Ellipse Layout - CNC Version

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Hey guys, I'm looking at building some dip bar attachments for some gym equipment and would like to get the math down good enough to cut these ellipses/ovals out of the side of the tubing on my plasma table. The two handles will be going through a piece of 2x3 11 Ga. tubing at a 75 degree angle, it will pass through so I can get welds on both sides of the 2x3 tubing. My two questions are as follows - 1) Is there a calculator or formula somewhere that figures up how long the ellipse needs to be based on the angle of the pipe? 2) How can I find the offset for the tubing going through the backside? Is this something that I am better off just laying out and dialing in? I was hoping for something that can get me perfect since I've got tight tolerances on my table that would cut down on alot of trial and error.
Reply:I'm sure there is a formula for it, but I would draw a elliptical about the size I thought would work cut it out of a piece of scrap and adjust accordingly A lot of times trial and error are about as fast when you have acces to the machine. Just my 2 cents worthMike
Reply:There are a lot of ways of making them.





See next post for rest of images. Sincerely, Wiliam McCormickIf I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.
Reply:This is the rest of it.

Sincerely, William McCormickIf I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.
Reply:Basic right angle trig will solve all this for you.To see what I mean, on a side view, draw to scale two 1/8" parallel plates representing the upper and lower part of your rectangle tube.Draw your round pipe through them at 75 degrees.Your offset and length of ellipse will be clearly shown.Pay special attention to which edges of the 1/8" plates it touches (small error here because of the plasma not piercing at an angle).Draw in right angle triangles where needed and use sine, cosine, tangent as needed. If your scale drawing is good enough, you may be able to take your measurements directly without calculations. I'm heading to a job so I won't be able to help with the math until evening.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.