Holesaw hole widening attachment - GIF

[BuffaloJohn]

would I or anyone interested be able to get a copy of that cad drawing

Cheers and thank you in advance

Tony..

I did it as a 3D model in FreeCAD. It's pretty simple:

The diameter of the wide bottom of the cone is 1/4" (~6mm) less than the inside diameter of the hole saw. The base is 1/8" (~3mm) tall. The top of the cone is 1" (~25mm) diameter and is 1" (~25mm) from the bottom of the base. I then put a through hole which should match the hole saw pilot. In my case, I guessed it was a 1/4" drill. That drill is replaced with a bolt that goes through the hole of this adapter into the hole saw arbor and is held in the arbor by a set screw.

As for the bolt, in the video, it is a wide head, not a standard head profile. I would just use a hex bolt and a large washer so the adapter will slip on the bolt when the drill turns.

As for the adapter, you could make it on a 3D printer or turn it on a lathe.

If you want my FreeCAD file, send me a private message (click on my name and the option for a private message shows) and I will email it to you...

If you want a specific diameter of the base, hole diameter, or height of adapeter, tell me what you want and it takes just seconds to modify. If you want changes and only want as STL or STEP, I can send you that as well...