On 2008-12-30, Pilgrim wrote:
I have a 4x6 probably 25/30 years old. It has always had a problem of
throwing the blade[the blade comes off while cutting]. The problem as
become progressively worse. If you remove the blade and spin the idler
wheel you can feel a roughness in the ball bearings. When taken apart
and the bearings rotated against a moving belt they seem fine. My
conclusion is that the bearing seats are not co-axial.

Now the questions:

Does this seem like a reasonable conclusion?

I'm not sure about the bearing at all.

If not what might be the
problem?

Typically, these have an Allen setscrew below the upper wheel
bearing block which tilts the upper wheel to control the angle so you
can minimize the chance of the blade walking off.

Aside from that -- you *do* know that the proper tension for the
blades is as tight as you can possibly turn that plastic blade
tensioning knob by hand? Actually -- that gets the blade to the low end
of the proper tension range. You *can't* grip it hard enough to
over-tighten the blade.

If so what can be done about it? I thought about turning down the shaft
so the bearings don't bind and seating them to the shaft with Locktite.

Try the bearing block tilt adjustment screw first -- and the
belt tension knob.

Good Luck,
DoN.

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