4.4.3 Entering bowler's span (Full and Cut to Cut)

Entering bowler's span (Full and Cut to Cut)

4.4.3 thumb

This page walks through the process of entering a bowler's span measurements into the Spectre Cloud spec sheet form. For a full explanation of the difference between Full Span and Cut to Cut measurement methods, and how to take each measurement from a bowler's hand, see 4.3.2 — Entering span measurements (Full Span and Cut to Cut). This page focuses on the form itself — what to select, where to enter values, and what to check before moving on.

🛠️ Step-by-Step: Entering Span in the Spec Sheet

Open the spec sheet and navigate to the Span section.
Confirm the Span Type selector is set correctly before entering any measurements:
- F — Full Span (edge of thumb hole to edge of finger hole)
- C — Cut to Cut (center of thumb hole to center of finger hole)
- O — Oval (see Book 05 — Oval Calculator)
Enter the middle finger span in the Middle field.
Enter the ring finger span in the Ring field — or use the 5/16" auto calculation if you have measured d. See 4.3.6 — Ring finger 5/16" rule.
Review both values against your fitting sheet or hand measurement notes before proceeding.

Verify with Spectre team: confirm whether the Span Type selector appears at the top of the span section or inline with the measurement fields, and whether changing the span type after values have been entered clears the fields or retains the numbers.

⚠️ Before You Save — Quick Checks

Span entry errors are among the most consequential mistakes on a spec sheet — a transposed value or wrong span type will position the holes incorrectly even if every other measurement is perfect. Before moving to the next section, run through these checks:

Check	What to look for
Span type matches measurement method	The `F` / `C` selector matches how the span was actually taken. A Cut to Cut value entered under Full Span — or vice versa — is the most common span error.
Middle span is entered in the Middle field	Transposing middle and ring is easy when working quickly. Middle span is almost always longer than ring span — if your middle value is shorter, double-check.
Values are in inches, not millimeters	If transferring from a legacy sheet that used millimeters, convert before entry. A millimeter value entered as inches will produce a hole drilled far too close to the thumb.
Values fall within a plausible range	Adult fingertip Full Span typically falls between `3⅝"` and `4⅝"`. A value well outside this range for an adult bowler is worth a second look before drilling.

🔄 Changing Span Type After Entry

If you realise the wrong span type was selected after values have already been entered, correct the selector before saving — do not attempt to manually adjust the numbers to compensate. A span value is only meaningful in the context of the method used to take it. If you are unsure which method was used on a legacy fitting sheet, re-measure rather than guess.

Tip: If a bowler's new spec sheet is being created by cloning an existing one, the span type carries over automatically. Confirm it matches the method you intend to use for the new drilling before proceeding — especially if the bowler is switching from a Cut to Cut fitter to a Full Span workflow.

✨ Common Entry Mistakes and How to Avoid Them

❌ Wrong span type selected — always set F or C first, before typing any numbers.
❌ Middle and ring transposed — read the values back from the screen against your notes before moving on.
❌ Millimeter values entered as inches — if a legacy card looks unusually high (e.g. 107 for a middle span), it is almost certainly in millimeters.
❌ Ring span copied from middle without applying the 5/16" rule — even if both spans look similar, they are rarely identical. Use the auto calculation or measure independently.

4.3.2 — Entering span measurements (Full Span and Cut to Cut) — full conceptual explanation
4.3.6 — Ring finger 5/16" rule — auto and manual calculation
4.2.3 — Selecting span type (F, C, O)
4.4.4 — Thumb slug and insert entry
Book 05 — Oval Calculator

Tip: Span is one of the few measurements on a spec sheet that does not change unless the bowler's hand changes — unlike thumb size, which can vary visit to visit. Once you have a confirmed, comfortable span on file for a returning bowler, cloning is reliable. The span type selector is the one thing always worth a visual confirmation before drilling.

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