Ask the expert: Sherpa
from Daizen News 1 May 2012
We started using Sherpa fasteners in 2008, experimenting to determine their viability. Now, Sherpa is a must-have fastener in Daizen’s timber framing.
Many connections work with wood joinery, and we do not push ourselves to use Sherpa, but when we see a challenging situation (like a long spanned beam to receive a floor joist normally in a dovetail or simply a housing), we use Sherpa so as not to take any wood out of the main beam, thus keeping it at maximum strength. Dai asked Maik Gehlof, Sherpa’s manager of technical support, to explain the Sherpa to us.
Q. Maik, can you give a brief history of Sherpa and describe how they are used in today’s market in Europe? I use it not only structurally, but also for stairs and railings.
A. Hi Dai, Sherpa was born from the need for a connector that is easily installed and assembled.
In 2005, the Austrian company Harrer needed a connector solution that just wasn’t available, so they came up with their own: the first Sherpa. Made of steel, it worked just as well as their successors today made of cold-rolled aluminum. Steel had some drawbacks; it’s not only heavy, making the connector harder to handle, but it also rusts and is much harder to machine than aluminum. Optimizing the Sherpa connector started right at its birth and will continue on with every new generation.
Today’s European market is a very competitive one. Structures get larger, wackier, and more dependent on their connections, while having very tight budgets and timelines. The Sherpa connector is tailor-made for this.
Sherpa is a standardized system with a known set of parameters, so it’s easy and fast to design with them. As you mentioned, Dai, you are able to keep main beams at their full cross-section, so they can be smaller, saving resources and money. Since Sherpa connectors are pre-installed in the shop’s controlled environment and even the screws are labeled for easy verification, pre-manufacturing is fast and efficient, which Europeans are very keen on as it controls both cost and quality. Onsite, crane time is minimized, as there is no need to line up bolts or maneuver very heavy beams into place.
All told, you have a product that allows you to save money at several stages, but foremost it gives you a way to budget and schedule a project accurately. That is what the European competitive market is asking for and what the Sherpa connector is able to deliver.
The shape of the connector resembles the traditional dovetail, offering numerous advantages that Sherpa connectors borrow and improve on since there is no short grain to fail. This image shows the cuts along the long grain.
You are absolutely right, Dai, on the multitude of uses for the Sherpa connector. We have a dedicated series of connectors—the assembly series—designed for projects like stairs. And, of course, a Sherpa connector in the hands of a creative person can result in very interesting structures.
A closer look at the connections and their curious symmetry.
Here’s how Sherpa connectors go together (YouTube).