On Saturday, March 18, 2017 at 3:52:48 PM UTC-5, J. Clarke wrote:

And yes, it is a problem. Circular saws turn in
one direction, the one in which (if the saw is
well designed) the friction tightens the bolt.
The Fein oscillates, one direction tightens the
bolt, the other loosens it. After a while no
matter how much you tighten it, it comes loose.
Doesn't help that it's tightened with a little
dinky Allen wrench.

Never knew that the early Feins had nothing more than a friction fit. Truly, that doesn't make any sense, and I can't figure out how the tool would ever work for more than the lightest applications. I expect my multi tools to be able to cut everything on the job without the blade coming loose, and even the cheap HFs do that just fine. They have crudely cut lugs (8) that hold the blades using a hardened, cupped washer held in place by a hex head screw.

Knowing that Fein was (is?) the undisputed king of oscillators, I have to shake my head with wonder that all the heralded German engineering couldn't solve the problem of slick blade retainage surfaces /before/ the tool was first released decades ago. Surely that had to be an issue they realized in testing.

I guess with nothing to compare it to, it was just accepted that blade slippage was the way the tool operated.

Robert