Glueing up a cabinet- how do I keep square? / How to correctly use clamps?

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Forum topic by Prizen posted 10-19-2019 06:35 PM 1208 views 0 times favorited 15 replies Add to Favorites Watch
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40 posts in 2455 days

10-19-2019 06:35 PM

Hi all

I’m very much a beginner skill level, never really have much time to practise, having two small kids.

I’m trying to build a cabinet/wardrobe for my daughter’s bedroom, and am trying to glue up the base cabinet carcass.

I set the bottom piece, two sides and back on the bench.
I dowelled the two sides into the bottom piece and clamped the two sides down into the base. I couldnt keep the two sides square, but then I glued and screwed the back in, while trying to keep each side square while screwing.

I clearly don’t really know what I’m doing and would appreciate some beginner advice.


15 replies so far

View Woodknack's profile


12924 posts in 2915 days

#1 posted 10-19-2019 06:45 PM

They have a whole series on cabinet building, good stuff.

-- Rick M,

View wildwoodbybrianjohns's profile


429 posts in 83 days

#2 posted 10-19-2019 08:00 PM

Google “clamping squares.”

You can make your own, dont need to buy the woodpecker version.

-- Wildwood by Brian Johns: It is wiser to find out, than to suppose (S. Clemens)

View Prizen's profile


40 posts in 2455 days

#3 posted 10-19-2019 08:46 PM

Thanks both

View bilyo's profile


868 posts in 1638 days

#4 posted 10-20-2019 12:45 AM

Based on your description and lacking any photos, my guess is that the pieces you are putting together are not square. If you haven’t got one already, get a good framing square and check all the corners to make sure they are 90 degrees. If you start with all the pieces square the glue-up is almost automatically square. A quick check can be made by measuring between diagonal corners. Both measurements of opposite diagonals should be the same if they are square.

If you find that the work pieces are not square, then you need to examine your tools and methods to determine where the errors are happening. Check back with some specifics and we will be glad to help.

View hairy's profile (online now)


2962 posts in 4067 days

#5 posted 10-20-2019 04:10 PM

This might help

-- Genghis Khan and his brother Don, couldn't keep on keeping on...

View tomsteve's profile


975 posts in 1754 days

#6 posted 10-20-2019 04:37 PM

Google “clamping squares.”

You can make your own, dont need to buy the woodpecker version.

- wildwoodbybrianjohns

i made a set of 4 from scrap 3/4” baltic birch ply quite a few years ago. i love assembly aids that cost free fiddy. they work great.

View Prizen's profile


40 posts in 2455 days

#7 posted 10-20-2019 07:46 PM

I tried again today, although with a smaller box. This time I increased the number of dowels and just dry fit everything together.

The result is a while lot better now. It seems as though clamping put things out of square.

The dowels are such a tight fit that it looks like there’s no need for glue.

Sorry, I don’t have pictures, it would be a hell of a lot easier to show you each assembly.

View TungOil's profile


1343 posts in 1030 days

#8 posted 10-22-2019 02:31 AM


The dowels are such a tight fit that it looks like there s no need for glue.


- Prizen

Uhh…use a little glue anyway, especially if this is for a child. Better safe than sorry.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View Andybb's profile


2149 posts in 1139 days

#9 posted 10-22-2019 02:45 AM

Clamping squares free and easy.

-- Andy - Seattle USA

View waho6o9's profile


8785 posts in 3112 days

#10 posted 10-22-2019 03:24 AM

If the diagonal measurements are the same it’s square.

Top and bottom inside rails help.

Pinch sticks work. Picture is from Public domain.

Great advice above as well.

View MrUnix's profile (online now)


7499 posts in 2734 days

#11 posted 10-22-2019 04:29 AM

Another great free clamp for gluing up square stuff (book cases, boxes, cabinets, etc…) from Izzy:

Uses wedges instead of clamps, are self supporting and can be made from scrap you already have around the shop. Work great for corners as well as “T” joints (like for shelves – see video).

How to make wood Corner Clamps! by Izzy Swan


-- Brad in FL - In Dog I trust... everything else is questionable

View Kelly's profile


2462 posts in 3479 days

#12 posted 10-22-2019 06:12 AM

Not mentioned is, running a clamp diagonally to pull the cabinet square. To make that easier, I use 3/4” blocks with ninety degree V’s cut into the center to make it easier to clamp the corners.

I have several squaring clamps to because they are just as important as clamps.

View therealSteveN's profile


4079 posts in 1109 days

#13 posted 10-22-2019 06:36 AM

Even the most basic jig, clamp or fixture is also made by someone for sale. Huge market for this, ask Rockler

For my money having something to hold that first piece still, while I bring the other around is most important. The old “crossed dados on a 5×5 or so piece of ply, MDF, some kind of 3/4” thick sheet good is quick and easy, but they can get

But for really great holding power, and on bigger pieces of plywood I really like these also from Fascap. The FastCap - Hands Free Upright Kiss Clamp System

This would be easy to make at home, but you would need to see one first to get the angles right. I can say they work like a charm.

-- Think safe, be safe

View Kelly's profile


2462 posts in 3479 days

#14 posted 10-22-2019 05:03 PM

A reminder: You can make “L” brackets using plywood, like above or, like some of mine (I have different sizes) use the heavy, metal “L” brackets sold in hardware stores. Too, there are the Strong Tie type that have a ninety degree bend to make otherwise flimsy metal pretty strong.

View AlaskaGuy's profile


5414 posts in 2844 days

#15 posted 10-22-2019 06:00 PM

What I have learned after clamping up hundreds of cabinet boxes over 40 + years is learn how to cut truly square parts. If your parts are square and you assemble on a flat surface you cabinet will be damn near perfect everytime. If you have to force a cabinet box very much into to square because of un-square parts you are going to put a twist in the box.

Sometimes depending on the cabinet I’ll use home made clamping squares hole it square while the glue sets. Like this 3 sided box.

Lots of good advice in this thread. There is more than one way to skin a cat.

-- Alaskan's for Global warming!

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