, that's only about 600 lbs clamping force.
Speed control is easily done with a flow control valve. No fancy electronics required. If you put the flow control on the outlet of the cylinder you can easily add a valve that bypasses the flow control to give you a full speed option.
Good suppliers are Festo and SMC.
The pneumatic clamps from Ritter are around $400 each new but they work well and are fairly easy to repair. You can find used Ritter clamp tables for good prices. There is one listed on this site for $950 that would be a good deal if it is big enough for your needs. I paid $2000 for a 5' x 8.5' Ritter with 8 clamps and have been very happy with the space savings and utility.
Above all, I now have a proper perspective of the scale, complexity and relative costs involved in my original question. Thanks everyone.