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Old 04-21-2020, 01:05 PM
threepiece threepiece is offline
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Default Ripping Channel Question

I am considering using 9x13.4 channel as floor joists for a two story barn. My intention later is to add a section of channel along the entire length of a joist. The new section would be positioned such that it would created two bottom flanges much like a Standard I beam so a trolley can run on it.

The section would be made by flame cutting a 9x13.4 channel along the middle (ripping). I know beams are cut down the middle by slitting to create a T section.

I’m wondering if a channel could be cut this way by flame without warping much?
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Old 04-21-2020, 01:08 PM
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Boing !

No matter how you cut it (hot or cold) it will release locked in stresses
and it will twist and warp
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Old 04-21-2020, 03:05 PM
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I don't know what would happen but it wouldn't be good, how about two pieces of 2"X3" angle?
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Old 04-21-2020, 03:47 PM
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You could cut intermittent slots down the middle, leaving tabs or a web, then cut the remainder after it cooled. And you could step around to avoid too much heat in one place.

Topics like this are discussed in such books as Lincoln's handbook of arc welding and the Linde Oxy-Acetylene Handbook. Old books, available cheap from used booksellers. These two were my bedside readers for a long time. Highly recommended.
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Old 04-21-2020, 05:15 PM
JBFab JBFab is offline
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You are right - beams are split all the time to make T sections for structural steel - they are used for bracing quite often on mid to large industrial structures. The same school of thought can be applied to splitting channels for the purpose you describe.

There are two main methods flame splitting and shearing. The shearing method incorporates a rotary shear and a rosebud heating the center line as it goes. This isn't to help in shearing, but rather to help keep the tees straight after they split. https://www.youtube.com/watch?v=O7r-WB8AoNw

Flame splitting can be done with either a torch or plasma cutter (or a laser I suppose). Most often I see them as "stitch split" this is as USMCPOP described (and the next video shows) where the cuts are made intermittently and allowed to cool before cutting the tabs later. If you do this BE VERY CAREFUL they will pop before you think - they will still be VERY bent after splitting. This is easy enough to fix by flame straightening. If you need some tips on straightening - let me know.

Again BE VERY CAREFUL if you do this. I had a guy lose a finger in our shop because he was splitting a beam and a full inch before he was through cutting split from the stress and smashed his finger against an adjacent piece of material. https://www.youtube.com/watch?v=Y3iw3azRL6U <- This is kind of a hokey little setup but you get the drift.
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Old 04-23-2020, 12:13 AM
threepiece threepiece is offline
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I started this thread thinking I was going to buy a test channel and confirm for myself however the consistent responses indicates I would be wasting my time and money; My steel supplier said the same.

I’m not going to go this route. I was trying to save on cost but there are 7 pieces of 16 feet long split channel I need for this barn, I’m not up to playing that game.

My plan at this point is to use a full channel backed up to the joist where the trolley is to run.

Thanks for the input fellows.
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  #7  
Old 04-23-2020, 08:02 AM
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Quote:
Originally Posted by threepiece View Post
I started this thread thinking I was going to buy a test channel and confirm for myself however the consistent responses indicates I would be wasting my time and money; My steel supplier said the same.

I’m not going to go this route. I was trying to save on cost but there are 7 pieces of 16 feet long split channel I need for this barn, I’m not up to playing that game.

My plan at this point is to use a full channel backed up to the joist where the trolley is to run.

Thanks for the input fellows.
Two channels back to back skip welded should not warp much.
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Old 04-23-2020, 08:52 AM
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Quote:
Originally Posted by milomilo View Post
Two channels back to back skip welded should not warp much.
Why not just BUY a proper I-beam ?
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Old 04-23-2020, 09:44 AM
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Quote:
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Why not just BUY a proper I-beam ?
Money.
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Old 04-23-2020, 09:49 AM
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Quote:
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Money.
Even scrap is sold by the pound, so buying (2) channels over (1) beam
will probably come out awash.

Plus, no welding or warping.
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