Spring pin for my custom tire carrier? (1 Viewer)

[White Shark]

I would gas braze the new pin on. The outcome isn't as pretty, but the disimilar metals will adhere and you are at about 140% of the strength of welding two similar alloys together. Welding produces 50-60k psi welds on the average, brazing generally can produce 80-100k psi+ and disimilar alloys are not usually a problem. Take it to a local bike builder, or commercial a/c repair shop. They will have oxy/acetylene and brazing rods on hand. When conducting stress tests by stretching two tabs of metal that are welded or brazed together, the weld will almost always break, separating the strips. The tabs that are brazed together will tear the metal before the brazed lap joint gives up. Plus you can join different alloys. You do have to careful though. Silver braze is the way to go with stainless steel as it is stronger than brass and won't cause other issues than can occur with brass brazing. Don't heat the join to hot, as chrome oxides will form, causing loss of adhesion. It's a bit more complex than welding, but well worth the trouble for the increased strength. Attached is the Thomas Register list of companies around the U.S. that shoud be able to do the job without any problem. Good luck! http://www.thomasregisterdirectory....ainless_steel_brazing_services_0059255_1.html

 

[honk]

I would gas braze the new pin on. The outcome isn't as pretty, but the disimilar metals will adhere and you are at about 140% of the strength of welding two similar alloys together. Welding produces 50-60k psi welds on the average, brazing generally can produce 80-100k psi+ and disimilar alloys are not usually a problem. Take it to a local bike builder, or commercial a/c repair shop. They will have oxy/acetylene and brazing rods on hand. When conducting stress tests by stretching two tabs of metal that are welded or brazed together, the weld will almost always break, separating the strips. The tabs that are brazed together will tear the metal before the brazed lap joint gives up. Plus you can join different alloys. You do have to careful though. Silver braze is the way to go with stainless steel as it is stronger than brass and won't cause other issues than can occur with brass brazing. Don't heat the join to hot, as chrome oxides will form, causing loss of adhesion. It's a bit more complex than welding, but well worth the trouble for the increased strength. Attached is the Thomas Register list of companies around the U.S. that shoud be able to do the job without any problem. Good luck! http://www.thomasregisterdirectory....ainless_steel_brazing_services_0059255_1.html

Errr, while brazing can produce strong joints they are rarely as strong as a fusion welded joint. Brazing CAN join dissimilar metals and it easily joins parts of dissimilar thicknesses, fitup can be easy and precise and mistakes are easily fixed but brazing is not a penetration joint where materials are flowed together to become as one. Still, it'd probably work OK for these pins.
Tig is the way to go joining stainless to carbon steel.

 

[Arya Ebrahimi]

learn something new everyday.... I never thought about brazing them together... I've brazed a few things in shop class and it was never as strong as a simple oxy/act fusion weld(even when not using a filler material) Guess I'll have to go play with the brazing rods some more.

Ary

 

[NorCalDoug]

No, the new pins are larger, so they do not retrofit.

Bummer.

I was hoping for a quick-n-easy-3-minute fix.

Not a huge deal though. Thanks for the info Christo.

 

[White Shark]

http://www.handyharmancanada.com/TheBrazingBook/Section 1/What brazing is all about/Part 1.htm

Regarding silver brazing: " On non- ferrous metals and steels, the tensile strength of a properly made joint will often exceed that of the metals joined. On stainless steels, it is possible to develop a joint whose tensile strength is 130,000 pounds per square inch. ( 896.3 megapascal [MPa] ). Brazed joints are ductile, able to withstand considerable shock and vibration. Brazed joints are usually easy and rapidly made, with operator skill readily acquired. Brazing is ideally suited to the joining of dissimilar metals. You can easily join assemblies that combine ferrous with nonferrous metals, and metals with widely varying melting points. Brazing is essentially a one-operation process. There is seldom any need for grinding, filing or mechanical finishing after the joint is completed. Brazing is performed at relatively low temperatures, reducing the possibility of warping, overheating or melting the metals being joined. Brazing is economical. "

Brazing strength will exceed base material and weld strength in certain applications. As hard as it is to believe that a nonwelded/brazed application is stronger than a weld, it is possible and commonly used.

