Need Angle Help

Ok guys remember there are no stupid questions, only old guys that have forgot their geometry. I am cutting tubing for my frame. I know if I want to join two pieces of square tubing and make it match for a 90 then I divide by two and cut two 45's like a picture frame, but I get dumb after that. Here is a picture of one of the joints I am cutting. The two pieces are cut at 30 degrees on the chop saw. The inside angle is around 135 degrees, as you can see I need to cut it different to close up the gap and make it match. What's the rule for this or a good web site, with pictures.

i might be wrong so try it on paper but im pretty sure you want it to equal 90 degrees so if one cuts 30 the other should be 60

angle

looking at your angle guage it is a little off but the inside measurement is between 50 and 52 try the cut at a 25 or 26 somewhere close to that, it is way easier to cut up a wood 2 x 4 to get the angle right, then cut the steel at the angle

Thanks guys but I guess I'm going to have to cheat on this. I cut some poster board 3 inches wide and over lapped two strips at the angle I want. I then took some scissors and cut inside point to outside point. Both pieces have identical angles. I then took one of them and set up the chop saw. The chop saw shows around 20 degrees. Anyhow, I guess I'm making a paper doll Rat Rod.

kzoldman said:

Thanks guys but I guess I'm going to have to cheat on this. I cut some poster board 3 inches wide and over lapped two strips at the angle I want. I then took some scissors and cut inside point to outside point. Both pieces have identical angles. I then took one of them and set up the chop saw. The chop saw shows around 20 degrees. Anyhow, I guess I'm making a paper doll Rat Rod.

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sounds like the perfect solution. -- then you can just use the posterboards reverse (flip it over) for the other side... working smarter not harder

Good idea. Simple and cheap works for me. I too use card board or what ever I have lying around when designing brackets and mounts.

Lightspeed Mike

With that little angle finder doohickey machine you can read another angle off it and halve it for the saw angle.
If you see the three numbers with the 135 being the middle one I think the bottom number should read around 40 so divided by 2 = 20.
I think.
Bob

You are correct Bob. I rechecked the angle and got a good reading and it was 130. Directly under that in the cut out hole was 50 for the degrees going left to right and then under 50 was 40 for the degrees going right to left starting with 90. I knew I should not have thrown the direction away to this thing

22.5 degrees for each tube will get you 135 degrees. The total should equal 180 degrees.

180-135=45 degrees divided in two = 22.5 degrees

It is the square root of your shop X Pi. Works for anything you need to cut

kzoldman said:

Anyhow, I guess I'm making a paper doll Rat Rod.

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Don't do it... that stuff don't rust!!! [ddd

BoB

Thanks guys for the help. Got it all cut out but have not been able to get to the welding. If nothing comes up this weekend like it has the last two......maybe I will get some metal stuck together I have taken a little time to practice on some joints to see how the metal was going to pull and have a plan at least. I am going to stick weld it because that is what I have and trust if I'm doing the welding. I am using 6011 rods for the tacks. They "dry" quick and do not have much slag, tacking the joints in an x pattern, like the way you would tighten lug nuts. Then I am going to weld it all up with 7018 AC rods. I am beveling the edge of the joints all the way around on both sides and leaving a slight gap at the root to insure good penetration. After all is said and done I am welding plates at each joint. It should be good and strong. I hope to post some pics soon of a frame. [cl

Glad to hear you have it figured out. I usually mock my angles up on the garage floor in soap stone and get my cuts figured out from there.

Also sounds like a good plan on welding it all together, all I can offer is to clamp down and measure measure measure!!!! Heat and distortion is the root of all evil!! LOL

Good luck on your project and can't wait to see some pics!