Hello GRB,
I guess you're referring to the bottom blade (bedknife) screws.
It is unusual that all 4 should not budge using these methods.
First try a centre punch and hit counter-clockwise on each screw head.
[This has worked many times for me]
If that fails, the only safe way will be by carefully drilling the screws out
from the top. The objective is to not damage the threads in the bottom block.
The Model 40 sprocket is screwed onto the reel by a left-hand thread (I think).
A piece of soft wood on the sprocket should budge it.
Hopefully, someone who has worked on the Model 40 will assist here.
We currently have no user or parts lists (unfortunately).
Hope this helps.
------------------------------
JACK.
