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help in forming roof

Posted: Thu Feb 01, 2018 8:48 am
by Mike Walsh

I'm looking at forming a roof for my boxcab electric in 1" scale ride on railroading.

I've attached the following diagram. I have several thoughts on how to do this.

I will say that I am OK with having ribs welded to the roof, for structure/rigidity.

For that reason, one option is to calculate the arc length of the 30 inch radius, then position my 3/4" radii accordingly. Then form/force the roof to the ribs, and tack weld them in place. This might be something I can do with minimal tooling. Perhaps a piece of bar clamped to the table.

I'm not sure what my other options are, yet. Thoughts? I have access to a sheet metal brake if needed.

Mike Walsh

Re: help in forming roof

Posted: Thu Feb 01, 2018 10:57 am
by NP317
Can't roll in the radii?
That's how I formed the steel roof(s) for my locos.
Careful rolling and visual testing, and it worked out OK.

Re: help in forming roof

Posted: Fri Feb 02, 2018 3:53 pm
by Russ Hanscom
A wood former and a rubber hammer are one way to make the tight bends. Make multiple passes bending a little each time and you should get there.

Use a piece of wood closet rod fastened to a 2x4? for the former.

Re: help in forming roof

Posted: Tue Feb 13, 2018 11:26 am
by senorgilamonster
what gauge is the metal?

Assuming that your brake can handle the gauge AND if the bending edge can be spaced backwards a can put a half or quarter round on the bending edge. If the gauge isn't that hefty, you should be able to use wood - try it on a piece of scrap first. :-)

I've used the method Russ described above (it works fine), but instead of a rod connected to a 2x4 I took a piece of MDF and routed the edge. To my surprise the MDF held up fine. It was very easy to radius the edge with the router and very smooth.
radius edge.png

Re: help in forming roof

Posted: Wed Feb 14, 2018 5:28 pm
by senorgilamonster
Here I am forming a 1/2" I.D. radius 90 degree bend on 18 ga steel. Harbor Freight $44 30" bending brake plus some MDF that was free in the Home Depot Cull pile.

1. I rounded the 1/2" thick MDF with a standard 1/2" round over bit in a router. Cuts like butter and very smooth.
2. Put the rounded edge of the MDF face down on top of the metal to be bent. Aligned edge, etc.
bend 1.jpg
3. Bend an usual. (works the same in a DIY brake). Over-bend as required.
You can see how the bend follows the radius of the edge of the MDF
bend 3.jpg

Re: help in forming roof

Posted: Thu Feb 15, 2018 2:00 am
by Harold_V
Nice bend!
Well done.