Creeper Designs

[FallingDuck 0]

Dose anyone know where I can get some general specs for a creeper or some other type pf belly board?

[tdog 0]

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Dose anyone know where I can get some general specs for a creeper or some other type pf belly board?

Um.... Rule 1: 4 casters, not 5...

Rule 2: There are no more rules...

A bit of 3/4" Plywood, with foam glued on the top, and casters bolted on the bottom, seems to work well.

If I was doing it... I would put a piece of plywood on the floor. I would have an average size friend lay on it, arms up, legs spread to shoulder width.

I would trace the body including the legs. (Hope your friend doesn't mind where you will be putting the pen).

Top cut at shoulders.

Legs cut somewhere between 1/4 and 1/2 way between the crotch and the knee (closer to the crotch).

That is how I would do it...

Eloy has some stainless steel plate cut to this shape. Very durable and no splinters. But most places have plywood.

P.S. There are premade plastic units, but I prefer the ply or metal ones...

[DougH 270]

Has any one considered making an offroad design? We don't have any smooth surfaces at my DZ besides the parking lot.

Considering how well the tandem students drive I thought it would be in our best interest to try and build a set with heavy duty pneumatic casters so we could creep on the grass.

"The restraining order says you're only allowed to touch me in freefall"
=P

[PhreeZone 15]

Wider is better then narrower. I fell off a creeper that had its casters too close together for a few dozen times last year. Thing kept tipping to one side when I'd do more then a 90.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Eule 0]

Doing a search on "creeper design" found this thread with some ideas.

I agree with that thread that it's worth spending a few bucks on the casters. Besides the places mentioned in that thread, Grainger and McMaster-Carr have a decent selection of casters. Grainger has branch offices in larger cities, but sometimes they don't want to do retail. The university may have an account with them, and many large industrial and warehouse facilities will have accounts, if you know anyone that works at a place like that. McMaster doesn't have branches but will happily take a credit card and ship it to you.

As far as bolting the casters on, the simplest way would probably be to use carriage bolts. If you do this, you might want to work it so the heads of the bolts are flush with the board - this way you're less likely to feel the bolt heads when you lay on it. The easy way to do this is to crank on the nuts until the bolt heads sink into the plywood a little. The right way is to "spot face" the wood with a spade drill bit that is the same diameter or slightly bigger than the bolt head, then drill the clearance hole for the shank of the bolt. You can use the same approach to use normal bolts, but you have to go a little wider (for socket clearance) and a little deeper (the bolt heads are a little thicker). With either kind of bolt, use nuts with a nylon locking ring, or plain nuts with Loctite (a little drop will do ya), or even a nut and a jam nut. This will keep the nuts from backing off.

Another way is to buy some T-nuts - these are nuts with a spiked flange. You drill a hole in the wood, then hammer the T-nut into the wood from the top of the creeper. Then put the caster on the bottom and install a regular bolt up through the caster into the T-nut. You do need to choose your bolt length carefully so you end up with enough threads engaged - too short and the bolts will tend to tear out of the nuts; too long and the bolt ends will poke you when you're lying on the creeper. If the bolt is just a little too long, an extra washer or two under the head will probably do it. If it's a lot too long, thread a nut onto the bolt, cut the bolt to length with a hacksaw, and then thread that nut off of the cut bolt - the nut will help fix any threads that got boogered up when cutting. You might use the same nut for this on all your bolts, then throw that nut away when you're done, as the nut threads are liable to be a little boogered up by then. The "correct" tool for this is a thread cutting die. For this approach, use Loctite on the threads to keep the bolts from backing out.

Don't use wood screws or lag screws to attach the casters. You'll strip out half of the holes when you try to screw them in and the ones that you don't strip out will pull out after a short time.

For padding, a couple of types of foam were mentioned in that thread, and you can find more at your local craft store. If you use foam, cover it in something... it tends to tear, and some kinds will oxidize and start to crumble after a few years. For covering, you can get vinyl, fake leather, Naugahyde (do you have any idea how many Naugas they have to kill to make that stuff?!), or similar at a local fabric shop. Use staples (from an industrial staple gun - not your office stapler) or large-headed tacks to hold the material to the bottom of the board.

If you don't want to do padding, sand everything really well. Paint it if you want. Paint or no, do a few coats of polyurethane varnish - this will make it smooth and help with the splinters.

If the creeper will get stored by leaning it against the wall, you might want to put some rubber bumper "feet" on one of the edges. This will keep it from sliding on a slick floor when propped up against the wall, and will help keep the covering from wearing out on any kind of floor.

One of the photos in the above thread shows a creeper with handles cut into the wood. That's convenient but it might be a minor PITA to get the covering on if you use padding and covering. Another way would be to get some nylon webbing from your friendly local rigger and make a soft handle. Clamp the end of the webbing between two blocks of wood and drill a hole through the wood and the webbing. Then bolt the webbing ends to the wood with a bolt, fender washer, and locking nut.

If this is for the University skydiving club, you might be able to commandeer some University resources to help make the creepers. You'll probably have to buy the parts yourself, but the engineering and/or theatre departments will probably have a workshop with the needed tools that you can use.

Eule

PLF does not stand for Please Land on Face.

[Eule 0]

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Considering how well the tandem students drive I thought it would be in our best interest to try and build a set with heavy duty pneumatic casters so we could creep on the grass.

You could just bolt pneumatic-tired casters onto the bottom of a regular creeper, but I don't know how well that would work, since those casters tend to be a lot taller than hard-tired casters. Moving forward and backwards would be OK, but I think the creeper would tend to tip on side-to-side movements.

A better way would probably be to fabricate some brackets in kind of a "Z" shape. The bottom part of the Z bolts on to the bottom of the creeper board, and the caster bolts on to the top part of the Z. The board would sit close to the ground, between the casters. This would be more stable, but would also limit how close two creepers could get side-to-side, which might be a problem for dirt diving some jumps.

Further afield, make the creeper board a little longer in the back part (between your legs), then bolt a weedwhacker/chainsaw engine to it or maybe an electric motor. Put a fan on the motor shaft and maybe a bicycle innertube around the bottom outside edge of the board - a hovercreeper!

Or, use regular creepers, but take the casters off of the bottom. Build a plywood platform with a grid of closely-spaced small holes. Put a big blower under the platform and you've made a giant air-hockey table.

Eule

PLF does not stand for Please Land on Face.