calculating compound angles

[thatsnotafestool]

I'm fitting a cornice to the top of some kitchen cabinets. This cornice has a slope of 30 degrees. I've found a program that calculates the external mitre (26.5 deg) and bevel (37.7 deg) angles but my brain is confused as to how I do the inside corner.

[''The village idiot'']

You can have a look at this it may it may not. But I have got a chart in the work shop well I think I have and if I have I will scan it and let you have a look.

[Scrit]

I would have thought that a gadgeteer such as yourself might consider a Bosch DWM40L digital angle finder which will automatically work out the bevel and mitre angles for you even if you don't already know the spring angle (and BTW 30° seems a bit low, most are 45/45 or 52/38). Yes, I do have one, yes they are useful, but for a few joints they are overkill. Mine's mainly for roofs and attics

I'd also suggest taking a look around the web for articles on installing crown mouldings (the American term) as they do a lot more than we do, although a starter might be this article from the deWalt USA site which has a table for compound mitre cuts (albeit only with 45/45 and 52/38 spring angles)

Scrit

[mrgrimsdale]

Jul 27, 2008 6:33:02 GMT thatsnotafestool said:

I'm fitting a cornice to the top of some kitchen cabinets. This cornice has a slope of 30 degrees. I've found a program that calculates the external mitre (26.5 deg) and bevel (37.7 deg) angles but my brain is confused as to how I do the inside corner.

Simplest is to make up a mitre box big enough to hold your moulding propped up at 30 deg - against a mark or a stop, and cut it at 135 or whatever.

cheers
Jacob

[mack4]

The only time you need a 'compound' mitre for moulding is when it is too high for the saw's fence.Then you would need to cut on the flat requiring, tilt + angle.Rutlands do an adjustable jig but it is quite easy to make one yourself.