1/4" vs 3/8" loose tenons - Woodworking Talk - Woodworkers Forum
 
Thread Tools Display Modes
post #1 of 14 Old 07-16-2012, 12:42 AM Thread Starter
Junior Member
 
Join Date: Jan 2012
Posts: 21
View JollyRoger808's Photo Album My Photos
1/4" vs 3/8" loose tenons

When creating loose tenons on 3/4" stock, I see people either use 1/4" tenons or 3/8" tenons. Which is better? I intuitively thought 1/4", because of the 1/3 rule, or is there something I'm missing?
JollyRoger808 is offline  
Sponsored Links
Advertisement
 
post #2 of 14 Old 07-16-2012, 07:22 AM
Old School
 
cabinetman's Avatar
 
Join Date: Jul 2007
Location: So. Florida
Posts: 24,027
View cabinetman's Photo Album My Photos
Quote:
Originally Posted by JollyRoger808 View Post
When creating loose tenons on 3/4" stock, I see people either use 1/4" tenons or 3/8" tenons. Which is better? I intuitively thought 1/4", because of the 1/3 rule, or is there something I'm missing?
I don't think you're missing anything. I don't know about any "rule". I use ¼" for tenons in ¾" stock, and ¼" for splines. I guess I just have ¼" stuck in my mind, as I use that dimension for rabbet and dado depth for ¾" stock.

IMO, leaving ¼" for wall thickness affords adequate strength.





.
cabinetman is offline  
The Following User Says Thank You to cabinetman For This Useful Post:
JollyRoger808 (07-17-2012)
post #3 of 14 Old 07-16-2012, 09:33 AM
Senior Member
 
Dave Paine's Avatar
 
Join Date: May 2012
Location: Eastern PA
Posts: 7,222
View Dave Paine's Photo Album My Photos
I have also read the 1/3 rule for mortise and tenon joints, although I would be pressed to find the reference.

If the tenon was going to be a tight fit, then once glued in place, either 1/4in or 3/8in would work, since the tenon would be attached to the surrounding wood of the mortise, so the joint would be strong.

I would not use a 3/8in loose tenon in 3/4in stock, I would be concerned at the thin 3/16in wall of the mortise. This can be overcome by using a gap filling glue like epoxy.

Personally I prefer to use the yellow glues where possible. Easier for me to deal with.

I would therefore use a 1/4in loose tenon.
Dave Paine is offline  
The Following 2 Users Say Thank You to Dave Paine For This Useful Post:
Icutone2 (07-16-2012), JollyRoger808 (07-17-2012)
Sponsored Links
Advertisement
 
post #4 of 14 Old 07-30-2012, 09:44 AM
Senior Member
 
Join Date: Sep 2011
Posts: 26,077
View Steve Neul's Photo Album My Photos
If I am making a tongue and groove joint on 3/4" stock I make the tenons 1/4". If I am just making a mortise and tenon joint I use 3/8" tenons. I worked for a company one time that made the faceframes for their cabinets with a mortise and tenon joint and they used a 1/4" tenon. It was a daily experience for someone to break off the tenon handling the cabinets. Then it had to be repaired with corrugated fasteners. Eventually they changed to a 3/8" tenon and the breakage stopped.
Steve Neul is online now  
post #5 of 14 Old 07-30-2012, 10:00 AM
Old School
 
cabinetman's Avatar
 
Join Date: Jul 2007
Location: So. Florida
Posts: 24,027
View cabinetman's Photo Album My Photos
Quote:
Originally Posted by Steve Neul View Post
If I am making a tongue and groove joint on 3/4" stock I make the tenons 1/4". If I am just making a mortise and tenon joint I use 3/8" tenons. I worked for a company one time that made the faceframes for their cabinets with a mortise and tenon joint and they used a 1/4" tenon. It was a daily experience for someone to break off the tenon handling the cabinets. Then it had to be repaired with corrugated fasteners. Eventually they changed to a 3/8" tenon and the breakage stopped.
Sounds like just poor craftsmanship.




.
cabinetman is offline  
post #6 of 14 Old 07-30-2012, 02:20 PM
Senior Member
 
Join Date: Sep 2011
Posts: 576
View Midlandbob's Photo Album My Photos
I like Steve' reply. It depend on the engineering. Where the joint is.
If you are reducing 3/4 stock to 1/4 by a thin tenon in a critical stress bearing joint, the priority would be to maintain as much wood carrying the load so go with 3/8. If it has a twisting force, then the cheeks would be mor important to preserve.
Most rules are guidelines.
Bob
Midlandbob is offline  
post #7 of 14 Old 07-30-2012, 03:48 PM
Senior Member
 
Join Date: Sep 2011
Posts: 26,077
View Steve Neul's Photo Album My Photos
Quote:
Originally Posted by cabinetman View Post
Sounds like just poor craftsmanship.









