$12.99 Each
In stock
Align it, clamp it, and fasten it to get perfect 90° angles every time!
  • Buy 4 for $11.69 each and save 10%

Rockler Clamp-It® Assembly Square

Item #
90% of 100
Here's a solution that's so simple, you'll wonder why it took so long to develop! The Clamp-It® replaces custom clamping jigs, acts as a third hand, and eliminates the need for long bulky clamps. Simply put, the Clamp-It® is a square you can clamp. In fact, you can even assemble a cabinet one corner at a time! Works with any joinery technique, from nails to hand cut dovetails.

It's ideal for every stage of construction, from assembling plywood cabinets to face frames and drawers. Clamp-It® is also perfect for framing decks and installing rails and balusters. Attach it to a work surface, and it becomes a right angle fixture for bench assembly. Clamp-It® is computer designed and manufactured from high impact, rigid polycarbonate to ensure strength and accuracy. Size of the Clamp-It® is 8" X 8" X 1 - 1/2".

Great for:

  • Drawer Assembly: Clamp-It® is designed for use on either the inside or outside of a corner, making it ideal for assembling drawers with lipped fronts.
  • Deck Rails: Use Clamp-It® to hold deck balusters at a perfect 90° angle while fastening.
  • Bench Jigs: Clamp-It® can be secured to any work surface to create a simple 90° assembly jig.
  • Clamp-It® Bar Clamps sold separately
(1) Clamp-It® Assembly Square
More Information
Brand Rockler
Weight 0.8000
Length 8"
Style Square
Prop 65 WarningWARNING: Cancer & Reproductive Harm - www.P65Warnings.ca.gov

