Wheeled vehicle construction (cont from tracked thread)

robotland · Post by **robotland** » Tue Mar 14, 2006 3:28 pm

Atar, I believe that your enthusiasm and ingenuity have given me a much-needed transfusion of creative energy in regard to my own vehicular project. Thanks, man.

Atar · Post by **Atar** » Wed Mar 15, 2006 1:08 am

Thanks guys, I might look into the bike steering-head idea. And Robotland, I must say that I'm grateful I was able to share some of that creative juice across the net

Creative juice all around!

Now, to find some stuff to get that welder to work....

Atar · Post by **Atar** » Wed Mar 15, 2006 11:04 pm

How would you guys go about constructing something like this? I can probaly fetch some metal pipe from somewhere, but do you guys just start and then work freestyle or design it from the bottom up and then start buildig?
I have a clear vision of what it should look like, but whether thats gonna come out right is what worries me.

Mozy bonz · Post by **Mozy bonz** » Sun Mar 19, 2006 8:19 pm

Mister Jellyfish Mister · Post by **Mister Jellyfish Mister** » Sun Mar 19, 2006 9:27 pm

Hey you guys! I musta got lost... you are making great strides and I must read more/catch up. So far I'm thrilled about the possibilities!

Kudos to Jafe and Robotland and all the other amazing gear heads here.

Atar · Post by **Atar** » Sun Mar 19, 2006 9:38 pm

I've got my next part, the pivot-point of sorts. It came from an old kiddies bike.

Should work nicely.

edit, those are 1x1 foot tiles (for comparison).

can't sit still · Post by **can't sit still** » Mon Mar 20, 2006 8:36 am

[quote="Atar"]

Now, to find some stuff to get that welder to work....[/quote]

Atar, if you want to learn to use a welder, you should start with 6013 rod. 3/32 for light material and 1/8 dia. for heavier stuff. You need a mask with a # 10 shade. If you can afford it, an automatic dimming mask is wonderful. A good starting amperage is about 105.
Find a scrap metal yard and buy old pieces of "wrought" iron fencing. It's square box tubing and can be used to build anything light. It won't weld worth beans where it's painted.
A small grinder is invaluable for cleaning and removing flux.
Welding gloves are handy, but not essential.
The best place to find nice little drive train parts is from old riding tractors. I found a little belt-drive transmission that only weighs 8 lbs.
You can find the most amazingly useful stuff in scrap metal yards.
Dan

Atar · Post by **Atar** » Mon Mar 20, 2006 9:15 am

Wow! Thank you Can't Sit Still!
Thats really good to know, I was planning to get some electrodes but I didn't have a clue as to what types existed. I can easily remove the paint from the stuff I plan to use but how about chromed stuff or galvanized? Would that be a problem?

Tiahaar · Post by **Tiahaar** » Mon Mar 20, 2006 1:34 pm

Atar wrote: how about chromed stuff or galvanized? Would that be a problem?

it can be welded but produces nasty fumes. don't breath them. better to grind off the stuff before welding but still have lots of fresh air.
your welder ac or ac/dc stick? if ac go with 6011 rod, it is real spattery but penetrates great and is harsh enough to weld rusty steel. a real bear to get good at though. 6013 is for clean tight fitting joints but gives a very smooth arc and bead. you can cut with 6011 at high amps, or if you do have the ac/dc weld electrode positive (reverse) for good cleaning and cut with electrode negative. have fun!

robotland · Post by **robotland** » Mon Mar 20, 2006 4:37 pm

Atar wrote:I've got my next part, the pivot-point of sorts. It came from an old kiddies bike.

Should work nicely.

edit, those are 1x1 foot tiles (for comparison).

Hee Hee! I've got two matching kiddie Giant bikes- One pink, one purple- That say "Puddin'" on the sides. Not sure I have the heart to paint them over. Missed a GREAT vehicle frame at the thrift store, too- The frame of a workout device dubbed "The Butt Blaster". Likewise with the graphics, had I scored it.

can't sit still · Post by **can't sit still** » Tue Mar 21, 2006 8:47 pm

Tiahaar, I'd be willing to bet that he has a Lincoln A.C.buzz-box. That's why I told him 6013. It's the easiest thing to learn on. He can always drag-start 6013. 6011 has more pen but he's just doing light stuff.

Atar, you mentioned chrome plated and galvanised. It's best to grind the plating off but if you can't, try to put a fan to blow the fumes away from you. If the fan is too strong it will blow away the shielding gas produced by the flux on the rod and the weld will have bubbles.

As you weld something, the material heats up and the arc often gets too hot/burns through. This is one of the basic problems that seem to mystify beginning welders. Cool the material or lower the amperage.
Dan

EspressoDude · Post by **EspressoDude** » Tue Mar 21, 2006 9:03 pm

Sounds like an interesting project. Got to watch the amps on the arc welder tho.....Bicycle frames are very thin wall tubing and an arc welder will go right through in a hurry.

