first kart build (learning to weld)

[azarak]

Haven't sat on a kart in probably 30 years. Never been on a race kart, fun stuff only. Had to learn to weld for work(still a LOT to learn!) Figured a kart would be good practice.
I have always had a soft spot for 60's-70's rear engine race karts. I know my design is far from a racer of 40 years ago but that's where the inspiration comes from.
Not taking anything too serious just having fun.
I'm a big boy and can handle criticism so be honest......what do you guys think?

 

[landuse]

You have made a good start so far. Welcome to the forum

 

[Allenboy0724]

The only problem I see is length. How tall are you? The frame looks like it would fit a child comfortably. Otherwise the design looks great.

 

[azarak]

The only problem I see is length. How tall are you? The frame looks like it would fit a child comfortably. Otherwise the design looks great.

The door I'm using for my build surface might be giving the wrong impression for dimensions. Its a really big door. Its almost 8' tall and well over 4' wide.
That being said, my dimensions are based mostly on guess work. There are 4 of us in the fam and I'm the tallest at 5'10" (at least for now). I plan on building another kart after this one and will adjust overall size either bigger for me, or smaller for the kids. We will see how accurate my estimations are (or aren't!)
Bumper to bumper = 66.5"
Wheelbase ======= 48.5"
Rear track======== 40"
Front track======== 38"
Front of engine to ft bumper== 54"
Frame at widest(rear)===== 27"
Frame at narrowest(ft)====16"

 

[itsid]

I think it's looking good so far (even size-wise)

Only one little thing (purely cosmetic) the front bumper section is straight, and offset to the main rails..
that looks odd to me; I understand the reason for that completely;
but just for the looks.. I think I'd made them match up the side rails.

'sid

 

[azarak]

I think it's looking good so far (even size-wise)

Only one little thing (purely cosmetic) the front bumper section is straight, and offset to the main rails..
that looks odd to me; I understand the reason for that completely;
but just for the looks.. I think I'd made them match up the side rails.

'sid

you have no idea how long i struggled with that decision!
original plan was to follow the same angle of the main rails, and yes, it looked much better. but, it gets real skinny up there.
i would set the tubes up how they are and then stare at them. then i would set them up inline with the main rails, and stare at them.
i repeated this process for what seemed like hours!
but in the end the tape measure won. i don't have pedals or any steering components yet, and like i said, all of my dimensions are based on educated guess rather than experience. so i felt it better to leave myself more room to work with.
i will probably add an upper section to the front end and we will see how that changes the look of the chassis, this will be installed after pedals and steering.
but yeah, i totally agree with what you are saying.

edit: also installing them straight, but inline (same intersection/different angle) with the main rails interfered with wheel/tire clearance.
i tried it all

 

[OzFab]

But, it still looks cool, I like the overall shape; good work so far...

 

[azarak]

Well I'm all out of parts.
Finished the frame mounted brake caliper and axle, ran the engine for a bit to break it in. Need different tires for the ft. I also am not sure about the camber on the ft wheels, it seems excessive in the neutral position. I think I may have to purchase new spindles with negative camber built in them. I don't trust myself to cut and re weld or heat and bend the ones I have.
We will see what happens

 

[itsid]

indeed excessive

but also bad455

I like your wheels.. those are nylon azusas right?
they look cool...
when you're done with your kart you definitely should let us know how well they hold up

Uhm, I think you have the spindles the wrong way around..
the edge support thingy should point downwards not up;
so swap LtoR and vice versa.

maybe that helps reducing the excessive camber a tiny bit as well

'sid

 

[88nightrider]

Uhm, I think you have the spindles the wrong way around..
the edge support thingy should point downwards not up;
so swap LtoR and vice versa.

maybe that helps reducing the excessive camber a tiny bit as well

Might also reduce the ground clearance at the front as well!!!

 

[itsid]

Might also reduce the ground clearance at the front as well!!!

yupp, most likely.. but I can't help it, they're the wrong way around

'sid

 

[azarak]

Well looks like I get to try my hand at making spindles after all
Yup, if I flip them the nose will be on the ground.
I put the axle together with 10* neg camber and 10* positive caster, so if I make spindles with 10* pos camber then the front should sit right and hopefully handle well.
Yes they are azusa nylons, I don't really expect too much from them, just something to get things rolling( terrible pun!)
Was going to do yard work tomorrow..........not anymore!

 

[OzFab]

Use a thin cutting wheel on a grinder & only cut the side & bottom welds then bend the brackets in, pivoting on the top weld. This will reduce the excessive camber &, quite possibly, increase ground clearance...

 

[azarak]

The front end geometry is based (loosely) on sprint kart specs.
I have a chop saw and am going to cut the spindle axle off the barrel, grind the butt of the axle 10* and the re weld the axle to the barrel.
The whole point of this build was to practice welding and spindles are cheap, so why not?
Success or failure, hear we go!

 

[azarak]

OK, this turned out much better than I was expecting.
Yes the spindles are still installed upside down however the yardkart spindles I bought provide no Ackerman effect (sp?). So the tie rod tabs will have to be modified for proper steering. When the rest of my steering parts arrive I will probably cut the tabs off and reposition them correctly.
Still have some clean up to do on the welds, but the corrected angle should help with ride height also. May have to weld a spacer on spindle shaft.
So far so good

 

[itsid]

See.. I know you could

Oh, if your steering shaft has a two hole pitman arm, than that is going to provide the Ackermann angle (well.. it should at least)

'sid

 

[OzFab]

That's not exactly what I would've done, I hope it works...

I also hope you V'd bothe edges to get the weld deeper into the shaft & didn't just weld the outer surface...

 

[azarak]

That's not exactly what I would've done, I hope it works...

I also hope you V'd bothe edges to get the weld deeper into the shaft & didn't just weld the outer surface...

Yes, once I had the angle right I ground the circle into a square. A 45* on four sides, then several passes on each side.
I don't want a wheel flying off

 

[Dieselchanic]

Nice build! I love to see projects that come to life from the ground up. I built a mini chopper to learn to weld 11 years ago and it was a great experience.

The only problem I see, and I don't know if it's a problem because I tend to over engineer stuff, is the front axle where the angle is welded. If you're still learning to weld, and those welds look a little cold, I'd reinforce it there just for insurance. I'm not picking on your ability just constructive criticism. It's got the same area welded as where the spindle mounts are but the angle experiences more leverage... I included a pic showing what I'm talking about..

Kart is looking cool though!!

 

[azarak]

Nice build! I love to see projects that come to life from the ground up. I built a mini chopper to learn to weld 11 years ago and it was a great experience.

The only problem I see, and I don't know if it's a problem because I tend to over engineer stuff, is the front axle where the angle is welded. If you're still learning to weld, and those welds look a little cold, I'd reinforce it there just for insurance. I'm not picking on your ability just constructive criticism. It's got the same area welded as where the spindle mounts are but the angle experiences more leverage... I included a pic showing what I'm talking about..

Kart is looking cool though!!

I appreciate the input.
And I agree that is a good place for a gusset. I tend to overbuild myself as well, which is a problem in this build as I am trying to keep weight down.
As for my cold welds...... practice practice practice.