Braced my 1100F Swingarm today....

Posted: Thu Mar 16, 2006 3:36 am

1" molly tube... on stock 1100F swingarm...I had a guy from my local welding shop make this for me... Pictures on the bike tomorrow (I hope)...

He will fab the brace and weld these for us for $325 USD + shipping for individual orders on an exhchange basis...If he can get 10 orders at once, $275 ea. Buyers would send their stock 1100F swingarm with bearings removed and receive back what you see with primer coat, etc... Includes removing any of the tabs desired, etc and all welds cleaned ready for prep and paint...

Hey, it's no Metachex, but the price is one heck of a lot less and I think they look the part...

Whaddayathink?

Posted: Thu Mar 16, 2006 3:44 am

looks awesome............ Wink

Posted: Thu Mar 16, 2006 4:18 am

That looks pretty cool there Luke, good job.

Posted: Thu Mar 16, 2006 4:28 am

NIce

Posted: Thu Mar 16, 2006 8:05 am

Well i think we are going to do some riding on the 26th Luke Very Happy

Looks perfect now that it's painted Exclamation

Posted: Thu Mar 16, 2006 11:58 am

Does he stress relieve?

Posted: Thu Mar 16, 2006 12:02 pm

stoutblock wrote:

Does he stress relieve?

Any guy that says he doesn't - is lying Very Happy

.

Posted: Thu Mar 16, 2006 1:37 pm

stoutblock wrote:

Does he stress relieve?

Martin....

Other than Pontiac's interpretaton of this question.... Please explain what you mean...

Posted: Thu Mar 16, 2006 2:04 pm

i thought it meant to keep the surrounding areas of the weld cool whilst welding.... please correct me if im wrong.

just welding it up would put enough heat to twist the unit as it ccols id imagine. youd need a jig to be sure its true b4 and after i thinks.

just my 3cents

Posted: Thu Mar 16, 2006 2:39 pm

im thinking that he means shot peen or flap peen to remove the concentration of stress from welding by restoring a uniform surface....
bead blast would do the trick also just dont overdo it..

Posted: Thu Mar 16, 2006 4:47 pm

PapaLuker wrote:

stoutblock wrote:

Does he stress relieve?

Martin....

Other than Pontiac's interpretaton of this question.... Please explain what you mean...

The primary purpose of stress relieving is to remove residual tensile stresses caused from welding and to stablize the component. Applications are:

1) Remove residual stresses from a component to stabalize before machining so that its geometry wont change / shift during the removal of metal.
2) To improve corrosion resistance of the weld zone in some alloyed steels
3) Remove residual stresses to improve fatigue life of weld connection

Stress relief can be done by primarily two methods, that being by the use of heat and by shot peening. Removing residual tensile stress can be done by, 1) heating the entire part up to a specific temperature (typically 50degC below the steels specified tempering temp) holding for a specific time, then allowing to cool slowly, and 2) shot peening. Shot peening can reduce the tensile residual stresses and actually produce beneficial compressive stresses that can improve the fatigue life of the weld connection.

If the swing arm and its bracing is put into a jig and retrained during tacking and welding, stress relieving will not be required and serves no benefit. Stress relieving will actual reduce the strength and ductility of the joint in some metals.

Hope this helps.

Posted: Thu Mar 16, 2006 10:54 pm

This is what I have been told and what I did. I made a chromoly tube roll cage for my racecar. I was told that by MIG welding chromoly the welds would be brittle. I had to "normalize" or stress relieve the welds. This was done buy using an oxy/acetelene torch and bringing the welds and four or five inches on either side up to a cherry red. Then packing it in sand to allow it to cool much slower. The metal returned to its normal molecular design and everything was back to normal. Considering I flipped the car three times in one incident and kept landing on the roof, it does work, no welds were broken in that "test".

Posted: Thu Mar 16, 2006 11:09 pm

Larry wrote:

This is what I have been told and what I did. I made a chromoly tube roll cage for my racecar. I was told that by MIG welding chromoly the welds would be brittle. I had to "normalize" or stress relieve the welds. This was done buy using an oxy/acetelene torch and bringing the welds and four or five inches on either side up to a cherry red. Then packing it in sand to allow it to cool much slower. The metal returned to its normal molecular design and everything was back to normal. Considering I flipped the car three times in one incident and kept landing on the roof, it does work, no welds were broken in that "test".

Nascar frame builders and NHRA top fuel dragster builders dont do it so why should you. I am a welding metallurgist by education and manage a leading welding research facility so I do know a "little" about these things.

Posted: Thu Mar 16, 2006 11:17 pm

I realize that there are people here that have considerable more knowledge and education concerning this process that I can ever hope to obtain. I was just trying to explain the procedure I went thru. At the time I did it under the advice of others and it made sense to me. Again, I was ignorant of the process at the time but was the process I used that much different than the one you described as option one for stress releif in the post previous to mine? I would like to learn the correct procedure if what I am doing is wrong.

