CAD Forum - Database of tips, tricks and utilities for AutoCAD, Inventor and other Autodesk products [www.cadforum.cz]
CZ | EN | DE
Login or
registration
  Visitors: 5162
RSS channel - CAD tips RSS tips
RSS discussions

Discussion Discussion forum

 

HelpCAD discussion

 
CAD Forum - Homepage CAD discussion forum - ask any CAD-related questions here, share your CAD knowledge on AutoCAD, Inventor, Revit and other Autodesk software with your peers from all over the world. To start a new topic, choose an appropriate forum.

Please abide by the rules of this forum.

How to post questions: register or login, go to the specific forum and click the NEW TOPIC button.
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

The information that you provide in this form will make up your forum profile which can be viewed by other forum members. Your email address will only be visible by forum admin and moderators and will be used to send you Forum Notifications. To cancel your account, use the page Opt-out or contact webmaster@cadforum.cz.

Technical Drawing Question (Tangent To 2 Circles)

 Post Reply Post Reply
Author
dery View Drop Down
Groupie
Groupie


Joined: 31.Jan.2018
Location: United States
Using: AutoCAD 2014
Status: Offline
Points: 53
Post Options Post Options   Thanks (0) Thanks(0)   Quote dery Quote  Post ReplyReply Direct Link To This Post Topic: Technical Drawing Question (Tangent To 2 Circles)
    Posted: 23.Nov.2021 at 17:06
I know I can do it by using the Ttr command in AutoCAD, but that's not what I want to know.

Can someone please tell me how to draw an arc that tangent to 2 circles using traditional method (e.g. using compass)?

For example, how to draw such as below image in AutoCAD using traditional method with the given 2 known-diameter circle with a distance of 7 between its center point? How do you draw an arc with radius of 12 that tangent to these two circles?

Thank you




Back to Top
philippe JOSEPH View Drop Down
Senior Member
Senior Member


Joined: 14.Mar.2011
Location: France
Using: AutoCAD Mechanical 2017
Status: Offline
Points: 1280
Post Options Post Options   Thanks (0) Thanks(0)   Quote philippe JOSEPH Quote  Post ReplyReply Direct Link To This Post Posted: 24.Nov.2021 at 15:03
Hello Dery, you must :
Draw a circle R : 12 - ( 3/2 ) = 10.5 at the center of the circle diameter 3.
Draw a circle R : 12 - ( 2/2 ) = 11 at the center of the circle diameter 3.
At the junction of the 2 circles you must draw a circle radius 12 that will be tangent to your  circles dia. 3 and dia. 2 and that will have a radius r : 12, then you trim the circle r : 12 to your circles dia. 3 and 2.
I'm afraid this is basic design.
Back to Top
philippe JOSEPH View Drop Down
Senior Member
Senior Member


Joined: 14.Mar.2011
Location: France
Using: AutoCAD Mechanical 2017
Status: Offline
Points: 1280
Post Options Post Options   Thanks (0) Thanks(0)   Quote philippe JOSEPH Quote  Post ReplyReply Direct Link To This Post Posted: 24.Nov.2021 at 15:21
Back to Top
philippe JOSEPH View Drop Down
Senior Member
Senior Member


Joined: 14.Mar.2011
Location: France
Using: AutoCAD Mechanical 2017
Status: Offline
Points: 1280
Post Options Post Options   Thanks (0) Thanks(0)   Quote philippe JOSEPH Quote  Post ReplyReply Direct Link To This Post Posted: 26.Nov.2021 at 07:07
Dery, if you do the work with or without the TTR command and then you lay the dimensions r10.5 and r11 you should try and found the method by yourself wich is not a bad thing.
Back to Top
dery View Drop Down
Groupie
Groupie


Joined: 31.Jan.2018
Location: United States
Using: AutoCAD 2014
Status: Offline
Points: 53
Post Options Post Options   Thanks (0) Thanks(0)   Quote dery Quote  Post ReplyReply Direct Link To This Post Posted: 29.Nov.2021 at 13:24
Why do you choose R10.5 and R11 in Step 2?
I don't understand, please explain.

Back to Top
philippe JOSEPH View Drop Down
Senior Member
Senior Member


Joined: 14.Mar.2011
Location: France
Using: AutoCAD Mechanical 2017
Status: Offline
Points: 1280
Post Options Post Options   Thanks (0) Thanks(0)   Quote philippe JOSEPH Quote  Post ReplyReply Direct Link To This Post Posted: 29.Nov.2021 at 15:08
Hello Dery, the solution for drawing the radius R12 to be TANGENT to both the diameters 3 and 2 is FINDING the CENTER of that radius R12 by DRAWING CIRCLES to find the COMMON POINT / center of the radius R12.

That center is found by subtracting values to R12 and it can even be done informatically with non exact radius and diameters values on AutoCAD by working with line lengths. 

The radius R12 will be at radius X from the center of diameter 3 and that will be R12 minus the radius of the diameter 3 that is 3/2, so : R12 - ( diameter 3 / 2 ) = 12 - ( 3/2 ) = 12 - 1.5 = 10.5.

The radius R12 will be at radius X from the center of diameter 2 and that will be R12 minus the radius of the diameter 2 that is 2/2, so : R12 - ( diameter 2 / 2 ) = 12 - ( 2/2 ) = 12 - 1 = 11.

Normally the steps are self explanatory and you could have found the solution with a paper  and a compass and some tests.
I hope this will make cense because I'm loosing my mind by doing these explanations in my non native language ( sorry ). 
Back to Top
philippe JOSEPH View Drop Down
Senior Member
Senior Member


Joined: 14.Mar.2011
Location: France
Using: AutoCAD Mechanical 2017
Status: Offline
Points: 1280
Post Options Post Options   Thanks (0) Thanks(0)   Quote philippe JOSEPH Quote  Post ReplyReply Direct Link To This Post Posted: 29.Nov.2021 at 15:17
Back to Top

Related CAD tips:


 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0,078 seconds.