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Positive rake, 40CrMo, and a chip breaker

GBJ GBIUO-48EF156, three holders with TCMT inserts

Three holders rather than seven, with the two things this hub’s buying tip asks for both published: a positive rake and a built-in chip breaker.

GBJ three indexable lathe turning tool holders with TCMT inserts

GBJ GBIUO-48EF156, three holders with TCMT inserts

Three holders rather than seven, with the two things this hub’s buying tip asks for both published: a positive rake and a built-in chip breaker.

Amazon reference
B0D4C8H9PX
EAN
0797999724115
  • States a positive rake cutting angle and a built-in chip breaker — exactly what this hub’s buying tip calls for on a small machine
  • Publishes the holder steel, 40CrMo, with a black oxide finish
  • Three holders: no threading, grooving or parting tool

Best for: External turning and facing on a light lathe, where three holders cover the work

≈ $23
Check price on Amazon

Specifications

Amazon reference
B0D4C8H9PX
EAN
0797999724115

Three holders is a deliberate choice rather than a cheap one. AL-8 and AR-8 are left and right external turning holders and the E-8 covers the third common job, which between them is most of what a bench lathe does to the outside of a part. What you give up is threading, grooving and parting — the seven-piece sets on this shelf cover those, mostly with one insert each.

The two specifications that matter here are both published, and they are the two this hub’s buying tip is about. The inserts have a positive rake cutting angle, which is what lets a light machine cut rather than rub, and a built-in chip breaker, which turns a hot steel ribbon into chips that fall away. At least three of the thirteen listings on this shelf state either; this one states both.

The holder steel is named — 40CrMo, black oxide — rather than being called cemented carbide as it is on three other pages here, and the insert is identified as a TCMT32.51, so a replacement can be ordered from the page. A TCMT is a 60-degree triangle: stronger than the 35-degree rhombus on the Hunricho listing and correspondingly less able to reach into a corner. Two typographic slips in the text are worth a mention only because they are in the title and the first bullet: “Repalcement”, and three “trox” keys.

Availability

Read on the day this page was built: $30 at the American Amazon shop.

Read from Keepa on the day this page was last revised; stock and price both move without notice.

Prices quoted in this text were read on 2026-10-07. The live price is at the top of the page.

The questions welders ask

Why does positive rake matter on a small lathe?

Because a negative-rake insert needs force this hub’s machines do not have. This shelf’s buying tip says it directly: negative geometry requires depth of cut and rigidity a bench machine lacks, so it rubs and chatters instead of cutting. A positive-rake insert with a chip breaker shears a curl of metal at light depth with far less force. Three listings on this shelf state positive rake; the rest say nothing about geometry at all.

What is a chip breaker for?

Turning a ribbon into chips. Without one, steel comes off as a continuous hot spring that wraps round the work, the tool and occasionally the operator; a ground step on the top face of the insert curls the chip tightly until it breaks. On a small lathe, where you are standing close and the guard is minimal, it is a safety feature as much as a cutting one — and it is stated here.

More lathe tooling

  • Joogto 21-piece indexable turning kit with 10 mm shank holders

    Joogto 21-piece 10 mm kit

    The same seven-tool spread built on a 10 mm (0.39 in) shank rather than 12 — which is the size most small bench lathes actually take.

    Amazon reference
    B0BYZJG3BW
    EAN
    0602835344252
    • A 10 mm (0.39 in) shank, which is what most 7 by 12 and 7 by 14 bench lathes are tooled for
    • Names all seven holder designations, every one of them in the 1010 and 0010 series
    • Claims its holders are "crafted from cemented carbide and tungsten steel", which no holder on this shelf is

    Best for: A mini lathe whose tool post will not close on a 12 mm (0.47 in) shank

    ≈ $46
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  • KinRite seven indexable lathe turning tool holders with inserts fitted

    KinRite Seven-holder 1/2 in set with C6 TiN inserts

    The only listing on this shelf to publish a holder hardness — HRC 48 — in the same sentence that calls the holder cemented carbide.