Gas welding or brazing works great. brazing especially because you can re-flow the joint a couple times to make it look good.

Here's a pic of a bike I make for last year BM, (brazed frame), and am just finishing a second one like it

good luck on your project see you on the playa

btw don't waste money buying a gas welding outfit that uses the little propane sized bottles, you will go broke on gas and will loose patience, they are not hot enuff.

Sorry abt the image size folks

Atar · Post by **Atar** » Wed Mar 22, 2006 3:50 am

Thanks for the advice guys, after all the advice about welding on bike frames and that you can burn through rather easily I'll make sure to practice on the scrap metal I've got left from the kids bike. And I can probaly grind all the paint off, but chrome might be hard, thats why I asked.

The plan is to do it like this:

The red bar would be the bar that is right now attached to the saddle of my skatebike. The black part would be metal plating to make the whole thing more rigid. It will also allow me to attach more plating to the sides that will prevent the front to turn a full 360. I hope that explanation was clear enough.

can't sit still · Post by **can't sit still** » Wed Mar 22, 2006 8:56 am

Atar, it was mentioned that brazing would be easier. If you just don't have access to welding tanks, you're stuck with electric welding.
Your materials are pretty thin so burn through will be a problem.
If you use heavier materials for your braces[3-4mm], you can hold the rod closer to the brace than the bike frame. This will dump the majority of the heat into the heavier material and minimise burn through.

I see that you're in the Netherlands. I don't know if 6013 rod is called the same thing in Europe.
Dan

Atar · Post by **Atar** » Wed Mar 22, 2006 11:56 am

I might have access to a shop with a brazing unit (if thats what its called?). But first I need to get more acquainted with the owner. Its been some 8 years since I last saw him and he said I could do another project there I'm working on (cut out a sword out of metal plating to use as my fire sword).
After that I might pop the question if I could work on this trike there. If not, I know about other people that use them, but they live far off

Either way, I'll figure it out eventually in the meantime I'll just start welding on some scrap metal.

can't sit still · Post by **can't sit still** » Wed Mar 22, 2006 6:28 pm

Brazing is normally done with 2 tanks; oxygen and acetyelene. Sometimes propane is substituted. Oxy-acet are explosive in any proportion from 3% to 97%
I've found that if you put it in trash can liner bags, the static electricity produced from inflating the bag is enough to detonate it.
Your friend will be more likely to let you use his torches if you are quite familiar with the setup. There are many books http://www.cartertools.com/wfarqa.html
Also , there are a lot of classes available.
There's no substitute for practice.
Dan

dragonfly Jafe · Post by **dragonfly Jafe** » Mon Mar 27, 2006 9:34 am

in case anyone can make it to Philomath, OR this weekend (near Corvalis), there is a seminar this weekend on building bicycle powered stuff, held by the group Elliot hangs out with in his other life...(I am planning on attending)

Format
Kick-start your own construction project. Experienced builders and racers provide a variety of minilectures covering topics important to building human-powered, allterrain vehicles. Emphasis on important engineering concepts and sourcing parts. Local vehicles on-site for demonstration and testriding. Excellent preparation for Hands-On workshop in the fall.
Bring
Paper and pencils/pens.
Time
9:30 A.M. 'til 5ish. (Sat., April 1)
Location
Consumers Power, Inc., 6990 SW
West Hills Rd, Philomath [near
intersection with Reservoir Rd].
KSR signs on roadway.
Fee
Includes lunch and handouts. Pay at class (cash or check). Sliding scale: adult, newcomer $15; former racer/builder $13; team of 3 or more $10/person; middle and high school students accompanied by an adult also attending class $8.
No refunds.

Contact
Inka 541-929-6405

Elliot · Post by **Elliot** » Mon Mar 27, 2006 4:28 pm

Atar: Sorry to disappear on you -- I travel a lot. And I was in a hurry the last time I was here.

You were looking for a word -- the thing that allows you to hold your feet still while the wheel turns. It is call a freewheel.

As for stick (arc) welding -- I like 6011 rod because I can see the puddle better. Actually seeing what you are doing is vital. Just pointing and firing only works with shotguns. Be sure you actually see the little puddle of molten steel, or you have no idea what is happening.

You might also want to ask your welding supply store for a special rod made for thin materials. When I lived in Norway, we had something called "tynn-plate-tråd". That translates to "Thin Plate Rod". Sheet Metal Rod.

Many of my friends swear by a type of welder called a Wire Welder. Also known as Wire Feed. Or MIG. There are many small such welders made in Europe. One brand is made in Italy, I know. My friends say it is easy to use and suitable for thin steel.

