Monster Square

(52 reviews) Write a Review


  • Monster Square
  • Monster Square
  • Monster Square
  • Monster Square
  • Monster Square
  • Monster Square
Frequently bought together:


The original Monster Square is available in a 12 or 8 inch size with two material choices: Cast Iron (FE) or Cast Aluminum (AL). All Monster Squares feature a stiff “flange and web” design that is fully machined on all outer edges with tapped holes on the sides for mounting tabs.

Made in USA, Patent Pending

Designed to quickly set your work-piece to 90 or 45 degrees

Speed squares and machinist squares are made for visual inspection and checking AFTER setup, the Monster Square is designed to get those parts square in the first place.

Tabs help eliminate twisting and warping in the final work-piece

The machined squares and tabs always create the perfect plane for your work-pieces to rest on. Bonus: The tabs also let you easily hold round tubing.

Clamping is simple with multiple surfaces for quick and rigid attachment

Stop spending your time and focus figuring out clamping strategies, or worse, clamping your straight work-piece to crooked surfaces.

Use the radius on the tabs to use the Monster Square as a traditional speed square for layout.

Flange & Web

  • 12” squares have a profile similar to an I Beam where the web is centered on the flanges.
  • 8” squares are similar to a “C” channel where the web is off to one side of the flange.

Customer Reviews
"I love these squares I'm planning to buy a few more. Especially the adjustable angle square. I'm an artist and have difficulty angles to weld or figure out. These squares help to ensure one step of a process will be free of errors. Thank you for creating these squares."
Alma L.
"I’ve had this square for not long at all and already I’ve used it a ton! Either at work at a fabrication shop or at home doing side work. It makes getting things square the first time so effortless, no more cutting tacks and re-squaring!"
Patrik K.


Monster Square 12"

For tubing 2 inch and larger, we suggest 12” squares (3” wide)

Monster Square 8"

For tubing 2 inch and smaller, we suggest 8” squares (1.5” wide)

Size (in) Weight (lbs) Material Flange (in)

Monster 12" FE

12" x 12" x 3"


Cast Iron


Monster 12" AL

12" x 12" x 3"


Cast Aluminum


Monster 8" FE

8" x 8" x 1.5"


Cast Iron


Monster 8" AL

8" x 8" x 1.5"


Cast Aluminum


Cast Iron


  • Great for heavy duty projects
  • Excellent resistance to deformation and raising burrs when scratched.
  • Some natural resistance to weld spatter.


  • Heavy (Not ideal for mobile welding)
  • Susceptible to rust.

Included Accessories

4 Edge Location Tabs

Our revolutionary tabs allow you to align your material up so that you don’t even need a welding table! Don’t spend thousands on a flat table, just use our squares! Tighten the tabs onto the front or back of your square and you can immediately get to work. Sure, there are different jigs out there, but can they line your material perfectly in seconds?

4 Tool-less Thumbscrews

But it doesn’t stop there. We reinvented the game by introducing our thumbscrews. Say goodbye to your hex keys and Allen screwdrivers and freely adjust the tabs with only your fingers!

Optional Add-ons

Edge Alignment Pins

Install our edge alignment pins on any square to create a large, overhanging edge which can be used to index the square on a different plane. Depending on the square, this allows you to create edges which are 90 degrees (perpendicular), 45 degrees, parallel, and even 60 and 30 degrees from the edge.

  • Use it with our Monster squares to create a speed square for layout.
  • Use it to hang the square off the edge of a table for working vertical or perpendicular to table surface
  • Use it to elevate the squares off the ground or table for extra clearance when you’re fitting and welding entire frames
  • Tip! If trying to create a parallel edge with the mega square for marking, use our shims to get that perfect distance!

What is Black Oxide?

Black Oxide, blackening, oxidizing, oxiding, black passivating, gun bluing . . . these terms all refer to the process of forming a black iron oxide on the surface of ferrous metals.

The black oxide process is a chemical conversion coating. This means that the black oxide is not deposited on the surface of the substrate like nickel or zinc electroplating. Instead, the black oxide coating is produced by a chemical reaction between the iron on the surface of the ferrous metal and the oxidizing salts present in the black oxide solution. These oxidizing salts include penetrates, catalysts, activators and proprietary additives which all take part in the chemical reaction. The result of this chemical reaction is the formation of black iron oxide, magnetite (Fe3O4), on the surface of the metal being coated. Black oxide has a range of unique properties and benefits including corrosion protection & reduced friction.

Our Other Square

  • The Mega Square is designed to quickly set your workpiece to 90 or 45 degrees.
  • Tabs help eliminate twisting and warping in the final workpiece.
  • Clamping is simple with multiple surfaces for quick and rigid attachment.
  • Roomy joint access for welding, gluing, nailing, riveting, etc.
  • Use it as an ordinary, adjustable angle square that adjusts from 40 to 180 degrees.
  • Right Angle 90 Degree Square with generous weld accessibility. Total height of 8” in this configuration.
  • Tall 12” square when fully opened and locked into place
  • Remove the fasteners to get two individual squares
  • Use the large V-groove to hold large round tubing or pipe
  • Compact configuration for use in tight spaces.
  • 6" x 4" x 1.5", the 4" width is perfect for picket spacing on gates and fences.
  • They are the first square we offer which has a built in 60/30 degree angle.
  • The cutout provides just the right amount of joint access when using it to clamp things at 90 degrees.  
View AllClose

52 Reviews

  • 5
    8” Aluminum monster square

    Posted by SC on Mar 3rd 2021

    Seems all built and super fast shipping to California.

  • 5

    Posted by William Foltz III on Feb 25th 2021


  • 5

    Posted by Jereme Huss on Feb 18th 2021

    By far the best square you could ask for. I've heard a lot about fireball tools and always thought about getting one and now that I have one I don't know why I didn't get it sooner. I was actually going to get one of the package deals but they were sold out or back order I don't remember. But I will be order the package deals

  • 5
    Monster Square

    Posted by Dolores Torrez on Feb 17th 2021

    Our metal team loves the Monster Square! It has been a great addition to the tool collection and the best tool for finished professional project.

  • 5
    8" monster squares

    Posted by chipper chipps on Feb 13th 2021

    4 foot by 12 foot 2x2x1/8 tube rectangle using 8" monster square cross measurements where only 1/32 out thanks

  • 5

    Posted by Natanial Wenrich on Feb 11th 2021

    This is best looking tool I have ever owned!

  • 5

    Posted by Sonny Quinn on Feb 3rd 2021

    Arrived and immediately put into use. Hobbyist/tinkerer welder, a must have even for me. So much better than those red magnets! Thank you

  • 5
    Perfect Tool for the Job

    Posted by Bryan on Jan 27th 2021

    I saw this tool demonstrated on YouTube and thought, "What a great idea!" Since I don't have a welding table yet, I build things on the shop floor. The red magnets that are very popular are great for some things but this tool is what you want when it needs to be square. If you haven't watched the videos, do that first then buy this tool and a couple of clamps. You won't regret it. Seriously, it's that good.

  • 5
    fireball monster square

    Posted by Ebbin Martin on Jan 22nd 2021

    awesome square. has immediately improved the quality of the things im making

  • 5
    12" Aluminum Monster Square

    Posted by Stephen Wilson on Jan 4th 2021

    This product performed better than expected. I followed Jason's technique as I built a 2x2 frame for my metal work table and it was spot on. Thx

  • 5
    Monster Square

    Posted by Mark Maxwell on Dec 19th 2020

    Great tool. Well made and performs as advertised.

  • 5
    Excellent addition

    Posted by Dan on Dec 12th 2020

    This is a wonderful tool to add to your shop. I was struggling as a new welder to get things square for my table, and this made it easy much less frustrating.

View AllClose
Read more: