Mystery Super Small Carbide Cutters & Holder

Hi All,

Just going through a pile of auction lots and came across this small tin of really small brazed carbide cutters and ONE holder or collet.

Each cutter has a spring at the back.

The back of the "collet" has 4 numbers as shown?

I am guessing watchmaking lathe or similar but no idea really?

Any help most welcome

Cheers, Martin

Drag engraving or vinyl cutting maybe?

Martin C

Look similar to the microbore system which can be had with brazed or insert holders, I've a couple of the insert ones and use them for things a bit bigger than your average watch.

I have some similar to that and came to the same conclusion as Jason, they are still in the drawer!

How are these held in the lathe and what is the spring for please?

Martin

The boring bars have a suitably shaped socket with a couple of pockets to that the small lugs so that the tool does not rotate in the hole. You unlock the tool and turn the adjuster which looks to possibly be 10 divisions down the side so 40 divisions total so if a 25tpi thread one division on the sid eof the adjusting screw will advance the tool 1 thou. Put on the required cut and lock it back into position and take a cut. Spring ensures the cutter moves outwards as the adjusting nut is turned.

The Microbore ones that I have have the graduations on a square head flange nut and use spring washers on the opposite side to so the same job as the spring on your ones

Thanks Jason, all now crystal clear.

Cheers, Martin