Precision Mensuration & Layout Tools

Precision Mensuration & Layout Tools

Layout Tools, Precision Gage Blocks, Surface Plates, Surface Gages, Height Gages, Universal Gage, Z-Offset Gages,
Indicators, Inside Diameter Gages, Pin Gages, Runout & Bore Gages, Calipers, Micrometers, Dial Test Indicators,
Indicator Holders, Transfer Punches, Thread Gages, Protractor, Optical Protractor, Angle Gages, Radius Gages

Mensuration - The act, process, or art of measuring. Measurement of geometric quantities.

Resolution - Smallest difference between indications of a displaying device that can be meaningfully distinguished.
For a digital display device, this is the change in the indication when the least significant digit changes by one step.

Accuracy - Closeness of the agreement between the result of the measurement & the true value of the measurand.

Measurand - A quantity that is being determined by measurement.

Also refer to, how to drill a hole where you want it & how to drill the center of a rod.

Layout Tools

Various types of squares, small rules, & protractors. Starrett (USA) & Mitutoyo (Japan) are of highest quality.

Outside calipers, spring divider, hermaphrodite & inside calipers.

Scribes & automatic center punches.

Automatic center punch exploded detail. Assembly order is left to right, top to bottom.
If the middle row far right cylindrical part is turned around, the punch will not work properly.
The flat side faces the point & the curved side faces the ball bearing.

Automatic center-punch replacement tips. Lower-left: General No. 79P.

Precision Gage Blocks

81 piece, Grade B, hardened, rectangular precision gage block set, from 0.050 to 4.0", ą0.000050" at 20°C (68°F).
Excellent for use with height gages, depth gages, sine bars, sine plates & sine vises, setups, etc., (import).
Example of a calibration reference table.

Low-cost spacer gage set.

Accurate, 1-2-3, 2-3-4 & 2-4-6 (inches) precision-ground, hardened, steel blocks.
⅜-16 threaded & clearance holes allow clamping. Handy for surface-plate measurements & mill setups.

Surface Plates

Granite surface plates (ą 0.0001") in 18"x12"x3" (85 lbs.) & 12"x9"x2" (30 lbs.) sizes.
The relatively heavy plates have Teflon pads on the bottom to ease movement on the bench.

A simple, all wood (glued only, no metal) cover to protect the surface from damage.

Surface Gages

Starrett surface gage holding its hardened scribe.

Starrett surface gage & Starrett Last Word dial test indicator on the granite surface plate
measuring a 1-2-3 block. If possible, move the part not the gage when indicating a surface.

Height Gages

A Mitutoyo, 8", 543-244 digital height gage with fine adjustment mechanism. When combined
with a granite surface plate, they make an accurate combination for measuring parts or laying out
precisely scribed lines. Resolution: 0.0005". Absolute electrostatic capacitance type linear encoder.
A fine adjustment carriage mechanism is a requirement for fast, accurate, height settings.
See the Mitutoyo 543-244 digital height gage manual & dimensional drawing.

The heavy base has an excellent ergonomic design. The bottom surface is ground to perfection.

Hole center-finder attachment.

Hole center finder animation showing how the fine adjustment of the height gage is used to zero the needle.

Height gage with digital indicator for both height & tolerance measurements.

A carbide-tipped (Mitutoyo) 10", dial height gage on a granite surface plate (ą 0.0001"). High accuracy can be
achieved using gage blocks to set the specified heights. Use layout die to make the scribe marks easier to see.
Mitutoyo height gage manual. Surface plates are useful for precision alignment when assembling parts, too.

Depth attachment. Rod accepts different 4-48 threaded indicator points.

Measuring distances between holes using a center-finder attachment from Mitutoyo.

Depth & center-finder attachments for the height gage, detail.

Height gage with digital indicator for both height & tolerance measurements.

Using a test gage in conjunction with a height gage allows measurements of
both dimensions & tolerances without having to use separate instruments.

Mitutoyo OEM wooden case.

