Video: New Quick-release Twin-screw Vise Technology

Michigan engineer Len Hovarter has developed a new vise mechanism that looks more like a magic trick than bench hardware.

The vise hardware is patent pending and should be available in September, Hovarter says. This hardware is just so cool, that I wanted to share it with you now — in case you are planning on building a bench this fall. I’ve ordered a set of the hardware from Hovarter, so I’ll be testing the stuff myself. Until the hardware becomes commercially available, we’ll just have to enjoy these photos and a short movie.

So what’s so amazing about it? Well it’s a quick-release vise and from the outside it looks like a traditional twin-screw with two hubs. When you open the vise, things start to look curious. The two shafts between the jaw and the bench are smooth , no threads.

Turn either handle clockwise a little (they are linked by a steel plate under the benchtop) and the vise cinches down hard. You also can skew the jaws a little for working on tapered work.

It’s a mechanism that doesn’t look like it should work. And in fact, Hovarter didn’t think it would work when he first devised it.

The tale of this vise begins in 2005 when Hovarter decided to improve his hand-tool skills and was getting frustrated with his workbench , a solid core door mounted on 2x4s. He started researching benches and liked Mike Dunbar’s workbench with a big twin-screw vise. But he thought it would be cool if it was a quick-release vise.

“I went through hundreds of sheets of paper sketching ideas until I thought of using a flat ‘transfer bar’ to transfer motion between the two clamp housings,” Hovarter wrote in an e-mail. “The first prototype was a complicated monstrosity which required a third shaft to effect clamping. I thought if I could combine the clamping and handle rotation into two shafts I might have a workable vise. I didn’t think the vise in its current form would work. And in fact the early prototypes didn’t work.

“I just kept trying different things to eliminate the problems. Eventually I ran out of problems and was left with a vise. I wish I could say the idea just ‘popped’ into my head, but it really was a lot of trial and error. I still have not improved my hand tool skills, but now I have a decent bench and the vise I dreamed of five years ago.”

And he has some other dreams. Hovarter is now working on a prototype quick-release leg vise using his hardware; it won’t require a parallel guide. He also has plans for face vises, end vises, carving vises, shoulder vises, leg vises and an enclosed tail vise. He’s also working on a web site to take orders and getting the assembly instructions ready for customers.

While some details could change between now and when the vise is released, here are Hovarter’s current plans.

The twin-screw hardware will be made in the United States. Most of the machined parts will be made on Hovarter’s CNC mill; other parts such as the vise’s rack, pinion and ductile iron casting will be supplied by companies that specialize in making those parts. The vise will be supplied as a kit of loose parts that will be assembled into the housing.

“The assembly is pretty easy to do, and I think it is fun even after I have done it hundreds of times,” Hovarter writes. “The assembly of the parts into the housing does not require tools other than hands.”

In addition to the hardware, the vise will come with instructions for making the clamp hubs, handles and knobs. He’ll also sell those wooden parts separately.

The price for the hardware kit for the twin screw vise isn’t firm yet, Hovarter writes, but it will be “in the $350 range.”

And for those of you who are wondering, Hovarter has the chops to pull this off. He’s a mechanical engineer who graduated from Purdue University and learned machining in middle school shop class and carried that all the way through college with machine design. He grew up in Fort Wayne, Ind., where his dad had a sheet metal shop for his heating and air conditioning business, and also dabbled in woodworking.

Hovarter was recently working for an auto parts supplier that went into bankruptcy; now he is employed by a major car manufacturer as a heating and air conditioning systems engineer.

“I would love to retire and have vise making be my full time job, and woodworking my full time hobby,” he writes.

For more information on the vise, contact Hovarter at len@lencotools.com

– Christopher Schwarz

Other Vise Resources You Should Investigate

– Check out the other twin-screw vises from Veritas and Lie-Nielsen Toolworks. These versions are linked by a chain instead of a transfer bar.

– Want to read about workholding until you are blue in the face? Buy the blue book “Workbenches: From Design & Theory to Construction & Use.” A companion book to this will be available this fall.

– You are not a bench geek unless you visit workbenchdesign.net.

– Finally, if you haven’t heard, I have a new DVD on building the workbench featured on the cover of the August 2010 issue of Popular Woodworking Magazine. The DVD shows how to build a monster 18th-century workbench using hand tools.