Wall Update

I have been climbing on the wall for a few months now. Usually once or twice a week in addition to whatever other climbing I manage to squeeze in, and now that the weather is getting nice it is really motivating to be able to open up the garage door and get some fresh air while climbing. It’s not climbing outside but it’s pretty sweet for a tuesday night.

I digress. I think that climbing on the wall through the winter usually at temps of around -5 °C the chain stretched, that or I am wearing it out faster than I would expect. Either way come spring time some of the planks weren’t quite getting pulled around in time to make it onto the return guide on the back of the wall and it was stalling. So I had to cut the return channel a bit and bend the return guides out a little more by hand, shown below. Bending by hand didn’t make for that pretty a product, but things are running again and I didn’t have to tighten the chain.

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Guide flange cut longer and bent out further. The bend started at the slotted hole previously. The black goo on the boards is a combination of wax (lube) and mill-scale, it’s not a problem.
The next version of this design will definitely have longer lead ins like this from the get go. It will help avoid problems and I see no trade off in doing it. I will climb on it like this for a couple more months then check the chain to see if it has stretch significantly. If so I might consider going to a heavier chain than the #40 I am currently using.

Also, I had added the slotted hole so the lead ins would be easy to bend by hand, but with a crescent wrench it was pretty easy to bend the longer ones by hand. So next time there will be no holes and they will be a lot sturdier.

I am putting on 200 to 400 feet per session and I am guessing I have put at least 6000 feet of mileage on the wall and there are no serious problems cropping up so I think it is doing pretty well for a prototype.

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Update: Guard and Holds

I now have holds (not just hunks of 2×4) and the finger guard on the wall. Video Here.

Having had the wall running for a few weeks now, I can say that I am pleased overall with how it is functioning, no break downs yet, and that it is proving a usable piece of exercise equipment. It hasn’t supplanted my trips to the gym but I no longer feel any impetus to go to the gym without a ready partner. And I genuinely can squeeze in a 1/2 hour climbing workout when I don’t have time to go to the gym, just as I had hoped. So I am climbing more.

I only recently acquired a decent stash of holds so up to this point the “route” on my wall has been pretty hard and I haven’t been able to do any endurance training. The upside of this has been to demonstrate to me that the wall is a VERY effective anaerobic endurance training tool. I can get a mad pump on in about 5 minutes, without any trouble. And interval training on the wall is alot of fun.

Given the response to my last video I elected to get the guard finished rather than leaving it in the corner to rust. The brush on the guard isn’t as stiff as the ones I have used at my work so the guard will need a little tweaking to compensate for the sagging brush. As is it still keeps your fingers out of the pinch point but I am losing valuable inches of climbing room.

Success!

With the bigger motor I can run the wall at 15 feet per. minute (fpm) with no problem, without a climber on the wall. I might be able to go faster but I haven’t tried it yet. I guess having tripled the available torque was a safe bet.

15 fpm is a quick but not a super fast climbing pace. For the endurance and interval workouts I have tried so far it is certainly fast enough. I will play with it and post an update when I find out what its top speed is.

I made up a simple plywood bracket and hung all the power supply and driver, off the gear box. This kept all the wiring nice and tight. You just have one power cable and one control cable running up to the bundle of stuff up top. It would also make things easy to enclose if you wanted to make a weather resistant version. For now the controller is sitting on a paint can next to the wall but I will be building a bracket to put it up around face level.

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My bundle of electronics at the top of the wall. Not pretty but entirely functional and it definitely could have been worse.

 

And here is a video of me climbing the wall at 14 fpm. It starts slow and ramps up to full speed by about 20 seconds into the video.

Electrical/Software Design

My new, massive NEMA 34 motor and driver arrived in the mail a little while back. This thing is going to have enough torque to drive the wall no matter how much drag there is in the tracks! (3x current motor)

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New motor and driver setup

I was going to build a simple tone generator circuit with a 555 timer and a big control knob to adjust the speed. Using the rough design below.

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Basic wall controller circuit. Scribbled out on the back of some other work.

But while I was digging parts for this circuit out of my junk electronics box I came across my old handyboard. I built this thing more than a decade ago and have hardly used it, but as the name implies it is actually handy…. or it should be.

I started programming it to control my treadwall and found I wanted a little more functionality than it normally offers. So I wasted two weeks trying to adjust the timer output from a non-standard pin. ugh. But it is now set up how I would like and ready to go. Just not as handy as it could have been.

Right now the available menus look like this:

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I did add a big control knob for adjusting speed and other options as an additional means of user interface as well as using the start and stop buttons on the handyboard. I will likely add another button too, cause it feels like it needs it.

I am thinking I will add a motor to adjust the angle of the wall in the future. At which point it will be really cool to add workout modes that adjust the wall angle automatically.

I would love to hear ideas for additional workout modes. Please comment with suggestions! Include ideas for workouts that change wall angle if you have any.

Testing Update

A quick update: I did more testing last night after adjusting a plank and managed to get the wall up to 10ft/min; a very reasonable climbing speed. Ultimately, i would like to get it running up to 15 or 20ft/min.

I suspect that the stalling issue I had recently was due to a change in temperature as much as issues with the planks. Basically, the small, low torque motor I am using only has to overcome the friction in the gearbox. It doesn’t need to really drive anything, but when the temperature drops and the oil becomes more viscous that drag in the gearbox increases.

