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Re: A Bender for Arch Bars

Posted: Thu Nov 23, 2017 4:54 pm
by Pipescs
Definitely and interesting method and it obviously works.

Re: A Bender for Arch Bars

Posted: Fri Nov 24, 2017 8:28 pm
by Pipescs
Spent a little time in the shop today.

I worked out the parameters for the top bar.

This required working out the flat bar length to get the overall length right when bending . This came to 12 and 3/8".

It only took two attempts to work out the bends and set the marks on the bending handle to be able to reproduce the bends with reliability.

I still had to take a hammer and anvil to the bent pieces to get them to drop into the drill fixture. but we are talking less than five minutes each for the bent bars.
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Re: A Bender for Arch Bars

Posted: Fri Nov 24, 2017 8:32 pm
by Pipescs
The bar clamp did not work at all. When bending the bar, it would move the clamp out of place.

I ended up with a scribe mark on the face of the bending bar for each of the two bends.

Re: A Bender for Arch Bars

Posted: Fri Nov 24, 2017 9:52 pm
by Pipescs
After working out the details on a couple of first attempts I now have consistency.

1. Cut the top bar blank to 12.375" on the band saw. Actually cut all you need for the prodject
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2. Insert the blank to the line on the bending arm. This side of the bar is marked for the top bar. I will flip the bar and mark it for the larger angle on the middle bar.
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Bend the bar to the angle line scribed on the Base plate In this case I have it marked to 155 degrees. I don't bend it to the line but parallel to it. Also note the end of the bar moves past the mark you started with. This is why the clamp did not work.
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Reverse the bar and bend the other end the same way.
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insert the blank to the inside mark and bend the outside bend
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Re: A Bender for Arch Bars

Posted: Fri Nov 24, 2017 9:57 pm
by Pipescs
Reverse the bar and do the other outside bend.
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It should drop right into the fixture, but it doesn't as the bender is not perfect. If the bends are too sharp, the bar is too tall to go in the slot. bends to shallow and it is too loose in the fixture. Simple matter to bend them a little tighter or relax them with a hammer and an anvil. None have taken more than three to four minutes to make and fit to the fixture.
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Then the fixture is stood up on its side and the holes are drilled in the drill press.
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Re: A Bender for Arch Bars

Posted: Sat Nov 25, 2017 8:37 am
by Fender
Great job, Charlie!

Re: A Bender for Arch Bars

Posted: Sat Nov 25, 2017 8:42 am
by BClemens
Looks great! The lever is the trick!


BC

Re: A Bender for Arch Bars

Posted: Sat Nov 25, 2017 8:56 am
by Pipescs
Yes the lever needs to be at least 24 inches long. I use a cheater pipe. Also the radius on the die block needs to be fine tuned to the material and the angle of the bend.

Today I will be working the numbers on the middle bar which, due to its angles, will require a longer blank to start with.

On the material used; I am doing the test bends with 1/4" X 3/4" HRS Bar. This because it is fairly inexpensive at $15.00 per 21 foot stick.

I am also bending bars that are 1/4" X 5/8" CRS as when I drew my original frame drawing I designed around that size. This is not cheep at about $21.00 for a 12 foot stick not including shipping. I am changing the drawings to be able to use either size

The bender will bend the CRS fine but it does take more force to bring it in line and the blacksmithing to get it into the fixture takes substantially more hammer power.

Re: A Bender for Arch Bars

Posted: Sat Nov 25, 2017 9:48 am
by tomc
Following along and enjoying your ideas

Tom C.

Re: A Bender for Arch Bars

Posted: Sun Nov 26, 2017 9:18 am
by Pipescs
The bender thread is officially done.

I turned out two sets of top and middle bars for the trucks I am working on with very consistent bends and the holes line up with the ones drilled in the J.B. The columns still need to be machined.

The fixture is the key. The bender is not quite consistent but once bent and fine tuned they drop right into the drill fixture. I would upload the drawings for the fixture but it is truck dependent and easy to understand how you would make one for any truck



Should anyone ever want a copy of the bender drawings send me a PM with an email I can send them to.
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Re: A Bender for Arch Bars

Posted: Mon Nov 27, 2017 5:34 pm
by gwrdriver
Well done Charlie.

Re: A Bender for Arch Bars

Posted: Mon Nov 27, 2017 8:10 pm
by Pipescs
Thanks for all the input. It was a fun project that has worked as advertised. Can't give Gregg Glos enough credit for his original design.