Retro build log

I did not take as many pictures (not even mentioning video) years ago when I built this machine, but I have a few. The project started out as a standard 24"x36" granite surface plate. I got this from a friend, who apparently bought it in the 1980s.

Another friend gave me some beefy ground-on-all-sides stainless rectangular tubing on which I based the superstructure. After placing them loosely in place and marking mounting holes, I drilled and tapped those using the Bridgeport.

I felt that since both the tubing and the surface plate were square it would be easy to use angle plates and 1-2-3 blocks as connection pieces.

This then resulted in a gantry that I could slide around on the granite table to make markings.

I started with some layout fluid and then marked the wholes in the angle plates with marker. I was unhappy with the accuracy of the marking, so I also used a transfer punch on top of that. To protect the marking from the next step, I put some clear tape over the top.

Next, inexperience and bad judgement caused stuttered progress. First, I had some help moving the granite plate onto the Bridgeport.

So far so good. But next I tried to drill through the plate with a cheap diamond bit chucked into the quill. I don't have a picture of it, but this bit was almost solid, with only a small wedge missing for chip evacuation. No hole through the center. I thought I could get this working by blowing compressed air at the drill and weighing down the feed arm as a sort of auto feed. Progress was very very slow because the dust did not ever get out of the hole after a certain depth. Of course, even if this had worked blowing all this abrasive stone (and perhaps diamond) dust around the machine was a bad idea.

To improve the dust evacuation, I attempted to blow air into the crack using my self-build fogbuster. I also added an attempt at dust collection. This worked better, especially when periodically lifting the drill but still was inadequate. The drill broke on the second hole...

So I rethought my approach and decided that the machining needed to be done wet somehow. First, I bought a decent drill with a quill adapter. This was a much better product. Here what it looked like after drilling all the holes. Almost as good as it was new.

I needed a way to irrigate the cutting area and block the slurry from getting into the machine. My first preference would have been a rotary union, but they were incredibly expensive back then - at least the ones I was able to find. So my solution was to use a pond pump and construction foam to make a circulating system. This worked incredibly well. The drill cut very fast, all I had to do was to lift the quill out every now and then to aid in slurry evacuation. I made sure not to drill all the way through so the water could not escape.

At the end a small tap with a hammer caused all the drill cores to break out at the bottom, leaving me through holes.

The linear actuators can then be mounted. I used NEMA 34 stepper motors on all axes.

As a table, I used a cast iron fixture plate. Then I just wired up the 3 stepper motors to drivers.

Unfortunately, at this point the unit had to go into storage, so I broke it down and transported it with some very friendly help from others. It was stored nearly 8 years before I got to unpack it again.

Here a quick overview of the state of the mill after I got it out of storage: