Test hammer calibration and maintenance

- Jan 12, 2018-

The test hammer is a very common construction non destructive testing equipment in nowadays, then how should we maintain it to ensure reliable test result and longer tooling life? There are some experience and methods shared to you below.


1. Under what status should we send the test hammer to a authorized verification organization for calibrations?


1.1 The accumulated strike times over 6000  

1.2 Any of the main part was replaced.

1.3 Spring holder front end not in the initial place or reset screw loosen

1.4 Has been subjected to serious impact or other damages


2. Under following conditions, users can calibrate by themselves.

2.1. need to perform continuous test for days, should calibrate it every day after daily operation
2.2. If found the calibration result not accurate, should do maintenance then calibrate again, if still not accurate, then should send to authorized organization to calibrate.



3. Under what conditions the test hammer needs maintenance  


3.1 Striked over 2000 times

3.2 Have doubt on test result

3.3 Calibration value not qualified


4. Test hammer regular maintenance method


1. Decouple the strike hammer and take out the core, uninstall the strike rod (take out the buffering spring) and triplet (strike hammer, pull spring, spring holder)

2. Use gasoline to clean every part, specially the centering guiding rod, strike hammer, the inner hole and impact surface of strike rod, after cleaning smear on the center guiding rod with a thin layer sew machine oil or watch oil, other parts do not smear any oil.

3. Clean the enclosure inwall, unsintall the scale ruler, ensure the pointer friction should be in 0.5-0.8N;

4. Should recalibrate the test hammer after maintenance, the qualified calibration value is 80±2



1. Do not rotate the zero adjusting screw rod on the end cap which has been fixed

2. The test hammer should be issued with calibration certificate after calibrated by the authorized verification