Thanks: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 15 of 23
Thread: Strong dowel joints?
-
7th August 2018, 07:44 PM #1New Member
- Join Date
- Feb 2018
- Location
- australia
- Posts
- 4
Strong dowel joints?
Hey everyone, I’m currently drawing up plans for a timber/glass display table. The glass I’ll be using for the top will be 3/8” thick (I was recommended this thickness for strength) and although I’ve never been involved with glass in my life, I’d assume it’s pretty heavy in a 900x650 panel.
The table design only has 3 glass panels (top, front and side) while the remaining sides will be timber top to bottom. My preference for the leg design is to look like a mortise-tenon joint as them I’ll have 4 endgrain corners on the top.
However the length of the timber I have won’t be long enough to make a tenon, and I figured my next best bet was to simply dowel it. But because of the weight of the glass on the front right corner I am concerned if timber dowels will be strong enough? Could I substitute them with stall bar the same diameter? Or is there a better method I could use? Thanks guys 😃
rs1262.pbsrc.com/albums/ii609/alex_grant2/8B24200F-1D26-40E9-85AA-AC3304CC48F6_zpsdcrbi0r9.jpeg?w=480&h=480&fit=clip
-
7th August 2018 07:44 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
8th August 2018, 12:31 AM #2
a 900 x 650 glass panel 3/8" thick will weigh around 15 kg, which is not that much at all for a table frame to support.
regards from Alberta, Canada
ian
-
8th August 2018, 12:31 AM #3China
- Join Date
- Dec 2005
- Location
- South Australia
- Posts
- 4,475
What size is your timer what is the table going to display e.g. weight, I would be including corner brackets
-
8th August 2018, 05:01 AM #4GOLD MEMBER
- Join Date
- Apr 2011
- Location
- McBride BC Canada
- Posts
- 3,543
I can only imagine that this glass will not be a single point load.
Many of my house windows are 60 x 90 sliders. Heavy but more awkward than anything.
Lifting them out for washing is a PITA.
Glued dowels ought to be OK.
-
8th August 2018, 12:38 PM #5New Member
- Join Date
- Feb 2018
- Location
- australia
- Posts
- 4
Thanks guys. The timber will most likely be 50x50mm and yes the glass will be supported on all sides, I plan to have it recessed so it’s flush with the timber top and can’t just slide off the frame.
In regards to regular dowel, would I be better off doing several I say an X pattern or just do two vertically? Thanks again everyone 😃 and thanks for the 15kg Ian, I was assuming much more haha.
-
8th August 2018, 06:15 PM #6Taking a break
- Join Date
- Aug 2008
- Location
- Melbourne
- Age
- 34
- Posts
- 6,127
2 vertical dowels should do; if you have them in an X pattern, the ones on the inside will cut into each other and be kinda useless anyway.
Also, it's a good idea to have the glass toughened and any exposed edges ground so they're not sharp.
-
8th August 2018, 07:10 PM #7
Hi Alexander
I agree with Elan; glass should be toughened and edges polished.
You might like to check with your glazier whether 3/8" is adequate for the size of your table panel. It must be able to withstand some ill-treatment!
I have toughened glass sheleves in my kitchen cabinets - maximum size is 700 x 300 mm - and glazier recommended 8 mm toughened glass. When loaded with crockery you can see some deflection. Certainly wouldn't want anything less than 8 mm in my case.
Cheers
Graeme
-
8th August 2018, 07:28 PM #8GOLD MEMBER
- Join Date
- Aug 2011
- Location
- bilpin
- Posts
- 3,559
I wouldn't use dowels on a glass table. That's a job for mortise and tenon. As your timber is too short to cut a tenon you could use slip tenons cut from a separate piece of timber. You then have the luxury of selecting a suitably strong piece of stick for the slip tenons.
Dowels are for canary perches.
-
8th August 2018, 07:34 PM #9Taking a break
- Join Date
- Aug 2008
- Location
- Melbourne
- Age
- 34
- Posts
- 6,127
-
9th August 2018, 09:08 AM #10New Member
- Join Date
- Feb 2018
- Location
- australia
- Posts
- 4
Lots of really helpful advice guys 😃. I’ll definitely be in touch with a professional glazier before I start the build, but wot the frame being relatively chunky I should still be able to have it recessed into the top no problems.
-
9th August 2018, 11:44 AM #11GOLD MEMBER
- Join Date
- Aug 2011
- Location
- bilpin
- Posts
- 3,559
-
9th August 2018, 12:14 PM #12
Actually, I would say it depends on how well designed the table and where the joint is.
If the rails are resting on top of the stiles and the dowels are just to stop lateral movement in the joint then dowels are fine.
If the rail is butt-joined to the side of the stile - in which case the dowels could be considered load-bearing... Loose tenons are at least a bit stronger structurally used in that way.
- Andy Mc
-
9th August 2018, 12:49 PM #13New Member
- Join Date
- Feb 2018
- Location
- australia
- Posts
- 4
Yep, butt joined 😂
But only 4 of the 8 connections will require a dowel. As the table will be sitting against a wall corner the back two sides will be timber top to bottom, most likely rebate joined to the verticals, with the top horizontal rail attached to these firmly.
The reason I opted for dowel was because they’re hidden. As I said before would using a metal rod in place of a weak timber dowel be more beneficial?
-
9th August 2018, 03:59 PM #14
Metal? Not recommended. If you want to go that route I'd usggest dowels, then screw through from the other side, with the heads countersunk & plugged. They'll be hidden, right?
Why? Metal expands/contracts with temp changes more than anything. Timber, change in humidity is a bigger factor, although temp does affect things. So the metal and timber would move at different rates, eventually causing the glue to fail.
It's also one of the reasons why we try to make the loose tenons out of the same timber as the carcase they're going into. Using a different timber can have similar issues as different wood types have different movement rates. (Another argument against dowels in general. )
- Andy Mc
-
9th August 2018, 06:21 PM #15
Similar Threads
-
Strong structural joints using a mitre saw? What is possible?
By l2oBiN in forum WOODWORK - GENERALReplies: 7Last Post: 8th January 2016, 12:58 PM -
Mortise vs Dowel Joints for Chair
By kpphotos in forum WOODWORK - GENERALReplies: 5Last Post: 7th November 2014, 11:22 AM -
easy qn about dowel joints
By s_m in forum WOODWORK - GENERALReplies: 6Last Post: 3rd June 2007, 10:00 PM -
unglued M&T joints. Strong enough?
By antisense in forum WOODWORK - GENERALReplies: 22Last Post: 29th June 2005, 05:24 AM