I am not sure if this is the best place for this post but if the moderators need to move it, you have my permission to do so.
I started using my CNC module today just to get a feel for its accuracy and ease of use. I wanted to engrave 2mm plywood coasters that were 100mm square. I tried all manner of clamping the pieces and could not make the clamps work effectively for two layers of wood (4mm). I was using the second layer as a spoil board in case the milling piece broke through the workpiece.
I have noted how the clamps are used in many demonstration video presentations but found the clamping action somewhat uncertain unless there was far more of the clamp placed onto the wooden workpiece. I get the rationale behind the 90mm square limit and I thought that it could be resolved by having a few more tapped holes in the bed. This would permit a variable method of workpiece clamping that could allow more metal to hold the workpiece while keeping it outside of the work area.
The clamping method used is quite time consuming to get set up and to arrive at a satisfactory solution that holds the workpiece firmly enough… so that it does not move under the influence of the speedily revolving milling bit. I would like to see a development that permitted a holdfast type of clamp. I use them all the time for my woodwork workbench and they are super fast in use and very secure, especially for odd shaped workpieces.
So what I was hoping to promote was the idea that the CNC plate should have a few rows of holes in it. If they were as now and threaded, it would allow for some asymetric clamping options that would help with irregular workpiece shapes. If the holes were not threaded as now but able to take a clamp similar to the holdfast clamp illustrated below, the holdfast clamps can clamp a workpiece outside of the area of interest upon which one wants to work.
Your thoughts would be very welcome.