In the interests of using the SM1 capabilities fully, I have drawn up a plan to make a new bed. The holes will be drilled and tapped for M4 set screws of varying lengths. The original clamps tended to mark and bend easily with moderate pressure so I have looked at the possible solutions.
For my needs, the idea clamps would have the smallest profile that was able to do the job and they would not mark easily nor would they been prone to bending under load. It would also be useful if they could be applied at many different points on the bed. The original SM1 only has three fixing points moving inwards from each corner. I had thought about adding points but rather than adjust the original equipment, I thought I would design and make my own bed.
The limitations would be the size of the bed permissible and the fixing points. This would also need some thought insofar as the depth of the bed so that the original fixing thumbwheels could be used if required. More holes is a simple matter and placement of them for maximum utility value is an easy choice. Materials choices are many and varied and I decided to opt for a material with good qualities for bend resistance and easy to work or machine.
I don’t have very much in the way of machinery to machine metal so much of what needs to be done such as drilling and tapping straight holes must be done with a drill press and tapping by hand. The bed material I have selected is 4mm thick T6 6061 aluminium plate. Corrosion resistance, high strength, low weight and resistance to formability are some of its characteristics. It will be ideal for the clamps I intend to make. These will take the shape of an upside down ‘L’ with a single hole for fixing to the bed.
The attached image below is to show the arrangement of holes in the bed. I suspect that this is the sort of arrangement that will be able to permit mounting of odd shaped items and different length M4 set screws will permit uneven shapes to be held. The intention is to have the holding part of the clamp no longer than 5mm but if possible, I feel it would give more machining room if it was even shorter. I will experiment with the drilled inverted ‘L’ shape as a general clamp, once my materials have shipped and arrived. Further information postings as progress permits. The holes may need some different spacing around the central fixing point to the ‘Y’ rail.
All comments and ideas welcome. 
