Simple, Adjustable, Flarable Crack Machines

Lifting a weight with a ring lock in a handscrew clamp

Living in rural Montana near vast quantities of granite is amazing for climbing...part of the year. Some of the locals are tough enough to enjoy wading through snow to climb dripping rock in fridged temps. We recent transplants from more temperate climates will need to get creative with our training if we hope to keep up come spring. 

These rocks are dripping wet and covered in snow and ice at the moment

I've always sucked at ring locks and off fingers and I would like to train those and a few other specific types of jams this winter. I think I've found an ideal tool, 10" Wood Handscrew Clamps.

Fist Jam

Handscrew clamps are a nifty bit of mechanism that my Dad uses in his shop for holding pieces of wood together while glue sets. Each clamp consists of two long blocks of hardwood mounted on threaded rods with handles so that you can adjust the width and flare of the clamp.

Without any modification they are perfect for all sorts of finger, ring and fist jams as seen in the photos above. Adjusting the flare allows you to make the the jam easier or harder.

I've been lashing the clamp to a free weight and dialing the flare so I can hold a jam for under ten seconds and then doing sets (say three sets of ten) like a weightlifter (I use a hangboard the same way). You could also hang them and use them like rock rings though I haven't tried this yet.

The corners are a bit sharp (like some real cracks) and I might take some coarse sandpaper to them at some point to smooth out the sharp bits and roughen up the faces.

Maximum Width of this clamp is about six inches. 

It is flarable...

...in two directions.

You can quickly adjust the width by spinning the clamp.

They don't really work for hand jams which require more surface area than the jaws offer. To solve this I will probably attach boards inside one of my two clamps. I also have some 12-Inch Handscrew Kits (unfortunately not available through amazon at the moment) and some 8 foot 2x12's that I plan to turn into a ceiling height crack machine.

Future plans include adapting for hand and thin-hand jams and an 8 foot crack machine

I was originally considering mounting the clamp kits at odd angles to allow the crack to be bomb-bay flared but I think this is impractical which means it might be quicker to just order 12-inch clamps. There are a couple of things I need to figure out to make this work well:

• How to mount the crack so it can be adjusted and flared but can't shift while in use. 
• Some kind of crank and chain system to allow quick adjustments. Turning the shafts by hand is too slow when you can't spin the clamp.
• An easy way to mount the crack so it can be tilted into an overhang or roof crack.

I'll post updates as I get all this figured out.