Starrett No. 3751 digital height gage. Auto-off in 5 minutes but retains zero. Auto-on when moving the slide.
0 to 6.45" max range, ą0.001" (ą 0.03mm) accuracy & 0.0005" (0.01mm) resolution. Supplied with an extra
scribe & carrier plus an excellent, padded, hard aluminum case. The vertical column is set in from the tip
of the base's nose for better stability. Zero is saved between uses. This height gage's compact size is
especially valuable when measuring parts with very small features. The scribes are not carbide-tipped.
The fine-edged, HSS scribes are limited to soft metals & the rounded tips limit scratch depth.

Adjusting to a specific height can be accomplished by picking it up & using it much like a regular caliper.
Slightly increasing the slide resistance of the transducer (a small, side set screw) helps adjustability.
Setting an exact numerical value with this type of adjustment mechanism is slower than
that of a height gage equipped with a fine adjustment carriage mechanism.

Starrett No. 3715 digital height gage manual.

Universal Gage

Starrett No. 995 (USA) universal precision gage set is best in class. This gage has multiple uses:
height gage, scriber, planer/shaper setup, an adjustable parallel to measure a gap, transfer
measurements, precision level, & layout work on a surface plate using gage blocks or a sine bar.

Nominal dimensions of the base are 5.25" x 2.5" x 0.75" (W x H x D). Hardened & precision ground.
The slide has a combination of both a flat & a V-way to provide excellent accuracy.

The slide has a fine adjustment mechanism allowing faster & more accurate settings.
No other similar gages have this important feature. Note the mineral spirits bubble level.

Offset attachment with clamp bolt extends the nose for a minimum height of 0.1700" & allows use in narrow areas.

The 1" extension rod.

The extension rods can be screwed in at four different locations.

The 3" extension rod.

The 1" rod also screws into the 3" rod to provide a 9.5" maximum height.

A toe clamp holds a hardened, HSS scribe which is shown being set at 3.0000" height using a gage block.

Z-Offset Gages

4.000" height, Z-axis tool length setting gage (USA). One-inch contact face picks-up all the flutes of
large end mills, easy to read 2.2" dial face, a setting repeatability of 0.0002", & hard, red anodize.
Needle-based Z-setting gages are not damaged by over travel like some electronic types.
The unit's overall ergonomic & mechanical design is excellent & has a good, heavy feel. Sells on ebay.

Z-axis offset animation showing a ž" end mill being set at 4.000" above the vise bed.

A 3.000" height offset gage using a 40 mm (1.5") diameter face Mahr dial indicator (GER) that reads to 0.0005".
Stem is 8mm (.315"). The 7.5mm (0.295") diameter flat tip is an ideal shape. The bracket is all steel construction.
All critical surfaces of the parts, including the round post ends, were precision surface ground for high accuracy.
An adjustable, brass, over-travel stop was added so the needle can only turn 1ž revolutions.

The bottom of this Z-offset gage needed lapping which was performed on a granite surface plate first using
320 followed 400 & 600 grit silicon carbide papers. Move the part in a figure-8 pattern to insure an even
removal of material. Significant surface improvement resulted. The edges were de-burred with an India stone.

This offset gage has a magnetic bottom which attracts debris.

This Z-offset gage is 2" high. A 3" micrometer & a 123 Joe block were used to set the gage's zero at 2.0000".
The micrometer was first locked at 3.0000" using the gage block.

Mill Z-offset gage (instructions) used to set tool lengths. Needle-based, Z-offset gages set the
mill more quickly & accurately than illuminated types plus they are not damaged by over travel.

Animation showing a 2.000" tool Z-offset height being set on the Taig CNC Z-axis using the MPG in step mode.

Indicators

Mitutoyo electronic indicator (˝" range). Resolution is 0.00005" (50 millionths). Using a linear encoder, it always
displays the spindle's absolute position from the origin at power-on. Digimatic indicator manual & drawing.

Mitutoyo electronic indicators (˝" range) with a Noga magnetic base indicator holder (all from Japan).
See digital indicator manual.

A two-inch range digital indicator that reads to 0.0005" resolution.

Two dial indicator comparator stands. Used for quality assurance (QA) size
measurements of many parts. Serrated anvils are purportedly more accurate.

A wooden holder for ⅜" stemmed digital & dial indicator gages.

Their positions are offset to accommodate the lug back mounts.

