-- The Home Page of the Finishing Industry
Serious Education & the most FUN
you can have in metal finishing smiley

No popups, spam, registration or passwords
on this site
current topics
topic 60790

Chrome plated pin gage is oversize

July 6, 2018

Q. I purchased Chrome plated Pin gages that seem to be expanding more in the heat than normal pins. I have class ZZ Pins that are .3135. Yesterday on the shop floor, they Measured(with micrometer) .31375 in the heat of the shop. After sitting in the Metrology lab (72 °F) it still reads .3137. I purchased a few of these Pins. I measured another pin from the same package at .3135 right where it should measure. Can someone explain why this could be?

iliana gutierrez
- Kenosha, Wisconsin

July 2018

A. Hi Iliana. I think that, for whatever reason, you have a defective or improperly marked pin which is actually .3137 dia. at 72 °F

The coefficient of expansion of chromium is lower than that of tool steel, which is about 11.5 x 10^-6 per degree K. If you measured .3137 at 72 ° and .31375 at 96 °F, that would sound just about right. 0.3137 x (1 + 11.5 x 10^-6 x 24 °F x 5/9) = 0.31375


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

If you have a question in mind which seems off topic, please Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.