Calculating/cutting angles for metal tubing
- Thread starter alex2929
- Start date
whateg01
Well-known member
Divide the angle by 2 for equal sized tubing.
Or model it in cad and let the computer figure out out.
Or model it in cad and let the computer figure out out.
easy, nonmathematical way ;
layout the tube to the dimensions and bisect the where the tubes cross
layout the tube to the dimensions and bisect the where the tubes cross
RoninB4
Well-known member
-No need to feel silly, you're asking a valid question.
-Advice given in the two posts above but you might need math at some point. Whether measuring for dimensions or angles some solid numbers are likely going to be involved. The intended purpose, skill level, and how you're going to cut these weren't mentioned.
-OTOH, if the purpose of intended assembly isn't overly fussy (purpose wasn't mentioned) then you can create templates to help you. Get some moderately stiff construction paper that can be easily cut with a razor knife. Ordinary paper won't stay flat by itself and is a bit more difficult to work with for this purpose. Cut out some lengths of 1" wide rectangles and arrange them as needed so the ends overlap at the joint a bit. Hold the paper firmly in position and cut through both with the razor knife to bisect the angle, that's what's done with carpeting. Same procedure for the 3rd piece, it just needs to reference the other two pieces properly. You'll now have 3 templates to attach to the actual tubing for layout and have used CAD (carboard assisted design). How well this works out will depend upon how exacting you cut out the construction paper to match the actual dimensions of the 1" tubing and attach them for scribing layout lines. Cutting the tubing to match the templates can/will affect the angles when joinery is involved. Very little math involved using this method.
-I use trigonometry, measuring instruments, SolidWorks (CAD program), and a milling machine when it's got to be a bit particular.
kerrynzl
Well-known member
@alex2929
When you do a pie cut always deduct the wall thickness from 1 side.
So a 2" square with 1/8" wall thickness need the pie cut 1-7/8" deep.
If you want a 25° finished angle , you need to cut 12.5° each side of perpendicular [that way both sides meet equally]
If math isn't your strong point use this online calculator
http://www.csgnetwork.com/righttricalc.html [you must use decimal instead of fractions]
Here is an example of a 2" tube with a 0.125" wall and a 25° finished angle.
The pie cut needs to be 12.5° each side of perpendicular and 1.875" deep.
On the calculator
Angle "A" = 12.5
Side "b" = 1.875
Side "a" = 0.420" each side of perpendicular
Here is an example [I scribed and cut with a 1mm cut off blade]
You can see where I stopped just shy of the outer wall on the radius
When you do a pie cut always deduct the wall thickness from 1 side.
So a 2" square with 1/8" wall thickness need the pie cut 1-7/8" deep.
If you want a 25° finished angle , you need to cut 12.5° each side of perpendicular [that way both sides meet equally]
If math isn't your strong point use this online calculator
http://www.csgnetwork.com/righttricalc.html [you must use decimal instead of fractions]
Here is an example of a 2" tube with a 0.125" wall and a 25° finished angle.
The pie cut needs to be 12.5° each side of perpendicular and 1.875" deep.
On the calculator
Angle "A" = 12.5
Side "b" = 1.875
Side "a" = 0.420" each side of perpendicular
Here is an example [I scribed and cut with a 1mm cut off blade]
You can see where I stopped just shy of the outer wall on the radius
jack stand
Well-known member
You're better off capping the 110* (at 70*) and butting the 70* into it.
This is because of the unequal lengths of the mating surfaces that will never match.
This is because of the unequal lengths of the mating surfaces that will never match.
zimman
Well-known member
This would be better to cope, and cap. If not, use square tubing. Why does it have to have a sharp peak?
Zim
whateg01
Well-known member
A welder doesn't care and will fill the gap. The bigger issue is a bandsaw or coldsaw won't go that far off 90.You're better off capping the 110* (at 70*) and butting the 70* into it.
This is because of the unequal lengths of the mating surfaces that will never match.
Rccrawlerguy
Well-known member
- Joined
- Dec 11, 2011
- Messages
- 262
Does It have to be 110*? If you are using tubing that is fairly thin wall, say less than 1/8" it is going to make that end almost razor thin. Maybe unless its thick wall, but still a really, really pointy end. If it has to be, I would probably cap the end( like mentioned above) then mate the next tube to it.
kerrynzl
Well-known member
I was taught by an engineer 45 years ago ............. "It's f***ed when a welder can't fix it"
slowtwitch73
Well-known member
Make a full size drawing.. take measurements off it (or use CAD etc as mentioned).
dr_clyde
Well-known member
What are you talking about? A symmetrical angle cut on both tubes will match up just fine.You're better off capping the 110* (at 70*) and butting the 70* into it.
This is because of the unequal lengths of the mating surfaces that will never match.
dr_clyde
Well-known member
It all depends on how you want to measure it. From the flat (180°) or from the end plane (off 90°).
I modeled it quick to show you the various ways to lay out a symmetrical angle tube frame.
Last edited:
dr_clyde
Well-known member
Starrett makes a cool miter protractor that does the math for you on miters.
www.rockler.com
Starrett 7" ProSite Protractor - Durable Aluminum
Takes error-prone calculations out of the process of miter cuts to ensure perfect miter joints every time!
www.rockler.com
I have one of these. Bought it at a restore for a few bucks not quite being sure what it was. It's damn handy for doing miters. It's worth the $100 if you do a lot of them, or you're doing something important.Starrett makes a cool miter protractor that does the math for you on miters.
Starrett 7" ProSite Protractor - Durable Aluminum
Takes error-prone calculations out of the process of miter cuts to ensure perfect miter joints every time!