Odd- Electric Mechanics creeper

[fredk]

Hi All,

This is a bit odd, however it is closest to a go-kart so I thought I'd give it a shot here. Appreciate anyone's help.
Will follow-up with build pictures/status.

Bought a house w/out a basement, only a shallow below ground crawl space.
I'm gonna be doing a lot of crawling around down there to clean out construction debris and add drain/sump pump, remove gravel.
So, I happened to see my Dad's old mechanics creeper and though about building a very low slung motorized creeper to save my knees.

Ground is packed gravel, need wide wheels
Max height is maybe 22-24"
I'm 5' 11", ~200#, so total length/width might be 82" x 24", 250#.
Trying to avoid a steering wheel and go with foot steering w/front wheels on a cross-member?

I've got a Mig/Flux-core welder, and between my old shop skills and my BIL, we should be able to either knock up a frame or add onto the creeper I have.

I am looking at the scooter motors in the 400-500w range, as I don't need much speed.

Initial questions:

1. Does the power range look feasible for very low speed operation?

2. Should I be looking at a scooter motor with the gear reduction attached?

3. I'm thinking I need a max 10f/sec max, or 6.8 mph.
Per below, looking at using 10" wheels. Probably have to weld a sprocket to the drive wheel. Not sure how to figure out gear ratio/sprocket size/tooth#.

4. Being part Scottish, I am hoping to minimize cost and
use the HF wheels (http://www.harborfreight.com/10-inch-pneumatic-tire-30900.html)

I expect I may have to make the frame hang below the wheel centerline so I am only 2-3" above ground.



Totally appreciate any suggestions, and Thanks for your time!


Fred

 

[Flyinhillbilly]

Power window motors from a junkyard might be the ticket. Slow, small, powerful, and cheap.

 

[mckutzy]

Maybe a reconfigured mobility chair, they typically have a joystick, not meant to go fast, and can haul a fare amount depending on the type...

 

[Whitetrashrocker]

How about one of those new hoverboards on the front axle. Pivot and steer with your feet like you planned and then make a trailer for you to lay on.

 

[itsid]

first NEVER use HF wheels.. NEVER!

second: gravel... 500W.. could work... but frankly, I almost doubt that tbh... a 1kW motor with a matching controller can be had for ~120-150 USD (unite my1020 & matching yinlun controller)
you maybe able to save 50 bucks by cutting the power in half and end up with a kart'ish vehicle that's not up for the task.

Check this thread to see what power you'll need roughly,
just to be sure first.

'sid

 

[Bbqjoe]

Have you tried home depot?
I hear there's some cheap labor just standing around.

 

[Ebrownie]

first NEVER use HF wheels.. NEVER!

'sid

I know they are an absolute no no on a kart, but this thing will only be going 5 mph... which is pretty much how fast a wheelbarrow goes. Obviously they are still poor quality, but I think you could get by with them.

 

[Flyinhillbilly]

I know they are an absolute no no on a kart, but this thing will only be going 5 mph... which is pretty much how fast a wheelbarrow goes. Obviously they are still poor quality, but I think you could get by with them.

I agree.
This seems to be the rare exception to the HF wheel rule.

 

[itsid]

Well, they might hold for longer than a minute (as opposed to a kart)
but will that pay off?
bad quality is bad quality.

He'll probably need to change his tyres in the first few months of using it,
he'll likely bend the rim when trying to pry the old ones off...

And while he's not faster than a wheelbarrow, let me ask a different thing:

Would you install HF wheels to a wheelbarrow you need to rely on being functional on a more or less daily basis?

See, me neither frankly

'sid

 

[fredk]

Wow, thanks for all the replies folks!

1. I was under the impression windshield wiper motors were low power, however there is a YT guy with an ebike....

2. Mobility chair would indeed be great, slim picking on CL so far though.

3. I've looked at a lot of the hub motors, however they are more expensive, much more, it seems than plain escooter.

4. 1Kw probably is a better idea considering the time and money retrofitting would be, I agree.

5. HD, just moved from SF Bay Area to WNY. Not so much around here.

6. I know HF is junk, however one the 10" SKU's is supposed to be pretty reliable, and this is low speed. 468 reviews at 4+ Stars seems worth a shot at $24 - 20% coupon on the first go around. If not, I'll be back asking for cheap alternatives...

I've seen a few YT video's with people using W/W motors on bikes, and one guy using an 18 wheeler starter on a kart.
I'm thinking of going with what seems more powerful, the starter.
I know Japanese cars use a type of starter that requires less amperage, and was thinking of getting one of these to test with. Ahh, here: http://www.elreg.com/blog/direct-drive-vs-gear-reduction-starters

I'm thinking something off of a small 4 cyl. or even a Metro 3 cyl.

Please comment if I am being a dunce here...

 

[Flyinhillbilly]

Windshield wiper motors are low power, power window motors are not. We're talking about two different things. I think with the right gearing that electric window motors would be a pretty fair choice, you can get them cheap at any junkyard, an they run forward and backward by design. I think for hauling a human around on fairly level ground underneath a house that the HF wheels and tires will be fine.
I hope you're planning on posting a build thread when you start this project as I'd enjoy seeing what you come up with.

 

[fredk]

Thanks for the correction, power window motor.

I will check into it, however from what I understand while they are hardy in their own right, theres a good chance they'll burn out when in continuous duty. Read that some people have good luck with them when used in a PWM fashion, however that would entail more R&D on my end with ucontroller work.

I'll keep it in mind, however a small starter seems like it would definately have the power/torque from the word go.

Also looking on CL for used cordless chainsaws or 3/8-1/2 drills.

I will start a build-thread once I decide.

 

[Wheelchock]

I think that you are on the right track with the cordless drill motors.
Readily available, high torque, speed control, forward/reverse, fast re-charge + multiple batteries.
I built a small go cart using a pedal car frame, razor scooter tires and a 20Volt Dewalt drill motor for my daughter. It has a lot of torque (pops a wheely if not accelerated cautiously!), will go over a mile on a charged battery (and a mile return with the second battery .
Obviously you will want to slow it down even more, but there are many options.
Also, you have a cordless drill for your tool box when the project is over.

 

[fredk]

Couldn't help myself....

Just ordered a starter and solenoid/relay for a 2017 Suzuki Boulevard C50T for $30.

Found some good info:

Attach ebike sprocket- https://www.youtube.com/watch?v=fAB3z6XwOSk

Maybe attach a timing gear to axle- https://www.youtube.com/watch?v=XG8gWS_-CzM

Now to eBay to find a 40-50a PWM

 

[fredk]

Also eBay'd:

10-50V 40A PWM Reversible DC Motor Speed Control Controller CW CCW Pulse Driver
( 132085607715 )

LED Digital Voltmeter Ammeter Amp Volt Meter + Current Shunt DC 100V 50A Dual
( 151775490121 )

2Pcs 20W Waterproof LED 12V Daytime Running Light DRL COB Strip Lamp Fog Car
( 272594907016 )

Now I need to find sprockets.

 

[fredk]

Cool, picked up a laser tach from ebay for $8, will match my HF laser temp probe

http://www.ebay.com/itm/221942286516