Building a dog walk

[wildo]

So today I decided to start a dog walk build. I'll use this thread to create a "how-to DIY dog walk." My main goal was to design a dog walk that anyone could build, meaning- no welding. Well, to be fair- you'll probably need to be a bit brave, and certainly will need your significant other to help with muscle power, but otherwise, you should be able to make this no problem. Anyway that meant I needed to find a material other than aluminum for the frame. After some thought, I settled on a standard 2x12 (12' long to meet regulations) for the planks. The problem is that a board this long is very flexible and once my 75 lb dog starts sprinting across it, it simple will be too wobbly. My solution is to use a piece of galvanized steel unistrut. This material can be found in the electrical aisle at your local home improvement store. So follow along if you like. This will be a multipart process...

Material List:

• 3- 2x12x12' pressure treated lumber
• 4- 2x4x10' pressure treated lumber
• 4- 2x4x8' pressure treated material
• 3 - 12 guage 10' Unistrut
• 15 - 3/8" Unistrut cone nuts
• 15 - 3/8" x 2 1/2" bolts
• 15 - 38" flat washers
• 8 - 3 1/2" brass hinges
• 8 - 1/4" x 2" bolts
• 8 - 1/4" x 2 1/2" bolts
• 16 - 1/4" lock nuts
• 16 - 1/4" flat washers
• 16 - 1/4" fender washers
• 4 - 3/8" o-rings

Task #1 Plank Stabilization
We need to stabilize the 2x12's so that they won't be so wobbly with our heavy GSD's sprinting across them. To do this, we can bolt a piece of Unistrut to the board.

First, find the center of the 2x12 and the unistrut, and mark the 2x12. You since the wood plank is 12' long, and unistrut only comes in 10' lengths, you should measure in 1' from either side on the board. Then center the unistrut width-wise as well:


Then you want to mark five equidistant holes through the unistrut (so one at both ends, one 2'6" from either end, and one at 5'). Mark these holes with a pencil. Then you can drill a small pilot hole at the center of each mark:


Next, you will need (hopefully) the only specialized tool you'll need for the build- a forstner drill bit. This is a special drill bit much like a hole saw, except that it drills a flat-bottomed hole. We are essentially using it to countersink a bolt head You should use a size equivalent to the size of the flat washer (which was 7/8" for me):


Once the hole is drilled, it will look like this. Note the flat bottom. This can only be accomplished with a forstner drill bit:


Now that the countersink is complete, you can complete the hole for the bolt- 3/8":


Next, put the flat washer on the 3/8" bolt:


And pound it through the hole:


At this point, you can turn the board upside down and see the bolts sticking through:


Finally, you just need to slide the cone nuts into the unistrut, flip it onto the bolts, and tighten it down. This is basically nothing different than a really heavy erector set:


You will need to make three of these assemblies.

So how effective is this, you ask? Well- see for yourself:

YouTube - Stabilizing board for Dog Walk

YouTube - Stabilizing board for Dog Walk

You can see that the board by itself is very wobbly and wouldn't work well for a dog walk. But with the strut attached, it is very secure. Note that it does rock back and forth parallel to the board, but that is just the 2x4 blocks I have it sitting on. Also note that while it still deflects with me standing on it- it isn't wobbly our bouncy any longer. It's very, very strong and secure. Finally- when both Pimg and I are standing on it in the video- that's a whopping 355 lbs standing right in the middle of the board! It's VERY strong! (And also very heavy, as you can see.)


Tomorrow I will build the legs.

[TaraM1285]

Exciting! I'm so jealous that you have space for a full-sized dog walk at home!

[wildo]

I measured my backyard a couple days ago, and it came out to basically 82' x 90' of more/less usable space. Well- as long as it doesn't rain. I have practically no grass at all back there, and it turns into a giant mud pit when it rains... I have just shy of .5 acre in the city. Here's my yard on 11/18/07 when I actually DID have grass (what happened to it all!?)


The backyard is 95' to the back fence, and 87' wide

[TaraM1285]

Nice! I'm moving this summer and will be looking for a place with a nice sized yard like that to work with, if so I'll definitely be revisiting this post for dogwalk plans.

