Hexagonal Drive Shaft Heads to the Finish Line

The drive shaft being machined into the patented hexagonal profile on a horizontal boring mill at Tech-Max Machine, Inc.

The drive shafts for Wind Harvester 4.0s are almost to the finish line at Tech-Max Machine (IL).  The photo above shows our IP protected (US Patent No. 12071930) hexagonal drive shaft “end (interface section)” in the step before painting with critical interfaces (such as bearing seats and the hex section) masked or selectively coated

Two drive shafts plus two upper and lower bearing housings will soon be sent from Tech-Max’s 100,000 square foot facility in iIllinois to join the three Schaeffler bearings per driveshaft and tower top plates at the drive train assembly facility with Action Machine in Indiana by the end of July. 

We are so happy with this invention and the companies like Tech-Max that have the machinery to make its unique shape for many. The main ones are that with it, we can use an inexpensive, super strong flatsided mast to more simply connect hinges and vertical braces from the mast to the arms. VAWTs have always used more expensive and problematic pipe type masts with flanges and horizontal welding. High preload bolted connections can improve fatigue performance and simplify assembly compared to welded tubular mast designs

The first step in the driveshaft process occurs after ScotForge, located a few miles away, hammer forges the basic shape of the shaft and ships it to Tech-Max. The photo below shows the driveshaft after several machining steps, prior to machining the hexagonal shaft end. Critical bearing seat areas are machined to tight ISO tolerance classes (such as h6 and r6) to ensure proper fit and load transfer.

Diagram of hexagonal connectors in patent

Tech-Max Sales Manager Tom Szkwarla explains: For this operation, the shaft remains stationary while a CNC‑controlled toolpath on a horizontal boring mill machines the hex profile into the shaft. The machine follows a programmed toolpath that gradually removes material to generate the hexagonal geometry. It is a fascinating process to watch because the final shape emerges from what initially appears to be a simple cylindrical shaft 

The total machining time for the hex operation is significant due to the size of the component, the amount of material being removed, and the precision required. While exact cycle times vary, this is not a high-volume operation where dozens of parts would be produced each day. The focus is on accuracy, repeatability, and maintaining dimensional integrity throughout the machining process.”

We expect to have photos and video later in the summer of how the precision interference-fit bearing rings are installed using thermal or hydraulic mounting methods on the drive shaft when that step occurs.

The drive shaft that has been forged, before machining begins to shape the hexagonal section