Dimensional Measurement · Dial Indicators
Mechanical dial indicator and dial gauge for comparative measurement, in 0.01 mm and 0.001 mm graduations with dial diameters from 42 to 80 mm.
A dial indicator is the instrument that answers the question a drawing usually asks. A dimension has a nominal value and a tolerance band around it, and the practical question on the shop floor is not what the size is but whether it is inside the band. A dial indicator answers that by being set to zero against a reference and reading the departure, which is why it remains in use alongside instruments that can read an absolute value to a finer resolution.
It is also the instrument that most depends on how it is held, because it measures movement, and anything that moves other than the part appears in the reading.
The material is a combined collection rather than a single maker’s catalogue. It covers mechanical dial indicators resolving to 0.01 mm in six ranges from 0 to 3 up to 0 to 50 mm, and mechanical dial gauges resolving to 0.001 mm in three ranges from 0 to 1 up to 0 to 5 mm. Dial diameters run from 42 mm to 80 mm, and the contact thread is M2.5 throughout.
Because it merges sources, it states plainly that forms of the same range differ in dial diameter, stem length and accuracy, and more than one accuracy figure is given for several ranges. The page carries that as stated rather than reducing it.
Along the plunger runs a precision rack, and the rack drives a geared train that turns the pointer. The gearing is what allows a movement of a few hundredths of a millimetre to be shown across a face large enough to read; on the finer dial gauges a second hand on a concentric dial records whole turns of the main pointer, so that a travel of several millimetres is still unambiguous.
The instrument is set to zero by rotating the bezel until the zero mark sits under the pointer at the reference position. Everything read afterwards is a departure from that reference. The graduated dials are laser-marked on chrome plate, and the movements are jewelled and described as shock-resistant, which is the construction that keeps a comparator repeating over a long service life.
The tolerance decides the graduation first. A tolerance that has to be read as a number rather than estimated needs a graduation fine enough to resolve it, which on this material means 0.01 mm for general work and 0.001 mm for a tight one. The range then has to cover the largest departure expected with the plunger still on its travel, which is the departure rather than the nominal dimension.
The dial diameter follows from where the reading has to be legible, and on this material it is not fully independent of the range, since the longer ranges are offered only in the larger dials. Finally, settle how the instrument will be held, because a magnetic base or a universal magnetic base is supplied separately and the stand is part of the measurement.
Two figures that decide how well an indicator works as a comparator are absent from the material: repeatability and hysteresis. Both matter more here than the accuracy figure, since the instrument is used to show a departure rather than an absolute size, and a comparator that does not return to the same reading has nothing to offer. The page records the absence rather than substituting a figure.
The material’s own description of itself is worth carrying forward: it merges several sources, so a buyer ordering to a tolerance should establish which form and which accuracy figure will actually be supplied for a given range. The photograph, for its part, carries third-party brand marks, a model number and a watermark, all of which are exclusion items; none of them is reproduced in the text.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
| 0 to 3 mm | 42 mm dial, 10 to 16 mm stem, accuracy plus or minus 0.01 mmStandard |
|---|---|
| 0 to 5 mm | 42 mm or 58 mm dial, 16 to 21 mm stem, accuracy plus or minus 0.01 mm on the 42 mm dial and on some 58 mm dials, plus or minus 0.02 mm on othersStandard |
| 0 to 10 mm | 58 mm dial, 18 to 30 mm stem, with a sealed form at 30 mm; accuracy given as plus or minus 0.01, 0.02 or 0.03 mm, the loosest figure belonging to an economy form with lugs on the back coverStandard |
| 0 to 20 mm | 58 mm dial, 36 to 37 mm stem, accuracy plus or minus 0.01 or 0.02 mmStandard |
| 0 to 30 mm | 58 mm dial, 42 mm stem, accuracy plus or minus 0.01 or 0.02 mmStandard |
| 0 to 50 mm | 58 mm or 80 mm dial, 55 to 58 mm stem, accuracy plus or minus 0.01 mm on the 58 mm dial and plus or minus 0.02 mm on the 80 mm dialStandard |
| Repeatability | Not stated in the material, and it is the figure that matters most on an instrument used as a comparatorInformation required |
| Measuring force | Not stated in the material, although the material refers to a limiting device on the plungerInformation required |
