bending 1/2 inch wide stock to a 3/8 inch radius

[mm]

bending 1/2 inch wide stock to a 3/8 inch radius

I need to make a bracket for rear turn signals for my new-to-me '69 Honda cb450. I'm going to use a steel rod? [I don't know what you call it. The Home Depot cash register calls it "flats"] 1/2"W by

1/8"T x about 18"L, and I need to bend it twice, 90 degrees at each location, to make a rather square C shape, but the corners have to have a 3/8" radius (to look good where it wraps around the luggage rack. Can't figure out how to do this, and don't want to try too many times. I look to you sages.

A. My vice has a rounded part at the end away from the vice, but it's sort of conical.

B. I could clamp it in the vice at the start of the curve and clamp two 6-inch pieces of 2x4 (or 1x2, or thinner if I could find some steel to use) the right distance from the start of the curve ( (2 pi R)/4 = one quarter of the circumference plus a tiny bit more for the circumference of the outside side of the flat), but this assumes the metal bends evenly. Is it likely to?

C. I could clamp the flat to the bike luggage rack and clamp two

6-inch pieces of 2x4 the right distance from the start of the curve same as in B), but this assumes 1) bending it around the luggage rack tube would make it bend evenly, and 2) that I could bend it in that situation. Usually I bend this kind of stuff by hitting it with a hammer, and here the luggage rack might be too springy to let it bend, or I might break the luggage rack.

D. I could find some other rod or tube that is 3/4 inch in diameter (2x3/8), clamp that in the vice, but then how to I hold one end of the flat while I hit the other? This would be a problem for A too.

How would you do it?

BTW, the cycle ran for three seconds today. It's 2 cylinders. How do I know if all of the good sounds are from one, or from both? Both cylinders give a spark during testing, and both have a gasoline-wet spark plug afterwards.

Spraying ether hasn't helped much. It says on the can, "Contains upper cyclinder lubricant". Is it still bad for the bike?

[BobK207]

mm-

Home brew metalworking is always difficult.........

You don't says "tall" the "C" is or how low the return legs on it are.

But if I were attempting this I would make a wooden mandrel that was as wide as my C was to be tall.

I would radius the wood (but make the radius smaller than the desired resultant radius becuase you'll get some spring back)

Dependign on how tall the C is I would use one or two C clamps to hold the flat stock to the mandrel. Hold the mandrel in your vise & just wrap the flat around the it. You need to leave the legs long (at first) so you can get some leverage on the stock.

Once it's basically formed, slide it off the mandrel & blend it a little more to square up the C.

When your happy with the shape, cut off the excess leg length.

Good luck....buy two pieces of stcok & return the unused piece if you get it right the first time

Let us know how it works out

cheers Bob

[<aemeijers]

I&#39;d diagram it out full size on graph paper, and have the local machine shop do it. How much is your time worth? By the time you build jigs, and probably mess up the first stick of metal, they could have it whipped out for you, and probably even plate it to match the other accessories on the bike. They have bending jigs and machines to make about anything.

aem sends...

[mm]

[My four bad, or at least mediocre, ideas deleted.]

Yeah, but very satisfying.

Sorry. I was going to measure the "height" but forgot. It&#39;s about 10 inches high (the width of the motorcycle&#39;s "luggage rack") and the horizontal legs are about 4 inches**

Great idea. I didn&#39;t even come close.

And I see why you asked about size. Size shouldn&#39;t be a problem.

Sounds good.

OK

I can&#39;t promise, but I intend to. Because this is two major steps instead of just one, it will take longer than the method I had in mind,

There are other threads I haven&#39;t given follow-ups on because the weather is good, and I spend all my spare time outside working on the motorcycle and getting the house and car ready for winter. When it&#39;s dark I do a little personal email, and try to go to sleep early so I can work some in the morning too.

**4 inches long to attractively hold the new rear turn signal lights. Made in 1969, it didn&#39;t have turn signals at all, afaict, according to the owner&#39;s manual, although it does have lights in the front. and a switch added on to the handlebars. But no indication there were ever such lights in the back. Well, it has wires going half-way back the rear fender, under the seat, but no sign of where they might have been attached to the bike. My friend who gave me the bike can&#39;t remember such details from 35 years ago, or he doesn&#39;t want to try.

