Modifying the SM1 Table and its Clamp System

I have now completed the bed and clamp modifications for my SM1. My original feeling was that it was sometimes quite awkward to hold items to the bed when trying to use the CNC milling functions for SM1. One limitation that I ran into very quickly was the 90mm square workpiece limitation. I assumed that this was partly due to the travel of the head and the length of the clamps that were supplied with SM1. The illustration which follows shows the clamps which were quite long and quite soft and they marked easily and bent under moderate clamping forces as well as leaving clamping marks on the workpiece.

Another limitation which I ran into was the placement and number of the screw holes in the SM1 table. The illustration shows just 4 screw positions are available, starting 5mm in from each corner. If the most central holes had to be used, the workpiece would have to be very small to fit inside the dimensions permitted by the screw holes. The dimensions of the table were fixed at 130mm square.

I planned to make a new table and to permit it to have a few more screw positions. The table was to be made from 6061 T6 aluminium so that it had good resistance to bending forces. I used a 4mm thick sheet so that the size was no different in thickness than the existing table. In my mind I had wanted a table that would permit me to clamp items from many different points, not just the corners. My thinking was that this would permit odd shaped items to be held securely for CNC milling. The illustration shows the proposed screw holes in yellow.

The blue holes in the corners are as they were in the original table and the central holes in blue are for fixing the table to the ‘Y’ axis rail with the supplied thumb screws. Many a time when removing the table to change a jig, I wished for a more convenient system. The SM1 machine has to be removed from its enclosure and tilted so that the thumbscrews can be reached. Some sort of easily accessible toggle clips would be a better solution than this method.

The new plate was drilled, countersunk then tapped for M4 threads and polished to remove many of the marks left by machining. A couple of mops using tripoli compound and white rouge were used for polishing.

Along with the improvements in the SM1 table, I chose to redesign the clamp system. It had to be versatile and strong and be small enough to permit a larger work area for CNC milling than 90mm square. It also had to be helpful when trying to clamp irregularly shaped workpieces. The next illustration shows what I had planned to create from a piece of 6063 T6 aluminium tubular bar.

With my clamps completed i added a finishing touch of 1mm of cork to the clamping surface. The thinking was that it would preclude using various bits of packing and keep the clamp dimensions small, My clamp design was to use the smallest possible clamping area. I had thought that a semi-circular protrusion extending just 5mm would be workable. I placed the hole for the screw off centre to increase the ease with which irregular workpieces could be held. With enough holes in the table, I could clamp many different styles of workpiece securely while still keeping the clamps out of the pathway of the milling bit.

The next illustration is an irregularly shaped workpiece of 120mm in length and 90mm in width and 38mm in depth, clamped with just 4 clamps to my new 130mm square table. The workpiece is held securely and could be CNC milled to any point that is just 6mm inside of its edges.

It is worth noting that although the workpiece is soft pine and it is held very securely for milling, there are no clamping marks on the workpiece, as is shown in the following illustration.

The clamp had to be strong so that it would not bend under moderate or any pressure. The following illustrations show the clamp detail. Very poor jpeg images so the quality is not great.

I am not sure how long the self adhesive cork will last but I will modify it as and when necessary. The whole project has taken a while because I do not have many machine tools. I used an engineer to shape the clamp bodies because I had no milling machine. The drilling was easy and countersinking was also easily achieved. The parting tool which was used was done at the engineering company because I have no lathe.

What I have learned from this is that consideration should usefully be given to how any tool may be used. I think the SM1 bed did not follow what appears to be normal practice for clamping options for this type of machine. Being new to this whole world of 3D/Laser and CNC work, I had little idea of what was needed. Within a short time of use, I found myself brushing up against the limitations imposed by the design of the clamps and the table of SM1. I have learned a great deal while modifying my machine and I feel that I have now extended its usefulness.

The clamp design makes sense to me because it can be extended to cope with other material sizes that are irregular in height. I have created some 10mm thick drilled spacers that can raise the clamps. I have numerous lengths of M4 cap head set screws so that the screw does not have to protrude through the bottom of the table but it can remain within the threaded 4mm thick portion of the table.

