Cyclekart progress, Nov 1, 2009

(Edit, 2012-07-10: In case it’s not obvious (it is obvious), this was never intended to be an example of “good welding”. It’s obviously terrible welding. This is pretty much the first thing I ever attempted to weld, and it’s obviously terrible. Hence why I described it as the “world’s shittiest welding job” and referred sarcastically to my “super excellent welding skills”. This was *obviously* never intended to be any kind of “here’s how you weld…” instructional blog entry, more like “here’s what happened when I, a complete beginner, attempted to weld some stuff while making my cyclekart.” Notably, the shackles (“world’s shittiest welding job”) needed to be redone. The plates on the side of the frame rails really don’t do anything — if they fail, nothing happens. It’s precisely because they aren’t critical that I chose them as something to try as a beginner. What follows is the original post, circa Nov 1, 2009)

The weather has finally cooled off enough that I was able to work outside comfortably, and so I’m back on the cyclekart project. This weekend, I built half the front suspension.

First I had to fabricate a spring shackle:
Above, the raw steel parts used for the spring shackle. I welded the three parts together, then drilled holes on each end to accept the bolts (grade 5 steel) that connect the frame frail to the leaf spring.
Above, you see the spring shackle assembled. Note the world’s shittiest welding job. Yeah, I did that.
Next, I had to cut a hole in the bottom of the frame rail to accept the spring shackle:
It’s ugly, but that’s ok, because I welded some metal slabs over the side to (I hope) make it stronger where the cut has weakened the frame rail, and also to make the wear on the bolt that connects the frame rail to the spring shackle less severe.
Above, you see all the suspension parts disassembled.
And here they are assembled. Putting it together is a bit harder than it looks because all the holes don’t exactly line up perfectly, and the spring has to be stretched a wee bit to get it to all fit together.
Above, you can see how the shackle connects to the frame rail through the hole, and to the spring. And, you can see some more evidence of my super-excellent welding skills. 😉
And, one final shot of the assembled frame rail. I was surprised how bouncy it was. As stiff as that spring was, I wasn’t sure the spring was even going to move at all, but it seems to work pretty well.

~ by scaryreasoner on November 1, 2009.

12 Responses to “Cyclekart progress, Nov 1, 2009”

  1. You have some good ideas going on with your kart. I am also building one. How wide do you intend to have the frame at the front? I am concerned about the tire rubbing if it is too wide but will look odd if too narrow. I have not seen any comment on this issue.

  2. My kart’s body is 13.5 inches wide at the frontmost part (the rails extend past this another foot or so). The axle I’ve made is 25 inches wide, not counting the spindles, which are 6 inches apiece.

    I too was/am a bit worried my axle wouldn’t be wide enough, relative to the body to prevent the wheels from hitting the frame rails (the frame rails adding an extra inch on each side of the 13.5 inches of the body. — and as the frame rails aren’t parallel, the body will be even wider at the trailing edge of the rear wheels. We’ll see. If I need to make a bit wider axle… that’s not hard — a couple bends with a pipe bender, and a couple cuts with a hacksaw. I think it’s probably ok as is though. I based my axle width on the stevproj site’s specifications. My kart body is a little longer than what is specified, so it grows wider more slowly as you move towards the back of the kart, if that makes any sense. I guess whether it’s a problem depends on how tight a turning radius you need.

    BTW, if you have anything online related to your kart, I’d love to see it. And, if you haven’t already joined the yahoo cyclekart group, you definitely should.

  3. Thank you, I appreciate the information. I also followed up and joined the Yahoo group and am getting more info from it. I will be glad to post photos as I get along with mine. I do intend to do rear suspension which will float the engine and axle, as is necessary to keep the chain tight. I have not get the details worked out but am well on the way to having it sketched out. Thanks again. Mike

  4. Hi,
    Just found your website by means of your comment on Refreshing idea to put the shackle on the back side inside the Frame. The end result will be a more clean appearance, nice.

    As an autodidact myself, I know how frustrating it can be if the welding does not turn out the way you planned. Until I mastered oxyacetylene welding I used the Mig as my main welder. These movies helped me a lot:
    Basic mig

    Advanced mig:

    If I can help you out on the welding part, please contact me.

    I’ll follow your build and make a link on my weblog.
    Keep up the good work!

  5. Looks like you are making good progress. As to the welding- are you using flux core wire, or any shielding gas? It looks like it’s not getting shielded, which is really necessary for solid welds.

