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Lines & plumb bobs

Tajima Quick-stabilizing plumb bob, 21 oz, tip guard

The heaviest bob here, and the only one with bumpers to stop it marking the wall it hangs against.

Tajima quick-stabilizing 21 oz chrome-plated plumb bob with tip guard

Tajima Quick-stabilizing plumb bob, 21 oz, tip guard

The heaviest bob here, and the only one with bumpers to stop it marking the wall it hangs against.

Stated dimension or range
21 oz / 600 g — the heaviest bob on this shelf, where the lightest is 5 oz: a factor of four. This shelf's introduction says weight sets how quickly a bob settles and how little it swings in a draft, which makes this the bob for an open site, a stairwell or a long drop
Measuring mode
Quick-stabilizing: stops wobble AND SPIN within 6 seconds, stated. The same figure as the maker's 10-ounce bob on this shelf, which is the interesting part — doubling the weight does not halve the time, because the design rather than the mass is doing the work. Spin is the half nobody else mentions: a bob that has stopped swinging can still be rotating, and a rotating bob with an off-center tip traces a circle
Body and fittings
EMBEDDED SIDE BUMPERS, stated to protect both the bob and the work surfaces. Nobody else on this shelf has them, and they solve a real problem twice: a 600 g (21.2 oz) steel bob swinging into a finished wall marks it, and the same impact chips the bob's own plating
Functions
A thick ELASTOMER TIP GUARD, stated to keep the tip safe and secure. The tip is what a bob dies of — one drop rolls the point over — and a guard is the other answer to that problem; the brass kit on this shelf answers it with four spare tips instead
Material
Chrome plated to resist rust and corrosion, stated. Chrome is harder than nickel and resists the chip that starts the rust — which matters more on a 600 g (21.2 oz) bob, because a heavier bob hits harder when it is dropped
Supplied
A snap ring as standard, to connect and disconnect from a plumb line, stated. A snap ring rather than a knot means the same bob moves between a short line and a long one in seconds. NO LINE IS SUPPLIED — this is a bob, not a kit, and the shelf carries 250 ft of braided mason's line for under nine dollars
Amazon reference
B00023S4SK
EAN
0049296054267
  • Twenty-one ounces: the steadiest bob on this shelf
  • Six seconds, and it stops SPIN as well as swing
  • No line supplied at all

Best for: A long drop outdoors or in a draft, where a light bob never stops swinging

≈ $31
Check price on Amazon

Specifications

Stated dimension or range
21 oz / 600 g — the heaviest bob on this shelf, where the lightest is 5 oz: a factor of four. This shelf's introduction says weight sets how quickly a bob settles and how little it swings in a draft, which makes this the bob for an open site, a stairwell or a long drop
Measuring mode
Quick-stabilizing: stops wobble AND SPIN within 6 seconds, stated. The same figure as the maker's 10-ounce bob on this shelf, which is the interesting part — doubling the weight does not halve the time, because the design rather than the mass is doing the work. Spin is the half nobody else mentions: a bob that has stopped swinging can still be rotating, and a rotating bob with an off-center tip traces a circle
Body and fittings
EMBEDDED SIDE BUMPERS, stated to protect both the bob and the work surfaces. Nobody else on this shelf has them, and they solve a real problem twice: a 600 g (21.2 oz) steel bob swinging into a finished wall marks it, and the same impact chips the bob's own plating
Functions
A thick ELASTOMER TIP GUARD, stated to keep the tip safe and secure. The tip is what a bob dies of — one drop rolls the point over — and a guard is the other answer to that problem; the brass kit on this shelf answers it with four spare tips instead
Material
Chrome plated to resist rust and corrosion, stated. Chrome is harder than nickel and resists the chip that starts the rust — which matters more on a 600 g (21.2 oz) bob, because a heavier bob hits harder when it is dropped
Supplied
A snap ring as standard, to connect and disconnect from a plumb line, stated. A snap ring rather than a knot means the same bob moves between a short line and a long one in seconds. NO LINE IS SUPPLIED — this is a bob, not a kit, and the shelf carries 250 ft of braided mason's line for under nine dollars
Amazon reference
B00023S4SK
EAN
0049296054267

What the maker puts in writing

  • 21 oz / 600 g · “Unique quick stabilizing bobs stop wobble and spin within 6 seconds”
  • Embedded side bumpers protect both the bob and work surfaces
  • Thick elastomer tip guard keeps the bob tip safe and secure
  • Chrome-plated to resist rust and corrosion
  • Comes standard with snap ring to easily connect and disconnect to/from plumb line
  • Available in 7, 10, 14 and 21 oz sizes

NO LINE SUPPLIED. No bob dimensions.

