Compund Mitre angles

[sadsjon]

Hi all, after some recent posts here regarding mitre angles, I am making slow progress.

I have calculated the hard way (as all the compound mitre calculations on line are american, confusing and keep referring to a "Miter") using measurements from a fixed point and my sons protractor that with a piece of 4x2 I need to cut the 4 inch face at a mitre of 40 degrees to the long side and then bevel this at 30 degrees on the 2 inch side.

I am blowed if my De Walt will let me do that.

I have 0 to 45 degrees bevel (thats 0 degrees from perpendicular) and

0 to 45 degrees mitre.

I need to bevel down to a setting of 60 degrees on the perpendicular and to 50 degrees on the mitre and I just don't have those stops on my saw.

Did I buy the wrong saw or do I need to apply some lateral thinking that currently escapes me?

I did consider that I could put my 4x2 end on into the saw but that looks dangerous to me.

help !!!!

:-)

cheers all,

jON

[Stuart Noble]

Can't visualise what you're doing, but often subtracting your angles from 90 helps. 30 and 40 degs are the same as 60 and 50 depending on whether you're looking at the workpiece or the offcut.

[Ben Blaukopf]

Take as big a piece of wood as you can cut in one go (both deep and wide), and cut a 45 degree mitre AND a 45 degree bevel in it.

Now you can stick your 4x2 on that, and cut a 5 degree mitre and a 15 degree bevel.

Then let me know it it worked alright!

Ben

[sadsjon]

Hi All, I am attaching a couple of links to pictures that I took showing the piece of timber face on and edge on.

am trying to work out the angles needed to cu and fit battons and block insulation to the void as well as shoring up some of the timbers.

I want my cuts to be as accurate as possible.

This piece I cut with an old fashion push pull thing ... a handsaw I heard someone call it once ... its close enough for my liking but hard work ! (I think the saw is blunt :-) (ignore the circular saw marks on the face - I was tidying the face up with the mitre saw)

The problem is that I can only mitre at up to 45 degrees, regardless of whether I use the offcut side of the other side. My stop is at 45 degrees both bevel and mitre.

I can only bevel at anything up 45 to 90 degrees but I need to bevel at 30 degrees.

If it can't be done then I reckon I would be better off using a handsaw, I can see your idea Ben but I think a handsaw will probably give me more accuracy. I am not sure how I can get the timber fixed to a mitre and a bevel at the same time in any case ???

jON

[Stuart Noble]

Offer the sample piece up to the saw and it should become obvious whether you can do it in one cut or not. Has to be possible in 2 cuts which would still be a big improvement over a handsaw

[Ben Blaukopf]

[Ben Blaukopf]

What I meant to say was...

What about doing the main cut on the mitre saw (or hand saw if you feel the urge), and then tidying it up with a plane on a shooting block?

OR:

I agree, clamping for a compound mitre will be difficult. So you may need to do it in two stages. Prepare two separate shims, one for the mitre, one for the bevel, and do the cut in two steps. You'll need to place the workpiece next to the mitre shim, but on top of the bevel shim. I'll try drawing a diagram if that doesn't make sense.

The trouble is you've now got to position the wood precisely for the second cut, but at least if you start a little long it's easy to shave off half a mil.

Ben

[Mark]

Get yourself a nice new hardpoint handsaw, if you cut the wood in the picture by hand you have the necessary skill. I still find it quicker to cut angles like that by hand rather then farting about setting up a compound mitre saw.

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