The spring sprang, about a year ago.
When we revised the design of the frame to permit it to mount the
quick tensioning lever, we had to do away with the spring. There
just wasn't room for it.
(Some people like to peer straight down past the nose of the frame.
If we made that section tall enough to add the spring, it'd whack
them in the eye.)
It would have been nice to be able to keep the springs, but the MkII
saws have blade clamps that move more freely than the original ones
on the Mk I saws. (with the springs.) So to our minds, the added
good of the quick tensioning lever outweighed the loss of the spring.
As far as the knobs go, on no version should the knob fall off the
screw. (and the length is the same between the two versions, so
that's not it.)
There is one thing about the knobs though: the threaded part of the
knob is actually an aluminum insert inside the plastic knob. It sits
a little more towards one side of the knob than the other, so if it
comes off and you put it back on backwards, you'll start having
trouble. Put it back on with the 'fat' side of the knob facing the
blade clamp, and up against the washer against the frame when it
When it comes to unscrewing the tensioner when you change blades,
there isn't any 'sacred' length. If it looks like the clamp will
come out, or the knob fall off--stop. The only thing that's important
is that the blade be firmly up against the rear sides of the threaded
holes that make up the clamps. As long as the blade has any bend
in it from banging up against the back walls of the holes, you're
Hope this helps,