| Hysteresis | Not stated in the materialInformation required |
| Dial gauge ranges and resolution | 0 to 1, 0 to 3 and 0 to 5 mm at a resolution of 0.001 mmStandard |
|---|---|
| Dial gauge movement | A jewelled movement with a revolution counter on the dial faceStandard |
| Body materials | Aluminium, steel or stainless steel depending on the form, with a steel body stated for the dial gaugeStandard |
| Movement construction | A one-piece brass movement on some forms, carrying six jewels, described as shock-resistant and wear-resistantStandard |
| Scale | Laser-marked graduations on a chrome-plated dialStandard |
| Pointer | An alloy pointer, described as responsiveStandard |
| Other features | A shock-resistant head, a plunger limit device, and a dust cap on some formsStandard |
| Body material per size | Not stated as a table; the material gives the materials in general terms onlyInformation required |
| Stem and mounting thread standard | Not stated beyond the M2.5 contact threadInformation required |
| Mounting for measurement | Magnetic bases and universal magnetic bases, supplied separatelyStandard |
|---|---|
| Detachable contact | The contact is detachable and takes an M2.5 thread, so tips can be changedStandard |
| Packing | A plastic or cardboard case depending on the form, with a certificateStandard |
| Forms with lugs | Some forms have lugs on the back cover so the instrument can be clamped in a standStandard |
| Contact tips offered | Not stated as a list in the materialInformation required |
| Model | Configuration | Key ranges | Availability |
|---|---|---|---|
| Dial indicator, 0.01 mm | Mechanical comparative indicator with a 0.01 mm graduation in dial diameters of 42, 58 and 80 mm according to range | 1.5 ranges from 0 to 3 up to 0 to 50 mm; accuracy from plus or minus 0.01 to plus or minus 0.03 mm; M2.5 contact thread | The general-purpose form for run-out, flatness, alignment and comparative sizing |
| Dial gauge, 0.001 mm | Mechanical gauge with a 0.001 mm graduation, a jewelled movement and a revolution counter | 0 to 1, 0 to 3 and 0 to 5 mm; steel body; M2.5 contact thread | The finer form for a tight tolerance where 0.01 mm would not resolve it |
| Sealed dial indicator, 0 to 10 mm | The 0 to 10 mm indicator in a sealed form with a 30 mm stem | 58 mm dial; a longer stem than the standard 0 to 10 mm form, which is 18 to 21 mm | The form for work where coolant or dust would reach the movement |
Certifications are only published once a certificate copy can be produced, so this section is deliberately empty rather than populated with assumed approvals. Tell us which approvals your application requires and we will confirm what is available for this instrument.
The following are required for a complete specification but are not stated in the documentation supplied to us. They are listed rather than estimated:
Showing how far something moves or departs from a reference. In practice that means shaft run-out, end-face run-out, flatness, alignment when setting up work, and comparative sizing against a setting piece. It is not the instrument for reading an absolute dimension directly, and where that is the requirement a caliper or a micrometer is the right tool. The dial indicator answers the question a drawing usually asks: not how big is it, but is it within the tolerance band around the nominal.
Because it is used as a comparator. Set zero against a reference and the reading is a departure from it, so what the instrument has to do is repeat and to return to the same reading at the same position, not to indicate a true dimension. That is why the repeatability and the hysteresis of a dial indicator matter more to the measurement than the accuracy figure, and why the absence of those two figures from the material is recorded on the page rather than glossed over.
Where the reading has to be legible rather than how accurate the instrument is. A 42 mm dial suits confined work and a 80 mm dial suits reading at arm's length, and the same range can be offered in more than one diameter. On this material the diameter follows the range to a degree, since the longer ranges are given only in the larger dials, so the two are not entirely independent choices.
On a stand, and the stand is part of the measurement. A magnetic base or a universal magnetic base is supplied separately, and because the instrument responds to movement, any movement of the body appears in the reading alongside the movement of the part. A rigid base with a short, well-locked arm, and the plunger set square to the surface, are what keep the reading meaningful. Some forms have lugs on the back cover specifically so that they can be clamped rather than held on a stem.
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