As for designing vehicles, I visualize the design in my head and then build it pretty much "freestyle", as you so appropriately call it. Other people make elaborate drawings. Do it whatever way works for you. There is no wrong way if it works for you!

I use simple tools to hold parts in place until they can be welded: wooden blocks, carpenter clamps, C-clamps and so forth. Rope, bungee cords, tape -- anything that will hold the parts until you get a few tacks in. Sometimes I use hose clamps and just weld right thru them. You're not building a watch!

dragonfly Jafe · Post by **dragonfly Jafe** » Tue Mar 28, 2006 5:32 am

...I use a MIG welder (220v ), and can weld thin steel without too much difficulty. I can go up to 1/4" or so without having to V&fill. I am starting to see why being able to use different rod material would be nice at times, however. I may add a stick welder at some point...

BTW - space is limited in that class, so be sure to call and secure a spot if you plan on attending.

can't sit still · Post by **can't sit still** » Tue Mar 28, 2006 9:58 am

I've been welding since I was 12. Everything from coathanger to thermite.
Different problems,,,different welders. In general, gas and mig are best with lighter material, especially with gaps. Stick doesn't work well with gaps [light material]. With stick, you can heat up your material before you put a lot of filler material in the joint.
With stick, you can work down in recesses where a mig is too awkward.
With mig, you can work in shallow recesses without having to fight with cleaning the flux after every pass.
With brazing, you can go over your work and clean it up or reposition pieces.
I believe that you should learn how to gas weld first. That way you can learn how to create a puddle and move it around. Electric welding is pretty much a "go for it" proposition. Manipulation of the puddle is the central point of welding. Once you learn that, you can use any machine.
I mostly use a 250 amp, 3 phase wire welder.
Dan

Elliot · Post by **Elliot** » Tue Mar 28, 2006 7:20 pm

.
Well said about the welding puddle!

Now on to something very different:

My computer is giving me so much trouble that I expect to throw it in the garbage can one of these days. So I thought I'd post my snail mail address -- which may be all I'll have in the future:

Elliot Naess
P.O. Box 2825
Clearlake, CA 95422.

Maybe my latest "uninstall-reinstall" nonsense will last a while, but I've really had it with this crap. I did fine without this thing up to three years ago; I know I can live happily without it again!

Keep building stuff! If I disappear from ePlaya, I'll still see you on the real Playa!

Elliot

geekster · Post by **geekster** » Tue Mar 28, 2006 8:35 pm

Anyone ever built anything using hydraulic motor drive? I have been dreaming of making something using the rocker-bogie type suspension that the Mars rovers use. The easiest way to power the thing that I have come up with so far is hydraulic motors driving the center wheels on each side. Steering would be done with hydraulics on the front wheels only rather than 4-corner electric servo steering like the rovers use. Steering would be assisted by having the steering connected to a valve that would vary the flow to the drive motors. While driving straight, both motors would get equal flow. In the full left position, the right side would get power, left side none ... or possibly a little reverse, not sure yet. So it would be a combination of conventional steering with the front wheels and skid steering on the center wheels.

I wouldn't plan it to be huge, so it wouldn't need as much oil as a large dozer or anything and I believe if I am careful, I can make something that is leak-free. It would be powered by a small gasoline or diesel engine that would power a hydraulic pump and an alternator at constant speed. I have in mind something using about the smallest car wheels I can find.

Looking at the catalog here gives me the idea that I should be able to get the parts I need fairly easily:

http://www.surpluscenter.com/hydraulic. ... =hydraulic

can't sit still · Post by **can't sit still** » Tue Mar 28, 2006 10:01 pm

Geekster, It looks like you have a nice project in your future. A skid-steer loader[Bobcat ] is hydrostatic drive. Hydrostatic is more versatile than hydraulic driven gear motors.
The equipment dismantlers should have a defunct skid-steer loader you could canibalise. You need the 2 motors and the power divider. The pump will probably be shot,,,and not rebuildable either.

If you use a power divider instead of a valve, it will be easier on the drive train.
You can find pumps cheap from equipment dismantlers. You could even use a power steering pump if the toy is small enough. If you want to build heavy, you're going to need a good size engine to power it all.

Scrap Daddy powered his hydraulic dragon last year with a V-6 Ford engine. I drove it for a while and it was plenty responsive.
Lindsay from San Diego had small hydraulic motors on his giraffe. It also walked. He didn't have enough primary power and it was slow as molassas. His only consolation was that the dragon was slower.

