Thanks to @Bigdaddy2166 for providing the impetus for adding an extra drain to my MR1.
I used a cheap Chinese core drill from Amazon: Vevor Core Drilling Machine
I did get this on sale for $239, but it’s now $299. It appears to go on and off sale often. It came with a 4.25" bit which was perfect (albeit a bit too long - more on that below).
I didn’t have any extra aluminum stock laying around that would work so I simply bought a stainless steel drain: Elkay LK99 Drain
First step was to remove my second SMW vise to enable me to mount the core drill to the base plate. Since I wanted to drill the center, rear pole ended up being in the way since the bit it came with is 14" long. I was able to just wedge the core drill under the pole and it fit (see photos).
I diverted the existing corner drains into some 5 gallon buckets so when I ran water during the cut, it wouldn’t pollute my lubrication liquid.
The cutting was simple and a non-event as the saw cut with ease. I too was concerned about drilling through the bottom, but it turns out that wasn’t an issue as when the drill breaks through the last bit of concrete there is a very discernible change in the feel of the drill (via the feed handle). When I felt this change, I stopped immediately and didn’t even scratch the metal surface of the bottom pan. The concrete lifted out with ease as expected.
Once that was out, I drilled out a 1 3/4" hole in the center of the pan. This allows a little play when dropping in the drain and the concrete epoxy readily fills any gaps.
Since the core drill such a clean and perfect surface, I simply used a rabbet router bit set to about 1/16" depth and 1/8" width to route out a lip so the drain would mount flush.
I used concrete epoxy to fill in solid mounting around the top and bottom of the drain (where the drain sits into the hole and where the tailpiece comes out the bottom). I was able to shoot all the extra epoxy into the cavity via extra space in the bottom of the opening (since the tailpiece is 1 1/2" and the opening was 1 3/4"). I did this since the tube only had one mixing nozzle so the tube is essentially a single use item.
The epoxy I used was: Quikrete Fast Acting Epoxy
My intent is to run a clear tube from the tailpiece into a 5 gallon bucket that will hold my filtering and ultimately feed back into the black tub.
#langmuirsystems #mr1 #cncmill Drilling a new and improved drain into the MR1 CNC Mill using a core drill through 4” of concrete. pic.twitter.com/hETKI2gI85
— Kevin Gregory (@kevingregory) August 20, 2023