4.5 / 5.0
389 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
The Clamp-it system is THE best!
I have tried all sorts of clamping systems to make boxes with true 90 degree corners. Each of them was deficient in some way or another. In desperation, I tried the Clamp-it system, and I was able to make a really nice box in a matter of a few minutes. You need one of these ahd one of the Clamp-it clamps. It helps to have two to work with so the work goes twice as fast.
August 21, 2019
6 months ago
Woodworking Experience:
Terriffic product
Great product!
August 7, 2019
1 month ago
Woodworking Experience:
An extra set of hands
The Clamp-it square works exactly like I expected it to. It’s simple design makes constructing a 90 degree angle easy. It’s something I use every day.
August 6, 2019
1 month ago
Woodworking Experience:
Use all the time —. For me a must have
July 28, 2019
6 months ago
Very happy
Very happy great addition to the shop
July 3, 2019
2 months ago
This works very well when building cabinets with pocket hole screws.
June 13, 2019
3 months ago
Woodworking Experience:
Perfect for assembly.
June 9, 2019
3 months ago
Woodworking Experience:
Complements the corner clamping jib
Works well with clamping jig. Don’ Know how it works on it’s own. Haven’t tried that yet.
June 3, 2019
3 months ago
Woodworking Experience:
great product - makes it easy to join parts square thanks
May 26, 2019
3 months ago
Woodworking Experience:
Handy to have several
I use these in all kinds of applications and they work quite well.
May 11, 2019
over 4 years ago
Woodworking Experience:
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 5 questions Browse 5 questions and 10 answers
Why did you choose this?
Rockler Store
Look like these will do the trick also, I'll see.
Ronald P on Aug 16, 2019
BILL on Aug 7, 2019
Look like these will do the trick also, I'll see.
Ronald P on Aug 16, 2019
Need an aid to square cabinet boxes.
Stephen J on Aug 14, 2019
BILL on Aug 7, 2019
Too go with my corner clamping bar
Lloyd B on Aug 5, 2019
Upcoming projects
Ronald S on Aug 2, 2019
Need to complete the Clamp-It® Corner Clamping Jig with Clamp-It® Assembly Square
Phillip S on Jul 19, 2019
Will help a lot with the small projects I have around the house.
Robert F on Jul 6, 2019
To complete Clamp-It Corner Clamping Jig set up
J.R. N on Jul 5, 2019
To help keep projects circular!
Rich C on Jul 2, 2019
For squaring modules
Michael A on Jun 28, 2019
Husband uses these on his projects.
Staci W on Jun 22, 2019
For future project
Thomas L on Jun 20, 2019
Easy to use
Mark J on Jun 19, 2019
Making some cabinets
Daniel P on Jun 16, 2019
Excellent method holding aggravating corners
Gary on Jun 16, 2019
It goes hand in hand with the corner clamp jig
Francis P on Jun 16, 2019
Great reviews and upcoming projects.
Roger R on Jun 14, 2019
It goes with the corner clamp
Debra B on Jun 14, 2019
Used them in the past easy to use. Lost my last pair in a move
MIKE K on Jun 14, 2019
after watching a short video on the use of the jig system this will help me on cabinet assy when working by myself
Donald Hauke A on Jun 12, 2019
quality merchandise
William S on Jun 10, 2019
making kitchen cabinets
Timothy F on Jun 9, 2019
Have 2 - Need to complete a full set - They work great
Jonathan D on Jun 1, 2019
Very useful when making chicken coop door frames.
Daniel W on May 31, 2019
To use with the Corner clamping jig
Chuck M on May 30, 2019
Jig 9+0 Degree Angle
Terry K on May 28, 2019
needed a few
craig h on May 26, 2019
I need it for the corner clamp I bought.
Mike D on May 25, 2019
You have to get one of these for every corner clamping jig. I wish they included this with the clamp
D O on May 22, 2019
Other Rockler jigs have been great!
Seth I on May 22, 2019
Squaring up some 2x6 legs for my son's bed frame.
Paul V on May 21, 2019
I will use this to compliment the corner clamping jig
Cornelius W on May 15, 2019
Assembling woodworking projects.
Robert R on May 10, 2019
I work alone most of the time this will be an extra set of hands or two
Rodney M on May 10, 2019
I feel that these squares will greatly improve my ability to make square corners in my woodworking projects.
Thomas W on May 7, 2019
I do a lot of projects that would require squaring up while adjusting something else - these look to be a time saver as well as KISS simple to use - we will find out
Louis S on May 6, 2019
look great hope they work well
don h on May 5, 2019
Lord knows I need to make 90 degree angles.
Andrea S on May 2, 2019
building a large cabinet this will really help
bob m on May 2, 2019
I saw a lot of positive comments on this so I wanted to give it a try.
Derek R on Apr 29, 2019
Have 2. 4 total would be handier
Rich on Apr 26, 2019
Adding them to my recently purchased corner clamping jig. Now have all 4 corners covered when making boxes.
Jim M on Apr 25, 2019
I currently own 2 of the assembly squares and the are invaluable since I always work by myself. I purchased 2 more just to make life a little easier.
Dorvan M on Apr 23, 2019
need a third hand in my shop when trying to screw wood together
vinny v on Apr 22, 2019
Easy to use
Doug K on Apr 20, 2019
lot of cabinet work
JOHN S on Apr 19, 2019
Part of the system for assuring joints are square.
Felix J B on Apr 19, 2019
works hand in hand with the corner clamping jig.
Edward H on Apr 19, 2019
just wanted to try it. I know two pieces of wood do same thing.
Donald C on Apr 18, 2019
Model railroading module
Stephen Erickson P on Apr 16, 2019
Need an aid to square cabinet boxes.
Stephen J on Aug 14, 2019
Too go with my corner clamping bar
Lloyd B on Aug 5, 2019
When should I use the Clamp-it Corner Clamping Jig vs. the Clamp-it Bar Clamps?
Jerry on Apr 28, 2017
BEST ANSWER: I work for Rockler. When the material is over 2" wide to be clamped, use the bar clamps. I fit is under the clamping jig works very well.
How many are in a package?
A shopper on Jul 29, 2015
BEST ANSWER: Just one. Clamps must be purchased also. Other clamps will work.
What are its complete mesures, 8"x8"x1.5"x?"...?
Carlos Otto C on Jun 21, 2018
What thickness of stock will this accommodate?
Ian L on Apr 14, 2019
BEST ANSWER: You can use this with any thickness of stock as long as you have a clamp that will open wide enough to clamp to it. If you are planning on using it with the fence clamps from Rockler you are limited to about 2 inches of thickness. You can also screw this to the stock which also allows for almost any thickness. It will usually support stock that is of reasonable size. I think I have used these to support 2.x4x3/4 inch plywood panels when making a set of shelves for my shop.
Does the screw holes line up to the holes in the clamp-it corner clamping jig ?
Larry K on Jan 16, 2019
BEST ANSWER: Yes, and the jig comes with the screws you need.