Product Description
The Jayhawk Oval Fitting System (15‑2281) is a complete solution for fitting and drilling custom oval thumb holes in bowling balls. Consisting of the 36 most common sizes of Jayhawk Custom Ovals, this system gives pro shops a simple, repeatable method for matching oval thumb shape to each bowler’s hand and then duplicating that shape precisely on a milling machine.
Each fractional size in the set has three different widths, allowing you to fit both the thickness and width of the thumb with the same insert. To use the system, the fitter slides oval inserts over the bowler’s thumb until finding the one that fits comfortably all the way around. That insert can then be placed in a Jayhawk adjustable measuring ball so the customer can actually feel what the new oval hole will feel like before drilling.
The inserts are machine‑cut for accuracy and include a built‑in 45‑degree oval angle. Once you’ve drilled the round thumb hole and determined the degree of oval your customer needs, the included chart shows exactly how far to move the mill table on each axis to recreate the same oval dimension as the fitting insert—step‑by‑step for cuts such as .030, .060, and .090 widths. This makes the Jayhawk Oval Fitting System the first simple, standardized method for fitting oval holes and duplicating them reliably across multiple balls.
Jayhawk Oval Fitting System FAQ
What is included in the Jayhawk Oval Fitting System?
The system includes 36 custom oval thumb inserts covering 12 fractional sizes, each with three widths (.030, .060, .090), along with detailed instructions and a chart for duplicating the fitted oval on a milling machine.jayhawkbowling+1
How do you use the oval inserts to fit a thumb?
You slide the oval inserts over the bowler’s thumb until you find the one that fits snugly around both the thickness and width of the thumb. Once selected, you can place the insert into a Jayhawk adjustable measuring ball so the bowler can feel the grip, or set it aside until the rest of the fitting is complete.
What oval angle is built into the inserts?
The inserts in the Jayhawk Oval Fitting System are cut at a 45‑degree angle, which is a common oval angle used in many modern thumb‑fitting approaches.
How does the chart help duplicate the oval hole?
After drilling the round thumb hole, you consult the chart to see how far to move the mill table left/right and toward/away from you to reproduce the same width and angle as the fitting insert. For example, with a 1" hole and a 1" x .090 insert at 45 degrees, the chart gives precise thousandths‑inch moves to generate .030, .060, and .090 cuts step‑by‑step.
Is the Oval Fitting System compatible with the Jayhawk Measuring Ball?
Yes. The inserts are compatible with the Jayhawk adjustable Measuring Ball. This allows you to install a selected oval insert into the ball so your customer can feel what their new oval hole will feel like before drilling.
Who is the Jayhawk Oval Fitting System designed for?
It is designed for professional pro shops and fitters who regularly drill oval thumbs and want a standardized, easy method for both fitting and duplicating oval holes. It has been a staple in the industry for decades and is frequently packaged alongside the Jayhawk Professional Measuring Ball in pro shop equipment bundles.
