help in forming roof

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Mike Walsh
Posts: 599
Joined: Sun May 06, 2007 10:14 pm
Location: St. Louis, MO

help in forming roof

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

Hello,

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.

Thanks,
Mike Walsh
Attachments
curved panel.JPG

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NP317
Posts: 1385
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: help in forming roof

Post by NP317 » Thu Feb 01, 2018 10:57 am

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.
~RN

Russ Hanscom
Posts: 1443
Joined: Wed Mar 15, 2006 11:10 pm
Location: Farmington, NM

Re: help in forming roof

Post by Russ Hanscom » Fri Feb 02, 2018 3:53 pm

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.

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senorgilamonster
Posts: 139
Joined: Sun Apr 23, 2017 1:37 am
Location: Puget Sound, WA

Re: help in forming roof

Post by senorgilamonster » Tue Feb 13, 2018 11:26 am

what gauge is the metal?

Assuming that your brake can handle the gauge AND if the bending edge can be spaced backwards a bit...you 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

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senorgilamonster
Posts: 139
Joined: Sun Apr 23, 2017 1:37 am
Location: Puget Sound, WA

Re: help in forming roof

Post by senorgilamonster » Wed Feb 14, 2018 5:28 pm

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.
bend2.jpg
You can see how the bend follows the radius of the edge of the MDF
bend 3.jpg
Presto
bend4.jpg

Harold_V
Posts: 17091
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: help in forming roof

Post by Harold_V » Thu Feb 15, 2018 2:00 am

Nice bend!
Well done.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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