Different types of dial gage interchangeable 4-48 threaded indicator points.
To keep from straining or breaking a gage's internal alignment pin, completely depress the plunger
so the rack absorbs the loosening & tightening forces before changing the points. Never use Loctite.

Baker dial depth indicator (India) with a 0" to 10" range & where one gradation = 0.001". Rod extension chart.

Inside Diameter Gages

Telescoping & half-ball Mitutoyo inside gage sets. The half-ball type can get into a shallow, blind hole
better than a ball type. Expand into hole, lock & then measure the gage with a micrometer or caliper.

Left: The small hole gage is expanded by the center wedge.
Right: The telescoping inside gage posts spring outward, self-center & are then locked.
They can then be measured with a micrometer or caliper.

Full-ball, small hole gage set.

Pin Gages

Pin/plug Gage Sets - ID measurement type gages for measuring holes & slot widths.
0.011" to 0.060" x 0.001" minus Class ZZ pin-gage set (50 pieces).
Tolerance +.0000" -.0002". 10ľm finish or better. Hardness 60-62 RC.

0.061" to 0.250" x 0.001" minus Class ZZ pin-gage set (190 pieces).
Tolerance +.0000" -.0002". 10ľm finish or better. Hardness 60-62 RC.

Detail of the 0.061" to 0.250" x 0.001" minus pin gage set (still in the grease). Two-inches overall lengths.

0.251" to 0.500" x 0.001" minus Class ZZ pin-gage set (250 pieces).
Tolerance +.0000" -.0002". 10ľm finish or better. Hardness 60-62 RC.

Go/no go pin gage handles. Shown holding 0.25" & 0.050" pin gages.

Runout & Bore Gages

Baker back-plunger dial indicator set (India) with 'G' clamp, universal clamp, swinging-arm assembly, tool post holder,
holding rod, Tommy bar & anvil. Swinging-arm assembly enables the back-plunger dial gage for use on internal
work to a depth of 1.6" (40mm); similar to a lever-type gage. Allows multiple types of mounting possibilities for
gaging applications like concentricity checks, alignment of machine tools, testing parallelism & surface plate work.

Back-plunger dial gage with swinging-arm attachment.

A self-centering, 1.4" to 6" cylinder bore gage (instructions).
The gage is first setup to measure a specific size (zeroed) then run through the bore to measure its variation.
To keep the extensions in order, a vibrator engraver was used to label each size on a non-critical surface.

The dial gage must be inserted deep enough to preload (or move) the needle about 1 revolution (0.050").
The black plastic shroud can be installed after calibration to protect the head under heavy shop use.

These ˝" travel digital indicators, preloaded to 0.050" depth, can also be utilized but others may not work.

Exploded view of the 1.4" to 2" measurement head, the 1.4" range anvil & knurled anvil lock nut.
The pointed rod end (at the lower left) engages a rod inside the handle.

Anvil install animation.

The center measurement anvil moves in & out.
The outside mechanism depresses under spring tension to center the head.

Small anvil animation.

Assemble the appropriate anvils & spacers (left side) for the target measurement size.
Then, using gage blocks, set a micrometer (e.g., 2") to the bore size & zero the dial scale.
The gage is then run through the cylinder & the variation from set size, noted.

Bore gage measurement animation.
Note how the small measurement anvil (left) depresses & how the self-centering guide mechanism slides to the right.

Calipers

Mitutoyo digital measurement tools: depth gage, caliper & micrometer (older models).

Mitutoyo Absolute Digimatic caliper (Japan).
An excellent digital caliper that is very accurate throughout its entire measurement range.
Always maintains zero, large LC display, greater than 3 years battery life. No irritating auto-off.

Mitutoyo digital caliper manual.

Hardened & precision ground depth base attached.

A digital caliper (manual) that measures & displays inches, millimeters & fractions to 1/64th inch.
Handy for wood work & sifting through raw stock. This LCD has a somewhat narrow optimal viewing angle.

Digital depth gage with a large base. See digital caliper manual.

8-inch digital linear scale for instrumenting tools like mills & lathes.

Micrometers

Superior quality Mitutoyo (Japan) digital micrometer that reads down to 0.00005" or 0.001mm.
The scales are engraved, not chemically etched thus have superior readability & durability.
Even if the battery is removed, the micrometer's scales allow it to be used as a standard instrument.
Micro-polished, carbide-faced working surfaces & an effective spindle lock.