Twenty-one ounces does not settle faster

Which is the finding, and it comes from Tajima’s own two listings.

This 21-ounce bob and the maker’s 10-ounce setter on this shelf both steady within six seconds.

So doubling the weight does not halve the time: the quick-stabilizing DESIGN is doing the work, not the mass.

What the extra weight buys is immunity to air. This shelf’s introduction says a heavy bob swings less in a draft — and six hundred grams on a long line in a stairwell is simply not moved by what keeps a light bob circling.

Bumpers, for the wall first

A 600 g (21.2 oz) steel cylinder on a line swings into whatever it hangs beside.

On a finished wall, a painted jamb or a tiled face, that leaves a mark to make good.

Embedded side bumpers take the impact on rubber.

The second benefit is the bob: chrome chips where it is struck, and a chip is where rust starts.

Nobody else on this shelf publishes bumpers, and this shelf’s introduction never raises the problem.

And it stops SPIN

Which nobody else mentions, and which matters.

A bob can hang dead straight and still be rotating on its own axis.

If the tip is not exactly on that axis, the point traces a small circle instead of marking a spot — and the bob looks perfectly still while it does it.

This shelf’s buying tip says to let it stop on its own. Watch the tip, not the body.

A snap ring instead of a knot

So one bob serves a short line and a long one.

Every other bob on this shelf threads a cord through a cap and knots it, which is a five-minute job to change.

A snap ring is a second.

What it also means: no line comes with it. This shelf carries 250 feet of braided mason’s line for under nine dollars.

Availability

On sale at around 31 € on the American Amazon store at the time of checking.

Prices and availability are what Keepa reported on the date this page was updated; both move.

Prices quoted in this text were read on 8 October 2026. The live price is at the top of the page.

What gets asked here

Does twenty-one ounces settle faster than ten?

Not according to Tajima, and that is the useful finding. Both this bob and the maker's 10-ounce setter on this shelf are stated to steady within six seconds — so doubling the weight does not halve the time, because the quick-stabilizing design rather than the mass is doing the work. What the extra weight buys is immunity to a draft: this shelf's introduction says a heavy bob swings less in a draft, and a 600 g (21.2 oz) bob on a long line in a stairwell or on an open site simply is not moved by air that would keep a 150 g (5.3 oz) bob circling.

What are the bumpers for?

The wall, and then the bob. A 600 gram steel cylinder on the end of a line swings into whatever it is hanging beside, and on a finished wall, a painted jamb or a tiled face that leaves a mark you then have to make good. Embedded side bumpers take that impact on rubber. The second benefit is the bob's own plating: chrome chips where it is struck, and a chip is where rust starts. Nobody else on this shelf publishes bumpers, and this shelf's introduction never raises the problem — which is a gap in the shelf rather than in this product.

Why does "stops spin" matter?

Because a bob can be perfectly still and still be wrong. Swing is obvious and stops visibly; SPIN is not — the bob rotates on its own axis while hanging dead straight, and if the tip is not exactly on the axis the point traces a small circle rather than marking a spot. Tajima is the only maker on this shelf to mention spin at all. The practical consequence is this shelf's buying tip: let it stop on its own, and look at the tip rather than the body to decide whether it has.

More mason lines and plumb bobs

  • Tajima PZB300D plumb bob setter with self-retracting line and magnetic head

    Tajima Plumb bob setter, 10 oz, self-retracting line

    The only bob here that says how long it takes to stop — and the only one you can hammer into a ceiling.