.
Hardly, It was a factory producing custom cabinets for 15-20 houses a week. The faceframes were mostly solid ash and the 1/4" tenons were just smooth breaking off.
Steve Neul is online now  
post #8 of 14 Old 07-30-2012, 04:29 PM
Old School
 
cabinetman's Avatar
 
Join Date: Jul 2007
Location: So. Florida
Posts: 24,027
View cabinetman's Photo Album My Photos
Quote:
Originally Posted by Steve Neul View Post
Hardly, It was a factory producing custom cabinets for 15-20 houses a week. The faceframes were mostly solid ash and the 1/4" tenons were just smooth breaking off.
How does that happen? The mortise is cut, the tenon is cut, the parts get glued and the tenon gets inserted in the mortise. What am I missing?





.
cabinetman is offline  
post #9 of 14 Old 08-02-2012, 08:01 AM
Senior Member
 
Join Date: Sep 2011
Posts: 26,077
View Steve Neul's Photo Album My Photos
Quote:
Originally Posted by cabinetman View Post
How does that happen? The mortise is cut, the tenon is cut, the parts get glued and the tenon gets inserted in the mortise. What am I missing?










.
The thin 1/4" tenons were breaking in two. Like everyone else there I thought when they changed to a 3/8" tenon it was asking for more problems but it worked. There were no more faceframes being broken from normal handling of the cabinets. It was primarily the top rails on long base cabinets that didn't have center dividers.
Steve Neul is online now  
post #10 of 14 Old 08-02-2012, 08:04 AM
Old School
 
cabinetman's Avatar
 
Join Date: Jul 2007
Location: So. Florida
Posts: 24,027
View cabinetman's Photo Album My Photos
Quote:
Originally Posted by Steve Neul View Post
The thin 1/4" tenons were breaking in two. Like everyone else there I thought when they changed to a 3/8" tenon it was asking for more problems but it worked. There were no more faceframes being broken from normal handling of the cabinets. It was primarily the top rails on long base cabinets that didn't have center dividers.
They don't break all by themselves.





.
cabinetman is offline  
post #11 of 14 Old 08-02-2012, 12:33 PM
John
 
Join Date: Mar 2010
Location: La Crosse, Kansas
Posts: 3,028
View jschaben's Photo Album My Photos
There is normal handling and there is NORMAL handling. I used to work in a furniture factory and dropping a sofa 4-6 feet was NORMAL.

John

If I strive for perfection, I can generally achieve good'nuff, If I strive for good'nuff, I generally achieve firewood
jschaben is offline  
post #12 of 14 Old 08-03-2012, 08:11 AM
Senior Member
 
Join Date: Sep 2011
Posts: 26,077
View Steve Neul's Photo Album My Photos
Quote:
Originally Posted by cabinetman View Post
They don't break all by themselves.










.
The 3/8" tenons didn't break at all.
Steve Neul is online now  
post #13 of 14 Old 08-03-2012, 08:35 AM
Old School
 
cabinetman's Avatar
 
Join Date: Jul 2007
Location: So. Florida
Posts: 24,027
View cabinetman's Photo Album My Photos
Quote:
Originally Posted by Steve Neul View Post
The 3/8" tenons didn't break at all.
That's fine and dandy. I prefer to have at least a ¼" wall thickness for ¾" stock. You won't have that with a ⅜" tenon.





.
cabinetman is offline  
post #14 of 14 Old 08-04-2012, 10:08 PM
Junior Member
 
Join Date: Aug 2008
Posts: 16
View Brian Hinther's Photo Album My Photos
FWW did a joint test a few years ago in which they had to go to a 3/8" tenon to get the joint to perform better than a Beadlock or Dowelmax. The 3/8" m&t withstood over 1400 pounds of stress--very close to the half-lap and bridle joint winners. The 1/4" variety was only good for around 700 pounds, barely ahead of pocket screws.
Brian Hinther is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Woodworking Talk - Woodworkers Forum 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










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
Difference between "Grizzly" and "Polar Bear" Planers? NickSaw76 Power Tools & Machinery 15 02-24-2012 11:20 PM
Loose tenon in 1 1/4" table legs.. dribron Joinery 4 06-30-2011 05:04 AM
"shallow-flute bowl gouge" = "spindle gouge" ? duncsuss Woodturning 20 03-11-2011 02:41 PM
All in One Clamp Guide Package (24"-36"-50") $69.99+Shipping upnorf General Woodworking Discussion 0 05-12-2010 03:19 PM
Loose tenons Terry Beeson Joinery 9 07-16-2008 04:24 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 Off
Refbacks are Off

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