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Post by steamcoal on Oct 30, 2014 5:56:52 GMT
We require to build a rail bending machine ( hand operated?) to pass through 30mm x 10mm x 6m lengths to construct a curve of 13 metre radius.
Is there a recognised design to do this task or will it require more commercial equipment.
Any help would be appreciated as we will have to build the equipment obviously to allow is to continue our track building.
Thanks.
Hayden
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Post by Roger on Oct 30, 2014 7:40:59 GMT
I don't know anything about this, but from an engineering point of view I would think it will want to twist as it bends if there's a flange on the bottom. You don't say what the section of the rail is and that's going to make all the difference in my opinion. If it's square steel stock then something simple along the lines of tube rollers would work. If it's a rail section then rollers that match the profile are probably going to need to be made and additional ones on the top and bottom faces to keep it from twisting. Here's a handy online calculator that may help getting the dimensions between the rollers to get the radius you need. Obviously it's going to spring back a bit but it may be easier to measure the radius of a short section with a straight edge and the amount the middle deviates from that.
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Post by ilvaporista on Oct 30, 2014 7:48:12 GMT
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Post by steamcoal on Oct 30, 2014 8:47:16 GMT
Roger.
The section is 30 x 10 flat mild steel.
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Post by ejparrott on Oct 30, 2014 9:35:02 GMT
I made rollers to suit our profile rail, but the same rig would would with just plain rollers for flat bar.
Its standard pyramid formation, thick steel base plate has two pins welded to it on which two rollers rotate. A steel guide is arrange mid way between be welding two pieces of strip to the plate with a gap between to suit a sliding plate, then two wider strips welded on top to stop said sliding piece lifting. The sliding piece has the third pivot welded to it for the third roller. Nuts and bolts and tapped bits of bar then arranged to apply movement to the sliding piece and apply pressure to the rail. The sliding roller has three 2' lengths of bar welded to it at 120degrees, each with a handle on the end, to drive the rolls and the rail through.
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Post by Roger on Oct 30, 2014 12:08:51 GMT
Roger. The section is 30 x 10 flat mild steel. Those simple machines that were on another post here ought to be ideal then. It ought to be easy enough to knock up something from a few bits of angle. I'd use a cheap ball race for the rollers.
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Post by Deleted on Oct 30, 2014 13:43:19 GMT
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Post by donashton on Oct 30, 2014 19:17:40 GMT
If you stand alongside the 30 x 10, about midway, and pick it up off the ground it will bend. What do you need fancy bending tackle for? Don.
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Post by springcrocus on Oct 30, 2014 19:55:16 GMT
If you stand alongside the 30 x 10, about midway, and pick it up off the ground it will bend. What do you need fancy bending tackle for? Don. I fully agree with Don. Flat bar will deflect quite readily to the radius specified, probably a lot easier than profiled rail. Steve.
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Post by donashton on Oct 30, 2014 20:46:09 GMT
Even our profiled alloy track is made in panels in a straight jig, them simply coaxed into whatever we want on site, then anchored. Don't look for a problem that isn't there.
Don.
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Post by steamcoal on Oct 31, 2014 4:16:28 GMT
What happens at the end of the rail length if it is not passed through a set of rollers?
Are the fishplates alone sufficient to make the joints on the curves smooth? Much like a continuous welded length?
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Post by donashton on Oct 31, 2014 8:49:48 GMT
You don't state any structure (ie. sleepers) to maintain the curve and gauge. Fishplates merely join the lengths. It should be easy enough to coax the curve into a permanent set and easing through a couple of bar ends stood in a vice can treat the ends which still think that they are supposed to be straight!
Don.
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Post by ejparrott on Oct 31, 2014 9:15:49 GMT
Our old bar rail track wasn't rolled
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Post by steamcoal on Oct 31, 2014 9:38:46 GMT
The sleepers are also 30x10 steel flat spaced about 400 apart. Julian will not be happy as the construction is similar to that mentioned in the Wellington, New Zealand construction. We are just not galvanising the rail. It is a private track and will not be used for heavy hauling and many 3.5" engines and just a driver. Lightly loaded railway. This one looks ok to me. www.youtube.com/watch?v=4HTw1u-Pc7Q
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Post by Deleted on Nov 2, 2014 15:31:02 GMT
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Post by goldstar31 on Nov 2, 2014 15:43:08 GMT
If it will not bend or warps, the simplest thing is a hammer and backing dolly or anvil. You hammer ONE side and the metal stretches.
If you want the authority, the construction of Spitfire wings were shaped this way.
The geodetic shape on the Wellington bomber( sorry, Steamcoal) was done like that.
Per Ardua Asbestos or Nil Illigitimi Carborundun
Norman
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