By Dave Banwarth
I was installing a new DRO system on my Bridgeport mill when I found the X-axis scale placement extended beyond one of the threaded coolant return holes in the table (Photo 1). I don’t use a flood coolant system and do not need the use of the coolant return holes, so I decided to seal the hole so oil and swarf would not accumulate behind the scale. I do use a spray mister on occasion, and the other hole will remain open if needed for coolant drainage.
In order to close the hole, I needed something that would be flush with the table, and I wanted it to be removable if needed in the future. I thought about machining a pipe plug, which would have been a lot of work. Then I remembered using electrical closure plugs on exterior electrical fixtures in the past and checked the size (Photo 2).
Sure enough, the plastic closure plugs seal tightly and are easily removed if needed! This saved a lot of fabrication and time (Photo 3).