cutting oval shape - Router Forums
 10Likes
  • 7 Post By Cherryville Chuck
  • 1 Post By aaronhooks
  • 2 Post By DesertRatTom
 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 01-27-2017, 12:21 PM Thread Starter
Registered User
 
inkslinger's Avatar
 
Join Date: Jan 2017
First Name: N/a
Posts: 9
 
Default cutting oval shape

Don't know if to post here , I have a big oval shape mirror in our guess bathroom an would like to add a wooden trim around it but don't know if it can be done with a router or how to go about doing it? Where can i look for info or has any done this? Would doing it in section be a better way? 36 X 27
inkslinger is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 01-27-2017, 02:12 PM
Moderation Team
 
Cherryville Chuck's Avatar
 
Join Date: Sep 2010
Country: Canada
First Name: Charles
Posts: 15,905
 
Default

Usually those frames are pieced together in sections and that is so they can avoid grain going crossways across the frame which would be very weak. I would be tempted to cut the pieces and then build it by overlapping 2 layers thick and staggering the joints between the layers which will give you good strong joints between the sections. I think you'll have to glue up the sections and then cut close to size and then use a template to rout to final shape.

I would probably use the mirror to make a paper template and then offset the line inward enough to lake the rabbet to set the mirror in.
harrysin, OPG3, DaninVan and 4 others like this.

Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.
Cherryville Chuck is offline  
post #3 of 7 (permalink) Old 01-28-2017, 09:00 AM
Registered User
 
aaronhooks's Avatar
 
Join Date: Oct 2013
Country: United States
First Name: Aaron
Posts: 20
 
Default Jigs are easy to make

Google search for oval or ellipse cutting jigs. They are pretty easy to make and work well. I have made 54 X 72 table tops with this type of jig.

Making a ring will leave some cross grain areas that are vulnerable. If there is no stress on it in the final application then it may not be a problem. Also, you will have waste (the center section) that doing it in pieces would eliminate.

Sounds like a fun project!
OPG3 likes this.
aaronhooks is offline  
Sponsored Links
Advertisement
 
post #4 of 7 (permalink) Old 01-28-2017, 10:27 AM
Forum Contributor
 
DesertRatTom's Avatar
 
Join Date: Jul 2012
Country: United States
First Name: Tom
Posts: 18,057
 
Default

I suggest after making a paper template, that you use a straight edge to bisect the oval, and mark the exact center. Then turning the straight edge at angles and across the exact center, mark an angle or two. Use a protractor to measure the angle of the new line, and set the straight edge to the same angle relative to the center line and mark the new line. That will give you the angles you need to cut on the straight pieces in order to form the oval. It will also tell you how long the pieces need to be (outside circumference of the oval).

Use a compas to trace the template outline about 3/8ths in from the outline to allow for the rabbet. Then use the same method to mark another line to the outside of the template's mirror size, out to the width you want the frame to be, and draw a second line. With the bisecting lines marked, you can then work out the width of the material you'll need to cut and assemble in order to cut out your final frame. It will be much wider than the frame width. You may find you need to add additional segments in order to use available material.

You will find that you need carefully milled material. Warps, twists, bowing will make it impossible to make a decent frame, so start with strong, straight grain material--you'll likely pay a premium, and the wider the stock, the more you'll pay and the harder it will be to find acceptable stock.

Cut the pieces a little over sized on length, then mark the angles as precisely on each piece. Be very careful to lay the pieces out and mark their locations, and the back so you don't mess up your cut. Personally, I'd produce two long pieces extra because being human, I WILL mess at least one cut up.

Cutting exact angles is always a challenge, particularly since they will vary around the circumference. I'd bet the pink slip on my car that you will have to use a block plane to perfect the angles and fit to make it form a closed oval.

I would cut slots and use splines to connect each part, cutting the slots face down on the router table. This will assure that your face will be relatively even. Since you cutting slots into the end of the long train, your spline can be long grain as well (whew, that's easier). There are all kinds of joints you could use for this, but splines are simpler and less likely to be messed up.

