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Assembling Mitred Corners of a Box

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Forum topic by doitforfun posted 04-19-2014 at 05:07 PM 814 views 0 times favorited 16 replies Add to Favorites Watch
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doitforfun

153 posts in 244 days


04-19-2014 at 05:07 PM

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

bondogaposis

2498 posts in 988 days


#1 posted 04-19-2014 at 05:59 PM

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

gfadvm

10760 posts in 1327 days


#2 posted 04-19-2014 at 06:06 PM

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

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doitforfun

153 posts in 244 days


#3 posted 04-19-2014 at 06:45 PM

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

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gfadvm

10760 posts in 1327 days


#4 posted 04-19-2014 at 07:05 PM

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

squaretree

145 posts in 208 days


#5 posted 04-19-2014 at 07:06 PM

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

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squaretree

145 posts in 208 days


#6 posted 04-19-2014 at 07:09 PM

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

Airframer

2416 posts in 590 days


#7 posted 04-19-2014 at 07:29 PM

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.

EDIT:

You can see what I am talking about here http://lumberjocks.com/projects/98276 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 - http://theidiotgaloot.com

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NiteWalker

2710 posts in 1214 days


#8 posted 04-19-2014 at 07:32 PM

Any strong tape will work fine.

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

View Jim Finn's profile

Jim Finn

1660 posts in 1559 days


#9 posted 04-20-2014 at 07:19 AM

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.

-- In God We Trust

View shipwright's profile

shipwright

4942 posts in 1435 days


#10 posted 04-20-2014 at 08:05 AM

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 ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

View MontanaBob's profile

MontanaBob

419 posts in 1321 days


#11 posted 04-21-2014 at 03:31 AM

I’ve been using these clamp blocks, as shown by (rachet@LumberJocks.com). 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…

-- To realize our true destiny, we must be guided not by a myth from our past, but by a vision of our future

View ellen35's profile

ellen35

2566 posts in 2069 days


#12 posted 04-21-2014 at 03:38 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.
Ellen

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

View LeTurbo's profile

LeTurbo

148 posts in 222 days


#13 posted 04-21-2014 at 10:46 AM

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

MBD

42 posts in 522 days


#14 posted 04-21-2014 at 12:11 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

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Earlextech

962 posts in 1327 days


#15 posted 04-21-2014 at 12:25 PM

Masking tape – stretched. Never had a problem.

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

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