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Crack Climbing Machine Plans

Original Post
Jacob Krenn · · Boulder, CO · Joined Aug 2008 · Points: 120

I'm looking to build a homemade crack machine for winter training, and haven't been able to find any legit plans online thus far. I'm thinking about something roughly 20' tall, and plan on suspending it from a fixed anchor inside my barn/workshop at a slightly overhanging angle. I have the common carpentry skills to build a fixed size crack, but would like to build something that can maintain several jamming sizes (i.e.- fingers to rattly fingers to thin hands to hands, etc) in one continuous crack. I have seen systems incorporating 2X6's bolted together with lug nut systems which can be adjusted throughout the crack, but would like some feedback before I start designing. Any input/suggestions/experience on the subject would be helpful. Thanks!

Jeremy H · · Unknown Hometown · Joined Jul 2007 · Points: 350

I had the adjustable style crack for awhile. be careful with making it to overhanging it just makes it really painful an you won't use it very much. I used textured paint to it wasn't so slippery. As far as design I am sure you have the idea. One side is fixed in place. then you put a bolt through it and lock a nut down tight. Put on another nut and adjust it to the desired width. Put on the second board, then the last nut. Washers everywhere is a good idea as well if you dont want the nuts to dig into the wood. As far as having a fixed size crack, I would make a wide hands crack the drill thin board shims on the inside to make sections smaller. I would also use 2 x 10s or bigger if you are going to go for sizes as big as hands. I would also put some small wood block foot holds on the outside of the crack so when your feet are just killing you you can still climb.

Good luck.

Jacob Krenn · · Boulder, CO · Joined Aug 2008 · Points: 120

Thanks Jeremy! That's the basic idea I was going to run with, and I was thinking about putting small crimps on the sides of each board, so, if necessary, I can resort to arete style face climbing. I plan on going 20' ft. plus, and I have a self-belay set-up in mind, so if I do get pumped, I can just hang and re-coup. Any suggestions for paint/wood? I was thinking pine, and didn't know what sort of paint to use/avoid. Did you sand the insides to avoid splinters?

Brett Brotherton · · Arvada, CO · Joined Jun 2008 · Points: 121

I have one made out 2x8s that is about 10 feet tall, held together with bolts so I can adjust the size. I can't remember what type of wood it is I think it may be pine. I was lazy and did not sand the insides, if you carefully select your wood pieces you should be able to get some with a good enough finish to use right off the bat. As far as paint I read that trying to paint or texture just made it painful. I don't really adjust mine use it at hand size and I can tell you there is absolutely no need for texture. I have done it vertical and overhanging and you can get solid jams w/o any texture plus then when you get on real rock it should be easier. Don't rely on your self belay too much it is great practice to downclimb.

Kevin Stricker · · Evergreen, CO · Joined Oct 2002 · Points: 1,197

If you use schedule 80 PVC(electrical conduit) as spacers for your bolts you can cut them at several sizes and use them to change the size of the crack. 2x6's will not work so well as you can reach through to the back from tight hands and up. Better to use 2x10's or 2x12's and use two bolts two inches from the front and back every two feet along the length of the crack. You can get away with longer stretches between bolts but will be able to open up the crack with a good jam.

Wooden cracks are very painful at overhanging angles, it will be challenging to face the pain if you are training in the cold. I would recommend taping up before sessions. I also would recommend using a router with a 3/8" roundover bit or at least sanding the inside corner to make it more comfortable.

Amos Patrick · · Estes Park · Joined Dec 2001 · Points: 337

I had a 25deg overhanging crack in my old woodie and loved it. It was not adjustable though, just fixed for hands (actually it was exactly the thickness of a 2x4). Personally, I would stay away from texture or paint. Mine was bare wood without any sanding. At first I found it very useful to have little jibs for my feet until I developed the correct jamming technique. You are going to want at least a 2x10 or else it will be to shallow. As Kevin mentioned, these will be surprisingly easy to flex apart so I would butt a 2x4 against the back of the 2x10 as if you were going to make an I-Beam.

Dan M · · Boulder, CO · Joined Sep 2005 · Points: 165

Crack machines are easy.
1)Beg, borrow, or steal some scaffolding planks. The smoother the better

2)Bolt them together for whatever size you want. I recommend hand crack size so you can lap the shit out of it.

3)Attach some hinges to the bottom of the two planks.

4)Bolt a couple of 2X4's to the hinges as your base

Your new crack machine is now ready to go. Hang the planks from some rafters or a tree and adjust the angle to whatever you want from vertical to way overhanging. I had this design for several years. Smooth wood is better. Use some tape gloves. The boards will flex as you climb. This is awesome as your jamming technique will have to be perfect. Eventually you'll be able to campus on hand jams.

Limited space? Try a crack machine hangboard.

1) Bolt two boards together about 2 feet long and 10 inches wide.

2) Use 4 12'' long threaded rods so you can adjust the size. I recommend fist size as this is a more natural position to do pull ups from.

3) Wrap both boards with Curity Kendall climbing tape and bolt one board above your door frame ala hangboard style.

