A Bender for Arch Bars

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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 27, 2017 10:39 pm

Last input.

I took three random bars from the stack and bolted up a set without having to do any tweaking to get them bolted up.

On to bigger and better things.
DSC_5089.jpg
DSC_5090.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
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Harold_V
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Re: A Bender for Arch Bars

Post by Harold_V » Tue Nov 28, 2017 1:13 am

Well done, Charlie!
H
Wise people talk because they have something to say. Fools talk because they have to say something.

Glenn Brooks
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Re: A Bender for Arch Bars

Post by Glenn Brooks » Tue Nov 28, 2017 1:20 am

Charlie, this is an invaluable reference. I’ve been head scratching for a year, off and on, worrying about how to consistently bend up the frames for some trucks I need to build.

Thanks for posting.

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

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JBodenmann
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Re: A Bender for Arch Bars

Post by JBodenmann » Wed Nov 29, 2017 9:43 pm

Hello My Friends
Here is a thread from a while back. I think there is some info on forming arch bars in there.
http://www.chaski.org/homemachinist/vie ... bar+trucks
Happy Model Building
Jack

Mr Ron
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Re: A Bender for Arch Bars

Post by Mr Ron » Sun Dec 03, 2017 11:59 am

Charlie, It would appear to me that the bar you wish to bend would have to be tightly clamped between the back block and the die block to keep the bar from "creeping" as bending progresses. Is this a problem?
Mr.Ron from South Mississippi

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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs » Sun Dec 03, 2017 12:16 pm

I found very early that the creep could happen. But it only takes a little finger pressure to hold it in place. The bar is slid into place with attention to aligning it to the mark for the first bend while keeping it flat on the table. This is to be a top bar, hence the T on the handle. I turn it over for the bottom bar as the marks are different due to the larger angles and lengths involved.
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It is important to hold the bar flat and with just a little preassure to stop any creep.

You can see how the bar blank end moves past the original line. This is why the clamp I made would not work. If anything it cause creep backwards on the arch bar.

You will also notice I have started bending past the reference line I have scribed on the base plate.

This is to make it easer to fit the arch bar to the fixture after the bends are all made. It is easier to relax an angle a little with a hammer and a anvil than it is to sharpen them up. Usually I can tweak a bar with two to four light hits with a brass hammer I have.
DSC_5120.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs » Sun Dec 03, 2017 12:21 pm

One thing the bender and fixture has done for me is that I can match the bars to my design drawing with little error. It is important that the space between the upper and lower bar be at the right height to fit in the two uprights

This worked out great and I will be buying Gregg's lunch next time I meet him at the club.
DSC_5102.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

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Pipescs
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Re: A Bender for Arch Bars

Post by Pipescs » Mon Dec 11, 2017 8:23 pm

All is working as advertised and the other side of the truck went together with no problem.
DSC_5133.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

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