See micrometer manual.

The holder adjusts to different angles & has rubber pads that protect the instrument from clamping damage.

Small, 0.6" (non-locking) & standard 1" micrometers. The smaller micrometer's scales are chemically etched,
the larger micrometer's scales, engraved. Superior instruments have engraved scales for clarity & durability.

2-inch micrometer.

Micrometer set zero through six inches with its wooden storage case (import).
One, two, three, four & five-inch sized standards plus adjustment wrench are included.
The plastic insulating grips on the standards reduce warming effects (expansion) due to handling.
Acquired for use mainly on the 9x20 lathe. Excellent accuracy, engraved scales, & a good value.
All micrometers read to 0.0001". The wooden case was re-glued in places & then sanded.
See micrometer scale reading instructions.

6" to 12" micrometer set. The smaller wooden case holds size standards 6" through 11".
All micrometers read to 0.0001".

6" micrometer, shown.

12" micrometer shown with the standards case, open. The holes lighten the instrument for easier handling.

Two micrometer sets covering the 0" through 12" range. Eleven size standards; 1" through 11".
Two separate sets can make handling/storing the boxes easier than one big 0" ~ 12" set.

A 0.6" micrometer compared to a 12" micrometer.

Hub micrometer that measures 0-1" to 0.0001" & designed to clear through a ž" hole.
Handy in tight places especially in milling setups. A spindle lock would have been better.

Deep throat micrometer; 0 to 1" maximum, with a 0.0001" scale. The throat is 6" deep.

Metal locking levers are a plus for durability & precision of the mechanism movement.

Caliper-type micrometer measures to 0.0001". Measuring anvils are approximately ž" above the micrometer.
The thread mechanism that keeps the anvil from rotating also acts as an effective lock.

Disk micrometer with a 0.0001 scale.

0-1" range, 0.07" diameter anvil, tube wall thickness micrometer that measures to 0.0001".

0-1" range, 0.19" diameter anvil, tube wall thickness micrometer that measures to 0.0001".

Carbide-faced electronic blade micrometer for measuring in narrow recesses.
The thread mechanism that keeps the anvil from rotating also acts as an effective lock.
A 0.00005" minimum readout. Non-critical parts are plastic. Digital blade micrometer manual.

Carbide-tipped, small faces or spline micrometer for measuring in tight areas. 0-1" range with 0.0001 scale.
The anvils are 0.0775" diameter.

Carbide-tipped, point micrometer for measuring in very tight areas. 0-1" range with 0.0001 scale.
Points have a radius of approximately 0.012".

Screw thread micrometer with five different anvil pairs to measure both unified & metric external pitch diameter.
0" to 1" measurement range with a 0.0001" scale. The left anvil holder floats back & forth to allow zeroing then
it is locked into place. However, the anvil itself always floats rotationally to maintain ease of measurement.

SCREW THREAD MICROMETER ANVILS

ANVIL #

1

2

3

4

5

TPI RANGE

64 - 48

44 - 28

24 - 14

13 - 9

8 - 5

METRIC RANGE

0.4 - 0.5

0.6 - 0.9

1 - 1.75

2 - 3

3.5 - 5

Anvil pairs are clearly marked for pitch range.

Example measurement of a ź-20 screw. The micrometer reading is 0.2160". Table pitch value is 0.2175".
A fast & accurate thread measurement tool. The bolt can freely rotate around the micrometer's anvil axis.

Carbide-faced inside micrometer gages. Top gage range is 1"-2" & bottom gage range is 0.2"-1.2".
They were supplied with 1" & 0.2" inside ring standards. One gradation = 0.001".

Micrometer depth gage with a 0-6" range & where one gradation = 0.001".

Dial Test Indicators

The Starrett, Gem, & Federal models have small side levers to select the needle direction.
The tips have multiple spring-loaded detent positions. No dovetail mount on the Starrett.

Excellent, rugged LS Starrett No. 711 Last Word dial test indicator & attachments (USA). One gradation = 0.001".

Gem dial test indicator (USA). One gradation = 0.001". Rod & dovetail mounting.
Gem dial indicators & accessories. See instructions on how to set tip geometry.