4) Impress your friends with sets of 10 fist jam pullups.

jmeizis · · Colorado Springs, CO · Joined Jul 2008 · Points: 230

I didn't want to start a new thread about this so I'm adding it here.

Anyone think about doing two framed pieces of plywood about 2 or 3 feet deep to practice everything from tips to chimneys? I'm wondering if threaded rod would be strong enough for something like that or if there would be too much flex in the rod. The plywood I'd be less worried about flexing if it had solid framing behind it but that's why I'm looking for some feedback.

How many threaded rods do you think I'd need? It sounds like texturing the inside isn't a good idea, sanding though? Need someone to bounce ideas off of.

slim · · Unknown Hometown · Joined Dec 2004 · Points: 1,103

a friend of mine has an OW crack built in a similar fashion. it uses plywood, and i think has some framing behind it. otherwise you will probably need to double up 2 pieces of 3/4" plywood to keep it from flexing. 3/8 inch threaded rods should work.

i had a crack machine in the past, and instead of making it adjustable, i used multiple planks side by side. this is a bit more expensive and time consuming to build, but saves you a lot of time changing sizes. instead of adjusting the bolts, you just move over a couple inches. i had probably 6 or 8 sizes from tips to tight hands. perfect hands are kind of a waste of time as they are too easy (unless it is extremely overhanging).

the error i made was trying to paint it, using sand in the paint. as others have said, just make sure the wood is sanded/doesn't have splinters. the bald wood is just right - not too grippy and not too slippy.

Jon Griffin · · Glenwood Springs, CO · Joined Feb 2009 · Points: 195

hey jacob,

Not sure if it has been stated already but putting skateboard grip tape inside of the crack is the easiest and best way to provide some texture inside the crack... Also for your different crack sizes, I would just make your different widths in sections and throw them up... It wouldn't be a continuous splitter, but at least you could have all your different sizes... Though it would not be adjustable though, which would prob be a big pain anyway. Have fun climb on!

Will S · · Joshua Tree · Joined Nov 2006 · Points: 1,061

Go with multiple planks/cracks, non adjustable, side by side. Might not even cost any more or much more because you won't have to invest in the all-thread and nuts/washers etc, just a little time to cut spacers from scrap.

Otherwise you'll quickly tire of adjusting the thing (I speak from experience). Also get something to use as screw-on foot jibs or your toes will protest if you're always trying to cram them into 1 1/4" or 1 1/8" cracks. Since you get almost no friction off the wood, the feet in the crack on hard sizes don't work well and you're really trying to train hand strength/technique anyway...just use small enough jibs that you can barely use them (it'll take more body tension to use tiny ones).

DO NOT put skate grip tape in there. You want it to be hard, not easy, and that shit will wreck your skin in short order, especially if you are pumped and sliding out on every move.

Make the whole rig tiltable so you can make it as steep as you want. 1/8" variations is a good "step", it's amazing the difference between 1", 1 1/8", 1 1/4"....I'd basically go with 6 total at 5/8", 3/4", 1", 1 1/8", 1 1/4", 1 1/2"...any bigger is a waste unless you go all the way to wide cups/tight fist and fist. Perfect hands is a waste for sure.

D Smith · · Marble, CO · Joined Aug 2010 · Points: 5

Here's what I did...

I took 2- 2x8's and positioned them parallel tall-wise.
I then drilled holes (rows of 2, about 1 1/4" from each edge) at 1 foot on center. This keeps the 2xs from bowing between each row.
I used 3/8" all-thread with washers on each face of the 2xs with a STRONG spring between the 2xs. This keeps you from having to use nuts on the inside... making it easier to adjust. Just make sure the collapsed spring goes as small as you want. I think you'd have to make two. One for fingers to small hands, the other for small hands to stacks. I just did the larger.
Grippy tape or sanded paint for texture.

I hung this almost horizontal and could stay jammed in with hands.

Kaner · · Eagle · Joined Jul 2006 · Points: 2,280

After my first trip to IC, I need to improve my crack endurance.  Has anyone put tape on the inside of the homemade cracks?  Instead of taping hands every time or using texture, just tape inside of boards?

Brian in SLC · · Sandy, Utah · Joined Oct 2003 · Points: 21,711
Kaner wrote:

Has anyone put tape on the inside of the homemade cracks?  Instead of taping hands every time or using texture, just tape inside of boards?

Is that to help keep the boards from getting those nasty, weeping pressure bruises?

Bryan · · Minneapolis, MN · Joined Apr 2015 · Points: 457

Thanks for bumping this thread. I'm just rebuilding my garage and would be able to put something like this in there. I can imagine fixing it to the cross beams (hanging) on the roof but are people anchoring to the ground as well? I have very limited carpentry skills/understanding but I want to take on projects like this in order to improve them. I think I would do fixed sizes next to each other: slightly overhanging fingers (with foot chips at first), rattley fingers, tight hands, perfect hands, and cups.

Guideline #1: Don't be a jerk.

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