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Building a 4 Spindle/3 Axis CNC Machine Router

My First Setback...

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Well it had to happen. Although, I did not expect it to happen on the first day.

Let me explain. In my over-ambitious lust for a new project, I ignored the first rule of carpentry. "Measure twice, cut once." While I never got as far as the cutting stage before I realized a potentiel disaster, I will admit, for a couple of hours, I was at a loss on how to solve the dilema that unfolded as I drifted off to sleep.

In my rush to get the MDF base glued up, I neglected to relize that 6 layers of MDF when glued up, become a solid mass that weighs in excess of 100 pounds and measures just under 4 and a half inches thick.

My original plan was to glue up the panels and then square off the base on our panel saw. It was a great plan until I realized as I was falling asleep that night, our panel saw can only cut a thickness of just over 3 inches.

The first solution came to me as I was driving to work this morning. I would stand the base up on one side and use the jointer to square up that side. I would then use the panel saw to cut as high as it could into the base. At that point, I would break off the MDF and then use a flush trim router bit to work my way around the base.

Did I mention that this thing already weighs well over 100 pounds?

I knew it could be done, but I also knew there had to be an easier and safer way.

Well, ironically, I used a CNC Machine to help me build my first CNC Machine.


Setting the base on my CAMaster, I created a vector that measured 31 by 48 inches. Using a 5 inch long 1/2 inch ball mill, there was just enough Z height to just squeeze over the top of the base by 3/8ths of an inch. With this bit, I was able to easily square up the base and cut the MDF to a depth of 3 and 3/8ths of an inch. When finished, I flipped the piece over, and proceeded to use a 1 and a half inch long flush trim bit with a 3 HP router.


The day started on a bad note but ended on a good one. I will begin to wrap the perimeter of the base next week. After that, the linear glide rails for the gantry will be installed.


Suggestions from others are welcome on this blog. If you have a tip or trick that will enable someone to square off a thick panel, please do not hesitate to post. I offered two solutions, one of which is potentiely dangerous and I do not endorse anyone trying it on something this heavy. The other is not an option for some, because not everyone has a CNC Machine at their disposal.

Updated 09-25-2009 at 11:10 PM by Guy Mathews



  1. Michael Schwartz's Avatar
    Contributed by Michael Schwartz

    This method is time consuming but It works. I have used it to build up laminations for steam bending bent lamination forms.

    I would start off with one squared off panel, and then glue 1-2 layers to it at a time, and then flush trim with a router.

    When building forms this way glue squeeze out was not a problem because I just screwed/brad nailed them together, but I suppose you would want something on the edges of the MDF to make it easy to pop the glue off.

    Editor's Note: Ideally this is a great and simple solution to the problem I had. I would like to add, as long as the squared off piece is on top during each vacuum pressing, gravity will take care of the glue that squeezes out. You will still have a nice edge to run your bearing on for the flush trim bit.

    Thanks Michael. This is a fantastic solution for this problem.

    Updated 10-28-2009 at 6:07 AM by Guy Mathews