How To Cut Sheet Metal With Tin Snips
Content Menu
● Types of Tin Snips and Their Uses
● Handling Different Materials and Thicknesses
● Practical Cutting Techniques
● Shop Examples and Advanced Tips
Introduction
Working with sheet metal means dealing with cuts all the time, whether it’s trimming parts for assembly, fitting panels in place, or shaping material for prototypes. Tin snips remain one of the most reliable ways to handle those jobs, especially when you need something quick and don’t want to fire up bigger equipment.
These tools have been around in shops for years because they fit in your hand, go anywhere, and let you feel exactly what’s happening as the metal shears. In many fabrication setups, guys reach for snips first for thinner stock—things like 24-gauge up to 18-gauge steel, aluminum flashing, or stainless trim. They work well in spots where a shear or nibbler won’t fit, or when you’re out on a job site without power.
Over time, the basic design has improved with better leverage and grips, but the core idea stays the same: long handles to multiply your squeeze, short blades to focus the force right where it counts. Shops still keep multiple pairs around because different jobs call for different cuts—straight runs, tight curves, notches in corners.
This guide covers the practical side, from picking the right pair to making clean cuts without wearing yourself out. We’ll look at types, how materials behave, techniques that work in real situations, keeping hands safe, and fixing common problems. Plenty of shop examples along the way to show how these tools get used day to day.
Types of Tin Snips and Their Uses
Most shops stock a mix of snips because no single pair handles everything perfectly. Straight-pattern snips, the old-school kind, have blades in line with the handles and work best for long, straight cuts or very gentle curves in lighter material. For instance, when laying out a flat blank for a simple bracket out of 20-gauge mild steel, straight snips let you shear the whole length in one pass without much wander.
Aviation snips changed things with their compound linkage—multiple pivots that give extra mechanical advantage, so you can cut thicker or harder stuff with less hand strain. They’re usually color-coded: yellow for straight, red for left curves, green for right. In a typical automotive repair bay, a tech might grab green-handled snips to follow a clockwise arc on a replacement quarter panel, keeping the scrap curling away and the good part flat.
Offset versions angle the blades down, which keeps your hand above the work and prevents knuckles from dragging across sharp edges. Common in roofing crews cutting aluminum coil stock—offset snips slide along without scratching the painted surface.
Bulldog snips have short, stout blades for heavy notching, like punching out corners in 16-gauge plate for weld prep. Duckbill or hawk’s bill styles narrow to a point for tight inside radii, handy when patching holes in ductwork or tanks.
In one HVAC install I saw, the crew used a combination: straight snips for roughing duct sections, then left and right aviation pairs to radius the ends for fittings. Another case in custom enclosure building—offset left-cut snips for long seams on stainless boxes, avoiding distortion that shows up under finish.
Picking the right one comes down to the cut direction and material. Trying to force a straight pair into a sharp curve just twists the sheet and tires you out faster.
Blade Features That Matter
Blades on better snips are forged from tool steel, often with micro-serrations to bite into slick surfaces like galvanized or oiled stock. That grip stops the metal from sliding mid-cut, especially on curves. Some have induction-hardened edges that hold sharpness longer when working abrasive aluminum.
The shear angle is usually slight, around 10-15 degrees on aviation models, to progressive the cut and reduce peak force. Compound designs spread the effort over the stroke, which studies on hand tool forces show drops required grip strength by 40-50% compared to simple snips on the same gauge.
Handling Different Materials and Thicknesses
Gauge matters a lot—tin snips shine on thinner sheets where powered options overkill. Mild steel up to 18-gauge shears clean with compound snips; go thicker and edges burr heavy or blades separate.
Stainless fights back more because it work-hardens, so serrated aviation snips on 22-gauge keep things moving without excessive force. In food equipment shops, crews cut 24-gauge stainless for splash guards, relying on the serrations to prevent slip on oily surfaces.
Aluminum and copper yield easier, letting you push to 16-gauge or more with heavy models. Roofers often cut 0.032 aluminum flashing with offset snips, following roof lines without buckling the soft metal.
Layered work, like seamed duct with multiple 26-gauge wraps, compound snips handle in one pass if blades are sharp. Temperature plays in too—cold shops make steel brittle, so slight warming helps smooth cuts.
Always stay within rated capacity; forcing heavier stock dulls blades quick and risks hand strain over a shift.
Practical Cutting Techniques
Mark your line first—scriber for precision, marker for quick. Secure the sheet with clamps or magnets so it doesn’t shift mid-cut.
Open snips fully, slide material deep into jaws for best leverage. Full strokes on straight runs: keep lower jaw flat, advance steady. For a long panel edge in 20-gauge, yellow straight snips shear clean with even pressure.
Curves need shorter bites—cut an arc, reposition, repeat. Right-cut green snips on clockwise holes let waste curl clear. Alternate left and right pairs for S-curves in complex shapes like vent covers.
Notching corners: bulldog snips bite square reliefs for folds. Long sheets: offset keeps hands clear, good for full enclosure sides.
In prototype work, rough with straight, finish curves with aviation. Always cut outside the line a bit, clean up with file.
Shop Examples and Advanced Tips
Production lines often use snips for trim after main shearing—quick flash removal on stamped 18-gauge parts.
Aerospace techs cut thin aluminum skins with upright-handle snips for better reach in mockups. Architectural metalworkers use circle snips for ornate brass grilles, tight radii without warp.
Repair jobs like truck bed patches: bulldog notches around old rivets, then straight cuts new 16-gauge insert.
Combine with nibblers—snip to start hole, nibble interior. Balance hands by switching left/right on symmetric work to cut fatigue.
Shallow bites distort edges; deep jaw insertion keeps flat. Rotate stock instead of forcing awkward angles.
Safety and Ergonomics
Sharp edges and flying scraps demand gloves and glasses. Cut away from body, keep free hand clear.
Secure work—shifting sheets cause slips. Lock snips closed in pocket or holster.
Ergonomic studies show compound designs and cushioned grips reduce grip force needed, lowering repetitive strain risk over long sessions. Alternate tasks, stretch hands.
Inspect pivots regular—loose means poor control.
Maintenance Basics
Wipe blades after use, light oil on pivot. Sharpen with fine file when dull—follow bevel.
Tighten pivot bolt snug but free-moving. Store hung to avoid nicks.
Binding cuts: switch to proper type. Jagged edges: realign or replace blades.
Conclusion
Tin snips hold their place in shops because they deliver control and speed on everyday cuts without setup hassle. Getting good with them means matching type to job, using solid technique, and respecting limits on thickness and curves.
From duct fitting to custom panels, the right pair makes work cleaner and faster. Focus on grip comfort, safe habits, and sharp blades, and these tools serve reliably shift after shift. Practice on scrap, try different styles, and you’ll handle most sheet metal tasks confidently. Solid hand skills like this still matter plenty in modern fabrication.