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08 · Measuring · Newark, DE

Gauge pin sets and dial test indicators picked for the tolerance you actually hold.

Class ZZ gauge pin sets, plus or minus, and dial test indicators in 0.0005 or 0.0001 inch graduation. For toolrooms and job shops that check bores and setups at the machine, not in a lab. Quoted on inquiry, shipped from Dawson Drive.

Per indicator or per set Quoted on inquiry

Send an inquiry Call (302) 366-0113

An outside micrometer measuring a freshly turned shaft still in the lathe chuck

Measure it before it comes out of the chuck. Once it is out, it never goes back in the same.

Two items, both checked at the machine

A test indicator for the setup, pins for the hole.

Neither replaces a CMM. Both answer the question before the part leaves the vise, which is when an answer is cheapest.

08.1

A dial test indicator on a magnetic base checking a bore on the mill

Dial test indicators

Lever-type indicators for tramming, bores and runout.

A dial test indicator has a swinging lever contact, not a plunger. It reads side-on, which is what you need to sweep a bore, tram a head or pick up an edge in a vise. Pick the graduation from the tolerance. If the drawing says plus or minus 0.001 in, a 0.0005 in dial reads it with room to spare and does not twitch at every vibration in the floor. Hold 0.0002 in and you need the 0.0001 in dial, with a range of about 0.008 in, which means it bottoms out fast if you are careless running it in.

Contact points come standard length or long. Long points reach down a bore, but the reading needs a cosine correction as soon as the lever sits at an angle to the surface. At 30 degrees you are reading about 13 percent high. Keep the lever near parallel to the work and most of that goes away.

Graduation: 0.0005 in, range about 0.030 in; or 0.0001 in, range about 0.008 in
Contact points: Standard or long, carbide or ruby ball, interchangeable on the same body
Mounting: Dovetail on the body; stems for collet or holder mounting on request
Face: Balanced reading 0-15-0 or 0-4-0 depending on graduation

Price basisPer indicator, quoted on inquiry

Typical lead time: common graduations usually a few business days

08.2

A gauge pin lifted from its case and entering a reamed hole

Pins go in by their own weight. If you are pushing, you are measuring your thumb.

Gauge pin sets

Class ZZ steel pins in 0.001 in steps, plus or minus.

Gauge pin sets are the fastest go and no-go check for a drilled or reamed hole. The set comes in a fitted case with each pin marked by size. Common ranges run 0.011 to 0.060, 0.061 to 0.250, 0.251 to 0.500 and 0.501 to 0.625 in, each pin 0.001 in larger than the last. Class ZZ steel is the workshop class and what most shops need.

Plus or minus is the part people skip. A minus set has every pin sized at or under its marked size. A plus set, at or over. Use minus pins for the go check on a hole, so a pin marked 0.250 is never quietly bigger than 0.250. Use plus pins for the no-go. Order both if you check both limits, or order one and know which limit you are really checking.

Class: ZZ, tolerance 0.0002 in on the pin
Direction: Plus or minus, stated on the case
Steps: 0.001 in
Ranges: 0.011 to 0.060, 0.061 to 0.250, 0.251 to 0.500, 0.501 to 0.625 in
Material: Hardened tool steel, ground and lapped

Price basisPer set, quoted on inquiry

Typical lead time: common ranges in about a week, Z and X class longer

Tolerance classes, plainly

ZZ, Z or X: what the letters cost you in tolerance.

Gauge maker's tolerance classes tighten as you go up. The price climbs faster than the tolerance tightens, so buy the class the job needs.

Pin tolerance by class, sizes up to 0.825 in
Class	Pin tolerance	Where it belongs	Our view
ZZ	0.0002 in	Shop floor go and no-go on drilled and reamed holes	What most job shops should buy
Z	0.0001 in	Inspection bench, tighter reamed fits	Worth it if your hole tolerance is under 0.0005 in
X	0.00004 in	Setting masters and lab reference	Rarely on a machine. Quoted on request

The usual rule of thumb: the gauge should be ten times tighter than the tolerance it checks. A ZZ pin checks a 0.002 in tolerance comfortably and a 0.0005 in tolerance poorly.

Graduation, chosen the same way

The ten-to-one rule applies to indicators too. A 0.0005 in dial is right for a 0.005 in tolerance. It is marginal at 0.001 in and wrong at 0.0005 in. Going to the 0.0001 in dial for everything sounds careful, but the short range means you spend the day re-zeroing, and a shop that re-zeros all day starts skipping it.

What wears them out

Pins that live loose in a drawer. A pin dropped on concrete gets a burr you cannot see, and it starts rejecting good holes. Keep them in the case, wipe them before use, and replace singles rather than a whole set. Single pins are quoted on request by size, class and direction.

For indicators, the killer is a side knock on the lever when the head rapids. Take it off before you jog.

How an order goes

Three things we need and what you get back.

The tolerance on the drawingNot the tolerance you wish you had. We size the graduation or class from it.
The range or the sizeFor pins, the full range or the single sizes. For an indicator, what you sweep with it and whether a long point is needed.
Plus or minus, if pinsIf you are not sure, tell us which limit you check. We will say which set suits.
The replyItem, class or graduation, a typical lead time and the price basis, usually the same business day.

Straight answers

Do you calibrate? No. We do not run a calibration lab and do not issue calibration certificates of our own. Where the maker supplies an inspection report with a set, it ships with it and the quote says so.

Who is this not for? Labs needing traceable master gauges with accredited certificates. Buy those from an accredited source.

The surface you are measuring probably came off a grinder. Grinding wheels and deburring tools are on the abrasives page. For runout on a holder, the tolerances are on toolholding.

Measuring inquiry

Nothing is charged from this form.