Screw slotting saw arbor

Once, in a hurry, I bought a set of three slitting saws with arbor.  Then I found that replacement blades for it are listed as screw-slotting saws. They have a 5/8" bore and the arbor that came with the set is far from good,  0.1mm undersized, making the blades to rotate off-centered.  As the blades are still fine, made a arbor for this blade set. I don't plan to have many tooling in inch sizes, but I already have these blades. 

It is very straightforward to make slitting saw arbors on the lathe, but care is needed checking dimensions for the blades to have a good fit, otherwise they will rotate off-centered. When turning the arbor, on finishing passes for blade fit, a small groove was made into the shoulder for the blade to fit correctly. Made the arbor with a 12mm straight shank, to use it on ER collets. The shank is 35mm long.

The large washer was counterbored for the M6 screw. A 6mm tommy bar fits a hole on the arbor for tightening the screw and for when changing blades.

Here is the new arbor and the one that came with the blades set.