Once all this is done, you can cut the paper template to the exact width of the final frame, and trace the shape onto the assembled and glued up blank you've constructed. I'd put green painter's tape on first and trace the line onto that. The tape will reduce tearout.

Cut the shape out very carefully with a jig saw. Cut a little proud of the line, and plan on sanding like mad to smooth the inside and outside shapes. A spindle sander will make this go faster, if you cut a pattern into 1/4-1/2 mdf, you could use a trim bit to really make it perfect, but you will want to pre cut about 1/8th or so proud with the jig saw.

Theoretically, you could rough assemble the straight pieces, using double stick tape to hold them down, then use a band saw to cut each piece first. I'd do this after fitting and cutting the slots. But frames are really tricky and you will have to make sure the joints are really tight when you mark them up.

Cut the rabbit into the assembled and glued up frame. Roundover the edges and if you're going to shape the front, you can do it now. It may be tempting to do any shaping on the unassembled straight parts, but the shape won't follow the curve, although after cutting the oval parts, you could shape them individually. Either way, plan on more sanding time, then double it.

You will then need to finish the frame, and add a backing to protect the mirror. Personaly, I'd cut a piece the same size as the morror and use brads or clips to hold that in. Use a lot of them.

To allow for shaping and the rabbit and backer, I'd start with 4/4 stock.

That is if you want a nice wood finish on the frame.

Now, if it were just going to be painted, I might consider simply cutting the frame out of a couple of sheets of MDF glued together, all in one piece. Cut two rabbits, one about 3/8ths inch for the mirror, one nearly the full width of the frame, for a 1/4 inch plywood backer, which will add strength to the frame. Why a wide rabbit? So the ply doesn't show at the edge. You could pre drill and use screws to hold the ply in place, or just glue it in place. Of course this will be far more fragile, but relatively quick to make

Hope you don't mind the novella. I'm sure folks will come along and add or suggest alternatives. I make frames for my wife's paintings. They are always a challenge, extremely exacting as to cutting angles so they fit. A tiny error in cutting angles multiplies as you add sides or parts, so that will be your challenge.
OPG3 and vchiarelli like this.

The more I do, the less I accomplish.

Last edited by DesertRatTom; 01-28-2017 at 11:13 AM.
DesertRatTom is offline  
post #5 of 7 (permalink) Old 01-28-2017, 10:33 AM
Contributor of the Month
 
OPG3's Avatar
 
Join Date: Jan 2011
Country: United States
First Name: Otis
Posts: 1,985
 
Default

or, just call someone in the framing business and get a price.

Otis Guillebeau from Auburn, Georgia

OPG3

Tweak everything!
OPG3 is offline  
post #6 of 7 (permalink) Old 01-28-2017, 10:36 AM
Registered User
 
Join Date: Mar 2014
Country: United States
First Name: Tom
Posts: 1,463
 
Default

Here's a pretty elegant way of cutting an ellipse

The Elegant Ellipse | THISisCarpentry

You could cut out the "OD" & "ID" off the same set-up by just changing the pivot points on the trammel. As noted, it's much easier, and less wasteful of material, to make the ellipse in segments. If you lay the ellipse out on a piece of heavy paper (rosin paper works well), you can cut strips the same width as the material you will be using to make the finished part and then place them over the layout until you get the best coverage. Cut the strips to make patterns and then cut the segments, join with biscuits and then cut out the ellipse.
tomp913 is offline  
post #7 of 7 (permalink) Old 09-07-2017, 01:38 AM
Registered User
 
Join Date: Sep 2017
First Name: N/a
Posts: 11
 
Default

Thanks for the link.
antgarcia 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











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
dado blade for spline joining sjonesphoto Tools and Woodworking 34 03-11-2014 11:11 AM
oval & circle cutting jigs frosty50 Jigs and Fixtures 3 12-22-2011 01:41 PM
Cutting out Circles and Arcs the Easy Way learnexperience Portable Routing 1 11-26-2011 01:29 PM
oval cutting colin.elwick New Member Introductions 2 10-18-2009 05:04 PM

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