[MaggieRoseLee]

Great job! You gonna copy/paste it into the DIY (Do it Yourself) Sticky? Please!!

Though we need a completed shot...

[Lin]

wowwwww, nice yard! And the building a walk stuff is way over my head

[AgileGSD]

Good luck with your dogwalk - I'll be curious how it works out being reinforced with steel. IME wooden dogwalks generally warp pretty quickly and it doesn't seem to matter how they are kept.

[wildo]

Task #2 Legs/Middle Assembly

Well, I took a ton of pics during the process but since I was making it up as I went, a lot of them showed inaccurate measurements. So I'll be a bit more general in this series of pics.

Cut two boards the width of the 2x12:


Line the hinges up at the ends of these two boards. This allows you to mark the holes. The outermost holes can't be used since they land so close to the edge of the board. This shouldn't be an issue:


Drill the holes and insert the 1/4 bolts. Be sure the backs of the hinges are against the boards:






Next we can start building the legs. I did a lot of measuring plus trial and error to get the leg length right. I ended up at 50" long with a 15 degree angle. I put the boards out on the floor, marked and drilled the hinge locations, and assembled the hinge assembly to the legs:




With the legs bolted together, I added the chain stays at the bottom. I put these 7" from the bottom, and again cut the ends to 15 degrees. To match the angle of the legs. Not shown in the pic is a second set of braces 8.5" from the top of the legs. You'll see them in later pics.


I drilled a 3/8" hole in the chain stay for the eye bolt:


Next I turned my attention to mounting the legs to the top board. I notched the hinge assembly as well as the cross pieces. This is called a lap joint. I just used a jigsaw for this. Had I thought this far ahead, I would have cut this prior to assembling the hinges.






Finally, I was able to screw the leg assemblies to the top board:




...And test it out:


It is extremely rigid and adjustable from 20" to 48". I was able to stand on it at 20", but with the legs splayed so far out like that, I didn't push it. I am comfortable standing on it from 24" up. Here's a video of our progress today. Before anyone says anything- I know it's a big no-no to ask Pimg to enter from the side. Yeah, yeah... I just was trying to get her on it to show how strong it is- nothing further. I was a bit surprised at her reluctance to jump up. I assume it is because it's something new, and relatively small surface area...

YouTube - Dogwalk

YouTube - Dogwalk

[wildo]

Very, very excited to say that I finally figured out how attach the ramps to the main center section. Despite the fact that you can get a set of ramp hinges here, they supply no info on the size or durability of the hinges. That is not acceptable in my book. So, for $5 more, I made my own. I used a set of gate hinges, but modified them by drilling a 1/4" hole through the male end to receive a hitch pin. This will ensure that the ramps are secured onto the center section.

Here's the male end of the gate hinge and hitch pin:


And I put the female end into the center section:


The ramps will be able to simply hook right onto the center section with no fuss:


And with the hole I drilled, I can secure it with a washer and hitch pin:


So the final product looks like this:


So all that is left is to bolt the unistrut to the ramp sections, and drill the holes for the male end of the gate hinge in the ramp ends. Well, there's painting too- but it's made 100% out of pressure treated material so I am not too concerned about that. I guess I do still need to figure out if I want to do the sand/paint thing for traction... I haven't really come up with any other options.

[wildo]

Finished the dogwalk tonight (omitting painting). Enjoy the pics...

I created a filler using PVC for the gap where the ramps meet the center section:


You can see the filler is pretty heavily modified in order to fit around the mechanical fasteners. It wasn't that difficult to cut though, and I think it was well worth it for safety:


Here you can see what the fasteners look like locked in place:


And here you can see how the hitch pins work:


Finally, a shot of the gate hinges without the hitch pins in place:


And a couple overall shots:




Lastly, I made a video showing Pimg on the dogwalk at 24" and 48" as well as how the hinging system works for the ramps. Enjoy! This sure was an extra fun project to build!

YouTube - Dogwalk II

YouTube - Dogwalk II