The advantage of hydrostatic motors is that you can vary the speed of the motor without changing the speed of the pump.
A 2 gear hydraulic trochoid motor is pretty much fixed speed.
You probably need about 40 hp if you want to go faster than the dragon.
Dan

Elliot · Post by **Elliot** » Tue Mar 28, 2006 11:20 pm

Possible source of parts:
I think I saw a hydraulic drive for the radiator fan of a 1980 Gillig school bus -- the kind with the engine in the rear and the radiator on the side.

geekster · Post by **geekster** » Tue Mar 28, 2006 11:32 pm

I am not interested in going fast and am not interested in getting large. Maybe a little larger than your average go-kart. There are some interesting things with a rocker-bogie suspension. There are no springs, all wheels maintain contact at all times, and a few other things. Some of it can be a little complex. For example, in the current Mars rovers the rockers on either side are connected via a differential. What this means is that as a rocker on one side pivots as a wheel rides over a obstacle, the differential causes the rocker on the other side to pivot in the opposite direction. In other words, as one side rides up over the obstacle, the body would want to "tilt" a little. The differential pushes the rocker on the opposite side down, raising that side and keeping the body more level. I found a slightly different way to do it in a demonstrator built a long time ago that does the same thing without the differential gearing using a mechanical linkage.

I cant use pure skid steering but I can use a hybrid of conventional/skid. The back wheels would simply be casters that pivot as needed. Front wheels turn, center wheels drive and skid steer, rear wheels caster.

In the real rovers, all six wheels drive and steer. That is more electronics than I want to get into. You have to sync all 6 motors in speed, take turning radius into account, when turning the steering servos you need to adjust for the Ackerman geometry, etc. You could spend a year writing the software for it. In the design I have in mind, you can just steer it like you would a normal car.

I don't want anything nearly as large as 40HP. Even half of that would be too big. Maybe something closer to 10HP. This wouldn't be ready for this year. I have to figure out how to construct the rockers and bogies. Probably some kind of pipe frame or something, not sure yet. Has to be able to support the wheels and hydraulic motors (which aren't light). I will probably have to add weight on the other wheel on the bogie to make them evenly weighted. The front wheel is the rocker which goes up bends at the pivot and joins the bogie at another free pivot. The bogie has the center and rear wheels. I have built a small model that uses differential gearing between the two rockers but the linkage method looks like it will be a lot cheaper.

can't sit still · Post by **can't sit still** » Wed Mar 29, 2006 8:22 am

When I said fast I meant 6 mph. You might look at the zero turn radius, hydrostatic lawnmowers. They have an interesting drive mechanism.
If you're still considering going electric, you can use a pallet jack motor to drive your pump. They're variable speed. I just found 4 of them in the scrap yard. Dan

geekster · Post by **geekster** » Wed Mar 29, 2006 8:58 am

I am not sure a conventional hydrostatic drive will work. The problem is that the wheels have a considerable range of movement and a device that is connected to both sides is going to have problems when the left wheel moves a couple of feet up and the right wheel actually goes the opposite direction (to keep the body level) due to how the sides are connected. In other words, having any kind of drive assembly that is connected to both sides with any kind of axles is going to be difficult. You almost have to have wheel mount drive motors. You can easily get into a situation where say the left wheel rises two feet and the right wheel moves down a foot (1 ft of motion in the bogie, another foot in the rocker which pushes the rocker on the other side down one foot). Now the distance between the wheel hubs on the two sides is greater. You can couple some kind of halfshaft like in a front wheel drive car to take care of the motion, but the increase in distance will want to pull them apart. Some kind of PTO shafts would probably work if they can be coupled to the drive. I have seen PTO shafts that are telescoping and will handle various distances to the load. Just not sure they are designed for a whole lot of in and out movement while they are turning.

I guess it depends on how authentic I want to get. I could use some kind of drive that connects to both sides if I considerable limit the range of wheel motion but then it isn't going to be a free-pivot rocker-bogie system anymore, it would be a conventional sprung suspension at that point that LOOKS like a rocker-bogie system.

can't sit still · Post by **can't sit still** » Wed Mar 29, 2006 6:17 pm

Geekster, you're definitely mechanically ambitious. The PTO shafts don't telescope much but the spline shafts like a driveshaft are designed for it and don't have much internal drag.
The Bobcat has a motor on each wheel.
You're talking about an enormous amount of suspension travel. Too bad the playa is flat.

If you decide to build a model, you should start with a drive from an old electric seat. An old electric bench seat has a motor in the middle and 2 heavy flexible drive cables going 1 to each side.
If you were light enough, you could use an electric window motor at each wheel. Of course, you could only go straight.
Actually, I just thought of the perfect drive system. It's what they used on steam saw mills. Variable, forward and rev and no gears or sprockets.
It's really nifty and made from cheap parts.
You just need a diff from a riding mower and 2 telescopic axles to go with it.
Dan

Tiahaar · Post by **Tiahaar** » Wed Mar 29, 2006 10:03 pm

ok 30 posts to a page? need two more to get past the scroll crap that mega image up there is creating

Tiahaar · Post by **Tiahaar** » Wed Mar 29, 2006 10:04 pm

one more...

Wheeled vehicle construction (cont from tracked thread)

geez I hate scrolling