Tolerance Check: Is Your Gage Hanging By A Thread?
Posted on: 12 May 2022
Like any part, thread gages don't last forever. You know your thread gage is getting worn out when its tolerance falls below the manufacturer's specs for go or no-go clearance. Tolerance means permissible variation that allows the part to pass inspection.
Inspectors measure parts with gages that specify that the part is a go or no-go. Go means that the thread gage fits the part. No-go means that it does not. Sometimes, however, a thread gage that's been used constantly needs to be replaced. Or does it?
Know Your Gage's Thread Tolerance
Thread tolerances are important when you are measuring parts. If the thread on the part that you are measuring with the thread gage fits, it's considered a go. That means that the part is within the allowable tolerance to be usable and safe.
If the thread gage doesn't fit, it is considered a no-go. This means that the part could be either too tight or too loose when coupled with another part. Too tight means that the amount of force that you have to use to screw the part onto another part would be excessive. Breakage could occur. On the flip side, too loose, and you may have too much movement within the part assembly. This could facilitate rapid wear.
That is why it is important that each thread gage measurement falls within allowable tolerances for quality assurance. If inspectors are getting all go parts or all no-go parts, something's amiss. Your thread gage needs your quality assurance engineers to look at it. Sooner or later, all gages will need replacement. But if you can prolong its life and maintain tolerances, it is a best practice to do so.
Three Top Best Practices
First, every thread gage, including British thread gages or those engineered for your company only, must adhere to ISO quality standards. To ensure your gage stays in tip-top shape, it is a best practice to take a non-abrasive cloth to clean your gage before and after use to prevent unnecessary wear and tear. After hours of use, thread gages can accumulate metal shavings and grease. These shavings and oils can get caught in the teeth of the gage and throw off its accuracy. This can lead to premature gage replacement.
Second, the company you are making the part for may use different thread gages than you do. Always check before running a part through quality assurance to make sure that you are using the right gage for your project.
Third, consider recycling thread gages if you can. Your engineering department can determine if your gage can be used to measure shorter threads. This will extend the life of your thread gage and give you the best return on your investment.
Share