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Front Axles: Welded vs. Formed

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burntblacktoast Matt Sutter
Leroy, Illinois, USA   USA
Hello All,

It may be possible that I have not found the most relevant term for a forum search, but I have been looking for some input as to front axle construction.

I would imagine that having a front axle formed (bent) is the most desirable route to take for many reasons; weight, parts count, strength, etc. Plus, it just looks good.
That being said, it would seem to me that this is one of the highest hurdles one would need to clear for a successful build. Im sure a competent machine shop could handle it no problem, but a one-of job with minimal dimensions to go off of makes it seem a little less than practical.

I have seen front axles welded from either square or rectangular section tubing, and it would seem like this could be more easily achieved by someone in their own garage.

Am I oversimplifying it? Is this a viable alternative?

Any input you may have is appreciated, like your personal decision making process, obvious (not to me) shortcomings in the welding option, or just how you explained to your local machine shop that you were attempting to build a miniature car for someone other than your children or grandkids!

Thanks

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Racie35 Bruce Thomas
Terre Haute, In, USA   USA
What's surprising is no one has made a jig to fab them up and offer them to builders. Lotta guys can't just bend that wall tubing correctly.
I know all builds aren't the same but most could use the same axle easy enough.

michaelbikel Mike S
Bridgeport, Connecticut, USA   USA
I had a lot of trouble getting mine done.

Tried to bend it myself and make a mockup but didn't do a great job.

In the end it was easiest for me to make the most accurate drawing of the axle I could and get it bent at a muffler shop using that drawing as a template.

It turned out just fine. Obviously the better the shop the better it will turn out.

If you ask a lot of the other guys on here you will get good info, they know their stuff.
Hope this was helpful.

-Michael

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alefoot Avatar
alefoot Derek W
Vernon, BC, Canada   CAN
1929 CycleKart Race Car "Le Camion"
In reply to # 6580 by burntblacktoast I have seen front axles welded from either square or rectangular section tubing, and it would seem like this could be more easily achieved by someone in their own garage.

Am I oversimplifying it?
No
Quote: Is this a viable alternative?
I certainly hope so smiling smiley
The front axles for many of the Gittreville cars are analyzed in this blog post. Some round, some square, some bent, some welded.

I have access to a bender, but my inspiration car had a beam section axle, and the geometry I wanted would have been difficult to bend. Cutting wedges out of square section tube and welding up the result is the way I went.

For me at least, this is one of those jobs which presented a bigger mental block than a physical problem.

Rhysn Rhys N
New Zealand   NZL
Oversimplifying, no.
I think that as Derek says, you can overthink it though. Whatever works for you is the right answer. There is no reason why you can't go back and re-do it in the future any way.

fatfendertruck Tony Sanchez
Show Low, Arizona, USA   USA
---Matt, I will probably build my next front axle out of some 3/16 flat stock. I will build it similar to the hot rod I beam axle, and weld king pin bosses on it similar to the tube axle that I built for my Menifee CK.

carChips Avatar
carChips Victor Harnish
Kelowna, BC, Canada   CAN
1933 MG Magnette
1973 Triumph Spitfire 1500 "Chip"
1989 GMC Sierra 1500 "Bush Truck"
You can also buy small I beams and cut and weld in your angle. Figure out what angle you need for the ends, divide the angle in half and then that is the angle you want to cut on each end piece. i.e. 45 degree angle on the ends equals two 22.5 degree cuts.

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Injunbike Avatar
Injunbike Mike Thorpe
Auckland, North Island, New Zealand   NZL
1914 CycleKart French
1914 CycleKart German "GP Mercedes"
1920 Other Custom
1922 CycleKart Great Britain "R A 30/98"    & more
I welded mine and its holding up fine. I also think the spring and U bolts fit better as the tube isn't deformed or the radius starting where the springs bolt up. I would weld my next one too.


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Rdstr31 Chad Ritter
Ney, Ohio, USA   USA
There's another way you can accomplish that bend in your tube axle--you can "kerf" and weld it. Locate the section of the axle where you want to place the bend and, using a cutoff wheel, cut 3/4 of the way through the tube from top to bottom. Move over about 1/4" and make another cut. Keep making cuts through the area that you want to bend until you can flex the tubing into the radius you're after. Then bevel the edges of each cut and weld them up. It's a bit tedious but it gets the job done. Not cutting all the way through results in a stronger axle, and since most of the strain on the axle puts the cut/welded section in compression, you don't have to worry if your welding skills aren't quite up to snuff.

