USBC publishes updated research report on string pinsetters

ARLINGTON, Texas - The United States Bowling Congress is sharing additional data and findings from research as part of a comprehensive scoring study of string pinsetters. A full data report is published on

Based off the collective data USBC has seen from the tests to date, a certification for string pinsetters to be used alongside free-fall machines for standard American Tenpins bowling would not be reasonable at this time. However, if significant changes were or would be made to string pinsetters and data supported these machines being used for standard American Tenpins bowling, USBC would consider it in the future.

USBC is investigating the possibility of certifying string pinsetters and string pin bowling as an independent category of equipment and competition, separate from free-fall machines and standard American Tenpins bowling.

After publishing a preliminary report in January 2021, the USBC Equipment and Specifications team continued its research, completing a series of comparative tests with more than 86,000 shots being made on multiple string pinsetters and free-fall machines.

The research featured testing using USBC's Bowlscore machine and Enhanced Automated Robotic Launcher (E.A.R.L.) to track pinfall and pin flight, a league simulation, analysis of string types and length, and pin testing.

Some of the key findings from these tests include:

  • Pinfall is significantly different between free-fall machines and string pinsetters.
  • String lengths and pit-end dimensions play a crucial role in the difficulty of split conversions as well as strike percentages.
  • Scoring is different between the string pinsetters tested. More data is needed to fully understand the variables and how they interact.
  • Several key issues have been identified where lack of standardization has resulted in differences that could be brought together with standardized specifications. These issues include:
    • String length
    • Pin consistency impact from drilling/affixing string
    • Curtain/backstop - layout in the pit in pin deck
    • Split-conversion percentage
    • String tension

String pinsetters currently are non-approved equipment and may not be used in USBC-certified competition, including USBC-certified leagues and tournaments.

If USBC does explore a certification standard for string pinsetters in the future, many of the manufacturing inconsistencies outlined in the report will need to be addressed and standardized for those seeking certification.

This could mean a wide range of equipment or installation specifications as well as potential rule changes to consider. An independent category of certification would be a meaningful step toward bringing string pinsetters into certified competition, while allowing time to continue research into the possibility of using them alongside free-fall machines in the future.

USBC will continue to publish updates as key milestones are reached, with the conclusion of the project scheduled for 2022.

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