[mm]

That&#39;s a thought, although I don&#39;t even know where the local machine shop is, or what it is called. Except for one I came across that might do this sort of thing. Despite all my objections below, it is a good idea, and I&#39;ll consider it.

One friend of mine rated his spare time (10 years ago, and he had a college degree and a job in physics) at 40 cents an hour.

But just think how much I would learn. My long-time plan was to build my own home, and it looks like I&#39;ll never do that. So maybe I can make a bracket.

Plating is expensive now because of water pollution requirements. I don&#39;t think I can afford that. I have more time than money.

Coincidentally, for a couple decades or more, the guy who gave me the bike owned a plating company, that he got from his father. Life was good until the run-off control laws he said, and he couldn&#39;t afford to stay in business after they were passed. Although I&#39;m sure the water is a lot cleaner.

Fixing this thing is really the project. I doubt very much I&#39;ll ride it more than 2000 miles and there is a good chance it will be no more than 200. And it still doesn&#39;t look nice enough to sell for much money. But I loved the project. I also had a long term goal to get an old classic car that didn&#39;t run, running, but I have no place to keep a non-running car. The motorcycle is small by comparison, and so far easier to work on myself.

Like I say, I will look into it. Thanks a lot.

[<aemeijers]

(snip)

Well, it may not be the US version, but Google Images has multiple pictures of 69 Honda CB350s. See:

for starters. Looks like it is mounted either to the rack, or the fender centerline. The other pictures show a bracket mounted to fender for the taillight- probably integral turn signals.

aem sends....

[<aemeijers]

Here&#39;s a better one, showing signals mounted to the seat frame.

Damn, now you have me curious.

aem sends...

[mm]

To add a little, this is not to say he&#39;s senile or anything. Far from it. He&#39;s only 69. I keep him abreast of the progress I&#39;m making, but tonight I pointed out that I don&#39;t tell him all the things I did to get there. He said, Don&#39;t bother. He doesn&#39;t want to know. So far, I think he feels bad that he didnt&#39; ride the bike more. 2600 miles from him and the first owner. Like he wasted money, or fun, or something. He said tonight he wished he had found a place to park it where it wouldn&#39;t have deteriorated so much, or rusted. But there was no way to get it into his parents&#39; basement, and their garage, where it say for 34 years, was nice enough, though unheated. Everything was rusty and the rear shock springs? have lost much of their case to rust.

[Edwin Pawlowski]

That would be flat stock. Rods are round and solid, tubes are round and hollow.

[mm]

I thought I posted this 90 minutes ago.

I don&#39;t use that as much as I could.

You are right that the US version is different. The manual has two wiring diagrams, and the US wiring doesn&#39;t show a turn signal, but the other one does, including the winker lights and winker relay. :)

What a beautiful bike. Mine is never going to look anywhere near that good, unless someone else does it. (I&#39;m willing to spend time on making a bracket, and some time with a wire brush and a bench grinder with a wire wheel, to get rid of the rust, but otherwise, I&#39;m not going to spend time on looks. I have no taste anyhow, except to admire other people&#39;s stuff. :)

This one is a little diffferent from mine, in that it has a tach and a separate speedometer. Mine has both in one oval thing.

But it&#39;s still vry much like it, and why would mine have front signals and not rear.

So maybe I should have mentioned this. The bike fell once on teh right side, and the front right turn signal post/pipe is bent a the base, one front right fender bracket was broken (but I glued it with PC-7), the rear feder is bent to the left, and has an exra 1/8 inch washer on the right (when I took that out, I couldn&#39;t tighten up the bolt), and.... The luggage rack doesn&#39;t look like the picture and isn&#39;t really a rack. It&#39;s just like a seat back for the passenger, except it&#39;s only 5 inches above the seat and no one would lean back anyhow. It goes straight up, with two rungs. It has no horizontal part, and I don&#39;t see its purpose. Nonetheless, I was sure it was the original "luggage rack" because it&#39;s broken on the right side two, at one of the brackets.

But maybe it is a replacement, and the original held the rear turn signals. I&#39;m tired but tommorrow I plan to look at your other images, and one or two others I know that I didn&#39;t pay enough attention to.

[mm]

I understand that entirely I understand the "damn" too.

After looking at teh picture above, I retract what I said about the vertical stuff being of unknown to me purpose. If I were a girl sitting behind me, I would like that five inch thing to make me feel like as long as I didn&#39;t hit it, I wasn&#39;t falling off the back!

My tail light is about where the base of that bracket is, and my license plate is below that. But it could have had rear turn signals like this one. I&#39;ll have to look in detail when it gets light out.

This also means that if the bike was made with signals, I have to replace them before the bike will pass inspection in Maryland. I&#39;m glad I&#39;m so far along**. That also gives support to having a machine shop make the bracket, because, unless they are backed up, they&#39;ll be done before I am.

**And not so easy. Inside the headlight case, it is a rat&#39;s nest. Nothing I have in the owners manual or Klymer spearates the wires as they come into the case. And there seem to be far more wires than I can identify as supposed to be there. It&#39;s like it&#39;s the Starbucks of my bike, where all the wires go to hang out.

For example, there are four, 4!, wires that aren&#39;t connected to anything! They were hard to identify. One was connected to a ground connection on the front bezel of the light, and since there was nothing grounding the rest of the case, the main part of the case (so that the turn signals were not grounded), I extended that wire and put it under the nut that holds the turn signal post in place. Doing it for one side fixed both sides. I wonder what used to ground the case.

Then the wire, meant to be hot, that went to the turn signal switch, was not connected to anything. (Maybe after the back was ruined, they disabled the front too?) And there was a hot wire (only when the ignition is on) that was taped up too. So I connected the hot to the prevoius wire, and the turnsignal switch worked in the front (though it didn&#39;t flash. There is no flasher to be found, another reason why I thought the bike didn&#39;t have one originally.) I have a flasher that came with the spare coils I just bought, but even with the rear light connected temporarily, it didn&#39;t flash, so I have to hunt through my old auto parts in the basement. I&#39;ve been saving a couple for just this reason.

So it&#39;s a rat&#39;s nest in there.

Wow, I didn&#39;t mean tto go on so long.

[-zero]

Get yourself a small torch kit with a bottle of mapp gas (yellow tank), and in the same area as you picked up your flat bar, find a short piece of

3/8" round stock. Vise up the flat stock pointing straight up, check that it&#39;s at 90° to the jaws of the vice then heat it at the bend until it&#39;s the color of your favorite orange. Put the round rod (your 3/8" radius) in front of it and easily pull the flat down towards you till your happy.

-zero

[Doug Miller]

Have you tried asking in rec.crafts.metalworking ?

[mm]

I meant to. Thanks for reminding me. Although the answers here seem pretty good.

[mm]

I might even have a bottle, just waiting for an occasion to use it! This could be it. :-)

You mean 3/4 inch, right? So the radius is 3/8.

I don&#39;t like oranges. Why are there always problems at every stage?

I"m getting happy already. Thanks a lot.

[Goedjn]

Clamp it in a vice with a 3/8" dowel, and push. If the part that&#39;s sticking out is too short to do it by hand, whack it with a finish hammer. Or a 2x4.

[mm]

Thanks.

[-zero]

Yep! That would be correct! 8-O

-zero

[Father Haskell]

Carve the desired radius into the edge of a hardwood block. Clamp to your workbench over a leg. Beat the metal strip against the block with a mallet.

Ain&#39;t gonna work, way too hard to control the bend.

Mild steel, less than 1/2% carbon, dead soft temper. You should have no problem.

Bend the strap you already bought.

If you screw up, go to the fence department and buy a few pieces of "stretcher strip." Same stuff, except galvanized so it won&#39;t rust, same size, cheaper cost.

[mm]

Thanks.

I didn&#39;t have the MAPP gas in the basaement, but I bought a bottle yesterday.

It was 8 dollars of course. That&#39;s why I didn&#39;t buy it when I considered it, but didn&#39;t have a use for it.