    Amazon reference
    B09CHDVNZ3
    EAN
    0706926112284
    • Publishes a hardness figure for the holders, around HRC 48, which no other listing here does
    • Publishes the lengths: two 150 mm (5.91 in) boring holders and five at 100 mm (3.94 in)
    • Describes the holders as "quality cemented carbide and tungsten steel（40CrMo）" — 40CrMo is an alloy steel, and HRC 48 is a steel hardness

    Best for: A 12 mm (0.47 in) tool post, where the boring holders’ length and lead angle are the deciding figures

    ≈ $40
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  • LYMMIYTC 21-piece indexable lathe turning tool kit

    LYMMIYTC SDJCR1212H07, 21-piece 12 mm kit

    A seven-holder kit indistinguishable on its published data from the VERFUTHL kit above it — down to an invalid holder code both listings print.

    Amazon reference
    B0CQPBNQG9
    EAN
    0756593187764
    • Names all seven holder designations
    • Fourteen inserts for seven holders, with eight matched wrenches
    • Its own contents add to twenty-nine under a "21Pcs Kit" heading

    Best for: The same 12 mm (0.47 in) tool post, at whichever of the two prices is lower on the day

    ≈ $39
    Check price on Amazon

Elsewhere in the workroom

  • Milwaukee 5-3/8 inch carbide metal cutting circular saw blade

    Milwaukee 48-40-4205, 5-3/8 in 30T carbide

    A cold-cut blade for a cordless metal saw, with cobalt in the carbide and vibration slots in the plate — and no arbor size, kerf or speed rating published.

    Amazon reference
    B0B4PBQ93R
    EAN
    0045242569199
    • Cobalt-infused tungsten carbide stated, which is a tougher grade than plain carbide for ferrous work
    • Laser-cut vibration damping slots in the plate, stated to reduce heat and noise
    • No arbor size published, on a circular blade — the one dimension that decides whether it fits

    Best for: A cordless metal-cutting circular saw on steel and stainless, where a cool, burr-free cut is the point

    ≈ $35
    Check price on Amazon
  • TOLESA 6 inch bi-metal reciprocating saw blades, five in a pack

    TOLESA T16141M, 6 in 14 TPI, 5-pack

    A five-pack of bi-metal blades that applies this hub’s three-teeth rule for you — it publishes the sheet thickness and the pipe diameter the pitch suits.

    Amazon reference
    B089NWRKYJ
    EAN
    0630808000010
    • Publishes the material range the pitch is for — 2 to 8 mm (0.08 to 0.31 in) sheet, solid pipe and profile under 4 in
    • Publishes the body thickness, 0.9 mm (0.04 in), which decides whether the blade wanders or snaps
    • A 14 TPI pitch is for thin and medium work; solid bar wants a coarser blade and this hub says so

    Best for: Cutting 2 to 8 mm (0.08 to 0.31 in) sheet and small pipe with a reciprocating saw

    ≈ $13
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  • TOLESA 9 inch bi-metal reciprocating saw blades, five in a pack

    TOLESA T19142M, 9 in 14 TPI, 5-pack

    The long version of the same blade, and the only figure that changes is the one that matters — the pipe diameter it will cut through in one pass.

    Amazon reference
    B089NV972C
    EAN
    0630808000027
    • Publishes the pipe diameter it will cut — under 7 in, against under 4 in for the maker’s 6 in blade
    • Same published material range for sheet, 2 to 8 mm (0.08 to 0.31 in), and the same 0.9 mm (0.04 in) body and 8 per cent cobalt
    • A longer blade flexes more and wanders more easily on a straight cut

    Best for: Cutting pipe up to 7 in across, where a 6 in blade cannot reach through

    ≈ $15
    Check price on Amazon

All lathe tooling