First offset build! Have some questions.

[thejm]

Hey guys so i have been playing with the design of my firebox door handle mechanism.

Here are some pics from my model. The "T" bar with the horseshoe rotates about that bolt and slips into a catch adjacent to it.

This pic is with the door locked.

This pic is with the handle turned to open the door.

At first, I had 1 long horizontal bar with a horizontal horseshoe on it but i rotated it vertical and made it into a "T" bar. I am happier with this design and think the vertical horseshoe will be easier to grab.

[thejm]

As mentioned earlier in this thread, I am also early in my trailer design and feel like i have made a fair bit of progress.

A few notes so far:
-I know I want to design it as a fully wrapped tongue for the extra strength.
-The frame material is 2" by 4" by 1/4" tube.
-Right now I am thinking about a single axle but am also considering tandem.
-Length of the frame is 110" (not including tongue) and the firebox hangs over the back edge about 18"
-The current design has a 48" wide frame and think thats a good width for what I need. It gives me the room to put a woodbox behind the smoker and allows me to keep the tongue length at a reasonable length of 55" from center of ball to frame while still maintaining the 50 degree tongue angle.
-My smoker is offset to one side by about 9"-this puts the edge of the smoker even with the outside edge of the frame vertically making it easier to reach meat in the back of the smoker. One other advantage of the narrow frame width is that this offset has less of an effect on the load each wheel will take. Based on my calculations, 1 wheel will take 57% of the weight and the other will take 43%. If my trailer was 60" or 72" wide, these percentages would be more line 30%-70" or 20%-80% which isnt the end of the world considering i am well below the weight limits but i want to avoid so that each tire/spring, etc wears somewhat evenly.
-The total weight of the trailer with smoker should be about 2200 pounds not counting the wheels, tires, and axle. Probably around ~2400 pounds total
-The woodbox dimensions are still in flux but they are currently 20" wide by 50" long by 18" high. I made it basically it'll be whatever will fit. I will probably make the sides of this out of expanded metal but am considering think gauge solid metal to protect wood against the rain while driving.

I am still tweaking things have not bothered to model things like fenders, lighting, etc.

Here is a video of me showing the trailer at a few different angles.

https://youtu.be/n9jcxwQX_Jc

Any comments or tips are appreciated. This will be my first trailer build!

[Dirtytires]

Looks like you have a good plan....definitely helps the build process be smoother.

[thejm]

Looks like you have a good plan....definitely helps the build process be smoother.

Ya im new to 3D modeling but its a huge help. I really like being able to see what its going to look like before building it. It also helps me in seeing building conflicts before they happen.

[Big T]

That should make a good looking trailer rig if it turns out like your video.

[thejm]

I had a few hours this weekend and have another build update!

If you will recall in my last few posts, I got the doors marked out and filled the valve holes with patches from the second tank I bought. At this point, the only hole in the tank is the hole I cut for the throat that the firebox will fit into. My next step was to weld the 2 supports on the inside of door 1 (the door closest to the firebox). I want to weld these in place before I cut the door out to try and mitigate against any warping the door may experience after its cut out. I knew this step would be a true PITA and I was right. It was at this point i was thankful I bought a P100 respirator!

I didn't take progress pics this time but here is where I ended up.

I started off taking my angle grinder with a cutoff wheel and cutting in 2 places on each of the 4 edges of the door. This allowed me to trace the sides of the door from inside the tank. Then I laid inside the tank and stuck a straight edge to the wall of the tank along the bottom edge of the door with some magnets. I then took a soapstone pen and marked that edge. I repeated the same thing with the top edge. And for the sides (that are on curved edges), I repeated the same steps with a curved piece of flat stock instead of a straight edge.

After I got the door marked out from the inside, I marked another vertical line 6" from the closest edge of the door. This was my mark for where the first support would go. For those wondering, my doors are 26" wide and my supports are 6" in from each side. As youll see below. They did the job just fine.

Next I needed to create 4 identical supports, 2 for each door. I started by creating a quick sketch of what I was looking for in Autocad. This was very simple. I just drew 2 circles, 1/4" apart and then cut them to my door dimensions (19" arc length). Next I made a line and offset it by 1". This is what it looks like. I did make 3 of them on the same page in case i messed up cutting 1 out.

CC door supports.pdf

(6.21 KiB) Downloaded 18 times

EDIT: I should note that if you print this out on 11" by 17" paper, it should be scaled correctly so if you want to use this template, feel free.

I cut the supports out of paper and traced them onto a piece of 1/4" steel plate that I cut the firebox sides out of. Then i cut 4 of them out using my plasma cutter. After a little grinding, the supports were ready to install.

