Centering ceiling fire sprinkler hole - GIF

[Altair]

Centering ceiling fire sprinkler hole.




Previously:

Overhead drilling jig - GIF
Back saver drill attachment - GIF
Large core drilling rig - GIF
Drilling hole on paper on top of balloon - GIF
Saddle tee hole drilling setup - photo

[ductape]

Gravity can be pretty useful, sometimes. An added bonus is the oil helps a little with cutting the hole in the panel. One can hope that they wiped away the excess so it doesn't end up dripping all over everything under it.

[nova_robotics]

I used to work at a salt mine. Everything metal there turned immediately to ****, so they wax dipped their sprinklers. The only time I've ever seen that.

[Toolmaker51]

Wrong mine, but cue 'Devo'; "Workin' In A Coal Mine".
Lawd, I'mmm Soooo Tierred, How Looong Can Dis Ga On?