How to use a compound mitre saw for proper mitres?

[slippyr4]

Hi all,

I have a sliding compound mitre saw.

When fitting skirting, in reality an external corner is rarely 90 degrees and the walls are rarely vertical.

Obviously you can get a great result with a compount mitre saw, but I am a bit stumped on how, in practise, you work out the compound angles.

Can anyone explain, or link me to a guide, on how you can measure up/ mark up etc to get a perfect join.

I guess this is a general carpentry thing too cos it'd apply to architrave etc when the architrace needs to angle up to clean reskimmed plaster that's proud of the door frame.

thanks

slip

 

[big-all]

no good trying to do compounds on skirting as each wall has to lean forward or back the same amount to work lol

lay a bit off paper or card in the corner
take a bit off skirting about 6" long
place into the corner on one wall and draw a line
move to the other wall draw a line
draw a line from the corner to where the lines cross and thats the angle you have to cut

 

[foxhole]

And even Alls method relies on walls being flat, any curve and when fixed the angle will change again.Have some filler ready.