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need help figuring this out

Posted:
Fri Jun 11, 2010 3:45 pm
by timlsalem
I have L molding that is 1 1/8" X 1 1/8". I've been trying to figure out how to cut this (miter). my hatch is at a 22.5 degree angle and then goes to a 90 degree. (look at pictures) How do I miter cut this? I will be using a hand finish saw. I just can't picture it in my head

and when I'm looking at it I don't know how to match up the two angles. It wouldn't be a problem if I weren't using the L molding.

Maybe you can direct me to a web site that shows how to make compound miter cuts? I think that's what I need to use here.

Posted:
Fri Jun 11, 2010 4:19 pm
by doug hodder
90+22.5=112.5 divided by 2=56.25 degrees each piece. If I'm understanding what you are wanting to do...that's not a compound miter, just a plain miter. Get a protractor and mark your aluminum and cut it with a chop saw, or miter box, or get good with a hack saw. Doug

Posted:
Fri Jun 11, 2010 4:40 pm
by rainjer
Are you trying to put the "L" metal on the edge of your hatch? If so, it looks like to me one leg will always be 90 degrees & the other leg need a miter cut.
For example where your angled part of the hatch meets the vertical part, the cut on the face fo the hatche would be 90 degrees & the cut on the sied would be 22.5 degress if the that is a a 45 degree angle.
To make the cut, draw the angle you need on the correct leg. Put the metal on a 2 X 4 on a bench with the line on top. Cut straight down on your line.
Jeremy

Posted:
Fri Jun 11, 2010 4:53 pm
by Dirran
If you are cutting a mitre, BOTH angles need to be equal.
It is not possible to leave one at 90 degrees and the other at 22.5 or whatever to make up the angle. The ends just won't meet up properly.
Mind you, this only applies if the two pieces of timber/metal are identical dimensions.
In this case, they are the same, so go as Doug advised.
Try it out on some scrap timber.
Anyone who has ever tried to mitre a corner as Jeremy has suggested knows what the result will be.

Posted:
Fri Jun 11, 2010 5:04 pm
by doug hodder
If you are talking about the long piece across the back and not on the sides...I'd just rip 2 pieces, seal underneath and attach them with a lap, and hit it with a file to smooth it all out. For the thickness of the material, and wanting to do like 5' of joint....I wouldn't bother with the angle. I thought you were taking about the sides where the vertical meets the sloped upper portion from the galley hinge on. Doug

Posted:
Fri Jun 11, 2010 5:19 pm
by timlsalem
ya Doug, it is the vertical and edge of the hatch that goes to the vertical. So if I'm hearing right I just add the two angles and divide by 2 and cut both pieces at that angle. Correct? Could I use my compound/miter cutoff saw to do this?
Practice pieces

Posted:
Fri Jun 11, 2010 7:20 pm
by eamarquardt
I"m not sure I have the right picture/idea of what trim you are working on. However, when I made my frame, I bent the side rails. I'm not sure if I was firing on all cylinders that day or not (although I hadn't been on drugs for several years) but my first cuts just didn't work out and the piece bent too much. I thought you just remove a pie shaped piece from the angle iron/tubing the same number of degrees (and an equal number of degrees on each side of the perpendicular) you wanted to bend the angle iron/tubing. After screwing it up, scratching my head (to no availl), I made some cardboard patterns first to determine how much to remove. Then, after I had "proof of concept" with the cardboard, I cut a wedge out of the tubing per the cardboard patterns and I was right on. Moral of story: cardboard is cheaper than steel tubing and aluminum!
I think it would be slicker to cut a notch out of the aluminum angle, aneal it a bit, and then bend it at the notch so the metal is continous as you face the back side of your hatch. This will leave a nice smooth piece of trim versus sharp edges (that you'd have if you cut it all the way on a miter saw). You'd have slits on the side of your hatch. A hack saw or saber saw will do a nice job of cutting the wedges out.
One thing I've learned when bending is that the distance on the inside of the angle or tubing is the measurement you determine where to notch. The outside of the material will stretch as required and your fit will be determined by the inside measurements.
Hope this helps, if not, post more pics, ask more questions.
Cheers,
Gus
revision

Posted:
Fri Jun 11, 2010 8:18 pm
by timlsalem
I'm working with wood. the" L" molding is pine. Just needed to know how to cut the miter so I don't waste a lot of material in the process. I will use the short piece I screwed up with to get the right angle of the dangle. Thanks all

Posted:
Sat Jun 12, 2010 9:18 am
by angib
Is this what you're looking for?
Andrew

Posted:
Sat Jun 12, 2010 10:21 am
by timlsalem
angib, that's exactly what I need. thanks