# Having a bit of a pickle on firebox to chamber opening.



## LongSmoke1032 (Apr 4, 2020)

I’m building my own smoker opted to build a regular offset as I’m somewhat of a newbie here. I have all my dimensions, how my set up is going to be everything but I’m having a bit off issues with the firebox to chamber opening. I seen a whole lot of threads, measure from the charcoal grate to top of fire box, keep intake vents at grate level, stack should be 30 + inches and so on but this opening has me stumped and math isn’t my best subject. My build includes using my chamber as a grill as well with slide out grates, slide out lump grate and ash tray. I’m using 1/4 inch carbon steel cylinder pipe and 1/4 inch steel plate for the firebox, any help and suggestions would be greatly appreciated. My build dimensions are as follows...

Chamber
24” x 48 Cylinder w/ 1/4 walk thickness. 
I used the 23.5” diameter for the calculation.

Firebox
15” H x 22.5”  W x 21.5” L these are measurements from the lump grate to top of fire box the actual dimensions are 21” H x 22.5” W x 21.5” L these are all inner dimensions. will as well have slide out lump grate and as tray.

Firebox to Chamber Opening
11.88” recommended half moon diameter with 55.47” square inch I’m stumped on this one here so please feel free to give your suggestions and help. 

Smoke Stack
5”calculator is giving s size of 17.71 inches tall but some threads say it should be 30 + inches tall, suggestions and help here would greatly be appreciated.

Intake Inlets 
4” calculator says I need 1.67 so I’m putting in 2 of them. Help and suggestions would help here as well, do the intakes need to be a solid opening with the adjust or the circular adjustable type?

Any and all help and suggestions would greatly be appreciated, this forum is great has a whole mess of information, thank you fellow meatheads.


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## daveomak (Apr 11, 2020)

You should not use Feldon's....   
Use our tutorial to build your smoker....   You will be glad you did...
FB /CC opening should be about 87 sq. in.






						Standard Reverse Flow Smoker Calculator... by DaveOmak and others... Ready to use..  rev5.. 6/19/15.
					

Here's to "Alien BBQ" and the folks that first put the calculator together and "1728 Software Systems" for this great "Circle Calculator" and all the folks at "SmokingMeatForums", with a special shout out to Ribwizzard, that contributed their ideas and feedback while this thing was coming...




					www.smokingmeatforums.com


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## LongSmoke1032 (Apr 12, 2020)

daveomak said:


> You should not use Feldon's....
> Use our tutorial to build your smoker....   You will be glad you did...
> FB /CC opening should be about 87 sq. in.
> 
> ...



Thank you I appreciate the help, so Feldons calculator isn’t at all worth using?


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## daveomak (Apr 12, 2020)

Feldon's is a great work put together by many dedicated folks...   
I used it for the base of the work done here by our members...
We just tweaked it a bit and  improved it a bit....


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## LongSmoke1032 (Apr 15, 2020)

daveomak said:


> Feldon's is a great work put together by many dedicated folks...
> I used it for the base of the work done here by our members...
> We just tweaked it a bit and  improved it a bit....


Thank you appreciate the information I’m not too far from putting everything together and definitely stumped on this firebox to cooking chamber opening. First build so going offset, again I appreciate the help.


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## shaydu (May 15, 2020)

Dave i searched the files and the thread you posted for the "plug an play caluclator" since the feldon calculator was not recommended. can you direct me to a more precise location to it in the thread please?


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## daveomak (May 16, 2020)

CLICK on the link below..







						Standard Reverse Flow Smoker Calculator... by DaveOmak and others... Ready to use..  rev5.. 6/19/15.
					

Here's to "Alien BBQ" and the folks that first put the calculator together and "1728 Software Systems" for this great "Circle Calculator" and all the folks at "SmokingMeatForums", with a special shout out to Ribwizzard, that contributed their ideas and feedback while this thing was coming...




					www.smokingmeatforums.com


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