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Message started by IslandRoad on 11/19/17 at 00:22:25

Title: Humble mod fail: Tell me yours
Post by IslandRoad on 11/19/17 at 00:22:25

I made a bracket from aluminum angle, to mount my chrome, mini-bullet turn signals just where I wanted them, on the licence plate bracket. I made tech drawings, four prototypes, then the final product. Polished it up real good and mounted it - Perfect!

Its been on the bike for about four months. The other day I rode to a mate's place and when I got there, the left turn signal was hanging from the wires and had been swinging against the tire. The bent arm had snapped off. The other side showed no signs of fatigue, but I did little more than touch it, and it also snapped off!! The turn signals are now mounted in the rear-most fender-rail holes.

It got me thinking about other 'simple' mods I've made. In particular, the aluminium spacers I made for the handlebar risers. I had to buy longer bolts - and I had to make the hex-head smaller to fit in the OEM handlebar clamps. That mod is now on my mind a bit!

Does anyone else want to share their 'mod fails'. It might make for some informative reading.

Title: Re: Humble mod fail: Tell me yours
Post by LANCER on 11/19/17 at 01:07:35

How thick was the mounts you made for the rear turn signals ?

Title: Re: Humble mod fail: Tell me yours
Post by engineer on 11/19/17 at 09:45:48

A similar thing happened on my bike but it wasn't a mod. The license plate cracked in two just below the bracket bolts, a clear case of metal fatigue. There must be a fair amount of vibration in the back. I made a backing piece out of 1/8 inch stock, drilled some extra holes and bolted it back on. That's not the first time a license plate cracked on me. When I rode British twins in the sixties it was fairly common, even the fenders would sometimes crack from fatigue.

Title: Re: Humble mod fail: Tell me yours
Post by jcstokes on 11/19/17 at 10:28:20

I had the license plate thing as well, indeed I nearly lost it. I made a couple of aluminium plates, glued them together and glued the license plate to those and bolted it back on.

Title: Re: Humble mod fail: Tell me yours
Post by IslandRoad on 11/19/17 at 10:48:49

I lost my licence plate recently too. I think the previous owner had backed it into something as it had a slight bend in it. It eventually cracked. A friend told me it would drop off. I didn't believe him. One day I got up in the morning and noticed the plate was gone - just a strip left under the bolts. Some f the local roads around here are a pretty patchy, so the rear probably gets a fair bit of stress.

Title: Re: Humble mod fail: Tell me yours
Post by IslandRoad on 11/19/17 at 10:50:19

4A47484543541411260 wrote:

How thick was the mounts you made for the rear turn signals ?

It was 4mm angle from the hardware store.

http://https://i.imgur.com/5V0W3pd.jpg

http://https://i.imgur.com/GiGnZ7m.jpg

http://https://i.imgur.com/TqCCDva.jpg

Title: Re: Humble mod fail: Tell me yours
Post by IslandRoad on 11/19/17 at 10:55:17

By the way, I wasn't happy with the LED signals either. They just weren't bright enough in daylight. I managed to find the same thing in a halogen (E rated) version, with amber lenses. They have the exact same housing, and internal mount for the globes - so at least I have a spare set of housings if I ever damage them.

Title: Re: Humble mod fail: Tell me yours
Post by SoC on 11/19/17 at 18:54:58

First the aluminum stock from the hardware store is pretty soft alloy, in picture it looks anodized, which is usually softer material. It experiences a lot of fatigue when bent. How did you bend it? In a break or possibly in a vise. Third did the bend involve a mallet? and forth was it a clean one shot to the correct angle or did it involve any bendies to get it at the right angle. Its always best to use a break and get angles correct with aluminum in one clean bend. If in a vise and hit with a mallet it fatigues the metal additionally. If it involved any tweaking bending to get angle correct that causes a lot of fatigue. There is a little science to bending aluminum, there are radius considerations, known as the minimal bend radius, which can be referenced on line. Also like mentioned with tweaking, you can bend aluminum, but can't straigten it if bent to far, that's why it's best to use a break.

