How to read and use a feeler gauge (and check its accuracy)
Each feeler gauge leaf is stamped with its thickness. Read the number, find the leaf that slides through with a light drag, and check the set's accuracy.
Material guide
Steel & stainless
What works on steel and stainless: the right drill bit and speed, cutting tool, epoxy, screws and rust prep, plus how to handle hot chips and sparks.
Quick facts
- Magnet test
- Plain steel pulls hard. 304 and 316 stainless are generally non-magnetic, but may pull a little after bending.
- Drill speed (HSS bit)
- Mild steel ~100 ft/min, about 1,500 rpm for a 1/4 in bit. Work-hardening stainless ~20 ft/min, about 300 rpm.
- Best drill bit
- Sharp HSS for mild steel; cobalt for stainless and Grade 8 bolts; carbide for fully hardened tool steel
- Best cutter
- Angle grinder with a cut-off wheel; metal-cutting circular saw for long straight cuts
- Best glue
- Two-part steel epoxy, e.g. J-B Weld: cures in 15 to 24 hours, rated to 550°F
- Before paint
- Wash, then wire-brush or power-tool clean loose rust and scale
Steel is iron with a little carbon. Plain steel is strong, cheap and magnetic, and it rusts. Stainless steel adds chromium, often with nickel, so it resists rust.
Steel is tricky because it's harder than wood and holds heat. A bit spun too fast gets hot, dulls and stops cutting. Stainless is worse. If the bit rubs instead of cuts, the metal hardens right under it. The fix is a sharp bit, slow speed, steady pressure and cutting oil.
Cutting and grinding throw hot chips and sparks. Fresh edges are sharp as a knife. And bare steel starts to rust soon after you cut or sand it, so plan to prime it.
Drill into steel & stainless
Center-punch the spot so the bit won't wander. Use a sharp HSS bit at low speed with cutting oil: about 1,500 rpm for 1/4 in in mild steel. For stainless, use cobalt, go slower, and keep steady pressure so the bit cuts instead of rubbing.
What to use: Cobalt bit set + cutting oil
Guides
- Best drill bit for hardened steel: cobalt or carbide?
- What is a drill bushing?
- How to remove a broken drill bit from metal, wood or concrete
- What is drill rod? Grades, sizes and what it's used for
- What is a magnetic drill (and when a DIYer needs one)
- How to drill into metal: speed, pressure, and the right bit (coming)
- How to drill stainless steel without work-hardening it (coming)
- Cobalt vs titanium vs black oxide drill bits (coming)
- Step bit vs twist bit for sheet metal (coming)
- Drill bit just spins or squeals on metal: what's wrong (coming)
- Do you need cutting oil? (And what to use instead) (coming)
Cut steel & stainless
For one or two cuts, use an angle grinder with a cut-off wheel and the right guard. For long, straight cuts, a metal-cutting circular saw is cleaner. Use a hacksaw with a fine-tooth blade for small jobs, and tin snips for thin sheet.
What to use: Angle grinder + Type 1 cut-off wheel and guard
Guides
- How to cut 1/4-inch steel plate at home
- Can a miter saw cut metal or aluminum?
- Table saw vs miter saw vs chop saw: which one do you need?
- What is a portable band saw used for?
- How to cut metal at home: grinder, recip saw, chop saw, or snips (coming)
- Angle grinder disc types: metal, tile, concrete, flap, wire (coming)
- Cut rebar, bolts, and threaded rod cleanly (coming)
- Tin snip colors explained (red, green, yellow) (coming)
Glue steel & stainless
Use a two-part steel epoxy. Clean off grease, then rough up both surfaces with a file or coarse sandpaper. J-B Weld sets in 4 to 6 hours and cures in 15 to 24. Let it cure fully before you load the joint.
