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SignalFailure

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What is the correct method to create a nice curved line between a straight line and a circle?

Specifically, if I'm trying to draw a simple connecting rod it would seem to be easiet to draw the ends as circles and the rod as lines and connect the two. I guess it's something like the 'fillet' command but that only seems to work where the lines to be connected are both straight.

TIA

Paul
 
Paul,

Not sure what CAD program you are using but I just tried this with AutoCad. The fillet command did not seem to work for me. What did work was to add another circle defined as tangent to the end circle, tangent to the connecting line, and of radius "x". The I trimmed away all the parts of each circle and the connecting line I didn't want. The result was a nice curved transition from the end circle to the connecting line between the two ends. This would need to be repeated four times...twice on each end of the connecting rod. Hope that makes sense. I am functional in AutoCAD but by no means fluent, so others may have a better solution. Again it may also depend on your software, but AutoCAD's circle command has an option "Ttr" for tangent,tangent,radius and that is what I used.

Hope this helps and doesn't add even more confusion.

Bill
 
Thanks Bill, that makes perfect sense even if I'm not sure how to do the trimming bit! I'm experimenting with TurboCAD learning edition for this drawing. I'm off to try that now,

Many thanks!
 
Paul,
Just wanted to check and see if you accomplished what you were after?

Bill
 
Not yet Bill. I've experimented a little with the arcs tangential to various things but no joy yet. Also tried the cutting edge/trim tool, plain arc and splines. There's bound to be a simple way I just need more time!
 
Use the fillet tool !
001-1.jpg
 
Paul,
Maybe someone here more familiar with TurboCad can jump in. Its quite likely that commands differ in the various programs. Actually what I used to clean up the inwanted line segments and portions of circles is what AutoCAD calls the 2 point break command. Anyway, keep after it...even though I know its frustrating, it ISN'T wasted time at all...more a matter of learning what doesn't work until you find what does.

Bill
 
abby said:
Use the fillet tool !

Doesn't work with arcs or circles mate. I'll experiment with the 'split' tool later - looks like it might do the job. Thanks for the help!
 
Paul,

I use TC14.

Draw the circle

Draw the lines and intersect them with the circle.

Split the circle at the 2 points where the lines and circle intersect.

Remove the created arc between the two lines.

Use the fillet tool to join the remaining arc and the 2 lines.

The fillet radius must be small enough to allow this otherwise wierd things happen.

Hope this helps. ???

Best Regards
Bob
 
Hi Paul,

I just did it with the Fillet tool in TurboCAD v3.01 which is an earler version than LE. LE is a very slightly dumbed down v4.xx. I'm pretty sure the Fillet tool works the same in LE. I don't have it here at work but do at home. I'll try it tonight to make sure.

You choose Fillet from the Modify menu, define the radius you want, click on the straight line portion of your con rod, then click on the circle. Voila! In the attached example I used .75 in. on the big end, .5 on the small end.

Fillet 1.jpg


Fillet 2.jpg
 
Maryak, thanks for the suggestion but I just tried Dickeybird's shorter solution and it works (!) which probably means Abby's suggestion would have worked too.

Q. Why didn't it work before?
A. Because I'd drawn the centre section of the rod as a rectangle (for speed) rather than separate lines.

Some CAD programs seem to treat rectangles as 4 separate objects whereas others treat them as one.

Problem solverd: Thanks to all :bow: :bow:
 
Paul said:
Q. Why didn't it work before?
A. Because I'd drawn the centre section of the rod as a rectangle (for speed) rather than separate lines.
Ahhhh! Good catch. That's the problem with computers & CAD; they do EXACTLY what we mere mortals tell them to do...no more, no less. ;D

By the way, you could Select/Format/Explode the rectangle into its 4 line segments and Fillet would work.
 

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