STH Thread Verification & Chasing Units

New Vista STH Thread Units

— For Automated Installations —

— For Robotic Applications —

…In use internationally, 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-SM2-1X-12.7-R

  • STH is the basic model designation.
  • 500 = an ‘L’ torque unit.
  • SM2 = Mitsubishi servomotor; SK = Kollmorgen servomotor; D = direct current motor.
  • 1X = direct drive; 4X = 4:1 gear reduction; 7X = 7:1 gear reduction.
  • 12.7 (or 16) is the output shaft diameter in millimeters.
  • R or R1 = designed to be wielded by a robot.

Thread Verification & Chasing Solutions
An STH-R mounted on a robot arm for verifying external threads.
A standard STH-500 tooled to verify internal threads.
A standard STH-500 tooled to verify internal threads.

Specifications And Capacities For STH Units

  • Cycle times shown below are for “typical” thread verification applications, with servo-driven versions, and where the thread lengths are twice the thread diameter. For very short, small diameter threads, cycles down to 0.8 seconds are possible.
  • 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 an –ES version.
250-SM2-1X-12.5 S M2 – M5 (#2 thru #10) 32mm (1.25 in.) 1.5 seconds
500-SM2-1X-12.5 L M5 – M22 (#10 thru 7/8”) 32mm (1.25 in.) 2.0 seconds
2000-SM2-4X-16 XL M12 – M50 (1/2” thru 2”) 32mm (1.25 in.) 4.0 seconds
2500-SM2-7X-16 XXL M19 – M64 (3/4” thru 2-1/2”) 32mm (1.25 in.) 6.0 seconds
3000-SM2-7X-16 XXXL M50 – M100 (2” thru 4”) 38mm (1.50 in.) 7.0 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 –CMB suffix for “GO / NO GO” (combination gaging) versions. Also for verifying high/low thread pitch diameter limits, as with pipe threads.
  • Quoted as Options:
    • Slide to advance the Unit. For STH foot-mounted versions: a RAM-250 or RAM-350 Slide Unit from New Vista can be employed for this purpose. For –R and ─R1 versions, your Robot provides this function.
    • Programmable Thread Depth Option.
    • 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 submit or send 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.