John E wrote:

I have some hardwood flooring to lay, and this will involve undercutting 8
door frames. I'm looking for the best tool for the job.

Door frames or skirtings too?

If you have a room full of skirtings, then it's time to shell out and
buy a Multimaster.

If it's just door frames (maybe you can lift the skirtings) then you
can do this quickly enough by hand. A Japanese-style pull saw is
easiest to use in this position, but they _really_ don't like to
encounter nails (one nail is quite possibly a dead saw). You could do
it easily enough with no more than a Happy Shopper tenon saw though.

I wouldn't use any powered saw other than a Multimaster or a dedicated
floor-fitting circular saw. Reciprocating saws don't go anything like
low enough and biscuit jointers are too high for most floorings. I'm
also not a fan of using biscuiters for other than plunge cuts. They're
not designed for it and you're left trying to mis-use a saw by sliding
it sideways while the spring is fighting against you. This is getting
unsafe.