Swingrat

[Wildcat]

I had forgotten about the steel pipe hung up for clothes drying when we moved in. My shop is now the drying room on laundry day. My wife mentioned this pipe when I was going about getting some tubing. This is only 11 feet long, so 4 pieces would be 33 inches each. That may be enough although I thought 36" would be the minimum needed. I'll re-evaluate the frame see if this 1" heavy pipe will work.

 

[Wildcat]

I laid it out again to see how 33" bars might work. I think I can go to 32" and still have clearance for my feet from the front tire. That's the limiting factor on the wheelbase.

I can't use any power tools while clothes are drying, so the tube cutter came into play. I think that pipe is 2 mm thick.

 

[OddJob]

Looks like you're getting into the 'swing of things' early on this one, WC! We might need a Swing Bike sub category with all these going on.

RaT oN~!

 

[SwissGuy]

 

[Wildcat]

That last line is what I sound like to the wife when I explain what I'm working on.

 

[Wildcat]

I laid out the frame to get a look, it sure is heavy. I need to wire brush the head tubes before welding. The top bar will get trimmed a couple inches to line up, especially the end with threads. I also found some caps for the tube ends.
If everything turns out well, I may make another frame with good tubing all around and swap it out. But for the build off, so far I'm using almost everything at hand, so I might finish up like that, heavy but using up leftover stuff.

I have some bar that would work for the rear struts. The rear fork is just bolted on for now. I'm waiting until I have the bike together to align the chain stays and BB, then they can be cut to fit and welded up with struts.

 

[Wildcat]

I searched for a larger band brake to get more stopping power. The 4 or 5 I have are all 80mm drums. All the bike shops have are the standard 80mm also. Online I found a 90mm brake so I sent for it. For just a couple bucks I thought it may have been false advertising. The guy at the bike shop said they only come in one size, kids or adult bikes are the same. But it is 90mm. Compared to the regular 80 mm:

I'm hoping it will make a big difference.

To install one of these, the drum part screws on clockwise concaved outward.

Washers or thin nuts are used to get the alignment of the housing so the band is directly over the drum. Yet the housing doesn't touch the spokes. I had to switch to a thinner nut to get it right.

I like to add one more thin nut to hold the housing on, but it's not necessary, when the wheel goes on it holds the housing.

 

[Wildcat]

I looked at the frame again and noticed that the bars will fit into the lugs! I only need two pieces of heavy pipe. The threaded end fit right in, so just a little grinding and they will fit snugly together while getting ready to weld.
The question now is the layout of the headtubes. Parrellel or opposing? I think it doesn't matter with the rear headtube as long as the front has the correct angle. I'm leaning toward opposing so I'll have a longer wheelbase.

Opposing head tubes are closer to the frame configuration of the originals:

 

[LeMad Hatter]

From what I understand, opposite head tube angles will naturally want to center themselves and having the same angles makes it very unpredictable. I'm in a FB group called Freakbikers Unite, so swing bikes, tall bikes, and even Dr Seuss looking bikes are very commonly built and shared there

 

[SkyknightJohn]

I agree with @LeMad Hatter , the opposite angles with lend to more stability.
(not a swingbike expert, just based of my understanding of geometry)

 

[Wildcat]

That's what I'll go with. The difference in tube length is 2.5 inches as they line up evenly.

I laid it out and have increased the length of the bike to 80 inches! I'm going to take 10 inches off the tube and check it again.

 

[Wildcat]

It looks to be just about the right length now.

I shortened both bars and they fit nice and snug.

I'd like to get them mig welded instead of the usual welding rod that is most common here. The welds are good but look like a clump of oatmeal. This frame actually looks pretty decent and I hope to keep it clean looking.

 

[LukeTheJoker]

Looking awesome Wildcat!

 

[GTHOtrod]

Looking really good so far. Nice work

 

[Wildcat]

I think it's a huge improvement over the four bar thing I had planned.

 

[Wildcat]

I looked it over while waiting for a welder. It's going to be the neighborhood welder, as I can't find any Mig or Tig welders here. Some said yes they do, but when I asked what Tig welding was, they didn't know. They only had welding rods. I'll just see how well I can clean up the welds.

I'm trying to see problems before it's too late and I again add to the metal scrap pile. I thought about the 10mm pin that will lock the rear portion so it won't swing. I remembered the seat stem and how long the bolt is. There is just enough room at the lower part of the head tube to drill the 10mm hole (where the blue dot is) without interfering with the seat stem, even when it's all the way down. The lip of the bearing cap won't be a problem either. I don't see any other problems yet.

While I was doing this, the wife called and said she found an old frame and bought it! Great! I again envisioned an old flat bar Schwinn or even an 80's Murray, but what showed up was another Chinese city bike. The third in a row, but the last two provided the head tubes for the Swingrat. This one had no wheels but she paid 1100 pesos for it (about 20 dollars). That's about 18 dollars too much. She said it came with some new parts as to why they wanted twice as much this time. I asked where the new parts were. "They're already on the bike!"
I was about to complain but I want her to get any frame she comes across. Nothing over 50 bucks though unless it's really nice or I can see it first. She might leave a good frame thinking they were asking too much. So I remarked how nice this frame was, and 26" to boot!

 

[Wildcat]

With more idle time I looked around and decided to use the springer off Chrome Molly and put the BMX fork from this build back on it.

A lot of swing bike builders have advised against too much rake, so the springer will work fine. I'm able to adjust the wheel by lengthening the spring. I did that with Chrome Molly but still have a couple more inches to go if need be. It'll be standard to start with and I'll adjust until the ride is best.

 

[BartRidesEternal]

Love the progress and you laying it on the ground to get a good look or glimpse of how this could be!
Personally I never do that, since everything is in my head and I like to sketch and draw.

I enjoy everyone working in their own way and methods. Everyone is swinging differently

 

[Wildcat]

My shop has big tiles and I use them like a big graph and a straight line.

 

[user 35233]

While I was doing this, the wife called and said she found an old frame and bought it! Great! I again envisioned an old flat bar Schwinn or even an 80's Murray, but what showed up was another Chinese city bike. The third in a row, but the last two provided the head tubes for the Swingrat. This one had no wheels but she paid 1100 pesos for it (about 20 dollars). That's about 18 dollars too much. She said it came with some new parts as to why they wanted twice as much this time. I asked where the new parts were. "They're already on the bike!"
I was about to complain but I want her to get any frame she comes across. Nothing over 50 bucks though unless it's really nice or I can see it first. She might leave a good frame thinking they were asking too much. So I remarked how nice this frame was, and 26" to boot!
View attachment 231587

I love wifey's pick!