A Bender for Arch Bars

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Brian Hilgert
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Re: A Bender for Arch Bars

Post by Brian Hilgert »

That is a nice design! Sure beats the way I did the arch bars for my shay!

Thanks for sharing the drawings!
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Greg_Lewis
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Re: A Bender for Arch Bars

Post by Greg_Lewis »

A slight cut into the bar at the bend point with a hacksaw will insure that the bend happens at the exact spot you want, and will give a nice sharp bend. Such a cut is unlikely to compromise the strength of the bar considering the forces applied to the truck, but you can fill it in with silver solder, which is what I've done.
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Soot n' Cinders
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Re: A Bender for Arch Bars

Post by Soot n' Cinders »

Brian Hilgert wrote:That is a nice design! Sure beats the way I did the arch bars for my shay!

Thanks for sharing the drawings!
I agree! The shop press bent the bars easily but some of mine got a little off so required some banging and prying to assemble. I’ll definitely give this idea a go when I start making rolling stock archbars.
-Tristan

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jeffsmith
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Re: A Bender for Arch Bars

Post by jeffsmith »

You might think about adding a set screw on the die block. I have found that no matter how tight the fit between the two blocks the force of bending the arch bar can make it slide from its original position giving inconsistent bends.
Just a thought.

Jeff Smith
BClemens
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Re: A Bender for Arch Bars

Post by BClemens »

jeffsmith wrote:You might think about adding a set screw on the die block. I have found that no matter how tight the fit between the two blocks the force of bending the arch bar can make it slide from its original position giving inconsistent bends.
Just a thought.

Jeff Smith
Center the die block and bend two angles at the same time...
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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs »

You might think about adding a set screw on the die block. I have found that no matter how tight the fit between the two blocks the force of bending the arch bar can make it slide from its original position giving inconsistent bends.
Just a thought
I discovered this too. As you say when trying to bend the 1/4" x 5/8" bars it tends to move no matter how tight the bolts.

My thought is to cut a rabbit about .0625 deep for the die block to sit down into the plate giving it a stop to go against.

I will try it this weekend.
Charlie Pipes
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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs »

I am thinking along these lines
Base.JPG
Bender Assy.JPG
Charlie Pipes
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BClemens
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Re: A Bender for Arch Bars

Post by BClemens »

Charlie,
Since you have drilled the arch bar blank material for the bolster pedistals, use the holes on dowel pins or bolts through the clamp blocks to assure the bends are the same distance from each hole when you turn the blank over to do the other end. Add a hole through the anchor blocks and slide a dowel pin or bolt through them with the blank between them. You may need to relocate the outer bolt holding the bend block in its seat slot.
Down and dirty 'out of perspective' sketch:
Attachments
Arch Bar Bender.jpg
BClemens
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Re: A Bender for Arch Bars

Post by BClemens »

ArchBarBender.jpg
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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs »

This is an interesting approach.

My drawings are a little misrepresenting as I am planning on using the fixtures to drill the holes after bending.

You method would definitely have merit.

I did this tonight before running off to church. it is a stop guide attempt. I also swung by the steel yard to get a piece heavy wall tubing to make a cheater bar for the bending arm.
DSC_5051.jpg
DSC_5052.jpg
DSC_5053.jpg
Out of curiosity. is your drawing in Solidworks?
Charlie Pipes
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Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
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BClemens
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Re: A Bender for Arch Bars

Post by BClemens »

Keycreator - it doesn't like being converted to a jpg. Stops are a good thing.
BClemens
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Re: A Bender for Arch Bars

Post by BClemens »

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