Regarding welding:
"It offers one big plus – strength. Properly made, the welded joint is at least as strong as the metals joined. But there are minuses to consider. The joints made at high temperatures, high enough to melt both base metals and filler metal. High temperatures can cause problems, such as possible distortion and warping of the base metals or stresses around the weld area. These dangers are minimal when the metals being joined are thick. But they may become problems when the base metals are thin sections."

Weld strength can exceed brazing strength, but loss of strength can occur in overheating the joint. Temps are easier to control with tig than with mig and generally produce superior joints. The down side to tig and mig is the inability to join disimilar alloys and maintain alloy integrity when the different alloys have different thresholds of structural soundness. A good outcome can be had with tig, but brazing temps are low enough that in most applications, the brazed joint will exceed the weld and base material strength due to protecting the integrity of the base material. The brazing never gets hot enough to remove metal temper. Tig can be used in certain disimilar alloy situations, but brazing is generally seen as being the preferred choice for disimilar applications due to strength, ease of use, and low inout cost, i.e. oxy/acetylene & rods vs. square wave tig setup, etc.

I like welding joints whenever possible, but when disimilar alloys are involved, I'll often braze the joint. Low prep, no clean up, easy fitment. The numbers are sound and the strength remains. Brazing is not for every application, but as honk said, it would be plenty strong for this pin application. I would also propose once again that the Slee pin/bumper combination would be as strong or stronger than a tig weld when properly brazed, (i.e. silver brazed with the proper flux to prevent oxidation), due to the ferrous to nonferrous connection between the mild and stainless steels but honk may be correct in saying that the tig weld would be stronger. This is based on the thickness of the material. Brazing excels in thin materials. Heat and temperature affect thicker materials less, allowing more heat dissipation and fewer potential problems with loss of temper and distortion, leading to a high quality fusion weld. Either method will work fine.

 

[rjjff]

Used for Wieght machines, not stainless but they worked well. Only $9.00 each, shipping is expensive $8.00 If you ordered a bunch it might be worth it. http://www.fit-senior.com/acatalog/Fit_Senior_Pull_Pins____Pop_Pins_264.html

 

[sleeoffroad]

Those look like the ones we used before

 

[Tooth Fairy]

I used the AWDirect spring deals. They are not as clean as what Christo has got, but, they work. I think they were only $6 too. If you wanna do it the best way buy Christo's crap. If you want a functional hack job like mine, well, then good on ya!

 

[honk]

Anyone look at the cost of silver rod lately?

This really comes down to the ability to ,maintain proper low temperatures for brazing over the span of a planned joint. Though these pins are not large assemblies, neither are they of a size small enough to keep at a uniform brazing temperature. So a brazed joint would have to be a very slow series of seperate joints in effect. A quote from white shark's source illustrates the point quite well:

"Welding is usually more suited to the joining of large assemblies than brazing. Why? Because in brazing the heat must be applied to a broad area, often to the entire assembly. And if the assembly is a large one, it's often hard to heat it to the flow point of the filler metal as the heat tends to dessipate faster than you build it up. You don't meet this limitation in welding. The intense localized heat of welding, sometimes a drawback, becomes an advantage in joining, a large assembly".

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i own the rock

 

[White Shark]

I agree. Fat parts require welding, tig to be exact. Thin parts are all about brazing. Braze works based on capillary action. It is drawn into the heat. The thick mass of the pin and bumper would make tig welding the preferred method on this particular item. Brazing by a skilled weldor could be applied to the same effect, but the tig would be easier and most likely stronger as capillary action would be difficult to attain on the heavier mass. I like a challenge. This ball goes into honk's court. My general purpose was to make everyone aware that other options are available, even if the end result is resolved using a more applicable technique. Fat=weld Thin=braze The other advantages with brazing are diverse. Brass to brass, brass to steel, steel to copper, etc. with really strong joints. I saw a guy braze a harmonica reed back together. He was in his 70's and knew what he was doing. Try that without melting that paperthin reed! A tig master might come close. Like I said before, welding and brazing overlap. You need to assess and troubleshoot the problem looking at all options before proceeding. Now I'm going to have to braze my next swingaway bumper pin just to show off! I've got three to work on. One for a 80, a 60, and a 4runner.

