From Current Schuler web site;
The Schuler Joint - "The first challenge I faced as a cuemaker was to develop a better joint. The ideal joint is 'nature's joint,' that is, no joint at all, as in a one-piece cue. My goal in designing the Schuler joint was to duplicate, insofar as possible, the hit, the hit transmission, and the weight distribution of a one-piece cue. Hit transmission is defined as the vibrations that move up the cue to the player's hand to give him feedback on each shot.
"Several joint designs were in use when I started making cues: piloted, flat-faced, and the all-wood joint that had long been popular in Europe and the Orient. The piloted, stainless steel joints were strong, but very heavy. That extra weight in the form of a large hunk of metal in the middle of the cue acts as an inertial stop to the dynamics of the hit and its transmission. It also poses serious problems for properly balancing the cue [See Weight Distribution and Balance below].
"The few flat-faced joints that were both relatively light and designed with wood-to-wood contact offered good hit transmission, as did the all-wood joint. They were, however, not strong or durable enough, at least to my mind. The all-wood design is also the most climate-sensitive joint because the threads will always expand and contract in response to changes in relative humidity and temperature.
"What I wanted was a combination of a piloted and a flat-faced joint, offering the advantages of both and the disadvantages of neither. And after a good deal of research and development, that is what I ended up with. The Schuler joint is piloted, but it has even more wood-to-wood contact surface than the best flat-faced joints. The piloted design assures structural integrity and durability, while the wood-to-wood contact optimizes hit transmission.
"The Schuler joint is also very lightweight, thanks in part to using aircraft aluminum for the shaft insert and drilling out the brass joint pin. A lightweight joint enhances hit transmission while contributing importantly to the balance of the cue.
"The Schuler joint was the first interference fit joint in a cue. Interference fit means that the pilot on the shaft fits into the corresponding cavity in the butt tightly enough to create friction, or interference, between the two components. This ensures that the cue will never loosen during play. An interference fit joint is harder to build because of the tight tolerances required, but the benefits in terms of strength, performance, and durability are well worth the extra work.
"Aesthetically, the Schuler joint affords the ability to use any decorative material at the joint - ivory, buckhorn, exotic wood, brass, stainless steel, plastic, et cetera - without affecting the performance or balance of the cue. The 'work' the joint does takes place internally, so the material used for the outside sleeve of the joint coupling is essentially a cosmetic consideration.
"When a stainless steel or brass joint 'look' is desired, my design allows the outside metal sleeve to be quite thin. Thus we are able to provide the look that many players prefer, without the penalties of extra weight and poor hit transmission that are typical of metal-jointed cues."
Weight Distribution and Balance - "The entire Schuler joint adds at most only 13 grams to the weight of the cue. And because I've never used a weight bolt in the butt, the weight of the cue is distributed along its entire length. This contributes significantly to the balance of the cue. A well-balanced cue will feel lighter in the player's hands than it really is. It will also feel and perform more like a one-piece cue."