compound miter angles - Router Forums
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 11-07-2009, 10:05 PM Thread Starter
Registered User
Join Date: Nov 2009
First Name: Glenn
Posts: 4
Default compound miter angles

I am building a buggy seat 2 sides and a back the sides and back are both at a 30 degree angle from the seat. My question is how do I figure out the miter and bevel angles ?
gdemo is offline  
Sponsored Links
post #2 of 5 (permalink) Old 11-16-2009, 09:33 PM
Registered User
Join Date: Nov 2009
Country: United States
First Name: James
Posts: 2,304

To get a 30 degree angle you divide the angle In two. Each side would be cut at 15 degrees. When joined together you have a 30 degree corner.

Whittier, CA.

Have a nice & safe day!
jlord is offline  
post #3 of 5 (permalink) Old 11-16-2009, 09:47 PM
Join Date: Nov 2009
Posts: 40

If your not sure of the exact angle. You can always use a sliding Bevel gauge
then just transfer your angle..

Not sure if this is the right info that your looking for.
Attached Thumbnails
Click image for larger version

Name:	sliding_t_johnson.jpg
Views:	42
Size:	21.5 KB
ID:	30001  

Mt-Pockets is offline  
Sponsored Links
post #4 of 5 (permalink) Old 11-18-2009, 12:31 PM
Registered User
Ghidrah's Avatar
Join Date: Oct 2008
Country: United States
First Name: Ronald
Posts: 1,466

You have a little bit of hip roof framing going on here and that's a bit complicated.
What you need is the angles for the saw cuts which requires much dimensional information, i.e., runs and rises of the material.

There's a non math option, I'd make a set of, (1/4 or 1/2) scaled test pieces 1st, to minimize waste. Take some scrap plywood, and draw 1/2 your seat backer with the 30 on 1 side and do the same for one of the side pieces. Rip the 30 along the bottom, (plate cut) of both pieces take the cut offs from the side cuts and use them to prop up the backer and piece at 30. The 30 side angles will be cut back later, they're always less than the 30.

Use a framing square, plywood or some other thing to create a 90 right angle, (pseudo seat) so you can slide the 2 pieces together at 90. When the tops, of the 2 pieces touch, (ridge cut) mark the bottoms of both pieces where they stop along the 90 corner.

1. Measure this distance off the 90 corner to the marks made, e.g, (X) = 3/4".
2. At a 90 angle measure (X) off from the point where the backer and side piece touched, (ridge cut) and mark both pieces.
3. Strike a line from the bottom, (plate cut) to and through (X), (new ridge cut)
4. Use speed square or whatever you have to discover the new angle
5. Cut new angle into both pieces and test on 90 corner, should line up perfectly for butt joint.

I'd go with a butt joint for screwage, if you're going for a miter cut it should be at or very close to 45

Never bite the hand that looks dirty!
The more you know the more you're worth
Ghidrah is offline  
post #5 of 5 (permalink) Old 11-23-2009, 03:40 AM Thread Starter
Registered User
Join Date: Nov 2009
First Name: Glenn
Posts: 4

Thanks Ghidrah, very helpful!
gdemo is offline  

Quick Reply

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


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

Email Address:


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
Bosch 5412L 12" Dual Compound Sliding Miter Saw and T4B Folding Stand Combo CanuckGal Tool Reviews 8 07-24-2009 01:19 PM
Compound Angles reible Tools and Woodworking 2 03-28-2005 01:34 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