What to use: Two-part steel epoxy
Guides
- J-B Weld vs epoxy vs welding: when glue is enough (coming)
- How long does J-B Weld take to cure? (coming)
- Does Gorilla Glue work on metal? (coming)
- Heat-resistant glue for metal and ceramic (coming)
- Best glue for plastic to metal (tested) (coming)
- Glue for rubber to metal and rubber to rubber (coming)
Screw or anchor into steel & stainless
For thin sheet steel and metal studs, use self-drilling screws with a drill point rated for the thickness. For thicker steel, drill and tap the hole for a machine screw, or bolt through. Rivets join thin sheets for good.
What to use: Self-drilling screws for sheet; bolts or tapped holes for plate
Guides
- How to remove a snap ring without pliers
- How to remove a spanner nut without the spanner wrench
- Self-tapping vs self-drilling screws (not the same thing) (coming)
- How to screw into a metal stud (coming)
- Pilot hole sizes for sheet metal screws in steel and aluminum (coming)
- Tap drill chart for DIY (SAE and metric) (coming)
- How to remove a rivet (and pick the right pop rivet size) (coming)
Sand or finish steel & stainless
Wash off grease first. Then remove loose rust, scale and old paint with a wire brush, sandpaper or a power tool, and sand glossy paint so primer can grip. Prime bare steel soon after, before new rust starts.
What to use: Wire wheel or flap disc, then rust primer
Guides
- How to drain and clean an air compressor tank safely
- Remove rust from tools (vinegar, Evapo-Rust, wire wheel: tested) (coming)
- Flap disc grit guide for metal (coming)
- Steel wool grades chart (0000 to 4) (coming)
- Sandpaper grit chart: which grit for which job (coming)
More steel & stainless guides
How to use a torque wrench (and how it works)
Set the handle, pull slowly at a right angle, stop at the click. How click, beam and digital torque wrenches work, plus storage and calibration rules.
How to sharpen a titanium-coated knife (without wrecking the coating)
A titanium-coated knife is steel under a very thin coat, so you sharpen it like steel. Use a stone or hand sharpener at 15 to 20 degrees; spare the flats.
How to organize a toolbox so you can find every tool
Empty it, sort by job, give every tool one home, and keep heavy tools low. A simple toolbox system for hand boxes, rolling chests and stack-up kits.
Safety basics
- Protect your eyes and face. Wear safety glasses, and a face shield when you grind or cut.
- Clear what can burn. Sparks travel far. Move rags, sawdust and fuel away from the work.
- Clamp the work. A bit can grab thin steel and spin it like a blade.
- Wear gloves for handling, not drilling. Edges and chips are sharp and hot, but gloves can catch in a spinning bit.
Sources
- Magnetic effects of stainless steels (Australian Stainless Steel Development Association)
- EML2322L Drilling speeds and feeds: HSS surface speeds by material and the rpm formula (University of Florida, MAE Design Lab)
- ELITE SERIES 1/4 in. cobalt alloy steel pilot point drill bit: for stainless steel and hard metal (DeWalt)
- Center punches: use before drilling to keep the bit from wandering (McMaster-Carr, Starrett)
- DeWalt DWE4012 angle grinder manual: cutting with a Type 1 wheel and Type 1 guard (via ManualsLib)
- Evolution S185CCSL metal-cutting circular saw: max mild steel plate 5/16 in
- Klein Tools hacksaw blades: 18 teeth per inch
- J-B Weld Original twin tube: bonds metal, 6,220 psi, sets 4-6 h, cures 15-24 h, to 550°F; clean, degrease, roughen (J-B Weld)
- General construction products catalog: Teks self-drilling screws, drill point capacity by steel thickness (ITW Buildex)
- Stops Rust primer technical data SRT-11: wash, then scrape and wire brush or power tool clean steel; sand glossy coatings; lead dust warning (Rust-Oleum)
- OSHA 29 CFR 1910.133: eye and face protection
- OSHA 29 CFR 1910.252: welding, cutting and brazing, fire prevention