Question rolling a pipe smaller

Horizontal smokers with a side firebox and tuning plates.
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DoTheEyeThing
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Question rolling a pipe smaller

Post by DoTheEyeThing » July 20th, 2021, 1:06 pm

I have some 20" OD x 22" Long x 1/4" that I need to roll down to 18" OD for the inner part of my firebox. I think I could cut out a strip, pull the tube tighter with ratchet straps and weld it, but I'm wondering if the residual stress could cause some warping of it and what it's connected to from all of the hot/cold cycles in it. Would it be better to have it rolled to 18" at a machine shop? More worried about doing it right than cost.
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tinspark
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Re: Question rolling a pipe smaller

Post by tinspark » July 20th, 2021, 1:44 pm

If your straps are strong enough to accomplish it, you would likely have major door spring back. Which is a problem too, but can often be managed. If there is a shop in your town has a slip roll that can handle the thickness, I would personally go that route. You will find that after you slit your pip, it will spring open another 2”-4” depending how much stress is currently in the pipe. You would save yourself some time and headache to have a shop roll it. Depending on the shop I would think it’d be under $100 to do..They will ask you the wall thickness and the diameter that you are looking for. Also, I would try to cut it as close as possible to the original manufacturers weld seam…. Keep us posted how it goes!


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"tinspark's" build links below:
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https://smokerbuilder.com/forums/viewto ... 7a614a230a
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hogaboomer
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Re: Question rolling a pipe smaller

Post by hogaboomer » July 20th, 2021, 1:48 pm

It already has stress in it. When you split it, it pops open. I wouldn't worry about it. You aren't cutting a door in the side of it, are you?


I live on Hogaboom Road.

tinspark
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Re: Question rolling a pipe smaller

Post by tinspark » July 20th, 2021, 6:21 pm

hogaboomer wrote:
July 20th, 2021, 1:48 pm
It already has stress in it. When you split it, it pops open. I wouldn't worry about it. You aren't cutting a door in the side of it, are you?
Boomer is right. I misread your post and didn’t realize it was for your firebox. As long as you can close it up you should be fine. A and your FB door is on the end..…Also if you do manage to pull it together with ratchet clamps, be sure to check for an ggg shape prior to welding.
Last edited by tinspark on July 21st, 2021, 10:26 am, edited 1 time in total.


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"tinspark's" build links below:
Last build-GF:https://smokerbuilder.com/forums/viewto ... 30#p114730
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Santa Maria Rebuild: viewtopic.php?f=17&t=7533&p=112344&hili ... 34#p112344

tinspark
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Re: Question rolling a pipe smaller

Post by tinspark » July 21st, 2021, 12:25 am

tinspark wrote:
July 20th, 2021, 6:21 pm
hogaboomer wrote:
July 20th, 2021, 1:48 pm
It already has stress in it. When you split it, it pops open. I wouldn't worry about it. You aren't cutting a door in the side of it, are you?
.


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"tinspark's" build links below:
Last build-GF:https://smokerbuilder.com/forums/viewto ... 30#p114730
First build- Santa Maria Smoker:
https://smokerbuilder.com/forums/viewto ... 7a614a230a
Santa Maria Rebuild: viewtopic.php?f=17&t=7533&p=112344&hili ... 34#p112344

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Re: Question rolling a pipe smaller

Post by Dirtytires » July 21st, 2021, 10:52 am

Interesting concept.

Keep in mind that you will not be completely round after closing it back up but that may not be a concern. Also, remember you will need to find the difference in the circumstance of a 20 inch circle (62.83") and a 18 inch circle(56.55") to find the width of your cut. In this case it would be 6.28 " which would give you a pretty odd shaped oval in my opinion. If you are set on this, maybe cut the pipe in half, take 3.14" out of the top and bottom and then weld it back up.



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Re: Question rolling a pipe smaller

Post by SheffSmoker » July 21st, 2021, 6:26 pm

3.14 you say DT... It all ends up at pi(e). :)



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Re: Question rolling a pipe smaller

Post by Dirtytires » July 22nd, 2021, 11:06 am

Yep....pie is good.



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Re: Question rolling a pipe smaller

Post by DoTheEyeThing » July 30th, 2021, 12:21 pm

Hey all! Thanks for the replies - I need to setup email notifications or something so I see these sooner. So it went pretty much exactly as tinspark suggested. I cut out a 4.7" slice so my final ID would be 18" and it sprung open several more inches. Took it to a shop to roll it down. It got a little flattened near the seem so the ID there is 17 3/4" and the widest perpendicular ID is 18 1/8". Close enough I think! They only tack welded it for now - $35 was totally worth it.
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Re: Question rolling a pipe smaller

Post by tinspark » July 30th, 2021, 5:47 pm

Glad it worked out. $35 seems like a really good price
Also, remember the springback when you cut your pipe. Its a very good thing to remember IMO..
Especially if you do a smoker in the future, A lot of guys wonder why their doors spring open when they cut them from a piece of pipe.
Guys fight their door fit very often. A bunch of em have been on here asking how to fix it.. It is way easier to slit the pipe and relieve the tension in the pipe an fill it back in with a piece of flat bar. Then cut the door afterwards. The door will fit perfect every time.. It all depends on how much tension is in the pipe. I,ve seen em sprin open 4" That'd make a 24" OD pipe a bit over 25" OD after the tension is released.. The pipe stays 24" OD and the door will spring to 25" OD, Then its a fight to get the door shrunk back down. - or have it rolled back to the smaller size.


