"Howard Neil" hneil@REMOVE TO REPLY.co.uk wrote in message



Hi Howard.

Thank you for the prompt reply.

I think you are right when you say the blade is at fault, unless Stihl have
changed the format and left out a vital component/ adaptor which allows all
blades to fit.



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.



As I have all the parts you listed then it would seem that the blade is
definitely at
fault, the centre hole on the blade is 25.4mm, which is also written on the
top of the blade, the blade itself is 230, the full dimensions exactly as
written under the word STIHL© on the blade are 230 x 25.4

The odd thing is, there is a bit of paperwork, 2 pages with diagram
included inside the blade cardboard packing, it has all the Stihl FS numbers
on it up to 200, then it gives FR numbers up to 450, no mention of the FS
400,
but on the outside of the actual cardboard packing in which the blade came
in, it does give the FS 400 as being one of the machines that the blade
fits.

I measured the raised collar that you mentioned, using a caliper which read
20mm, which is part of a large washer that has 4 circular recesses in the
back to enable changing of heads by using the stop pin.
This washer with a fixed shim protrudes the cover plate by some 2mm, so if
this is all that there is to hold the blade centrally then I have definitely
been sent the wrong blade.

No wonder the shop assistant did not phone me back, either the blade was
packed in error at the factory which would explain why it was in the wrong
packing, or there should be an adaptor included to allow fitting.
They charged me £10.00 postage and packing as well, if I had have known in
advance that they were going to charge that much I would have picked it up
myself.



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.



I fully understand now Howard, the diagram which was included with the blade
makes sense at last, I was puzzled initially due to my knowlege of machines
in that anything that revolves at a high RPM must have a very secure
method of attachment, now I realise, thanks to you, its the blade that is at
fault.




++ 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).




It certainly has answered my question in full Howard, thank you again, I now
know enough to challenge the shop assistant and will demand a refund unless
they agree to put matters right at their expense.



Regards,

Chris.