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4.1.5 Bridge: standard bridge sizes and their purpose

4.1.5   concept

The bridge is the distance between the near edges of the middle and ring finger holes on a drilled ball — the strip of material, or land area, that holds the two finger holes apart. It's one of the smallest measurements on a spec sheet, but it's an industry-standard value that depends on grip type, and Spectre Cloud defaults it for you.

📏 Standard Bridge by Grip Type

The bridge default is set by the bowler's grip type:

  • ✅ Fingertip — 1/4" — the standard default for fingertip fits.
  • ✅ Conventional — 3/8" — the standard default for conventional fits.

Spectre Cloud applies the correct default automatically based on the grip type recorded for the bowler (see Autofill Bridge, below).

⚠️ The 1/4" Warranty Minimum

Whatever the grip type, 1/4" is the hard floor. Ball manufacturers will not warrant a ball that cracks if the bridge was drilled narrower than 1/4" — below that width, the land area between the finger holes is too thin to reliably survive repeated impact.

  • ✅ 1/4" is the fingertip default and the universal warranty minimum.
  • ✅ Conventional defaults wider, at 3/8".
  • ❌ A bridge narrower than 1/4" risks cracking the land area — and voids the manufacturer's crack warranty if it does.

🛠️ Autofill Bridge in Spectre Cloud

When Autofill Bridge (2.6.5) is enabled, Spectre Cloud pre-populates the bridge field with the standard value for the bowler's grip type — 1/4" for fingertip, 3/8" for conventional — so you don't need to enter it on a routine drill. The fitter only intervenes when a specific, deliberate reason calls for a different value.

🖥️ Bridge on the Spec Sheet

The bridge field sits in the insert and finger hole section of the spec sheet.

  • ✅ It's shown in whatever unit and format your account uses — fractional or decimal, per your display settings.
  • ✅ The autofilled value can be overridden by typing a different measurement directly.
  • ✅ A manually entered bridge is saved to the sheet's history and is visible when the sheet is reviewed or cloned.
  • ✅ When cloning a spec sheet, the bridge carries forward — confirm it's still appropriate for the new ball before saving.
  • 4.1.4 — Pitch terminology: Forward, Reverse, Lateral, Zero
  • 4.1.3 — Grip type definitions: Fingertip vs. Conventional
  • 4.1.2 — Span types: Full Span, Cut to Cut, Outer to Cut, Hole to Hole
  • 2.6.5 — Autofill Bridge: 1/4" fingertip, 3/8" conventional
  • 9.x — Tips & Troubleshooting: narrow bridge and land area considerations

Tip: Let Autofill Bridge set the grip-appropriate default — 1/4" fingertip, 3/8" conventional — and treat 1/4" as the floor you never drill below. Going narrower than 1/4" for any grip gives up the manufacturer's crack warranty, so only do it for a specific, documented fitting reason.

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