Largish Mitre Block

I think you will find people suggest scribing the corners rather than mitring. Hopefully, they will also describe how to do so better than I! Any specific reason you are not doing so?

Yes, but you still need to mitre any external corners. One of these is useful:

IIUC I'll do that for internal corners - I've got a coping saw. I'll practice on a few off-cuts - looks decidely upsidedown-backtofront to me!

We have not got many external corners in this house! So I fell to assumptions...

I'd use an electric mitre saw. The skirting can be turned round to do the full depth, its not too hard to line up the 2nd cut pretty accurately, just take the time looking along the blade to get it spot on.

NT

depth, its not too hard to line up the 2nd cut pretty accurately, just take the time looking along the blade to get it spot on.

Not usually one to pass up the opportunity of a power tool - but I can't see it being used beyond this one job. I was originally going to do the whole house - I've scaled that back to two rooms.

Having a degree of success with an adjustable jigsaw - but this is feeling increasingly like tools for the job . . .

Rob

The method I was shown for scribing starts with making a mitre... In any case, as someone else has said, most room need some external corners= as well as internal ones.

Hopefully whatever method the OP chooses will give better results than the = former owner of my house, whose approach to mitring 45=B0 corners was to cu= t one piece at 45 degrees and the other at right angles!

I've done plenty with the circ saw set to 45 degs and the skirting lying flat. You need both hands on the saw (it's a bit lopsided at 45), so I set up a jig to clamp in the jaws of my workmate. If you have a mitre at both ends, the measuring can be tricky to say the least. Mark and measure several times before squeezing the trigger :)

You don't want a mitre box, you want a "board mitre". Similar idea, but designed around shallow, wide boards.

This might help: