Any vehicle builders about?

If in Santa Rosa, go to 3200 Dutton Av, between Hearn and Todd. It's an industrial park and one of the shops makes electric vehicles, from scooters to cars. I don't recall the Suite # but it's next to the coffee/ sandwich place called "princess latte"

cheers T.Alan Kraus

One bunch of folks you might want to get in touch with is the EAA, as in Electric Auto Association. They have chapters all over the SF bay area.

You are a little bit far away to drive over for a chat but I'm willing to pass on my experiences building vehicles. I've been building things with wheels on 'em since I was a teenager. I built some electrics in NYC and I've built a space frame-ish clone of a Lotus 7 out here in LA. One thing I would say is to forget the EMT. For ease of construction you might want to consider using square tubing unless you are just in love with the idea of using round. Light gauge steel tube will cold bend with a wooden form if you don't try to make the radii to small. No special tools required to cut it, hacksaw, bandsaw whatever you have. Joining can be done by welding, brazing, silver soldering.

Do you have any frame design or even sketches yet? How many wheels? What's the wheelbase and track width? What's the anticipated load? What kind of suspension? What kind of braking system? What is the steering arrangement? What's the seating arrangement? What kind of motor control? Single speed drive train or multiple speeds? Electrical reverse or mechanical?

I'll be glad to help if I can.

Richard Coke

And for the experimenter, Telespar tubing is highly recommeded.

Richard Coke wrote: : forget the EMT. For ease of construction you might want to consider using : square tubing unless you are just in love with the idea of using round. Light : gauge steel tube will cold bend with a wooden form if you don't try to make the : radii to small. No special tools required to cut it, hacksaw, bandsaw whatever : you have. --Yah, not in love with round tube; just thinking it would be lighter weight than equivalent-strength square tube. Most everything I've made to date has been done with square, but have not attempted bends in this material either. I've got everything but bending tools, but it sounds like I don't need much. Then again I'd kinda like it to look as un-kludgey as possible; another vote for round tube that.

: Joining can be done by welding, brazing, silver soldering. --Yeah; I'd planned on using TIG, plus Formdrill for places where stuff would be bolted on.

: Do you have any frame design or even sketches yet? How many wheels? What's the : wheelbase and track width? What's the anticipated load? : What kind of suspension? What kind of braking system? What is the steering : arrangement? What's the seating arrangement? What kind of motor control? : Single speed drive train or multiple speeds? Electrical reverse or mechanical? --Woohoo too many questions! Anticipated max load with batteries: probably 400 lbs, with occasional "excursions" to 550 if a passenger hitched a ride. --Anticipated track width: 4ft; vehicle length: no more than 6 or

Ken Finney wrote: : And for the experimenter, Telespar tubing is highly recommeded. :

Get ye to the junque-yarde and looketh for a go-kart.

Admittedly, the tires tend to be smaller diameter and wider than what you mention in parts I've trimmed off your post, but otherwise they more or less exactly fit your specs. I don't know about making this street-legal, but you'll have the same issue with a scratch-built frame.

From: steamer

Ed, I don't know what your budget is for this project but take a look at these in a

If you are planning on a true space frame or close to it there won't be any bent pieces. All frame members are in compression or tension so round or square really doesn't matter. That being said I doubt if you will have a true, pure space frame design. Compromises always come in. In that case if you have two tubes with the same cross sectional area the square one will be slightly stiffer in bending and the round will will be slightly stiffer in torsion. Your choice. If you have a vertical mill or a lathe the necessary notching for round tube can be done without any sweat. The better you do your joint fit-up the easier and better looking the welds will be. For some frame ideas look at early Lotuses (Lotii?), Maserati Type

Richard Coke

How about standard 4.80x8-B trailer tires and rims, standard 4 on 4" trailer hubs and spindles. Cheap to buy, cheap to repair or replace.

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It isn't, if *stiffness* is what you actually mean by strength. Square tubing with a side width equal to the diameter of a round tube will be stiffer than the round tube because it encloses a greater area, ie has a larger moment of inertia.

It'll be heavier too, but not proportionately heavier. In other words, it will increase stiffness more than it increases weight. If you only need more stiffness in a single plane, then rectangular tubing will provide an even higher moment of inertia to weight ratio. This is why conventional auto frames use rectangular box sections rather than round tubing.

In a true space frame, stiffness doesn't matter. All members are in either pure tension or pure compression. But that's relatively hard to achieve in a practical auto frame. So using rectangular tubing can really save the day, while still keeping weight down to a manageable level.

It is also a *lot* easier to miter square or rectangular tubing joints for welding than it is to properly fishmouth and fit round tubes.

Gary