Assembling Mitred Corners of a Box

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Forum topic by doitforfun posted 04-20-2014 12:07 AM 1805 views 0 times favorited 16 replies Add to Favorites Watch
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199 posts in 2892 days

04-20-2014 12:07 AM

I’m working on a project that I will share when I’m done. Its a lamp where the shade is box with mitred corners. I had so much trouble assembling this thing. I finally stuck it between my saw fence and a block of plywood stuck in the mitre guage slots. I’m afraid the joints may fail because I was completely unable to apply steady pressure to them with a clamp. I guess its kind of late now since I already assembled it, but if it does fail I’d like to sand off the glue and try it again. What’s the best way to put this together?

Here’s a picture that shows the joints and pretty much how I got it assembled.

-- Brian in Wantagh, NY

16 replies so far

View bondogaposis's profile


6067 posts in 3635 days

#1 posted 04-20-2014 12:59 AM

I use band clamps for that that sort of glue up. There are a lot of specialized clamps for boxes that specifically address that very problem. Generally you need a clamp that applies pressure to all sides at once.

-- Bondo Gaposis

View gfadvm's profile


14940 posts in 3974 days

#2 posted 04-20-2014 01:06 AM

I tape across the joints with blue tape to hold it together, then apply ratchet straps (or band clamps if you have the extra cash for them). Then measure the diagonals before setting them aside for the glue to dry to make sure they are square.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View doitforfun's profile


199 posts in 2892 days

#3 posted 04-20-2014 01:45 AM

Thanks. I don’t have time or money for band clamps at the moment. I’m sure I could make something similar.

By the way so far it’s holding although the mitres aren’t as tight as I’d like. Part of that is due to some tear out at the very edge. It’s red oak.

-- Brian in Wantagh, NY

View gfadvm's profile


14940 posts in 3974 days

#4 posted 04-20-2014 02:05 AM

Ratchet straps work as well as the band clamps just not quite as convenient to use.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View squaretree's profile


160 posts in 2855 days

#5 posted 04-20-2014 02:06 AM

Brian, i seen someone post a homemade bandclamp they made out of a ratchet strap.

I like the design of this lamp shade, by the way. I cant wait to see the finished product.

-- if you can't find me, just follow the extension cord

View squaretree's profile


160 posts in 2855 days

#6 posted 04-20-2014 02:09 AM

Didnt see your post there, gfadvm. Sorry for the echo

-- if you can't find me, just follow the extension cord

View Airframer's profile


3117 posts in 3237 days

#7 posted 04-20-2014 02:29 AM

A rope tied around the box with a dowel or stick used to twist the rope increasing the clamp pressure works just as good and everyone has some kind of rope laying around. Once the desired pressure is reached just clamp a stop block next to the stick to keep it from unwinding before you want it to.


You can see what I am talking about here Yuri used it on his tool cabinet build. Just scroll about halfway down his description and you will see a pic of the process.

-- Eric - "I'm getting proficient with these hand jobbers. - BigRedKnothead"

View NiteWalker's profile


2743 posts in 3861 days

#8 posted 04-20-2014 02:32 AM

Any strong tape will work fine.

-- He who dies with the most tools... dies with the emptiest wallet.

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Jim Finn

2904 posts in 4206 days

#9 posted 04-20-2014 02:19 PM

When I do this kind of construction I always put a gusset inside each corner with plenty of glue. I pin nail it in place to hold the gusset in place until the glue sets.

-- No PHD just a DD214 Lubbock Texas

View shipwright's profile


8760 posts in 4082 days

#10 posted 04-20-2014 03:05 PM

If your mitres fit all you need is the tape. Blue masking tape works well but if you want to be able to inspect the fit at the corners you can use clear packing tape. Clamping in cases where the fits are good is overemphasized. If the pieces touch the glue will get it done. If they don’t, you need clamps.

If you want to add a little pressure you can wrap bungee cord around it. A length of it is cheaper than band clamps.

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese!

View MontanaBob's profile


874 posts in 3968 days

#11 posted 04-21-2014 10:31 AM

I’ve been using these clamp blocks, as shown by ([email protected]). I’ve made them several sizes. Works fast easy. I’d probably use a band strap around the middle of a piece this size, to make sure everything was tight…

View ellen35's profile


2750 posts in 4716 days

#12 posted 04-21-2014 10:38 AM

Doug Stowe, a master box maker (we have many master box makers on LJ too), turned me on to packing tape. Check out his website, books or articles. It is simple and costs nothing to do. It works great too.

-- "Don't let the perfect be the enemy of the good." Voltaire

View LeTurbo's profile


234 posts in 2869 days

#13 posted 04-21-2014 05:46 PM

Here’s a cunning trick I picked up recently. Dry assemble the joint by clamping it to a strap hinge (those ones with long sides). You can now open the joint to apply your glue, and close the joint again in the exact position you’d dry-fitted it. You can then apply a strap, or even rope (put a stick through a loop and twist to tighten).

View MBD's profile


72 posts in 3169 days

#14 posted 04-21-2014 07:11 PM

I glue all of mine up the same way Shipwright and qfadvm do theirs. Most of the time, blue tape or duct tape is enough to hold until the glue dries. Look at Andy’s art box blog, he explains this procedure well.

-- Matt, Mississippi

View Earlextech's profile


1164 posts in 3974 days

#15 posted 04-21-2014 07:25 PM

Masking tape – stretched. Never had a problem.

-- Sam Hamory - The project is never finished until its "Finished"!

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