    I’m just beginning, and am a little stuck on the front spindles- the center of the bike wheels is 12mm while the smallest diameter spindles are generally around 25mm that I can find. I could replace the bearings in the wheel hubs with larger ones, but I’m looking for a cheaper solution.

    • Not flux core, C25 gas. I’ve since gotten a bit better at the welding. I switched to thicker wire, and higher voltage, and preheated the parts with a propane torch.

      The reason, so far as I can tell, that the Honda wheels are specified is because the bearings they take have a much larger outer diameter than most wheels, which means you can change out the bearings for other bearings with a larger inner diameter. Most other bike wheels have a smaller outer diameter, and it’s not possible to get bearings with sufficiently large inner diameter.

      12mm is not big enough to be able to support the wheel from only one side. You need to replace the bearings. There are two approaches (at least) 1) get bearings with 3/4 inch inner diameter, and as close as possible to the outer diameter of the original bearings. (You won’t get exact, because 3/4 inch is not metric, and the outer diameter is metric.) Then machine the honda wheels to fit the new bearings. The 2nd approach is the one I took, which is to get metric bearings that fit the wheels, but with a larger diameter. The bearings are not that expensive. 10 for $30 or so at See this post:
      Here is what I’m doing for the front wheel bearings.

  6. Cool. Thanks for the lead on the bearings. Saved me $20 from mcmaster. I’m buying 25mm ID bearings with the 37mm od for the wheels. I found a set of 25mm spindles and will use a 25mm rear axle, so they should fit fine. Mine cost about $80, but worth it to make it right.

  7. Where’d you find the 25mm spindles? Also, which bearings did you get? 6805zz?

    At 7mm wide they seem a bit narrow… I guess mine are only 9mm wide, iirc. There is a 30mm wide(!) needle bearing (RNA6904) but I’m not sure it’s good for this application or not. Well, probably not, as the hole for the bearings isn’t 3cm deep on the outside or inside of the wheel, so at best they’d stick out. (Though I did cram 2 bearings into the outside of a wheel… was using one bearing to shove the other in, and they both went in.)

  8. I found the spindles on ebay- don’t know where else you would find them, but it seems like they should be a common size. Bearings were 6805-2RS Bearing 25x37x7 Sealed. With one inner and one outer, I’m not really worried about the width. I’ll cut a spacer to fit between them so I can tighten the nut on the spindle.

  9. Looks like an epic fail to me! See:

    • LOL. Well, that is embarassing. FWIW, a) I’ve gotten better since, though still not a good welder, b) it was pretty much the first thing I ever welded, and I had nobody at all to show me the ropes, c) I rewelded the shackle because it was obviously not strong enough, this time with closer to correct wire and power settings — so it came out a lot better 2nd time around (not saying much), d) if the welds fail for those plates on the side of the frame rails what happens is…. absolutely nothing (that’s why I started with those, I knew they weren’t critical). e) I knew it was shit, hence my comments in the original post about “world’s shittiest welding job” and (obvious sarcasm) “super excellent welding skills” and finally, f) I built a cyclekart, and (odds are) you didn’t: 😀

      It’s really not surprising that a bunch of guys on a forum dedicated to welding would find the efforts of a complete beginner who’s trying to figure things out with no instruction from anyone to be total shit. It was total shit. I freely admit that. Ignorance is not stupidity though. I’m merely ignorant (less so now than when I did the welding job in the post here, 3 years ago, but by no means do I consider myself a good welder even today). Ignorance is fixable though. And I’m not ashamed of this job because you know what? Most people would have been too intimidated to even have attempted to figure things like this out on their own. Failure doesn’t scare me (depending on the consequences of the failure — in this case, rewelding a few things). Failure is how you learn.

      • I am also a WeldingWeb member and all I can tell you is that self-teaching works only to a certain extent. I would suggest you join WeldingWeb, suscribe to WeldingTips&, search for free welding manuals in the sites of Miller, Lincoln, Essab, etc., search youtube for welding videos of all kinds and educate yourself.

        Before using welding to put together anything, you need to learn to weld. Practice on scrap untill you are good at it and then practice some more putting together stuff that in case of failure none is going to get hurt (say, a welding table or a welding cart for your welder).

        Then and only then, think about tackling projects like the one you posted here.

        I just read the first post (the one you just edited). Seems like you don’t have a total lack of commong sense, so congratulations. I bet you will be able to take all the constructive criticism from the previous post and after learning to weld propertly you will finish your project (if it hasn’t been finished yet).


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