SST PURE vs. Spine Alignment: What Is the Difference?

SST PURE is a specific patented, computerized shaft-analysis process. “Spining” is a broad term used for several manual methods of identifying shaft characteristics. SST PURE uses sensors, proprietary software and a standardized analysis to identify the shaft’s most stable orientation.

Last updated: October 1, 2026

SST PURE, spining and FLO compared

	SST PURE	Spining (spine alignment)	FLO (Flat Line Oscillation)
What it is	A patented shaft analysis and alignment process	A loose term for several different manual techniques	A manual technique for observing shaft oscillation
How it works	Sensors and proprietary software analyze the shaft’s structure and performance to locate its Neutral-Axis™	Varies: flexing the shaft in a clamp, rolling it in a tube-like device, and other methods	The shaft is set in motion and the builder watches for a flat, in-plane oscillation
Relies on	Computer measurement	Individual judgment	Visual observation
Documentation	An SST PURE Shaft Analysis Report for every shaft	None standard	None standard
Who can do it	Authorized SST PURE licensees using an SST PURE Shaft Alignment System	Any club builder	Any club builder

What “spining” means

Spining is a nebulous, undefined term that a lot of different people use to describe a lot of different processes. To some people, spining means putting the shaft in a clamp and deflecting it back and forth. To others, it means using a tube-like device to judge the straightness of a shaft. Because there is no single method, two builders who “spine” the same shaft can reach different conclusions.

What FLO means

FLO stands for Flat Line Oscillation. It is a manual technique some club builders use to observe how a shaft oscillates and find an orientation where it moves in a flat line. It has been used for decades, but it depends on what the builder sees rather than on computerized measurement.

How SST PURE is different

The SST PURE process is an engineering-based procedure that performs a structural and performance analysis on every shaft to locate its most stable orientation, the Plane of Uniform Repeatability. Because the analysis is done by computer, errors that might come from human judgment are removed. Every PUREd shaft comes with an SST PURE Shaft Analysis Report that documents the result.

In independent Golf Laboratories robot testing, drivers with shafts in the SST PURE orientation finished 13.2 yards closer to the center line on average than the same drivers with shafts in a suboptimal orientation. See the testing and data.

Is shaft PUREing the same as spine alignment?

No. The terms are sometimes used interchangeably in golf discussions, but SST PURE refers to a specific patented process and equipment system. Spine alignment can refer to many different manual techniques.

Can a club builder do SST PURE without an SST PURE machine?

No. SST PURE is the name of a specific process performed with an authorized SST PURE Shaft Alignment System. A club builder may use other shaft-alignment techniques, but those methods should not be represented as SST PURE.

How to make sure you are getting SST PURE

Use an authorized licensee. Every location in the official SST PURE fitter directory is an SST PURE licensee.
Ask for your Shaft Analysis Report. If someone says they can do “the same thing as PUREing,” ask for an official SST PURE printout. Learn how to read your report.
Look for the PURE mark. PUREd shafts are marked with a line for assembly, printed at 12 o’clock for ease of installation; the actual SST PURE plane is 90 degrees from that line.

Why terminology matters

A golfer searching for “shaft puring” may find builders describing manual alignment services as equivalent. SST PURE is a specific branded and patented process, and a shaft should only be described as SST PUREd if it was analyzed on the SST PURE system.

Which should a golfer choose?

It depends on what you want. If the goal is SST PURE analysis, a Shaft Analysis Report and the SST PURE orientation, the work needs to be done through an authorized SST PURE fitter.