That said, to be honest I would have felt safe in using a similar material for that application, maybe just shortened to height of the arms.

Title: Re: Humble mod fail: Tell me yours
Post by IslandRoad on 11/19/17 at 23:52:11

6564617370737C61797B120 wrote:

Hey SoC, thanks for the tips :)

To answer your questions, I tried a few different methods of bending the aluminium.

1. I put it in a vice and yanked it - snapped right off.
2. I put it in a vice and tapped it with a hammer - ended up obviously weak.
3. I held it by hand over the corner of the anvil-flat on my vice and peened it with a hammer, kind of working the radius as I went. I was careful not to go too far, so I didn't need to bend it back out at all.

The last method seemed to produce a good result. It withstood a moderate test of putting some pressure on it by hand. I thought it was pretty good, and went with that.

I was surprised after a few months when one arm fell off! I was especially surprised by the intact one. It showed no signs of fatigue, but it broke off with the slightest pressure.

I've now mounted the signals in the fender-rail holes to keep me on the road. I was going to make a new bracket from mild steel, and weld instead of bend. But, I kind of like them where they are now, so I'm re-thinking the setup. I want to add some kind of capacity to carry a small bag on the back, even if I carry a passenger. I'm thinking about a custom made sissy bar - I just don't like the stock fender-rails which the OEM sissy bar attaches to. I'm not in a hurry so I'll take some time to think, sketch, and prototype. A friend of mine knows a guy that does that kind of custom work, so I'll probably pay him a visit eventually.

In the mean time, I'm waiting for my Triumph Superbars to arrive for the other end of the bike!!

Title: Re: Humble mod fail: Tell me yours
Post by Dave on 11/20/17 at 04:32:51

You can soften the aluminum and reduced the bending induced stress by heating the aluminum before bending. Rub a piece of soap on the aluminum and heat it just until the soap starts to turn dark. The aluminum will be soft and easy to bend - then within a few days the aluminum will harden up again.....(it seems weird that aluminum self tempers at normal temperatures).

Title: Re: Humble mod fail: Tell me yours
Post by SoC on 11/20/17 at 10:14:40

Dave thanks for the soap tip on heating aluminum. Heating aluminum is tricky though and self tempering works with some alloys and not with others.

Another applying heat related tip for those who have ever tried to paint aluminum parts, heat does wonders to get primer to adhere. If you heat the aluminum with a heat gun before spraying primer it creates better bonding to the aluminum.

You don't need to heat it real hot. How it was explained to me is that there is a slight expansion of the surface and when it cools it locks the primer into the surface better. This assumes it was sanded and acid etched. If heated too much though it can flash the solvent too quickly and cause primer to bubble and fail immediately.

Title: Re: Humble mod fail: Tell me yours
Post by stewmills on 11/20/17 at 12:53:14

I had a similar issue with aluminum flat bar from ACE. Not being a metal guy, I bent and shaped some flat bar for my saddlebag hard mounts. Looked nice, but after a little road test I could see the aluminum cracking at the bend and later read up and realized that you can't do that. So, I had to make set #2 out of steel flat bar. Lesson learned for me.

Title: Re: Humble mod fail: Tell me yours
Post by piedmontbuckeye on 11/20/17 at 14:34:44

I have been a machinist for over 40 years, and have worked with many types of metal.

However, a word of warning. ANY metal you purchase at a hardware store, or big box store is not the same quality as that purchased by local machine shops, etc.

My recommendation is to pay a little extra and get your small pieces of metal from McMaster-Carr. They have an excellent online format, and over the years as a Purchasing Manager in various places, I have never had one bad experience with them.

Title: Re: Humble mod fail: Tell me yours
Post by IslandRoad on 11/20/17 at 21:02:38

706965646D6F6E746275636B657965000 wrote:

Thanks for the heads up. I buy aluminum bar from the local steel supplier. I'll do the same fur angle.