Edit: I forgot to include the 10mm spacer so to complete the project here are some additional pictures. The first image compares two clamp bodies (from the side) for length where one clamp has the additional 10mm spacer attached.

This image shows the circular spacer attached to the clamp from the front. It also shows the line scribed for me to file the flat on it.

The next image shows the spacer with the scribed line in a vice ready to file the flat.

The final image is the spacer after filing.

Any questions are welcome and I will do my best to answer them.


Hi @jepho, I am starting to think about creating a section for modification lol. Keep up the good work :+1:t2:


WOW @jepho those look amazing and i love the design.

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Hello Kai;
Yep, that could be a very worthwhile section. You know I will never be happy until I have made something do what I need, even when it could not by design or facility. :grin:

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Thanks Adam for your kind comments. :smiley:

Hi Jepho,
Your modification is neat!
The only thing is that the bed is only 5mm bigger than the original one.
I have an idea to make it even bigger moving the original components and making a bigger bed.
Bear with me:
if you move the X axis one hole to the right, the axis would travel for the space that is currently occupied by the motor. This would give about 70mm more.
Of course you have to move to the right also the Y axis by the same distance and screw on a bigger bed.
If you want to make things perfectly, you could redesign the main base plate and maybe put your name/image on it.

What do you think?
Let me know if you do it :slightly_smiling_face:

I made the bed the same 130mm square as the original. Elsewhere I have a flat clamp jig that was 200 x 150 but it meant keeping the door of the enclosure open so that I had the movement in the Y axis. In reality the CNC was only using the central piece of the jig so it was not an issue.

However what is really a major issue is that Snapmaker via Luban is limited to 90mm Square for CNC. You will see from the image showing my odd shaped piece of 120mm x 90mm clamped to the bed. Luban will not go outside its preset limits for CNC. The idea behind my work was to create more clamping options and only have 5mm of clamp intrude in the workspace and the height of the workpiece.

It is an interesting curio but nothing more were one to stick with Snapmaker’s Luban. I was on the verge of using Carbide Create for my Snapmaker CNC stuff but in the end I decided that the Snapmaker team were not especially responsive to complaints and suggestions. I did not purchase an SM2 but changed my allegiance.

Tomorrow, I become the owner of a Shapeoko 3 with a Makita trim router and a JTech laser. I am leaving the world of Snapmaker because I could not make the SM1 do what I wanted and the software was not supporting it.

Hi Jepho,

I also have a problem (3d module), and I’ve contacted support and looking in the forum. I found lots of interesting answers there that I can use.

On a different topic, are you going to sell your snapmaker now that you have bought a Shapeoko 3 with a router and laser?

Hi Momo,
I have already sold it. It went on the last day of my eBay advertisement. It will suit someone who makes less demands than I have made of the machine. I get that SM1 has a set of design parameters of which it is not expected to work outside. It is very frustrating to brush up against the limitations of SM1 in a few short months.

I really had no idea what I was buying and although the hardware is really nicely put together, the software has let it down badly. If I could have achieved more with the software, I may have been inclined to keep the machine for a year or so while learning a lot more about managing the CNC/Laser/3D print aspects of making.

As it is I am stepping into a completely different world now. The Shapeoko 3 machine is still a machine for a desktop and the hobbyist. It is far more capable than SM1 and I am looking forward to learning how to use it. It is a much bigger commitment with router purchase, laser purchase, milling bit selection, permanent bench construction to take a machine weighing in at 70lbs bare.

i hope to be up and running in a week or so and then I will be able to run some of the toolpaths that I have already created. For example, I was able to create a threaded workpiece after an hour learning the new software.

I have never used SM1 's 3D module so I have no idea how they can give problems. It always looked like there were too many variables outside of the control of the user to my mind. The very fussy starting, getting the layers to stick, and then getting the resolution and heat right also seemed like a little too much bother when all I wanted to do was give life to my creative ideas.