HF 6.5 1/2 inch frame kart.

[lucasszy]

DIY 1/2 inch frame kart - Full Weld Project

Just a quick place to start my build thread! Check out my weebly site for more pics and details, but I'll be posting here as well!

Cheers

Lucas


http://shizmo.weebly.com/

 

[T.E.D. Jordan]

looks like you're doing some great work keep it up

Keep away from the car when you're welding and grinding though. The sparks burn into the laquer and cause small rough rust spots in the paintwork over time :s

Jordan

 

[Doc Sprocket]

...And pit your glass, trust me!!!

What is the diameter and wall thickness of that tubing?

 

[Doc Sprocket]

...And pit your glass, trust me!!!

What is the diameter and wall thickness of that tubing?

 

[lucasszy]

Tubing is 1/2 inch with .065 wall thickness. Im building a pseudo ladder box frame. Will have pics up over the next weekend, as Im out of town for the week.

Already bought everything that I need for the drivetrain from BMI.

Axle
brakes
torque convertor
axle mounting hardware
steering column

and some odds and ends

This coming weekend I plan on mounting the axle, building the front end pieces, and most likely getting the HF wheels and seeing how Im going to do all that.

Plan is to weld,cut, and grind my way to a front end.

 

[lucasszy]

Videos coming

Another busy weekend. About 10 hours over the last two days so far.

At this time, the frame is complete, live axle hangars are welded in place. Front steering pieces are done on one side, tack welded, and so far the frame looks great.

I'll link a video shortly and update the build site as well.

Lots of pics are going to get uploaded later tonight!


http://www.youtube.com/watch?v=XIylPACds4o

 

[T-man]

nice, good start. that 1/2 is really usefull stuff , I'll be useing it on my trike ... well a little bit. 1/2 x 1 is good stuff also but you have to order that most of the time.

 

[lucasszy]

Im thinking I just may weld in some length wise supports down the whole center. The frame is strong as it is, but I want it rock solid. My idea of using the 1/2 has worked out quite well, especially considering how light the frame is so far.

Dont have an exact weight, but I'll weight it out. If I do the math, its right around 17 pounds as it is now. An azusa is listed as 33 lbs shipped, so my weight saving idea is really panning out, unless someone can share actual weights of commercially available frames.

Cheers

 

[EastCoast]

Looks good

 

[lucasszy]

Well, the wife and kids are back from vacation, so I dont have the luxury of working on weekdays, but here is where I got to up till now!

 

[lucasszy]

And a link to my so far un organized pics of the build to date.

These will all be cleaned up on the weebly site!

L

http://photobucket.com/gokart

 

[oldbikerarlo]

Do you think your frame will twist or bend back at the front without any crossmember?

 

[newrider3]

Looks cool, except the spindle brackets. It looks like you have no caster angle, or KPI. It will probably handle pretty funky the way it is now.

 

[lucasszy]

Do you think your frame will twist or bend back at the front without any crossmember?

I have another crossmember that hasnt been welded in quite yet. The plan is to weld it in once I have the steering done. That way I can work around any steering issues that come up.

 

[lucasszy]

Looks cool, except the spindle brackets. It looks like you have no caster angle, or KPI. It will probably handle pretty funky the way it is now.

This was one of the things that I havent gotten quite figured out. My thought after welding together the spindle was that I would most likely cut it off after a test drive and redo the whole thing.

Any ideas on how much caster and KPI would be a good start, or at least what is a best practice would be appreciated.

Beauty of welding... if it doesnt work, cut and grind it off and reweld a new setup.

The spindles were hacked together in about 30 minutes, but I was unhappy with my materials choice when it was all said and done.

Thinking of buying some 3 inch square tubing with a .120 wall thickness, and redoing them. I'll leave it for now, but will probably end up redoing them.

So whats the best caster and KPI angle?

Cheers

 

[lucasszy]

Since there seems to be about a million different views on KPI, caster, camber, and the whole front wheel geometry, Im going to point to a few articles that best explain it to me, then maybe someone will give me rough numbers to start working with!

Cheers

http://www.truckalignment.com/index.html

http://www.ozebiz.com.au/racetech/theory/align.html

 

[Doc Sprocket]

KPI is pretty straightforward. You should be able to draw an imaginary line thru your kingpin down to the road- and it should land right smack in the middle of the tire's contact patch.

A fairly average number is 10* off the vertical.

 

[lucasszy]

Decided on my geometry!

Will be cutting and rewelding new spindles with the following:

KPI - 10 degrees
Caster - 15 degrees

Based on the following:

gokarthandling.com

 

[landuse]

Is it just me or are those spindle brackets made of steel a little too thin

 

[lucasszy]

Is it just me or are those spindle brackets made of steel a little too thin

One of the things that I didnt like about the first design. Although, they did hold up to the hillbilly test. Put frame on jacks, under the spindles, stand on frame rails and bounce.

But, as already mentioned, they are going to be rebuilt, and that was one of the things that I didnt like about them!


Cheers