    Measuring mode
    Quick-stabilizing: the 10-ounce bob steadies WITHIN 6 SECONDS, stated. It is the only settling time published on this shelf. This shelf's introduction says weight sets how quickly a bob settles and the buying tip says to let it stop on its own rather than steadying it by hand — a published six seconds is what makes that instruction bearable, because the alternative is standing there not knowing whether to wait longer
    Reference and mounting
    THREE fixings in one head, stated: a setting pin for wood and drywall, a strong magnet for steel surfaces, and a hook for nails or studs. No other bob on this shelf offers more than two, and most offer none at all — a bare bob is tied to a nail somebody else put in
    Functions
    An AUTO-RETRACTING PIN STRIKER, stated for use with a hammer for overhead setting. That is the unusual one: you hold the setter against a ceiling and strike it, the pin drives in, and the striker retracts out of the way — so a plumb line can be dropped from a ceiling without first fitting a nail with a free hand you do not have
    Stated dimension or range
    10 oz / 300 g, published in both units, with a 14.5 ft self-retracting line. Ten ounces is the middle of this shelf, which runs from 5 oz to 21 oz
    Body and fittings
    A self-retracting line, stated for quick easy storage. Two bobs on this shelf retract; the rest use a hand reel, a card or nothing. The line construction is not stated — four listings on this shelf state braided, and this is not one of them
    Also stated
    Commercial grade for long-lasting durability, and described in the maker's own text as a compact and light-duty version. No tip material, no tip guard and no replaceable tip is published
    Amazon reference
    B001S2QNNW
    EAN
    0049296055066
    • Six seconds to steady, the only settling time here
    • A setting pin, a magnet AND a hook in one head
    • The line construction is not stated

    Best for: Overhead setting from a ceiling or a steel beam, where the fixing is the hard part

    ≈ $33
    Check price on Amazon
  • Alyco 500 gram plumb bob in steel and walnut hanging on its line

    Alyco Plumb bob, 500 g (17.6 oz), with 5 m (16 ft) line

    Five hundred grams of steel on 5 m (16 ft) of line: a heavy bob settles faster and swings less in a draft, which is the whole specification.

    Amazon reference
    B00KAFZ8RK (identical on 6 markets)
    EAN
    8421504979326
    Stated weight
    500 g (17.6 oz)
    Material
    zinc-plated steel and walnut
    Mechanism and finish
    5 m (16 ft) nylon line
    • Five hundred grams — second only to the Tajima’s 600 g (21.2 oz), and weight is what makes a bob settle
    • Supplied with 5 m (16 ft) of nylon line
    • Heavy to carry compared with a laser plumb point

    Best for: Establishing vertical where a laser cannot see, or where there is nothing to power one with.

    Check price on Amazon
  • AWF PRO plumb bob kit with brass bobs, reel and zipped case

    AWF PRO Plumb bob kit, 16 oz and 8 oz brass, 4 tips

    The only bobs here with spare points — which is the part of a plumb bob that actually wears out.

    Supplied
    An 8 oz bob, a 16 oz bob, a retractable line reel, two pencils, a pencil sharpener and a blue zipped carry case — stated. Two weights in one kit is unique on this shelf: a light bob settles slower but reaches further up a wall before it fouls, and a heavy one holds still in a draft
    Material
    SOLID BRASS, stated, precision made. It is the only brass on this shelf — the rest are steel, plated or chromed — and brass matters for a specific reason: it is denser than steel, so a brass bob of the same weight is smaller and swings in less air, and it does not rust at all rather than resisting rust
    Functions
    FOUR replaceable steel tips — two per bob, one of them hidden in the cap — with caps and tips interchangeable between the two sizes. Nobody else on this shelf sells a spare tip of any kind, and the tip is the part that goes: a point dropped onto concrete rolls over, and a rolled point puts the bob off center
    Body and fittings
    A reel with approximately 14 feet of bright orange BRAIDED nylon cord, RARE-EARTH magnets to attach it to steel or iron, and a fold-out bracket to hang it on a nail, screw or tack. A locking lever holds the cord; press again and the line self-retracts
    Scale
    The cord attaches by removing a screw-in cap, threading the cord through the center opening and knotting it — stated. Center threading is what keeps a bob hanging true, and a screw cap is what lets a worn cord be replaced rather than retied around a hook
    Also stated
    A specialty sharpener designed for cutting CARPENTER pencils, which is a different cone from a round pencil and is the reason an ordinary sharpener destroys a flat pencil. No settling time and no bob dimensions are published
    Amazon reference
    B074SW83JH
    EAN
    0855493007698
    • Four replaceable steel tips, unique on this shelf
    • Solid brass: denser than steel and it cannot rust
    • Fifty dollars, the most expensive thing on this shelf

    Best for: Owning one kit for years, where a blunted point would otherwise end the tool

    ≈ $50
    Check price on Amazon

Elsewhere in the spares drawer

  • Leopacat TM-902C handheld thermocouple thermometer with its wire probe

    Leopacat Type K thermometer with probe

    A probe with its own readout: a handheld type K thermometer for measuring temperature without occupying a multimeter.

