I built a Primo with a 24" X 24" cutting area and now just need to cut the spoilboard, which will sit on top of the table and will be screwed down, but am not sure what dimensions to cut it to.
The actual cutting area after drawing the largest square possible with the Dewalt 660 mounted without crashing into the sides or endstops is actually around 23.25" X 23.75".
So, would it be better cutting the spoil board rounded a little over the cutting area by making it 24"x24" or a bit under by making it 23"x23" or approximately 23.25"x23.75"?
My concern with making the spoilboard 24"x24" or larger is that I will end up making a pit after surfacing the spoilboard and later have difficulty cutting over sized boards.
In this case, I plan on using and surfacing a 3/4" MDF, which was what was left over from my MPCNC table made from a full 3/4" 4âx8â MDF sheet cut in half and will drill a grid of holes to add threaded insert nuts, but am unsure if it really matters if I go an inch over or under the cutting size.
What you do not want to do is to go over the cutting size (including the diameter of your biggest endmill) because if you plane it, you will have ridges and canât place workpieces on it any more that overlap the edge (because there is a ridge then).
Yes! So many of the builds photos I saw before I constructed my first V1 machine had the spoil board extend beyond the cutting area. Even the V1/Primo calculator assumes the feet are at the same level as the top of the spoil board. The smarter builds had cuts in the spoil board to easily replace the spoil board without required the CNC to be remounted, but still there is a pit. This is how I built my first machine (Burly), and I ended up with a pit.
When I upgraded to the Primo, I made my spoil board the same size as the cutting area and used the router with a chamfer bit to position it. Note that the surfacing bit is typically 3/4" or 1", so there is no issue surfacing if your position is not perfect.
Another thing I did was run the wires the long way around so that the cable chain was at the back of my machine. This makes it much easier to put stock in from the front. Another solution Iâve seen for this problem is to construct a âtrayâ between the legs so that the cable chain rides above the level of the spoil board, and stock can be inserted below the tray.
So, if I used this 1-1/2" surfacing bit Amazon.com and the radius is 3/4" that should compensate for the less than an inch difference in the cutting area if I cut the spoil board exactly to 24"x24", correct?
Iâm not any kind of expert, but, given we are using trim routers, I wouldnât go above 1" in diameter for the surfacing bit. And yes, the radius of the bit will extend beyound the working distance.
Cable sleeves are fine. I mostly see cable chains in the photos. My comment was more about where you place the chain/sleeve. If you place your electronics at the front of your machine (like most of the builds), then running the sleeve at the back of the machine will be a longer wire run. But having it along the back gets it out of the way for oversized stock inserted from the front.
