Bending an axle

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Rick Laton
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Bending an axle

Post by Rick Laton »

1. What is the best method to bend an axle for rail riding?
2. How many degrees do you bend it?
3. Where exactly one the axle do you make the bend?
4. Can someone post a picture of an axle that is bent the correct amount?

Thanks in advance
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sporty
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Re: Bending an axle

Post by sporty »

wow,


I think if someone has the info, count me on the want list.


No disrespect rick.


I insert my axle into our axle straitner tool. Then bend slightly with needle nose pliers. I mark on the head of the axle where I bent at.


I do a very slight bend. a little is alot.


However, I spend many hours on alignment now and I have no specific test or method for proper bend.

Simply due to, it's hard to factor in or asume the axle whole or slot is at a certain degree or on center.


But I have seen on here, talk of camber for rail rading at 1 to 2%.

But I am new to the rail riding.


Sporty
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Re: Bending an axle

Post by doct1010 »

Rick rather than repeat the words of the mastermind I will simply quote Warp "We prefer to insert the axle in an old wheel (or a new #18!) all the way to the axle head. Then we mount the axle in a lathe collet, or a pro-axle tool (everybody has one, right?) mounted in a vice. We leave the normal inner hub to body spacing (plus about .020) between the inner wheel hub and the holding fixture (collet/pro body tool). Keeping the wheel against the nail head, we gently push in the direction of desired bend. (about .002-.003)
It doesn't take much!!
This all helps ensure the bend is in the proper place, and not in the middle of the working surface.
We then mark the direction of the bend with a sharpie so it can be used as a reference.
When installing the wheel / axle into the car, rotate the axle so the sharpie mark is at the 12 o'clock (straight up) position. This tells us the bend is up. Now if you rotate the axle forward, it will steer towards the rail. Rotate it backward and it will steer away. I use some special made pliers for the adjustments, but a standard pair with a little tape on the ends to protect the axle head will do the trick. Make the adjustments (rotation increments) very small, as a little will make a big change depending on how much bend you put in. You can almost feel a tiny "pop" when the axle rotates a touch, and this is enough for another run."
Last edited by doct1010 on Thu Jan 10, 2008 9:04 pm, edited 1 time in total.
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Re: Bending an axle

Post by Pinewood Daddy »

We do it only for alignment instead of playing with shims (I still have nightmares!). Using Stan's method to check alignment and the Florian Alignment Computer, we check if a bend is required and approx how severe. We bend using the Pro Axle Press, mark the head of the axle (for orientation) and use a hammer and flat blade screwdriver to induce a bend. The the wheel and axle are reassembled to the car and alignment is checked again. Any alignment to that wheel is done by turning the axle to the direction the Alignment Computer tells me. If the alignment still can't be brought in more bend is added and the process repeated again, until alignment is as good as it's going to get (about 2am the night before the race!). I've heard mixing rum, coke and rogaine is a great way to reduce hair loss due to 10 hours of PWD alignment!!
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Re: Bending an axle

Post by rlaton »

OK. I think I understand exactly how and where to bend it and I understand how to mark it and rotate it until I find my "Sweet Spot". I still would like to see a picture of one that is already bent to help me visually see what 3 or 4 thousands looks like. Thanks in advance.
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Re: Bending an axle

Post by PWD_addict »

doct1010 wrote:Rick rather than repeat the words of the mastermind I will simply quote Warp "We prefer to insert the axle in an old wheel (or a new #18!) all the way to the axle head. Then we mount the axle in a lathe collet, or a pro-axle tool (everybody has one, right?) mounted in a vice. We leave the normal inner hub to body spacing (plus about .020) between the inner wheel hub and the holding fixture (collet/pro body tool). Keeping the wheel against the nail head, we gently push in the direction of desired bend. (about .002-.003)
It doesn't take much!!
This all helps ensure the bend is in the proper place, and not in the middle of the working surface.
We then mark the direction of the bend with a sharpie so it can be used as a reference.
When installing the wheel / axle into the car, rotate the axle so the sharpie mark is at the 12 o'clock (straight up) position. This tells us the bend is up. Now if you rotate the axle forward, it will steer towards the rail. Rotate it backward and it will steer away. I use some special made pliers for the adjustments, but a standard pair with a little tape on the ends to protect the axle head will do the trick. Make the adjustments (rotation increments) very small, as a little will make a big change depending on how much bend you put in. You can almost feel a tiny "pop" when the axle rotates a touch, and this is enough for another run."
So, I'm nervous about bending an axle that I spent 45 minutes polishing. Will I really be able to tell that the axle has bent just a little bit? I suspect I won't really be able to see it, will I?