Title: Re: Humble mod fail: Tell me yours
Post by springman on 11/20/17 at 21:32:59

You guys have given me an uh-oh moment. I made my rear turn signal mount by bending and cutting some aluminum flat bar from Home Depot and I painted it with liquid rubber paint. If it is cracking there is no way I am going to know until it actually breaks. :o

Title: Re: Humble mod fail: Tell me yours
Post by Ruttly on 11/20/17 at 21:43:09

You want the aircraft quality aluminum, it has a specific number for aircraft use but old and real tired and can't remember the number , Google it !

Title: Re: Humble mod fail: Tell me yours
Post by verslagen1 on 11/20/17 at 22:43:33

You'll probably can find 6061, the good stuff has the alloy marked on it.

It will harden to T4 in 3 days if you anneal it. Use the soap trick.

If you're going to use it as is, it will already be T4.

Bending it makes it harder... hard stuff is brittle.

Title: Re: Humble mod fail: Tell me yours
Post by Dave on 11/21/17 at 02:53:09

I buy metal for important stuff from ONLINE METAL. They have a huge selection and ship quickly.

http://www.onlinemetals.com/?utm_source=bing&utm_medium=cpc&utm_campaign=Metal%20General&utm_term=online%20metal&utm_content=Metal%20Online

Title: Re: Humble mod fail: Tell me yours
Post by piedmontbuckeye on 11/21/17 at 06:19:57

494E5F4D57535656493A0 wrote:

I have a specific design I used for a trailer hitch on my BMW to pull a trailer. I used flat steel stock from my local hardware. Bent it, welded it, and drilled. A year or so later, I found a hairline crack in the metal that would have been catastrophic had I not found it.

After that, I will never purchase any metals from local hardwares or box stores for any critical part.

I now always go to the metal suppliers. Takes more time and not as convenient, but definitely better and safer.

Title: Re: Humble mod fail: Tell me yours
Post by IslandRoad on 11/21/17 at 12:08:46

My little bracket provided an important wake up call for me. I don't have a mechanical background, and have had fun fabricating little projects for the bike, and tuning it.

It was when I was altering the handlebar setup that I really stepped back and thought hard. It was confronting to see the two little hex-heads on the bolts, which are basically all that holds the whole assembly onto the bike.

Adding the risers meant that I needed bolts that were 40mm longer than the the stock bolts for the old style risers, but they are the diameter. So I made my own risers on a lathe to make sure the centre hole accommodated the bolts snugly.

I researched bolt types, because the guy at the hardware supply gave me high-tensile bolts, because that was all he had. I read, however that the stock bolts are 'suspension rated'. I figure that makes sense. If your handlebar bolts are going to fail, then bend is better than break.

I believe Suzuki use their own code #7, whereas in the industry #8.8 is suspension rated. So I ordered and fitted some of those. However, I do still wonder about the fact I had to reduce the size of the hex-head with a grinder to fit the stock clamps - mostly thinking about the way heat can change the qualities of the metal. I've had them on for about 6 months - so far so good.

Title: Re: Humble mod fail: Tell me yours
Post by ohiomoto on 11/22/17 at 05:44:24

72494453424E555348404D52210 wrote:

---------------------

I'm not far from this place: http://www.themetalstore.com/

It's less expensive if you pick it up and they have tons of random cuts on the rack when you go in. Metal shops are very common in most major metropolitan areas. A much better option than ACE or Lowes, etc.

Title: Re: Humble mod fail: Tell me yours
Post by justin_o_guy2 on 11/24/17 at 09:25:38

I picked up two pieces of three foot long 7/8" sucker rod at the scrap yard for Free. They have aluminum. I got a chunk of stainless two inch. A magnet won't stick, at all.
But, there are no tags to tell you what it's made of or any given place where you will find what you need. But, if you're not in a hurry or you're trying to save money, it's a good place to start.