[paulrhyan]

I need a little help with calculating the start points and/or end points of angles and arc blends. For instance: [hypothetically} a lathe part that has a 30° taper that blends into a .125 (G02) radius that might need to blend into a 1.25 (G03) radius. It isn't often but sometimes I'll get a part to program that will have some kind of radius to an angle on it and I don't have a CAD/CAM package to fall on. I was once taught how to 'find the triangles' and calculate the points using simple trigonometry. Unfortunately, after [almost] learning this six years ago, I haven't had a need to use this knowledge since. Can somebody here point me to some kind of tutorial somewhere that will help me teach myself these skills?

Thank you.

PR

[deadlykitten]

hi / share your drawing, and i will post a video about building that inside CAD

if you like it, i may share the CAD, developed by razor blade and skidrow

win-win deal

[sinha_nsit]

One method is to make the drawing in AutoCAD, and extract the coordinates of the joints.

[ProToZyKo]

What control are you at? Fanuc has a option called "Direct drawing dimensions programming" which helps you with problems like this

[rcs60]

The Machinery's handbook has been one book that i got to to solve problems in the past the newest go to for me is daft sight (free version) which is similar to autocad

[paulrhyan]

Thank you for all the replies to this thread. The problem here is I DO NOT HAVE ACCESS TO CAD/CAM. I am expected to make these calculations with nothing more than a pencil, paper and a calculator. My employer does not have a CAD/CAM package. Uploading an ITAR print to a public message board and waiting for a good samaritan to calculate the points for me is not an option either.

What control are you at? Fanuc has a option called "Direct drawing dimensions programming" which helps you with problems like this

Thanks for the suggestion but I am at an older Mitsubishi control that does not have support for this.

The Machinery's handbook has been one book that i got to to solve problems in the past the newest go to for me is daft sight (free version) which is similar to autocad

Thanks for the tip. I will check my copy (27th edition) when I get a chance.

To summarize, I need to learn how to make these calculations at the machine. I've done some google searches but I haven't really been able to find anything that would help me. I've been working a lot of OT lately so my computer time is quite limited. I will continue my searching this weekend. If anybody has some links they could shoot me or has the time to help my one on one through this forum and/or via e-mail I would be quite grateful.

Regards,

PR

[sinha_nsit]

Ok. Post your drawing. Somebody will calculate it for you. In future, you may follow the same calculation method.

[deadlykitten]

in classical sectors, there may be "standard trigonometric tables", and "tiny math dictionaries ( or guides, etc )", developed for machinists, that helps calculating common things

some write their own, and stick them to the back side of the control panel; ( cigarettes are sttored in the upper left corner; drinks after the grinding machine, behind the metalic wardrobe, etc )

on the mill i have excel templates, ready to calculate common stuff

I will check my copy (27th edition) when I get a chance

what you need is inside the 1st edition

I was once taught how to 'find the triangles' and calculate the points using simple trigonometry. Unfortunately, after [almost] learning this six years ago, I haven't had a need to use this knowledge since

where is that guy now ?

---

https://www.mathsisfun.com/algebra/t...triangles.html

also, just like mr sinha said, please post your drawing / kindly

[paulrhyan]

Okay, I'm sorry it took so long. Working 70+ hrs. I can't provide the actual print and the job is complete so I don't even have access to it for reference purposes. I have provided a (very) rough sketch that I managed to draw in MS-Paint. I apologize for the crudeness of the "sketch". I just need to know how to calculate Points 1-4. How do I make the triangles to trig out the points?

Thanks.

[ger21]

You can't determine the X coordinate of P1 and P4 from what you have there. And you need to know the Y distance between the start and end.

[positiverake]

Web machinist is a $ cheap software that has a simple lathe cam and will do what you want and it will comp for the tool radius plus a lot of other good info. google it

[sinha_nsit]

You can't determine the X coordinate of P1 and P4 from what you have there. And you need to know the Y distance between the start and end.

It is a lathe part.
X-coordinates can be determined, but not the Z-coordinates.

[deadlykitten]

Okay, I'm sorry it took so long. Working 70+ hrs

if you dont get into math and/or cad, you will be soon working 700+ i hope you get payed for those extra-hours ...

[paulrhyan]

Very sorry about that. Thanks for the help. Lets say P1 is Z-.400. Do I need to provide a location for the center point of the arcs? Technically it doesn't really matter as the job in question is complete. All I need to know is HOW to make the calculations. If it will help at all, you can make up the points and just teach me how to create the triangles. I hope this helps a little. If we can't use my crappy Paint sketch I'll see if I can't google some kind of print or pull one of Peter Smid's sketches from the CD (if i still have it).

As always, I appreciate all the efforts of the community.

[deadlykitten]

hy / in attach archive are 2 movies : one with using autoCAD to get the coords, and another with using classical trigonometry

i hope you find them useful

at post #8 i shared a link to online math

even if you master this calculations, there is no need to use them : is enough to understand them, and after that use a CAD or something, or get a paper with "fundamental trigonometic values"

kindly

ps : in the shared video, i have forgot to add formulas for a point; pls find attached the point G; now, my work, is completed