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Hacksaw blade TPI

Updated: 21 October 2026

You fit a new blade, push, and the saw either grabs a tooth and jumps or sits there polishing a shiny line. Hacksaw blade TPI is the number that explains both failures. Teeth per inch decide whether the blade has enough gullet for the thickness in the vice. The [hacksaw comparison](/hub/power-saws/hacksaw) ranks frames. The stroke is [how to use a hacksaw](/hub/power-saws/hacksaw/sub/hacksaw-how-to-use). Figures come from those amazon.co.uk listings and from UK retailer guidance, dated 20 October 2026. We did not count teeth under a microscope. A qualifying purchase can earn a commission at no extra cost to you.

You fit a new blade, push, and the saw either grabs a tooth and jumps or sits there polishing a shiny line. Hacksaw blade TPI is the number that explains both failures.

Our top picks

Bahco Bahco 319 with Sandflex

Best overall

Bahco Bahco 319 with Sandflex
7.7/10about £16.99
View offer
Stanley Stanley 1-15-122 pistol grip

Rank 2

Stanley Stanley 1-15-122 pistol grip
8.1/10about £9.95
View offer
AIRAJ AIRAJ 300 mm, 10 blades

Best value

AIRAJ AIRAJ 300 mm, 10 blades
8.1/10about £16.99
View offer
On this page
  1. 1.What the number does to the cut
  2. 2.18, 24 and 32 on real jobs
  3. 3.Bi-metal blades, and numbers to ignore
  4. 4.If it still jumps or clogs

What the number does to the cut

TPI is how many teeth sit in one inch of blade. You want more than one tooth in the cut. When a single tooth drops into thin sheet, it catches on the return. Shark Blades, a UK seller, sets out the everyday rule of thumb for 300 mm bi-metal blades: 18 TPI for thicker bar, 24 TPI for typical tube and conduit, 32 TPI for thin sheet. Treat that as a shop rule, not as a timed test. A 32 TPI edge in the YSUY junior is not the red AIRAJ's 300 mm blade just because both cells say 32. Buy the length your frame takes, then the pitch.

18, 24 and 32 on real jobs

Use 24 TPI for 15 mm copper, steel conduit, a bolt and ordinary threaded rod. The Stanley 1-15-122 states 24 teeth on a 300 mm pistol-grip frame at £9.95. The Bahco 319 title also names bi-metal 24 TPI Sandflex. The contents line lists the frame only, and the table prints 18 TPI and 5.6 inches. If you want 24 TPI from that order, confirm the blade in the parcel. Use 32 TPI when a coarse tooth would drop through: sheet, a thin-wall cover, fragile trim. The red AIRAJ table says 32 TPI, with ten spare blades at £16.99. Use 18 TPI when a 32 TPI blade has gone shiny on thicker bar. No trustworthy title here leads with 18 TPI, so buy a separate 18 TPI blade for a frame you can tension. Frame choice is the hacksaw buying guide.
Bahco Bahco 319 with Sandflex

Testsieger

Bahco Bahco 319 with Sandflex
7.7/10about £16.99
View offer

Bi-metal blades, and numbers to ignore

For metal, bi-metal or high-speed steel is the specification UK trade listings describe. The listing data calls the Stanley blade high-speed steel. YSUY's material row says aluminium alloy, which is not a serious description of a toothed blade, so do not use that row to choose a pitch. A bundle is not a pitch. The black AIRAJ teeth cell says 10 because the title says ten blades. Eclipse's teeth cell says 192, which nobody fits in a 12 inch saw. WAIZHIUA's 32 TPI cell sits beside wood, glass and diamond edges. Those are not 32 TPI hacksaw blades. The Stanley box line does not include spares, so a 24 TPI refill is a normal follow-up, not a defect.

If it still jumps or clogs

Change pitch before you change brand. If a 24 TPI blade hooks in thin sheet, fit 32 TPI and ease the return. If a 32 TPI blade polishes bar, fit 18 or 24 TPI and let the teeth cut. If every pitch jumps, the work is loose or the blade is slack. Clamp it, and tighten until the blade does not twist under a light thumb. Gas pipe, live electrics and load-bearing cuts are not pitch problems. They belong to a Gas Safe engineer, an electrician, or the trade for that structure. If the teeth are right and the bow is simply the wrong length, that is junior hacksaw vs hacksaw.

Common questions

What TPI hacksaw blade should I buy first?
Buy 24 TPI in the length your frame takes, as a bi-metal or high-speed steel blade. That is the UK retailer rule of thumb for tube and conduit. Add 32 TPI if you cut thin sheet, and 18 TPI if you cut thicker bar. One blade of the right pitch beats a ten-pack of the wrong pitch.
Why does my hacksaw jump on thin metal?
The pitch is probably too coarse, so one tooth drops into the wall and snatches on the way back. Fit 32 TPI, clamp the sheet, and ease off on the return. Jump shows up in notes for widely reviewed frames, including the Stanley file of 6,672 reviews. A slack blade imitates the same fault.
Is 32 TPI better because it is finer?
It is better on thin material and worse on thick bar. The red AIRAJ's 32 TPI and ten blades suit sheet and light tube. They are a slow way through thicker stock. Finer is a match to thickness, not a quality score.
Are Bahco Sandflex blades always 24 TPI?
The 319 title pairs Sandflex with 24 TPI and a 12 inch frame. The same row prints 18 TPI, and the contents line names the frame rather than the blade. This listing does not prove that every Sandflex blade is 24 TPI, or that this parcel contains one. Buy the number you need, not the brand name alone.
What if the listing's TPI cell looks impossible?
Discard it. Eclipse's 192 and the black AIRAJ's 10 are not tooth pitches. They track a bad reading of the title, the way "13 inch" on the WAIZHIUA kit tracks the kit name. Where title and table fight, as on the Bahco 319, believe neither until you see the blade.
How often should I change the blade?
Change it when the cut stops moving unless you add pressure, or when teeth are missing. On one copper pipe a good bi-metal blade often finishes the job. On a run of conduit you may use more than one. These listings give no honest life in minutes, and we did not test it.

Related pages

Best hacksaw

Hacksaw

Hacksaw buying guide: frame size, tension and teeth

How to use a hacksaw: clamp, tension, straight push

Junior or full-size hacksaw for pipe, trim and gaps

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Listings captured 20 October 2026.

  1. HSE: Using the right type of PPE (retrieved 20 October 2026)
  2. HSE INDG271: work equipment selection (retrieved 20 October 2026)
  3. Shark Blades UK: Hacksaw blades (retrieved 20 October 2026)
  4. DTC UK: Eclipse hacksaw blades (retrieved 20 October 2026)
  5. GOV.UK trade tariff, heading 8202 (retrieved 20 October 2026)
  6. amazon.co.uk listings in this set (retrieved 20 October 2026)