Originally Posted by
GrayJay
Ive never used one, but it looks like the notching fixture being discussed has a shaft that transmits the torque from the drill arbor to the holesaw. The shaft is located in a sleeve of the fixture which should isolate most all of the side load from the drill press arbor bearings. No?
Correct.
The notchers shown above have a
shorter load path distance between the tubing fixture and the arbor - perhaps 6" or less and is usually heavy gage material. This prevents unwanted movement between the hole saw and the tubing - which in turn, prevents chattering and lockups due to torsional misalignment. The 'load path' distance on an 15" drill press is closer to 36", often more. While using the notcher (when mounted to the drill press table) still induces torsional loads on the drill press, the side-loading (or radial loads) is absorbed by the rigid notcher, and not by the drill press.