At 10ft/min the motor is turning at 600rpm, and having a torque curve like the one below, I am guessing it is putting out, at most, 200 oz*in of torque at that speed. So very little torque.

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I think my options for dealing with this are: lower oil viscosity, use a lower ratio gear box, or a higher torque motor. The use of a lower ratio gearbox might seem counter intuitive but if we go from a 60:1 gear ratio to a 15:1 ratio the motor will be at the same operating point and the wall will be moving much faster. Since the motor isn’t really driving the wall, it just needs to overcome the friction in the gearbox, which will be comparable, this should work. In the end I will probably end up trying all three options.

The 60:1 gearbox wasn’t my preferred choice when I was designing the thing i was hoping for 20 to 30:1 but it was at princess auto and it was cheap. I guess this is what happens when you compromise on your design.

More Testing

This week I pulled out and trimmed a couple of the planks that rubbed badly and things seem to be running smoother. I also did a test run with the wall set to 30° overhang. Aside from the climbing being really hard (I seriously need to buy some holds with texture) it ran pretty well.

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Me climbing on the wall, set to overhanging. Thanks to my shoe for taking the picture.

On the back side of the wall the chain was dragging on the cross members (due to the previously discussed lack of a track on the back side) but it wasn’t noticeable. I still think I will try to fix this in the near future, just to prevent undo wear on any components.

I am very impressed with how solid the thing feels with the wood in place. I had added more bracing to the design after playing with just the frame, but now I think I will take it out.

BUT when I put the wall back to vertical the damn thing seems to stall before ramping up to full speed. I’m not sure what the problem is but I’m guessing it is just a tighter fitting plank binding. I guess we’ll see.

Planks on Testing

Planks are finally on. It took a lot of planing and sanding, but they are on.

After getting the planks on I was anxious to start climbing. I looked around my garage and realized: I don’t own any climbing holds. I could have mooched and borrowed holds but I thought it would be faster to just start screwing whatever crap I had laying around my garage to the wall. Morgan also volunteered some scrap wood to the effort.

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The completed wall and very professional looking holds. I am pretty excited about this!

Here is a gif of my first, low speed test. And yes I realize my choice of climbing pants is around 15 years behind the times. Or you can see the full video in all its glory. Most of the noise in the video is from a crane across the street, not the wall.

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My initial thoughts are that the whole thing runs pretty well and feels solid. It squeaks a bit but a little more wax in the tracks will fix that. (I need to find some bee’s wax. It, apparently, is a better lubricant for wood.) The chain isn’t spaced perfectly on some of the planks which leads to thumping noises as they go over the drive sprockets. So I will be pulling off those planks to adjust their fit.

I do wish the whole thing was about 6″ taller just to lend a little more buffer when you are climbing, 12″ would be even better. I don’t think you would be able to make a wall any shorter than my 9′-2″ ceilings usable, unless you made it permanently overhanging. If I were to start from scratch I would knock a hole in the ceiling and have the top poke into the attic.

Running at ~30° overhang would let you fit the track portion of this wall under an 8′ ceiling, which would still be usable. So there are options for this to work with a lower ceiling.

After all the trouble it took to make the planks I would consider laminating 2 layers of 3/4″ plywood together to make the planks or trying 1″ plywood. This would eliminate the issues I had with twisted boards, bowed boards, and varying thickness. So it would remove labour from modifying boards while adding some by requiring gluing them together. I suspect it would lead to a better end product though. You would be able to use cheap plywood for the back layer and better stuff for the outside and it will make it easy to countersink the t-nuts so you can used the standard bolt for a given climbing hold. AND you could ensure that all the planks would fit snugly in the guide channels so they wouldn’t feel wobbly without any sanding.

Additionally, in the future, I would try including a track on the return side of the wall as well as the climbing side. This would keep the planks running vertically, and prevent the chain from rubbing on the crossmembers in the wall regardless of chain tension and wall angle. It could be a looser fitting track to keep friction down. I think this addition would make it easier to control chain tension and make the unit easier to use. I might try to add this feature to this wall just to try it out.

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Planks on return side aren’t in a track and sit crooked. This isn’t a huge issue but it does make chain tensions a harder to adjust, and it means when you have the wall set to overhang the chain will sag in the middle and might rub unless the chain is tight.

Next step will be electrical design. First, I think I will just purchase a prefab stepper driver, power supply, arduino etc and get this wall running as a stand-alone unit. Later I think I will design a custom board with everything on a PCB, maybe add some whizzy features like wifi so you can control it from your phone.

Lastly, I want to mention how impressed I am with my Bosch cordless rotary hammer (this one if your curious). I had only intended to use it for putting up routes, but my corded drill wasn’t suitable and I ended up using my hammer drill for everything on the planks. So it drilled around 150 t-nut holes (1/2″ x 1.5″ deep) and sunk around 150 1.5″ decking screws on about half a charge.

If you are shopping for a drill for route development this one is light enough for drilling on lead at 6.25 lbs and will punch more than a dozen 3/8″ x 3″ holes in moderately hard limestone per charge. However, if you only plan to bolt on rappel I would consider finding a heavier drill with a bigger battery (more Ah) to get a few more holes per charge. I am considering buying a bigger battery for this one; bosch makes compatible batteries with almost 3x the capacity.