Determining a radius cut - Router Forums
 
LinkBack Thread Tools Display Modes
post #1 of 8 (permalink) Old 06-22-2008, 10:36 AM Thread Starter
Registered User
 
RoyBullets's Avatar
 
Join Date: May 2008
Posts: 74
 
Determining a radius cut

I came across a note on in a article that mentions a radius cut of 40". The length of the wood piece is only about 24". I know how to cut arcs and circles from the jigs I have made for my other tools but I have not seen a radius described that way before.

Does this mean center my arc jig on the length of the board (12") and nail it down at 20" (half of 40") to achieve the correct arc for the radius.

Any help would be appreciated.
RoyBullets is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 06-22-2008, 02:52 PM Thread Starter
Registered User
 
RoyBullets's Avatar
 
Join Date: May 2008
Posts: 74
 
I was thinking I could have described this a little better. Does a 40" radius mean essentially a 40" circle?

I am going to try a back into the answer with a little trial and error since I know all the dimensions and how to calculate the radius.
RoyBullets is offline  
post #3 of 8 (permalink) Old 06-22-2008, 05:15 PM
Registered User
 
Join Date: Mar 2007
Country: United States
First Name: Joe
Posts: 187
 
Roy,

If your radius is 40" (inches) then the diameter of your circle will be 80". The circumference of the circle will be 3.14 times the diameter. That's a big circle! If your board is only 24" in length, then I would think your first calculation to be right.

Joe Z.

JoeZ If you never made a mistake, you never tried anything
cbsjoez1935 is offline  
post #4 of 8 (permalink) Old 06-22-2008, 05:54 PM Thread Starter
Registered User
 
RoyBullets's Avatar
 
Join Date: May 2008
Posts: 74
 
Quote:
Originally Posted by cbsjoez1935
Roy,

If your radius is 40" (inches) then the diameter of your circle will be 80". The circumference of the circle will be 3.14 times the diameter. That's a big circle! If your board is only 24" in length, then I would think your first calculation to be right.

Joe Z.
Thanks Joe. The more I thought about it the more it seemed correct. I guess I have just not heard the arc described that way before.

Got tied up today but this evening I am going to just lay it out on a piece of paper and draw the radius. In this case I know what the final dimensions should be. I need to get this one right because I have a nice piece of cedar I am going to be working on.

Thanks for the help.
RoyBullets is offline  
post #5 of 8 (permalink) Old 06-22-2008, 06:17 PM
Forum Contributor
 
Join Date: Jan 2006
Country: United States
First Name: Bj
Posts: 23,786
       
HI Roy

Definitions of radius

* the length of a line segment between the center and circumference of a circle or sphere
* a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere)
* a circular region whose area is indicated by the length of its radius; "they located it within a radius of 2 miles"
* the outer and slightly shorter of the two bones of the human forearm
* spoke: support consisting of a radial member of a wheel joining the hub to the rim
wordnet.princeton.edu/perl/webw

========

"It's fine to disagree with other members as long as you respect their opinions"

Marc Sommerfeld Tools ,Videos
http://www.youtube.com/channel/UCT-n...RWaEpMA/videos

Find all threads started by bobj3
http://www.routerforums.com/search.php?searchid=944097



Last edited by bobj3; 06-22-2008 at 06:19 PM.
bobj3 is offline  
post #6 of 8 (permalink) Old 06-22-2008, 08:09 PM Thread Starter
Registered User
 
RoyBullets's Avatar
 
Join Date: May 2008
Posts: 74
 
Nice Bob

You forgot one:

R = ((L^2) + 4(H^2)) / 8H

Radius I understand, just not in the context that I ran across it. I am good now though.
RoyBullets is offline  
post #7 of 8 (permalink) Old 06-22-2008, 11:18 PM
Forum Contributor
 
harrysin's Avatar
 
Join Date: Jan 2007
Country: Australia
First Name: Harry
Posts: 11,594
     
Send a message via Skype™ to harrysin
I don't know what the article is about but assume that a 24" length of wood is going to be curved, in which case mark the centre of the wood, draw a line 40" long at right angles to the centre of the wood and with a jig or a piece of string with a pencil tied to it's end draw an arc on the wood. These shots show in a crude but fast demo.of how I interpreted your first post.
Attached Images
File Type: jpg radius1.jpg (47.0 KB, 60 views)
File Type: jpg radius2.jpg (42.2 KB, 55 views)

Harry



Nothing but heaven itself is better than a friend who is really a friend. - Plautus






harrysin is offline  
post #8 of 8 (permalink) Old 06-23-2008, 08:10 AM
Registered User
 
Tale Gunner's Avatar
 
Join Date: Sep 2004
Country: United States
First Name: N/A
Posts: 19
 
Harry you are correct. Here is a picture that I refer to all the time to keep my mind straight.
[IMG][/IMG]
Tale Gunner is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Router Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Corner Radius bobj3 Tools and Woodworking 25 09-29-2007 05:51 PM
Working with radius MiamiSnookII Starting Off 5 01-07-2006 10:20 AM
3/4" Radius roundover bit with 1/4" shank chrisogrady Router Bits - Types and Usage 8 04-01-2005 08:08 PM
Router Table Plate Radius DONALD Table-mounted Routing 2 02-27-2005 09:26 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome