Fireball Tool · Mutant Square Series
Mutant Square V-Groove 8" — Cast Aluminum
Everything fabricators like about the Mutant Square — true 90° corners, a 45° angle and a wide-open cutaway for weld access — now with a V-groove on the outer wall for squaring round tubing from 1/4" to 4" diameter. All in a lightweight 8" aluminum body that rides along in the truck or tool bag.
- True 90° corners plus a built-in 45° angle
- Open cutaway corner keeps the joint clear
- Outer-wall V-groove squares 1/4"–4" round tubing
- Lightweight cast aluminum
- Tool-less tabs mount front or back
- Compact 8" size for tight assemblies
What's new
Square up round tube from 1/4" to 4".
Flat squares are great until the part is round. A V-groove machined into the outer wall gives round tubing two contact points to settle into, so it seats square to the tool and stays put while you fit and tack it. Same 8" Mutant you know, now ready for round stock.
- Fits 1/4" to 4" diameter round tubingOne groove covers everything from small rod and tube up to 4" round.
- Tube-to-tube and tube-to-flat jointsSquare round tubing to flat bar, square tube or plate without chasing it across the table.
- Railings, gates and framesHold round pickets, handrail and uprights steady for tacking.
How the Pros Use It
One square, three jobs it does better than a plain angle block.
Keep the joint open
The included L-tab clamps your parts in place while staying clear of the corner, so you can lay a bead without the fixture in the way. Use different holes in the tab for miter or butt joints.
Reach inside corners
The square locks in a true 90°, and the cutaway leaves room for your torch or gun to get right into the inside of the joint.
Hold it square start to finish
From fit-up to final weld, the square keeps both pieces aligned — round tube included — so the frame comes off the table the way you laid it out.
Specifications
Built on Fireball's C-channel profile with an offset web, so the edges stay usable for indexing off your work.
| Model | Mutant Square V-Groove 8" |
|---|---|
| Material | Cast aluminum (AL) |
| Overall size | 8" x 8" x 1.5" |
| Flange | 1.5" |
| Weight | Approx. 2 lb |
| Angles | 90° corners & 45° angle |
| V-groove | On outer wall; squares round tubing 1/4" to 4" diameter |
| Profile | C-channel with offset web |
| Includes | 5 edge location tabs, 4 tool-less thumbscrews |
| Origin | Made in USA |
Why Cast Aluminum?
The aluminum Mutant is the one you grab when the square has to travel. Here's what to expect.
Built for
- Mobile rigs, field repairs and tool-bag setups where weight matters
- Cast construction holds its shape better than squares cut from standard aluminum billet
- A light natural resistance to weld spatter
Good to know
- Not intended for heavy loads or repeated hammer impacts
- Aluminum can dent if dropped, so store it where it won't take a fall
What's in the Box
Edge Location Tabs
- Index the square off the edge of your parts in seconds
- Mount on the front or back of the square
- Get accurate setups even without a flat fixture table
Tool-less Thumbscrews
- Finger-tighten the tabs, no hex key needed
- Quick adjustments between setups
- Nothing extra to keep track of on the job
Optional add-on
Edge Alignment Pins
Snap them onto the square for an overhanging edge you can register against a second surface.
- Set the square at 90°, 45° or parallel to an edge
- Hang it off a table edge for vertical or perpendicular setups
- Lift the square off the surface for extra clearance on full frames
- Pair with shims to mark evenly spaced parallel lines