I got my stihl blade through today, as I do not have a manual, I am not
sure
how to fit the blade.
The parts I got with the blade are; 1 Collar Nut, 1 Thrust washer 4128
which is curved, and 1 Rider Plate 4119 galvanised cup thingy, I think
there
is a vital part missing.

When I phoned the shop an assistant told me its a washer I am missing but
I
do not think this is right

I think the part I am missing has to be something along the lines of a
collar because the hole in the middle of the blade is 25.4mm and the bolt
on
the strimmer for attaching strimmer heads etc is only 12mm, there should
be
some collar or central bush to slot over the bolt to make up diameter so
the
blade is kept centred and somehow I do not think a washer is going to do
this.

Advice please, thanks.

Chris

Hi Chris,

It sounds as if it is the blade at fault. You have all of the necessary
parts shown in the manual and I have confirmed this by taking my blade off.
The hole in my blade is 20mm and fits over a raised part of the shaft. This
raised part is just under 20mm.

If you start with the machine upside down (the obvious position for changing
heads/blades), the top of the shaft is threaded. Below that there is a short
section which is splined. Then the shaft opens out to a smooth collar (the
raised part mentioned above). This collar is only a couple of mm above the
flat cover plate (flat plate with hole in middle and with the outside edges
turned downwards). Below the cover plate should be a shim and then a
circular piece of metal (I am not sure of the official name) with four holes
in the surface. It is one of these holes that the stop pin fits into to stop
the shaft from moving when changing heads/blades.

To fit the blade, I will quote from the manual and then add my own comments
for clarity:

Cutting blade 230-4, 255-8, Brush knife 300-3

++ Slip cutting tool over shaft. Important: Cutting edges on cutting blade
255-8 must point clockwise.

My note: "clockwise" means viewed from above with the machine turned upside
down.

++ Fit thrust washer, convex side facing up.

My note: The thrust washer fits over the shaft splines and the top face of
the thrust washer must be a little above the splines (I think this is why
there is a shim below the cover plate). The reason for this is that the nut,
when tightened, exerts pressure on the centre of the thrust washer which
then grips the blade.

++ Fit rider plate (for mowing)

My note: If you are anything like me, it might be an idea to buy a spare
rider plate. They are not expensive and I have been known to break them
(they shear where gripped by the nut).

++ Block the output shaft.

My note: This means, insert the stop pin to engage the shaft and stop it
from moving.

++ Screw on the nut COUNTERCLOCKWISE and tighten down firmly.

I hope this either answers your problem or gives you enough information to
understand the way the blade fits sufficiently to be able to solve it. If
you have any questions, please ask. I will be a little busy today but I will
check this newsgroup from time to time (in case).

Regards

Howard Neil