The physics is settled. The archer isn't.
A string builder's reference. Custom bowstrings built to a bow, and a library of physics-first writing that explains what your string is actually doing — written from a compound perspective.
Advanced Spine Selection
Find your exact arrow spine.
Not a chart range. Not a starting point. Your setup — draw weight, cam, arrow length, point weight — runs through a physics-based calculation and returns the precise spine number your arrow needs to be. Works for compound and recurve. Both have calculators. Neither requires a chart.
Featured Articles
Peep rotation: forcing a straight object into a helical form
Equipment & jigs — what you need at the bench
Paper tuning — what the tear is actually telling you
Back tension — how much is right
The helix — string structure
Target panic — understood
Interactive
Where is your shot?
A diagnostic quiz for compound archers. 17–18 questions about how you actually experience the shot — not what you think you should say. The result is an honest read on where your shot process is and what it needs next.
Free Tool
Sight tape generator
Shoot in your yardage marks, enter the slider positions, and get a printable sight tape scaled to your bow. No account, no AI, no ads — runs entirely in the browser.
Free Tool
Archery calculators
Arrow spine selector, FOC calculator (including reverse: find the shaft GPI for a target FOC), and stabilizer MOI planner — all on one page. Runs entirely in the browser.
Free Tool
Group size projection
Enter your bow platform, arrow specs, tuning depth, and shooting conditions. The model uses an error-budget approach to project your expected group diameter at any distance — and shows which factor is costing you the most spread.
Free Tool
Score tracker
Log Vegas 3-Spot, Lancaster, Single Spot, and 5-Spot rounds on your phone at the line. Tap where each arrow hits, track X count and end-by-end scores, and see your shot bias build over time. No account, no login — all in the browser.
Free Tool
Call your shot tracker
Tap where your pin was when the shot broke. Tap where the arrow hit. Builds a heat map of your aim vs. impact drift — and tells you if the gap has a consistent direction.
Bow Specs
String specs for 200+ bows
OAL, ATA, brace height, and string and cable lengths — verified against manufacturer data for Bear, Bowtech, Elite, Hoyt, Mathews, PSE, and more.
PARA · Visually Impaired (VI)
Custom PARA tactile archery sight
Built to World Archery PARA VI equipment requirements. Made to order — dimensions set to the archer's stance, draw, and anchor. Contact us for a quote.
Want one built for your bow?
Every Axial string is built to a specific bow and use case — equalized, twisted to a real target length, stretched under load, and served with materials chosen for the job. Not pulled off a shelf.
Custom builder · coming soon