Federal Testmaster dial test indicator (USA). One gradation = 0.0001".
Note needle reversing lever & dovetail mounting.

An excellent Brown & Sharp (Swiss) dial test indicator set. One gradation = 0.0005".
This model incorporates an auto-direction (needle) feature & dovetail mounting.

Various dial test indicators that have dovetails. Top to bottom: Brown & Sharp, Federal, & Gem.

Fowler dial test indicator set (import). Moderate quality. One gradation = 0.0005". Dovetail mounting.

Co-Ax indicator (import) that takes measurements while the spindle is spinning (800 RPM maximum).
The point can be used to locate a punch mark. See centering indicator instructions.

Indicator Holders

Sparro 1^st Word dial test indicator holder (USA).

Using a Sparro 1^st Word holder & a LS Starrett Last Word dial test indicator
to check the tram of the mill/drill. Nicely made, very rigid indicator holder.

Animation showing how to check tram on the Rong Fu RF-25 mill table.

Noga indicator holder (Japan) for both dovetail & ⅜" stem types. Note the fine adjustment mechanism.

Noga NF1018 indicator arm (Japan) with ⅜" & dovetail clamp.
This style arm is very quick & easy to setup plus it has very good rigidity.

Noga arm held by a modified, V-groove tool post, mounted off the headstock side T-slot of the Taig mill.
Setup shows indicating a work piece before rotating to a specific cutting angle.
The Noga arm is good for tramming mills, lathes & rotary tables.

Zero-set universal dial test gage attachment (import).

A Federal 0.0001", dovetail mount, dial test indicator shown being used to check the Parlec vise's solid jaw tram.

This style universal dial test indicator holder gives a broad sweep of the mill table.

IndicOL #178 (USA) dial test gage holder attaches an indicator to the mill's spindle. Best in class attachment.

Half-round combination test dial holder (dovetail & stem) with a ź" shank.

Modified an indicator clamp to hold a dial test gage. Holds it close to the center & is rigid, compact & quick.
Reamed two, 3/16" holes & the thumbscrews are 6-32 SS hex-head screws with pressed-on plastic caps.

Added another set screw to hold the half-round combination test dial holder.

Detail of the close-fitting brass bushing (⅜" OD, ź" ID) that is held in using red Loctite.

Tramming a 6", 4-jaw chuck on a rotary table.

A Mighty Mag (USA) magnet holds ⅜" (or smaller) stemmed indicators.

Transfer Punches

Transfer punch sets: Fractional - 3/32" through 1" by 1/64th", 0.0025" undersized.
Numbered - 1 through 60. Lettered - A through Z. Metric - 1mm through 13mm by 0.5mm.
Black anodized & heat treated. Some of the original stands were replaced with Huot brand.
Note, import punches sometimes have off-center tips that need to be corrected using a tool-post grinder.

The supplied stand for the metric transfer punches was of very poor quality so an aluminum stand
was fabricated. The plates' dimensions are 5ž" by 2⅝" by 0.33" thick & the bottom plate is 1/16" thick.
A thick top plate keeps the punches vertical plus easier to take them in & out than the multi-plate designs.
The holes were made using each bit of the entire set of metric drills; the transfer punches are undersized.
After the plate was drilled, the top surface was fly cut & then the holes chamfered to make a nice finish.
1⅛" long, 4-40 steel standoff posts were used as spacers. The bottom plate corner holes were first threaded,
the posts were then screwed in followed by a nylon lock nut that secures the post & acts as the feet.

Integer sizes were stamped onto the top & filled-in with black China marker.

Transfer screw sets for mating parts especially blind holes. Hardened screws stored inside handle.
Handle end has a hex driver that serves as wrench. Top to bottom examples: ž-10, 4-40 & M10-1.5 (metric).

Thread Gages

Imperial & metric (yellow) screw thread gages (2), fractional & numbered drill size gages.
These plate-type thread gages would be more accurate if they were twice as thick.
Having just a few threads, it is easy to make an error.

These gages check both nuts & bolts. Metric have black oxide & Imperial have galvanized coatings.
Superior to plate-type gages which use only a few threads per size for testing.