Posted: Fri Mar 17, 2006 12:07 am

I too would LOVE to hear your input, Petrat. I am mainly a mechanic and machinist by training and decent experience. I came into the welding game late, so I am trying to soak up as much practical knowledge and experience as possible.

As an example it has been said that Hydrogen embrittlement of the weld is an issue with Chromoly. I was under the impression that it isn't a huge issue if you are welding mild steel and using Argon, but again, my knowledge is limited. If you were welding up mild steel trussing onto the frame and swingarm, what post welding processes would you be concerned with? Would MIG and TIG welding work equally well? I know that welder skill is a huge variable, but if you were welding up something like and entire frame, would you strictly TIG every joint?

Jose

Posted: Fri Mar 17, 2006 12:38 am

As a mechanical engineer, I too have studied strengths of materials.
Yes, its true about the need for heat treatment after welding,
but depending on the forseeable stresses placed on a component,
full annealing may not be required.
As long as you can apply some heat to the steel and bring it
to the recryastalization temperature, then control the cooling rate,
you will gain some measure of control over grain growth in the
crystal latus structure. Of course, how a steel will respond to
heat treatment greatly depends on the alloying metal content and
more specifically the carbon content.
The steel used in this swing arm would dictate the treatment required
and without knowing it's components, it would only be a best guess
as to what method to use.
So don't go spouting your mouth off one way or the other about the
best heat treatment to use unless you know more about the steel
and also what elements are in the welding wire or rod.
A good cheap and dirty method that will indeed accomplish some
increased normalization of the grain structure is the torch heating
and sand insulating method described above. Though it is rather
unscientific, it is effective in many cases.
If we had access to a manufacturing facility with a kiln, the most
controllable method of slow cooling would be to heat the part to the
recrystalization temperature and slow cool in the kiln over a period
of hours, determined by the part's geometry. Depending on
the thickness in certain areas of the part, heat sinks may also need
to be employed.
Fun stuff.

The swing arm looks great. beerchug

Posted: Fri Mar 17, 2006 5:40 am

In reality, as long as the swingarm didn't warp or stretch it probably won't make a difference whether it's stress relieved or not. As long as the welds are done correctly, not too hot and good penitration, you're never going to break it. Even if it did break a weld the whole thing isn't going to fall off. You may notice some flex come back in the rear end, but I doubt all the welds would brake at the same time.

I read recently on welding chromoly frames to tig it. Tig generally uses less heat in the area and greatly reduces the brittleness of the steel. Otherwise you should stress relieve the welds if you mig them.

I'm no engineer or proffessor in metalergy, but I do weld 10 hours a day on boat hulls. I know what breaks and what doesn't.

I can also weld up anyone who wants one for way less than that, a case of Alexander Keith's is all it would take.

Posted: Fri Mar 17, 2006 10:44 am

I would mostly be concerned about equal stress on both sides of the swing arm so that it works symetrically.

Posted: Fri Mar 17, 2006 1:17 pm

Da_Hose wrote:

I too would LOVE to hear your input, Petrat. I am mainly a mechanic and machinist by training and decent experience. I came into the welding game late, so I am trying to soak up as much practical knowledge and experience as possible.

As an example it has been said that Hydrogen embrittlement of the weld is an issue with Chromoly. I was under the impression that it isn't a huge issue if you are welding mild steel and using Argon, but again, my knowledge is limited. If you were welding up mild steel trussing onto the frame and swingarm, what post welding processes would you be concerned with? Would MIG and TIG welding work equally well? I know that welder skill is a huge variable, but if you were welding up something like and entire frame, would you strictly TIG every joint?

Jose

Hydrogen embrittlement can be an issue in ANY C-Mn steel depending on the steel chemistry and the final hardness in the weld and heat affected zone. The heat affected zone is adjacent to the fusion line of the weld and is the most hardest area of the weld zone. In Cr-Mo steels such as 4140, 4340, etc, these are quench and tempered steels that have at least 0.40% carbon to achieve their high strength to weight ratio. When produced they are quenched to produce a microstructure called martensite which is high in carbon (and very high strength), however this is very brittle so they temper the steel to relieve the stresses caused by quenching as well as reduce the hardness and improve weldability. So when you are heating a section up cherry red, you are softening the steel even further and reducing the strength and ductility. These Cr-Mo steels are susceptible to hydrogen embrittlement and is why low hydrogen practice is required. Hydrogen is broken down in the arc (soucres are hydrocarbons on the surface, moisture, etc) which will migrate to an area of high stress (normally the toe of the weld) and can embrittle this area further if sufficient hydrogen and tensile stress is present, leading to cracking. Cracking can occur within a few hours or days later, and is why this is normally called delayed cracking. A post weld stress relieve heat treatment can be done immediately after welding to drive the hydrogen out of the weld zone before the weld zone returns to ambient temperature, as hydrogen embrittlement will not occur if the weld is kept above 120C. If you can limit the source of hydrogen (keep everything clean and free from contamination and use a low hydrogen welding process) hydrogen cracking should not be a problem when welding thin walled Cr-Mo tube, especially when using TIG and MIG welding, as these processes are typically considered low hydrogen processes anyways. When welding you want to select a filler metal that matches the lower strength material (in this case the swingarm since I expect your modifying the original CB1100f one), as this is the weakest link anyways. Lower strength filler metal is also lower alloyed which will even reduce the chances for cracking, as the hardness and chemistry is directly linked together (higher chemistry = higher hardness). The lower strength filler metal (such as an ER70S-6 clasification) will not respond to a post weld heat treatment.

