STH Thread Verification & Chasing Units

New Vista STH Thread Units

— For Automated Installations —

— For Robotic Applications —

…For thread verification and thread chasing. The most popular Thread Units in the World!

Bank of Servo-driven STHs for oil filter application
SHOWN: Bank of servo-driven STHs for oil filter application.
  • “GO” verification (pitch diameter).
  • “NO GO” verification (pitch diameter).
  • “NO GO” verification (minor diameter).
  • Rate: 90 filters per minute.
U.S. PATENTS 7,059,055 and 7,513,720


  • Quickly and automatically verifies or chases threaded holes (or external threads) by powering a suitable tool into (or onto) and out of (or off of) the part. Versions are capable of “GO” gaging, “NO GO” gaging, combination gaging or thread chasing.
  • Sensitive high speed drive allows the tool to stop in case of missing, short, or improperly formed threads. This creates a “reject” signal.
  • Spring-biased spindle prevents damage to end of thread at start of engagement.
  • Will verify blind holes (or male threads) accurately for thread depth (length). Will mount in any orientation.
  • Will not jam or stick in short or obstructed (reject) threads.
  • Does not subject the part (or the spindle) to high force or torque levels…even with a reject.
  • A single STH Unit will work with a variety of threads. No leadscrew is employed.
  • Proven out for your application before shipping.
  • Shipped with complete installation instructions. Integration is simple.

Motors; Voltages; Gearing

A typical STH callout looks like this: STH-500-SK-1X-R.

  • 500 = an ‘L’ torque unit.
  • 1X = direct drive; 3X = 3:1 gear reduction; 7X = 7:1 gear reduction.
  • SK = Kollmorgen servomotor; SM = Mitsubishi servomotor; D = direct current motor.
  • R = designed for robotic operation.

Model STH-500-SK-R1; Robotic TVU. 1
Model STH-1000-D-ES; for mounting on rapid-advance slide.

Specifications And Capacities For STH Units

  • Cycle times shown below are for thread verification applications, with servo-driven versions, and where the thread length is equal to the thread diameter.
  • The maximum thread lengths that can be gaged are 6mm (1/4”) less than the maximum stroke figures shown. If more stroke is required, order a –ES version.
  • The Units listed below are all foot-mounted.
STH-250 S M2 – M6 (#2 thru 1/4”) 32mm (1.25 in.) 0.8 seconds
STH-500 L M5 – M22 (#10 thru 7/8”) 32mm (1.25 in.) 1.0 seconds
STH-1000 L M10 – M38 (3/8” thru 1-1/2”) 32mm (1.25 in.) 1.5 seconds
STH-2000 XL M12 – M50 (1/2” thru 2”) 32mm (1.25 in.) 2.2 seconds
STH-2500 XXL M19 – M64 (3/4” thru 2-1/2”) 32mm (1.25 in.) 3.2 seconds
STH-3000 XXXL M50 – M100 (2” thru 4”) 38mm (1.50 in.) 4.0 seconds (for M50 size)
  • Additional dash-number designations:
    • Add –FL for flange-mount versions.
    • Add –ES suffix for extra stroke versions.
    • Add –PD suffix to mount the Programmable Thread Depth Option.
    • Add –R1 suffix after the model number if the TVU will be used with a robot.
    • Add –CMB suffix for “GO / NO GO” (combination gaging) versions.
  • Included with every STH Series Unit:
    • Mounted motor, with drive.
    • Mounted depth sensors.
    • Prox and motor cables.
  • Quoted as Options:
    • Slide or Robot to advance the Unit. For foot-mounted versions: a RAM-250 or RAM-350 Slide Unit from New Vista can be employed for this purpose. For –R versions, the Robot provides this function.
    • Programmable Thread Depth Option.
    • A PLC and 24 volt power supply (for control functions).
    • Thread Gage Members, Thread Ring Gages, Chasing Tools and Toolholders: Please order separately.

Applications Assistance

An Application Form is available from the New Vista website: Fill in the blanks and send it to [email protected]. Or you can get help by calling this U.S. telephone number: 410-342-3820, then 0, and then ask for Applications Assistance. We speak English and Spanish. A New Vista Applications Engineer will help you select the proper Thread Unit and Thread Gage or Chasing Members — and work with you if you need a special, or a system.

* These models are to be used for reference only. The final product may differ from the models shown. Please contact a New Vista Engineer for more detail.
1 Catalog Publication 208-032 describes Toolchanging Componentry used in robotic applications. Also, please see New Vista Catalog Publications 208-029 and 208-031 for the various Toolholders and Adapters that are used in automatic tool changing applications.