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Lines & plumb bobs

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.

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

Specifications

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

What the maker puts in writing

  • “Quick-stabilizing 10-Ounce bob steadies within 6 seconds”
  • Setting pin for wood/drywall, strong magnet for steel surfaces, and hook for nails or studs
  • 14.5 ft self-retracting line
  • “Auto-retracting pin striker for use with a hammer for overhead setting”
  • 10 oz / 300 g · commercial grade

Line construction not stated. No tip material. No replaceable tip.

Six seconds, which nobody else publishes

And this shelf’s buying tip is why it matters.

“Let the bob stop on its own rather than steadying it by hand. A bob touched to stop it is a bob you have just pushed off vertical.”

So the only correct procedure is to wait. And waiting without knowing how long is where people reach out and grab it.

Six seconds is short enough to stand still for, and long enough to be worth saying.

Every other bob on this shelf publishes a WEIGHT — which is the cause — and leaves you to discover the effect.

A pin you hammer into the ceiling

Which is the clever part.

Dropping a line from a ceiling normally means holding a nail against plasterboard overhead, hitting it, then hanging a bob from it. Three operations, one hand short.

This setter carries its own pin. Hold the tool up, strike the striker, and the pin drives in with the line already attached — then the striker retracts so nothing stands proud.

Marking a floor point under a duct, a light position or a ceiling feature is exactly that job.

Three fixings, because ceilings are mixed

A magnet holds on steel: a purlin, a stud track, an RSJ. It does nothing on plasterboard or timber.

The setting pin covers wood and drywall. The hook covers a nail somebody already put in.

One other bob here has magnets and a fold-out bracket — two routes. Most have none at all and are tied to a nail.

Under a mixed ceiling, three is the number that means not changing tools.

And its own maker calls it light duty

Which is worth repeating rather than hiding.

Tajima’s text describes it as a compact and light-duty version, and the same maker sells a 21-ounce bob on this shelf.

Ten ounces settles in six seconds and swings in a draft more than twenty-one would. For overhead interior work that is the right trade; on an open site in wind it is not.

Availability

On sale at around 33 € 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

Why is a settling time worth publishing?

Because this shelf's buying tip forbids the shortcut. A bob touched to stop it is a bob you have just pushed off vertical, so the only correct procedure is to wait — and waiting without knowing how long is where people give up and grab it. Six seconds is short enough to stand still for and long enough that it is worth saying. Tajima publishes it on both of its bobs on this shelf and nobody else publishes it at all: the others state a weight, which is the cause, and leave you to discover the effect.

What is the pin striker actually for?

Dropping a line from a ceiling with one pair of hands. Normally that means holding a nail against plasterboard overhead, hitting it, then hanging a bob from it — three operations and one hand short. This setter has its own pin, so you hold the whole tool against the ceiling, strike the striker with a hammer, and the pin drives in with the line already attached; the striker then retracts so nothing stands proud. Marking a floor point under a ceiling feature, a duct or a light position is exactly that job.

Three fixings or one magnet?

Three, and the difference is which ceiling you are under. A magnet holds on steel — a purlin, a stud track, an RSJ — and does nothing on plasterboard or timber. The setting pin covers wood and drywall; the hook covers a nail or a stud somebody has already put in. One other bob on this shelf has rare-earth magnets and a fold-out bracket, which is two routes; most have none and are simply tied to a nail. Under a mixed ceiling, three is the number that means you do not change tools.

More mason lines and plumb bobs

  • 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
  • General Tools hexagonal nickel-plated steel plumb bob

    General Tools Hexagonal steel plumb bob, 8 oz, GGG-P-501e

    The only plumb bob on this shelf measured against a published specification — and the cheapest bob on it.

    Also stated
    Conforms to government specification GGG-P-501e, stated — the US federal specification for plumb bobs, which fixes the form, the weight tolerance and the finish. It is the ONLY standard cited anywhere on this shelf and the only one in the American chantier for this site: every other bob here is sold on its material and its weight, with nothing against which either is checked
    Stated dimension or range
    8 oz, 4 inches long and 7/8 inches wide — the only bob DIMENSIONS published on this shelf. Length and width matter on a bob: a long thin bob hangs closer to a wall before it fouls, and a short wide one has more surface for a draft to push
    Material
    A hexagonal body of COLD-DRAWN steel, nickel plated to prevent rust. Cold-drawn rather than cast or turned from bar: the grain runs along the body, which is why a cold-drawn bob survives being dropped on its side. Hexagonal, stated, which also means it will not roll off a board
    Body and fittings
    A removable cord cap for easy cord replacement, sized for 3/32 inch cords. A named cord size is unusually practical: it means a replacement can be bought by specification rather than by trying it
    Supplied
    A 10-foot 3 mm (0.12 in) BRAIDED cord and the removable cap. Ten feet is the shortest line on this shelf — the retracting reels carry 14 and 14.5 feet and the mason's line reel carries 250 — but it is braided, which this shelf's introduction says resists the stretch that makes a twisted line sag differently at each setting
    Measuring mode
    No settling time is published, and this shelf's introduction says weight sets how quickly a bob settles. Eight ounces is the middle-light end of this shelf, which runs 5 to 21 oz; one maker here publishes six seconds for a ten-ounce bob
    Amazon reference
    B00004T7TI
    EAN
    0038728426154
    • The only published standard on this shelf: GGG-P-501e
    • The only published bob dimensions: 4 in by 7/8 in
    • Ten feet of cord, the shortest line here

    Best for: A bob that has to be the right shape and weight, bought once and kept in a toolbox

    ≈ $7
    Check price on Amazon

Elsewhere in the spares drawer

  • 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
  • Taiss type K thermocouple probes with their flat miniature plugs and long leads

    Taiss Type K thermocouple probes, five-pack

    Five type K probes on 3 m (10 ft) leads — the pack to buy when several points have to be monitored at once, or when probes keep getting damaged.

    Amazon reference
    B07R8T6V46 (identical on 5 markets)
    EAN
    0789659567606
    Thermocouple type
    Type K
    Supplied
    five probes
    Marking medium
    3 m (10 ft) lead
    Stated temperature range
    −40 to 350 °C (-40 to 662 °F) stated
    • Five probes in one pack, so several points can be instrumented at once
    • Three-meter leads, long enough to keep the instrument away from the heat
    • A 350 °C (662 °F) ceiling, far below what type K itself can do

    Best for: Monitoring several points at once — a flow and a return, an inlet and an outlet.

    Search Amazon for this model

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