Personnally I would TIG everything for two reason, it looks better and believe it or not requires less skill to produce a "sound" weld deposit. Lack of fusion is a common occurance with MIG welding just because of the characteristics of the process. Under "equal welding conditions", MIG will actually produce a lower hardness (less brittle) weld zone compared to GTAW (because differences in their arc efficiencies and other welding physics mumbo jumbo), however again, when welding thin walled Cr-Mo tube, none of the above problems should be any issue, its when you get into thicker sections you can start expecting problems.

Didn't mean to jack the thread, just wanted to provide some insight into my world.

Edit: Pappa, the swingarm looks great.

Posted: Fri Mar 17, 2006 1:22 pm

stoutblock wrote:

I would mostly be concerned about equal stress on both sides of the swing arm so that it works symetrically.

If the swinarm bracing is designed right, welded in a jig to keep everything straight, it will work ok as long as he started with a straight swingarm to begin with.

Posted: Sat Mar 18, 2006 4:22 am

petrat is corect. if i remember correctly, these swingarms were made from something like 1020 mild steel dom tube, and mig welded. nothing fancy, just production material.it was 1983,remember? i prefer aluminum myself, but it looks like a great job,and will be very distinkive. hope it goes back togather well. crank.

Posted: Sat Mar 18, 2006 1:16 pm

weld it and run it man!!!

edit: forgot,"papa, ithink it looks rad!! sick!!(in a good way) Wink

Posted: Sat Mar 18, 2006 4:23 pm

I am unclear on the need for such bracing.

Posted: Mon Mar 20, 2006 7:18 pm

Papa I have had thoughts of doing something like this to my 1100 swingarm as well. Did you give any thought to mounts for a race stand. I think some race stand bobbins would look cool on your swingarm.

Posted: Mon Mar 20, 2006 9:23 pm

Da_Hose wrote:

but if you were welding up something like and entire frame, would you strictly TIG every joint?

Jose

I definitely would, it's a better weld as long as the fit is good and there shouldn't be any need to clean up the welds after. The only thing that looks worse than a bad weld is a good or bad weld that someone tried to clean up. Proper welds always look better left alone in my opinion.
You don't want your work to look like the factory welds that Honda did on these frames! Early robotics I presume.

Posted: Tue Mar 21, 2006 1:37 am

grump wrote:

I am unclear on the need for such bracing.

if you do it yourself.......can you say poor mans CALFAB............ Twisted Evil

Posted: Tue Mar 21, 2006 2:10 am

grump wrote:

I am unclear on the need for such bracing.

I'm with Grump what is the purpose of the brace. some one mentioned some thing about flex, I'm assuming of the swing arm, but is that a big issue. Or is the bracing purely cosmetic?

Posted: Tue Mar 21, 2006 3:46 am

The reason for bracing has to do with the mechanical forces at play when the supension is moving up and down under axial loads.

When you are turning, the forces on the side of the tire are pushing all your combined weight at an angle against the traction spot on the tire. All that force causes the swingarm legs to twist. The greater the force, the greater the twisting. Pretty simple. Our factory swingarms are tubular steel. With no bracing there is a fair amount of twist/flex while making even lower angle but high speed turns. Now think about us guys over 225 lbs. hitting bumps during a higher speed turn. There is tons of flexing going on and the rear end has a spongy/wobbly type of feel to it. Add the bracing and the rear end now tracks truer and feels more confident at speed. Also remember that we use twin shock absorbers. That adds to the problems as the separate fork arms can end up compressing and extending at slightly different rates. Not a huge deal in most cases, but push toward the extremes of traction (some of us do that from time to time - not always on purpose either) and the combined factors can really cause issues with handling when you are one of us big boys. If you look at modern swingarms you will see that many of the problems I talk about have been addressed by moving to a single shock with progressive geometry and by making the swingarms HUGE in cross-section width or by adding on factory over/under braces.

Jose

Posted: Tue Mar 21, 2006 2:58 pm

Thank Jose

I couldn't picture the flexing at first but I wasn't looking at it through a turn, and the part with the shocks not acting in unison makes sense.

how does the bracing effect ground clearance?
would running a gusset the lenght of the swing arm be as effective?
answered my own question no not on the cross bike twist

Posted: Wed Mar 22, 2006 3:58 pm

a question for papa: did you consider using square tubing instead of round at any point....for aesthetic reasons i mean