Butt joint advice.

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CanadianSteam
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Butt joint advice.

Post by CanadianSteam »

Hey folks,

I have a 1/4 scale case steam traction engine, and am making a dummy rivet joint for my boiler.

The "butt strap" is laser cut from 1/4 inch steel. However I need to form the steel to fit the curve of the boiler barrel.


I was wondering if anyone has some suggestions as to a good method of forming a curve into it? I thought of hollowing out a log, and using a brass hammer to shape the material. I'm trying to attach a picture but am having no luck. Could likely Pm a picture

Thanks!!!
1918, 25HP Waterloo Steam Traction Engine
1915, 20HP Sawyer-Massey Traction Engine
1898, 14HP Waterloo Portable Engine
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Fender
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Re: Butt joint advice.

Post by Fender »

Put the strap, supported between two round bars spaced a few inches apart, under an arbor press (or hydraulic press). Using a piece of pipe as a former, deform the strap by the press, wrapping it around the pipe a few inches at a time. Because the metal will spring back a little, you probably need a former somewhat smaller than the boiler diameter. If you can get a length of heavy channel, it will work better than the round bars.
Dan Watson
Chattanooga, TN
k36no4862002
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Re: Butt joint advice.

Post by k36no4862002 »

Hi,
Not sure about your setup, but are you able to put some small tack welds on it? If so you could put a rough curve in it to start with, then tack weld one end. Then you could put a heavy duty ratchet strap around it and crank it up to pull the steel up against the outside of the barrel, then carefully without burning through the strap you can tack the band in place.
Once the tacks are holding you can remove the strap and then drill the holes as needed.
A bit crude but I seem to remember doing something like this is the past.

Good luck
Paul
Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
apm
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Re: Butt joint advice.

Post by apm »

Can you tackweld to the boiler barrel, than heat it with a torch, work the torch around the boiler wrapping the strip as you go? Seems like the best ready made form is the boiler barrel itself.
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Greg_Lewis
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Re: Butt joint advice.

Post by Greg_Lewis »

apm wrote:Can you tackweld to the boiler barrel, than heat it with a torch, work the torch around the boiler wrapping the strip as you go? Seems like the best ready made form is the boiler barrel itself.
That's what I'd do, but I'd just use a pair of Vise Grips to hold the end. Heat it really red hot, go slow and with patience.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
CanadianSteam
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Location: Coldwater, Ontario, Canada.

Re: Butt joint advice.

Post by CanadianSteam »

Here's the photos. The butstrap needs to be formed length wise. Being a narrow piece, I think one of the best methods suggested would be to use a hydraulic press between two round bars,and slowly working in a curve.
Attachments
IMG_4233.JPG
IMG_4234.JPG
IMG_4235.JPG
1918, 25HP Waterloo Steam Traction Engine
1915, 20HP Sawyer-Massey Traction Engine
1898, 14HP Waterloo Portable Engine
User avatar
Greg_Lewis
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Location: Fresno, CA

Re: Butt joint advice.

Post by Greg_Lewis »

You realize that bending it will distort the holes. You might check for a fab shop that has a big press brake and die.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
apm
Posts: 391
Joined: Sun Jan 05, 2003 12:21 am

Re: Butt joint advice.

Post by apm »

I didn't realize we were going the long way, I pictured a strip wrapping around the boiler, now I see. I think for this part my first choice would be to buy a six pack of Heineken and give it to the guy who runs the press brake at work! Your idea of a hydraulic press may do something similar as long as you have two pipes/rods at the bottom and one at the top pushing down like a press brake does. You would need to keep the bars from spreading though. I suspect whatever you manage to do with your press will only rough you into where you need to go to where tacking heating and wraping/beating should get you the rest of the way.
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Greg_Lewis
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Re: Butt joint advice.

Post by Greg_Lewis »

The issue I see is getting the edges bent to the same radii as the central area. Again, look for a press brake.

I know that Monday morning quarterbacking doesn't help, but if you can't get this done, an oversize piece first bent and then cut and drilled might work out. Thus the edges that are difficult to bend would be cut off. I've done some forming this way and it has worked out well.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
k36no4862002
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Re: Butt joint advice.

Post by k36no4862002 »

Ah,
I too assumed we were going round the boiler and not along it.
A possibility is to find another piece of pipe of the correct diameter and to cut a new piece out of that instead. All the holes will go oval and may need drilling bigger to get them round again.
If you are going to bend that then a press with the correct die is probably the only way and could be more expensive than getting some pipe and starting again.
You could try heating it and forge it with a hammer but I'm not sure how well you will get on with it
Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
reubenT
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Location: Spencer TN USA

Re: Butt joint advice.

Post by reubenT »

Find a sturdy form with the right curve to it, piece of heavy curved metal. A little tighter curve than the boiler if working it cold. clamp the edge of the form in a strong vise along with the metal to be formed, and hammer it down to match the form. Heating the work piece to forging temp would help it bend easier, but 1/4" plate might bend ok without heat. I've been using a used oil torch(oil atomizing nozzle with compressed air) for various things, weld joint preheating and forging small things. At least the fuel is free.
CanadianSteam
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Joined: Sun Oct 19, 2014 7:15 pm
Location: Coldwater, Ontario, Canada.

Re: Butt joint advice.

Post by CanadianSteam »

Hey folks, The forming job is done, I used a piece of 1" thick, curved scrap boiler plate from a friend, and a scrap hoisting lug which had an almost perfect curve as the other half of form. Heated up the strap, and pounded it into submission. It turned out perfect. I then set all the rivets and sandblasted the whole outfit!

Here are pictures of the finished product. (Still needs to be attached)
Attachments
IMG_4346.JPG
IMG_4347.JPG
1918, 25HP Waterloo Steam Traction Engine
1915, 20HP Sawyer-Massey Traction Engine
1898, 14HP Waterloo Portable Engine
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