I'm worried that I'll try to bend it, and not really bend it at all and go through alignment check only to see no difference.

Perhaps I should take one of last year's axles and experiment. :?
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Re: Bending an axle

Post by doct1010 »

Or just shim it to be absolutely sure. I never felt comfortable bending perfectly stright axles, so we shimmed. I know warp and others have used the bend technique with success and are able to dial it in.
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Re: Bending an axle

Post by PWD_addict »

doct1010 wrote:Or just shim it to be absolutely sure. I never felt comfortable bending perfectly stright axles, so we shimmed. I know warp and others have used the bend technique with success and are able to dial it in.
Bending seems so much easier than shimming. I have shimmed in the past with success but it was tedious, to put it mildly.
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Re: Bending an axle

Post by colopwdfan »

I've found dropping the car from 3 foot 8 inches bends axles well. Though without precision in most cases! :roll:

John
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Re: Bending an axle

Post by Pinewood Daddy »

PWD_addict wrote:
doct1010 wrote:Or just shim it to be absolutely sure. I never felt comfortable bending perfectly stright axles, so we shimmed. I know warp and others have used the bend technique with success and are able to dial it in.
Bending seems so much easier than shimming. I have shimmed in the past with success but it was tedious, to put it mildly.
YES! Dialing it in with the bent axle technique is much quicker, but less exact. Adjustment is easier but twisting the axle make changes on 2 planes. So there's alot of chasing your tail. I still prefer it.
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Re: Bending an axle

Post by PWD_addict »

OK--I've "test" bent some axles to see what I can do. I was able to bend a couple to the extent that I could definitely tell that they were bent.
One that I bent I could just barely tell that it was bent. Which one was the better bend? Can you tell with the naked eye that the axle is clearly bent?

If I bend what appears to be a little too much to my eye, will it still align OK since you want some "up-cant" anyway? Or, is too much cant a really bad thing?

I think the slight bend is probably the best since I can rotate the axle to give it sufficient toe-in, as long as there is enough bend to give it sufficient cant to keep it away from the body.

When we did Space Derby in October, my son's rocket did poorly since one of the rubber bands came off the internal hook, unbeknownst to us. I keep having these horrible feelings that we are going to get to the Pinewood Derby this weekend and my son's car is going to do poorly for some reason. I wish I had a test track . . .
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Re: Bending an axle

Post by Rick Laton »

Still looking for a picture of a correctly bent axle. Anybody have one?
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Re: Bending an axle

Post by colopwdfan »

Rick,
Check in David Mead's "Official Scout" Pinewood Derby Speed Secrets book.

There's a close up and clear picture as well as instruction there for axle bending. Pages 82 and 83.

If you don't want to buy the book, it's probably available at your library.

John
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Re: Bending an axle

Post by Pinewood Daddy »

I got the info from Dave Mead's book also. http://www.derbychamp.com/v/vspfiles/speed_tips.htm

There alot of good info in there but much of it is illegal in our District.
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Re: Bending an axle

Post by derbster »

"When we did Space Derby in October, my son's rocket did poorly since one of the rubber bands came off the internal hook, unbeknownst to us. I keep having these horrible feelings that we are going to get to the Pinewood Derby this weekend and my son's car is going to do poorly for some reason. I wish I had a test track . . "

Last year we followed suggestions on this website, but without using much precision !!!

- extended the wheel base using slots created by mitre saw
- wedge design with solder weight to 5 oz
- COM about an inch infont of rear axel
- polished axels up to 600 grit paper. used silver polish after
- sanded wheels to remove outside marks
- rounded hubs "by eye"
- NO alignment
- Graphite the wheel bore with lots of spin-in

At our meet, we came in first without contest !! At the districts we probably came in 20 out of 100 or so entrants.

My point....implementing just the basic concepts will get you pretty far.
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