    Amazon reference
    B0CQJYQ1ZX (identical on 6 markets)
    EAN
    7362571391967
    Thermocouple type
    Type K
    Supplied
    handheld thermometer with probe
    Functions
    wide operating range
    • Comes with its own display, so it does not tie up a multimeter for the duration of a measurement
    • Type K, so any standard probe fits it
    • No accuracy figure published

    Best for: Leaving on a monitored point while the multimeter goes on doing something else.

    Check price on Amazon
  • Nxtop WRNK-187 type K thermocouple probe with yellow miniature connector

    Nxtop Sheathed type K probe, 1100 °C (2012 °F), 3 × 200 mm (0.12 × 7.87 in)

    The cheapest probe on this shelf, the hottest, and the only one that publishes a dimension for its plug.

    Type and plug fit
    Type K with a MINIATURE K-TYPE CONNECTOR, and the fork terminal spacing is published: 5 mm (0.20 in), 0.197 inch. It is the ONLY probe on this shelf that gives a dimension for its plug, and this shelf's introduction says in so many words that "the miniature flat plug that connects it is where fit fails". A nine-dollar probe answers the shelf's stated failure point, and the twenty-seven and thirty-dollar Kleins do not
    Probe style
    A SHEATHED ROD, 3 mm (0.12 in) diameter by 200 mm (7.87 in) long — the immersion style this shelf's introduction names. Total length 29.5 cm (11.6 in) with the cable gland, so roughly 9 cm (3.5 in) of that is body rather than probe. It is the only product on this shelf whose probe geometry is fully dimensioned
    Stated temperature range
    0 to 1100 °C (32 to 2012 °F), stated. That is the HIGHEST range published by any probe on this shelf: the Klein 69142 reaches 480 °C (896 °F), the published Taiss 350 °C (662 °F), the ZIBOO clamp 200 °C (392 °F) and the Klein 69140 clamp 100 °C (212 °F). Only the Fieldpiece ST4 meter claims more, at 1300 °C (2372 °F), and that is the instrument's range rather than a probe's. Like the Klein 69142 it does not go below zero
    Cable length
    30 cm (11.8 in), 12 inches, stated "not stretched" — the SHORTEST on this shelf by a wide margin. The two pipe clamps give 102 cm (40.2 in), the Klein 69142 three feet, the published Taiss 3 m (10 ft). Thirty centimeters puts your hand about a foot from whatever is at 1100 degrees, which is the real limit of this probe and has nothing to do with its sensor
    Stated accuracy
    NOT PUBLISHED, and no tolerance class is named either. Only the two pipe clamps on this shelf publish a percentage at all; this one publishes nothing. At $8.99 that is the trade being offered, and the sentence both Klein clamps print applies here too whether or not it is written: what turns the junction voltage into a number is your meter
    Heat resistance
    Implied by the 1100 °C (2012 °F) range for the sheath, and unstated for the cable. The listing describes the materials only as "Electronic Parts, Plastic" and the color as yellow, which is the standard color coding for type K in American practice. A plastic-insulated 30 cm (11.8 in) lead is what sets the working distance, not the stainless rod
    Also stated
    78 grams, against 11 g (0.4 oz) for the Klein 69142. The listing is written as a parts-catalog entry rather than marketing — product name, model, type, color, material, range, weight, fork spacing, probe dimensions, total length, cable length, package contents — and that is why it publishes more dimensions than anything else on this shelf
    Amazon reference
    B07DNGWLFS
    EAN
    0703064924915
    • Eleven hundred degrees for nine dollars
    • The only plug dimension published on this shelf — 5 mm (0.20 in)
    • Thirty centimeters of cable, at 1100 degrees

    Best for: Kiln, furnace, forge and flue work, where 1100 °C (2012 °F) is the specification and a 30 cm (11.8 in) cable is enough

    ≈ $9
    Check price on Amazon
  • Proster dual-channel thermometer with two type K probes attached, showing both readings

    Proster Two-channel thermocouple thermometer

    The instrument that measures a difference rather than a temperature: two channels, with T1−T2 displayed directly instead of subtracted by hand.

    Amazon reference
    B071RNW2C6 (identical on 6 markets)
    EAN
    0711583415319
    Channels
    Two channels · T1 / T2 / T1−T2
    Also stated
    J, K and T types
    Functions
    MAX, MIN, AVG
    • Two channels with a direct T1−T2 display — the measurement most temperature work actually needs
    • Accepts J, K and T type probes across very wide stated ranges
    • No accuracy figure published

    Best for: Flow and return, inlet and outlet, before and after — anything where the answer is a difference.

    Check price on Amazon

All mason lines and plumb bobs