Small Diameter Gages

Small Diameter Internal Functional Size/Pitch Diameter Inspection – (⅝” (.625″) to 1½” (1.500″) Diameters)

Pitch diameter and functional size inspections are pivotal to nearly every threaded connection. This can be especially true in smaller diameters, but these smaller diameters require a unique gage design to perform the proper inspections.

The SPG-6000 line of thread inspection gages measures internal and external functional size and pitch diameter of thread diameters between .625″ and 1.500″. Mainly, these gages are used on ANSI and ISO standard straight thread forms. Primarily among these groups, the gages are used on the ACME, Stub Acme, Stub ACME Modified-1 & -2, Metric & MJ, and UN, UNJ, & UNR Series of threads. However, these gages are versatile in that they can be modified to inspect nearly any type of thread in our .625″ to 1.500″ size range. The SPG-6000 can be equipped with either thread rolls or contact points. Contact points are applied for pitch diameter measurement, while thread rolls inspect functional size.

Pitch diameter inspection

Pitch diameter inspection requires the addition of contact point arms to hold the contact points. Contact point arms are sold in sets of two. Our standard contact point arms require straight shank contact points. Contact point arms designed for threaded shank contact points are available at additional cost

For functional size inspection, thread rolls attach directly to the gage. Thread rolls for certain thread types may have a designated set for internal threads or external threads, while other thread types have one set of rolls for both internal and external.

The SPG-6000 can be set using our MIC TRAC™ gage setting systems, rod standards, calipers, gauge blocks, or micrometers. For best results, Gagemaker recommends our MIC TRAC™gage setting systems or rod standards. For gage setting dimensions regardless of setting method or selecting additional contact points, our helpful, easy-to-use TDWIN™ thread engineering software program may be required.

Contact points, contact point arm sets, thread roll sets, gage setting devices, and software are all sold separately.

Gagemaker offers matched precision ground thread rolls for a variety of small diameter thread types. Thread rolls attach directly to the gage. If you do not find your pitch or thread type listed, additional thread rolls may be available. Please contact customer service for more.

To measure pitch diameter on small diameters with our SPG-6000 series of gages, contact points and contact point arms are required.

Gagemaker’s contact points are manufactured with carbide balls. Standard contact diameters are held to tolerances of ± .0002″. Contact point sizes are matched closely to thread inspection wire sizes. These contact point sizes are used in the TDWIN™ software program (sold separately). Contact points are sold individually and separately.

“SP” contact points only fit straight shank “SPA” contact point arms. Our “STPA” threaded shank contact point arms require threaded shank contact points, found here. Contact point arms are sold separately as a set of two.

Below, we’ve provided a list of our more popular straight shank contact points and contact point arms. However, if you do not find your pitch or thread type listed or need custom contact points, please contact customer service for more.