I'm no engineer but I think the prob with router cutters is that they
need to be accurately balanced due to being used at high rpm in a
small machine, so making them is a skilled precision machining
operation. I guess you'd start by turning the profile on a lathe, then
cutting out the throats for the cutters, then back off the cutter
edges.
Whereas spindle moulder cutters operate at lower revs in a big sturdy
machine which can tolerate some imbalance (not too much or the
bearings suffer). So I make a pair of matching cutters using angle
grinder for roughing out and 6inch bench grinder with various wheels
for finishing off .
Paired for balance but it is not essential for both cutters to be
cutting exactly, i.e. one can be set back slightly to make setting up
easier.
This sounds a bit rough and ready but infact it's possible to make
absolutely perfect matches of mouldings - identical to the eye that
is, because you are doing them by eye. They are astonishingly cheap
compared to router cutters and also endlessly adaptable, re-usable,
reshapeable etc.

cheers
Jacob

I havent tried it so I cant be sure, but it appears at first sight
that it shouldnt be too hard to make various shapes of router cutting
blade to fit a block. They would only be steel, not TCT, but should
still do the job ok. How to do you carve a bit of steel to shape?
angle grinder. Might sound crude, but if I can make good performance
drill bits with nothing more than an angle grinder I would think its
perfectly doable. A finer grinding wheel would be ideal for shaprneing
it, but even there I've used the grinder and produced a sufficiently
sharp edge to give a good result.


Regards, NT