Regards,
"tinspark's" build links below:
Last build-GF:https://smokerbuilder.com/forums/viewto ... 30#p114730
First build- Santa Maria Smoker:
https://smokerbuilder.com/forums/viewto ... 7a614a230a
Santa Maria Rebuild: viewtopic.php?f=17&t=7533&p=112344&hili ... 34#p112344

DoTheEyeThing
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Re: Question rolling a pipe smaller

Post by DoTheEyeThing » July 31st, 2021, 4:19 am

tinspark wrote:
July 30th, 2021, 5:47 pm
Glad it worked out. $35 seems like a really good price
Also, remember the springback when you cut your pipe. Its a very good thing to remember IMO..
Especially if you do a smoker in the future, A lot of guys wonder why their doors spring open when they cut them from a piece of pipe.
Guys fight their door fit very often. A bunch of em have been on here asking how to fix it.. It is way easier to slit the pipe and relieve the tension in the pipe an fill it back in with a piece of flat bar. Then cut the door afterwards. The door will fit perfect every time.. It all depends on how much tension is in the pipe. I,ve seen em sprin open 4" That'd make a 24" OD pipe a bit over 25" OD after the tension is released.. The pipe stays 24" OD and the door will spring to 25" OD, Then its a fight to get the door shrunk back down. - or have it rolled back to the smaller size.
Yeah I've been worried about that. Unfortunately with my current plan I'm locked in to the 20" diameter so I can't relieve it. I did some checking and since the door is fairly shallow I'm considering welding in a few bars from top to bottom to prevent the spring and it doesn't look like they would interfere really. I also noticed Moberg has the bars welded in as well. Others suggest the chain and jack method might not be bad, though I would have to buy a jack.



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Re: Question rolling a pipe smaller

Post by SheffSmoker » July 31st, 2021, 5:23 am

I think I had the only pipe in existance that sprung shut 3" rather then open. :)



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Re: Question rolling a pipe smaller

Post by hogaboomer » July 31st, 2021, 7:59 am

Something else to think about: sometimes the actual door opening will bow out on you. I had a giant headache with that on The Cadillac build. Bottle jacks can come in pretty handy when building smokers.


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Re: Question rolling a pipe smaller

Post by Dirtytires » July 31st, 2021, 11:09 am

[/quote]
Others suggest the chain and jack method might not be bad, though I would have to buy a jack.
[/quote]

I used a 20 ton jack cause that what I have but don't forget most full size trucks have a 3-4 ton jack behind the seat for changing tires. Definitely worth a try before buying one.



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Re: Question rolling a pipe smaller

Post by tinspark » July 31st, 2021, 1:24 pm

DoTheEyeThing wrote:
July 31st, 2021, 4:19 am
tinspark wrote:
July 30th, 2021, 5:47 pm
Glad it worked out. $35 seems like a really good price
Also, remember the springback when you cut your pipe. Its a very good thing to remember IMO..
Especially if you do a smoker in the future, A lot of guys wonder why their doors spring open when they cut them from a piece of pipe.
Guys fight their door fit very often. A bunch of em have been on here asking how to fix it.. It is way easier to slit the pipe and relieve the tension in the pipe an fill it back in with a piece of flat bar. Then cut the door afterwards. The door will fit perfect every time.. It all depends on how much tension is in the pipe. I,ve seen em sprin open 4" That'd make a 24" OD pipe a bit over 25" OD after the tension is released.. The pipe stays 24" OD and the door will spring to 25" OD, Then its a fight to get the door shrunk back down. - or have it rolled back to the smaller size.
Yeah I've been worried about that. Unfortunately with my current plan I'm locked in to the 20" diameter so I can't relieve it. I did some checking and since the door is fairly shallow I'm considering welding in a few bars from top to bottom to prevent the spring and it doesn't look like they would interfere really. I also noticed Moberg has the bars welded in as well. Others suggest the chain and jack method might not be bad, though I would have to buy a jack.
The shop that rolled your FB pipe likely can roll your door too if needed. For $35 it may be worth it IMO.
I personally would not use the jack and chain if i had another option. They should be able to dial it in for you.
They could also step brake it in their press brake..
But I work at a fab shop for many decades now and have access to the tools to roll or brake heavy plate, plus a modest home shop..
I am all for the chain and jack as a last resort, and would try it in a jam...


Regards,
"tinspark's" build links below:
Last build-GF:https://smokerbuilder.com/forums/viewto ... 30#p114730
First build- Santa Maria Smoker:
https://smokerbuilder.com/forums/viewto ... 7a614a230a
Santa Maria Rebuild: viewtopic.php?f=17&t=7533&p=112344&hili ... 34#p112344

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Re: Question rolling a pipe smaller

Post by dacolson » August 1st, 2021, 9:18 am

A pit like this is going to last near to forever. If you have access to a shop that will roll it for you, I’d cut it and bring it to them to fix if it springs. Get it done right and you’ll appreciate it for a long time.


Dave C - QueNorth Smokers
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Re: Question rolling a pipe smaller

Post by Big T » August 1st, 2021, 1:21 pm

:yth:


Measure Twice.....Cut Three Times.

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