 

[honk]

White Shark,
I love to braze - it was my first use of a torch and I use brass at every opportunity. I use it even when a capillary draw isn't expected though I think that watching that action is continually fascinating. I've also got about five pounds of silver rod to use for either more strength or when I prefer the color. It's true though that it's almost impossible to regulate a brazing temperature on a large joint whether the joint is large by using thick material or large by needing a lengthy joint. When I have tried things like that using o/a torches, even with 000 tip, the heat builds to the point that I'm melting metal and at that point the chance for a good braze is gone.
I've just bought a neat new toy that I'm expecting will open brazing opportunities for me on very small things (did you follow the link in the site you posted that describes RayBan's brazing of eyeglass frames?). It's called Smith's 'Little Torch' (something like that) with a set of the smallest tips you ever saw with hoses that screw onto oxy/acetyline bottles to give a tiny flame. I've tried it just twice so far and it's a cool miniature welding setup that gives high temp flames in small sizes - much better than any of the Mappgas, propane, or other wannabe things in the market.

Anyway, I put your source in my 'welding' bookmarks as I hadn't seen it before. Many people call brazing a lost art when speaking of the manual not dip process. I, and it sounds like you, disagree.

And, depending on the configuration and placement of the desired joint, I think that a brazing could be a viable way to attach these pins to a rear bumper.

 

[White Shark]

Brazing is cool. People are generally lazy by nature and tend to go the easiest route. I like a challenge, especially if I can get a better end result. Coolness is definitely a factor. Call it personal pride and satisfaction of a job well done. I was raised on the old school way of doing things and I just enjoy old techniques found in blacksmithing and early metalwork. Brazing has been used in the jewelers business for ages. Now that being said, a sine wave tig is a pretty cool thing. Likewise, time efficiency has it's benefits with a mig. That "little torch" sounds cool. I'll have to look into checking that out. I personally like the way early Fords were assembled. They kept falling apart until Herny found that the Polish immigrants were hammering the bolts into place. Nothing like the right tool for the job. There's always more than one way to do a job, it just gets done better when all options are put on the table for analysis.

 

[PHAEDRUS]

Honk,
You will be quite pleased withe the smith little torch. they are a lot of fun to use and can produce jewelers quality work, hell thats what must jewelers use for repair. I used to work in a welding supply house and was able to play wiht one a long time ago but it was awesome how much control you had over the heat input to the workpeicce.

that being said I just ordered the spindle kit and latch form christo and opted not ot use his pin because it was stainless and would cause a harder install than the stainless 1/2" pins in a ferrous steel pracket we unse on internal semi hold back doors. I fugure this will be easier.
Dave

 

[honk]

Honk,
You will be quite pleased withe the smith little torch. they are a lot of fun to use and can produce jewelers quality work, hell thats what must jewelers use for repair. I used to work in a welding supply house and was able to play wiht one a long time ago but it was awesome how much control you had over the heat input to the workpeicce.

that being said I just ordered the spindle kit and latch form christo and opted not ot use his pin because it was stainless and would cause a harder install than the stainless 1/2" pins in a ferrous steel pracket we unse on internal semi hold back doors. I fugure this will be easier.
Dave

Hi Phaedrus, yep, this little thing is growing on me. I have a set of small tanks from a Victor portable set that I'd never filled before. Took em in friday and exchanged for full ones and now have a neat little setup that I can carry around the house. I've got five tips with the torch and couldn't put the smallest (remaining) tip cleaner in my old set through the littlest one - the orifice must be like .00001" or something. I might have to invest in some small two stage regulators for this if we keep finding new uses for the small (read "tiny") flame. Glad I bought the torch!

 

[PHAEDRUS]

Kewl,

You will find many uses for it. Hell you will probably invent a few..
Dave