I just did this procedure on a go kart I'm building for my daughter. It's a 5/8 scale Model A roadster, but it's being built in much the same fashion as a cyclekart (which I'll be building for myself next!).

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Antioch Bob M
Langley, BC, Canada   CAN
1929 CycleKart French "LR2 Special"
I think, as mentioned, there are a lot if ways to do these.... However if you get in a bind & have few tools, the guys on one of the buggy sites suggest paying a visit to your local muffler shop. They usually have the right dies & they can do these very quickly. Depending on the shop I have heard of guys getting there bends done quite in expensively.



Rosengart LR2 special

http://rosengart.rzaplaser.com/rosengart-lr2-build/

ruth and son Avatar
ruth and son Gold Member Tom Ruth
El Paso, TX, USA   USA
1930 CycleKart Speedway Racer "The Perfect Circle Special"
Chad- Wow, that is one beautiful frame for a go-kart! Nice work buddy, and welcome to the club and forum. I have used the saw-kerf method myself before and it works really well for a low-tech solution... which I love.

Rdstr31 Chad Ritter
Ney, Ohio, USA   USA
Thanks Tom. I'll start a build thread on the custom kart forum at some point, when there's more to look at and I get the garage cleaned so the pics don't look so trashy! smiling smiley

I read somewhere else on this site about some front axles that had folded up while racing. Does anyone know if they were welded or bent? I wonder if it has anything to do with how some hydraulic tube/pipe benders "dimple" the bend? Would that give the axle a ready-made spot to collapse? Not trying to panic anyone with a bent tube axle--just thinking out loud....

Dove Linkhorn Avatar
Dove Linkhorn Charlie Moser
Elmhurst, IL, USA   USA
I've had quite a bit of experience with that Harbor Freight pipe bender. It's a brutal awful tool, but can be used to bend TUBE instead of pipe. One thing I did was to cap the tube on both ends after filling it with sand, then make sharpy marks every half inch on the tube. Jack the tube into place with your finger (thus taking out the slack) then use the Jack handle to bend it with five pumps. Then release, move the tube a half inch and do it again. Keep on this way until the final radius is achieved. It stinks but it can work.



Edited 1 time(s). Last edit at 2014-07-12 04:45 PM by Dove Linkhorn.

Rhysn Rhys N
New Zealand   NZL
In reply to # 7022 by Rdstr31 Thanks Tom. I'll start a build thread on the custom kart forum at some point, when there's more to look at and I get the garage cleaned so the pics don't look so trashy! smiling smiley

I read somewhere else on this site about some front axles that had folded up while racing. Does anyone know if they were welded or bent? I wonder if it has anything to do with how some hydraulic tube/pipe benders "dimple" the bend? Would that give the axle a ready-made spot to collapse? Not trying to panic anyone with a bent tube axle--just thinking out loud....

From what I was told the issue had nothing whatever to do with the method of construction, just material inadequacy on very rough ground. It's called empirical testing. If it never fails it's too strong, if it does it is not strong enough smiling smiley Everything can be fixed after failure.

Neilwheels Silver Member Neil M
Aurora, Illinois, USA   USA
I am working on a drop axle for my Stevenson frame cart. I don't know if anybody has tried this....... but I have a length of 1-1/4" x 1/16" square tubing that I cut with a 7" metal cut off wheel on my table saw. I made 2 cuts, measuring approximately 27° back from 90°. When I reversed the cut ends of the pieces, I ended up with a ~53° mating angle for my bends. I welded the pieces together, and all my angles seem to be correct. I found some 1-1/2" wide square u-bolts to attach the axle to the buggy springs. To give the whole thing a little more rigidity at the corner welds, I plan on cutting pieces of 1/16" flat steel to match the corner angles and welding them on each side of the tube as reinforcements- sort of 'sandwiching' the axle at the bends and into the u-bolts.

I am trying to keep the weight down, but I am a little nervous using 1/16" tube steel. It is the what is available to me at the moment. I'm not sure that this is going to work.

Any ideas?

Neil


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