What kind of hole cutter

[JoeLee]

Never saw the ones made by Jancy but have used these for years.

https://www.blairequipment.com/spotweld-cutters

JL.................

[jwmelvin]

The smaller ones look very close to my Jancy Roto-Bor, and all do appear to be hole saws of that nature:

[boslab]

Definately annular cutters, no flighting so must be thin stock as stated, handy in a rotobroach
mark

[psomero]

pin is for centering and ejection. hougen rotabroaches are similar but these with the solid shank are probably nicer to work with

[Illinoyance]

They look like cutters made by Jancy Engineering I think they were called RotaBore. They were intended for thin material. Jancy developed a mag base drill of high quality. They were bought up by one of the high end German tool makers. The cutter line was discontinued.

[Jim Stewart]

Spot weld cutter. Hit the center of the weld with a center punch for the spring center. It leaves the center of the spot weld on the opposite piece which makes it easy to reassemble - line it up and fill the gap with filler rod.

I have one that's about 3/8" OD - but are there really any 1-1/8" spot welds?

-js

[genea]

You can center the point on a punch mark, no need to drill a pilot hole. Also, probably helps with ejecting the disc.

[lugnut]

Not wanting to highjack the Hole Saw thread. When reading the hole saw thread I remembered these cutters that I picked up at a yard sale a few years back. Naturally they must be some sort of hole cutter, the largest is 1.125" the smallest is .343 as I remember. My question is why the removable spring loaded center pin?