First 3D printed golf club shaft: what it changes for engineers

• 1
  Why the first 3D printed golf club shaft is a geometry problem
• 2
  Layer direction and load path in a printed shaft
• 3
  Wall thickness, ribbing and where printing wins
• 4
  CNC turning still finishes the tip and hosel
• 5
  How to qualify a printed shaft before it reaches a player
• 6
  Printed shaft versus drawn metal shaft: when each one fits

A putter shaft looks like a tube. It is not. The wall carries bending from the head, torsion from the grip, and a small compression load from the swing. On a metal shaft those loads are handled by a constant section with a few tapers. On a printed shaft you can thin the wall where stress is low and thicken it near the hosel, which moves mass down toward the head without adding a separate weight.

That freedom is the whole point of the first 3D printed golf club shaft. Patrick and Scott Snarr and their partners set up Snarr3D to print custom putter shafts and shift weight distribution, aiming at better speed and distance control for the player. The engineering claim is weight placement, not a stronger material.

Printing a shaft also removes the joint between shaft and hosel. One printed piece means no epoxy bond at the highest-stress point of the assembly, and no bond line to creep under repeated loading. That is a real gain, and it is measurable in a bend test.

The trade is anisotropy. A printed wall is not uniform in every direction, and the next sections explain what that means in practice.

Most metal additive processes build in horizontal layers with the part axis vertical, so layer planes sit perpendicular to the shaft axis. Bending stress in a shaft peaks along the axis. That puts the weakest interface exactly where the stress is highest, which is the opposite of what you want.

The usual answer is to print the shaft lying down, so the axis runs in the build plane. Bending then loads the material along the layers instead of across them. The cost is support structure along the full length, more post-processing, and a longer build. Neither orientation is free.

Torsion behaves differently. A printed tube with layers stacked along the length carries torque reasonably well because the shear runs in-plane. A tube printed upright concentrates shear between layers, and a putter sees very little torque, so the upright build survives. A driver shaft would not.

This is why the putter is the right first product. Low swing speed, low torque, short length. The same geometry in a driver shaft at 45 in and 100 mph head speed is a different problem, and printed walls are not there yet.

Minimum wall thickness depends on the process and the alloy powder. Below roughly 0.8 mm, thin walls tend to warp, and the as-built surface gets rough enough that the effective wall is thinner than the model. A printed putter shaft usually lands between 1.0 mm and 1.5 mm at the thin sections and thickens toward the hosel.

Internal ribs are the cheapest stiffness you can add. A printed tube can carry three or four longitudinal ribs that raise bending stiffness without raising mass much, because the ribs sit near the neutral axis in torsion and away from it in bending. A drawn metal tube cannot do this without a weld or a mandrel.

Variable wall thickness is the same idea taken further. You can taper the wall along the length so the section modulus follows the bending moment curve. In a constant-section metal shaft, the material near the grip is mostly doing nothing. Printing lets you delete it and put the grams near the head.

Where printing loses: fine surface finish, tight concentricity, and a clean tip diameter. Those are turning operations, and they do not go away just because the part was printed.

A printed shaft is near-net shape. The tip diameter, the hosel bore and the butt end all need to hit a number, and printed surfaces do not hold ±0.005 mm. Turning the tip on a lathe with a soft jaw or an expanding mandrel is the normal route, and it takes minutes per part.

Concentricity matters more than diameter here. If the tip bore runs out relative to the shaft axis, the head sits at an angle, and the player feels it as a closed or open face. Chasing that with a printed feature is unreliable, so the tip is usually printed oversize and turned true to the axis.

The butt end needs a clean cut for the grip. A printed end has a rough rim and a slight taper from the top layers. Facing it in the lathe gives a flat seat and a known length, which is what a grip install depends on.

If the shaft carries a metal hosel adaptor or a weight plug, that part is machined separately. Our 5-axis and mill-turn cells hold ±0.005 mm on 6061, 7075, 17-4PH and Ti-6Al-4V, and parts ship in 3–5 days once the print is in hand.

• 1
  TipPrint oversize, then turn to the final diameter and concentricity.
• 2
  ButtFace the end so the grip seat is flat and the length is known.
• 3
  HoselMachine any adaptor or plug, do not print the fit.

Start with a bend test on the finished part, not on a printed coupon. The coupon tells you the material, not the shaft. Load the shaft in a three-point setup at the tip and at the grip end, and record deflection at a known load. Compare that to the same shaft after 1,000 cycles to see if stiffness drifts.

Then check the tip fit. Measure the turned tip diameter and the runout against the shaft axis. A tip that is round but off-axis is worse than one that is slightly small, because the head alignment error is what the player notices.

Torque is the third check. Clamp the butt and apply a known torque at the tip, then measure the twist. On a putter this number is small, and a printed one-piece shaft usually beats a bonded two-piece assembly here because there is no bond line to slip.

Finally, log the print parameters per serial number. Layer height, build angle and powder batch all affect the finished wall. Without that record you cannot trace a stiffness change back to the build.