Side-Drilled Hole — Definition & NDT Use
A small hole (typically 1-3mm diameter) drilled horizontally into a calibration block from the side, perpendicular to the scanning surface. Side-drilled holes are used in IIW and other reference standards to simulate point-source reflectors for ultrasonic equipment calibration and evaluation. They simulate small internal flaws and are excellent for establishing sensitivity and resolution. Proper positioning of side-drilled holes at different depths ensures full-thickness coverage verification.
On the job, Side-Drilled Hole sits between the procedure and the indication — its calibration record, serial number, and condition all flow into the inspection report and the audit trail. Calibration certificates, condition logs, and traceable serial numbers are what make the difference between an instrument that shows a number and an instrument whose number stands up in court or in front of an auditor.
The instrument's inspection scope is set by its OEM specification, its current calibration certificate, and any customer-specific qualifications that have been logged against it; a Side-Drilled Hole that is in calibration but unqualified for a customer's procedure is still off the job.
ASME Section V Article 4
Ultrasonic examination methods for welds and components.
ASTM E114 / E164 / E2375
ASTM straight-beam, contact, and wrought-product UT practices.
ISO 16810 / ISO 16811
General principles and sensitivity setting for industrial UT.
A frequent finding in audits is a side-drilled hole marked "in-cal" on the spreadsheet but with a current condition (damaged cable, missing cap) that would have invalidated the calibration if checked physically.
What does "Side-Drilled Hole" mean in NDT?
A small hole (typically 1-3mm diameter) drilled horizontally into a calibration block from the side, perpendicular to the scanning surface. Side-drilled holes are used in IIW and other reference standards to simulate point-source reflectors for ultrasonic equipment calibration and evaluation
Which standards govern the use of Side-Drilled Hole?
Side-Drilled Hole is most often referenced under ASME Section V together with the relevant ASTM practice or the matching ISO standard for the method; the contract or purchase order will name the controlling document and edition for any specific job.
What other NDT concepts should I read alongside Side-Drilled Hole?
The most directly related entries in this glossary are "reference standard", "iiw block", "calibration"; reading those together gives you the surrounding vocabulary used in inspection reports and procedures.