Laid in the bottom of the tank and used magnets to hold the support in place making sure to center it from the top and bottom of the door. Finally, I welded it in place. I then repeated those steps for the second support.

Finally the moment had come where I could cut out the door! I was going to use my plasma cutter for this but I knew that all 4 cut edges of the door would be visible on the final product and Im new to plasma cutting so my cuts aren't the cleanest yet so I decided to use my angle grinder. It made fairly quick work of the door. I learned that to cut a straight edge that follows my sharpie lines exactly with an angle grinder it was better to create an initial slight groove and then follow it up with several passes. Every time I tried to go deep on the first cut, my blade ended up drifting at an angle.

I was happy with the final product. The door came out without any warping or bending whatsoever! The only issue was that my tank warped a bit. See the pic below with the straight edge.

You can see that the straight edge is elevated at one side. The tank warped ~0.15"-0.20" in the middle with each edge being flush. The above pic is slightly exaggerated because the door is sitting a little low there.

My idea to fix this is below but I am open to suggestions! I am going to use a chain and a chain binder to pull the middle of that edge inwards. Ill also use some square tubing on either corner of that edge to support the outsides of the door. Ill need to do this with the top and bottom edge of the door.

On my next door, i think i'll temporarily weld some square tubing to the middle of the top and bottom edge to the opposite sides of the tank to prevent it from pulling out. If it does, i'll repeat the same chain and chain binder process.

Next steps are to do door 2, burn the tank out, then move onto straps and hinges!

[dacolson]

My tank sprung on my last build. Used the jack and chain method to get it back true. I’ve seen guys use a turnbuckle welded on the inside of the tank that looked like it might be a good approach. I’ll see if I can track down the post.

[Dirtytires]

Wow...that was a lot of work just to cut out a door.

[thejm]

My tank sprung on my last build. Used the jack and chain method to get it back true. I’ve seen guys use a turnbuckle welded on the inside of the tank that looked like it might be a good approach. I’ll see if I can track down the post.

That’s a great idea. I think I’ll try either a turnbuckle or the chain binder.

[thejm]

Okay so I’m going to have to do a folding smoke stack because it’s going to be too tall to fit in my garage. Can y’all send me close up pictures of how you did the hinge on the stack?

[Big T]

I don't recall seeing any folding stacks on the forum, there may have been 1 or 2 over the years but nothing comes to mind. I have seen quite a few on some of the FB pages and one of the commercial builders has done a few. Have you considered increasing the diameter of your stack to decrease the length or do you already have the stack material on hand ?

[thejm]

I don't recall seeing any folding stacks on the forum, there may have been 1 or 2 over the years but nothing comes to mind. I have seen quite a few on some of the FB pages and one of the commercial builders has done a few. Have you considered increasing the diameter of your stack to decrease the length or do you already have the stack material on hand ?

Thanks for the heads up on that. Currently I have it designed with a 6" stack. Going to an 8" stack would decrease the height from 52" to about 35" according to the calculator. Is there any difference in the draw from a more stubby 8" stack vs a longer 6" one? Is there any reason to make the 8" stack a little longer or will that cause the air to cool before it leaves the stack?

Here is one stack on top of the other.

EDIT: To clarify, this picture shows both an 8" stack as well as a 6" stack to show the height difference between them. I will obviously only pick one of them and it will have a uniform diameter throughout.

[thejm]

Wow...that was a lot of work just to cut out a door.

Ya...it was a lot of work but I didn't trust myself to uniformly bend that door back to shape so thats the route I went. I honestly didn't think that the tank itself would spring out so i didn't account for that. I think that will be easier to do if i brace the 2 sides of the door and pull on the middle.

[Dirtytires]

You can’t fight the stored energy from the initial bending of the tank. Just embrace it.

[Boston]

Here is one that uses a folding stack, not sure if it will help or not, but it might give you some ideas. Its the Mack Upgrade thread, on page 2.

viewtopic.php?f=11&t=7297&start=25

[Dirtytires]

And I Should mention, we just had a build that designed the exhaust exit in the middle of the end bell like you have pictured. He ended up having some troubles with consistent temps and ended up moving the stack to the top of the chamber to fix the issue.

Also, your picture shows you decreasing the size of the exhaust at the top. Not sure I would recommend that as it will increase the air velocity and mess up your airflow. Think of a water hose that you put your thumb partially over the end.

[thejm]

And I Should mention, we just had a build that designed the exhaust exit in the middle of the end bell like you have pictured. He ended up having some troubles with consistent temps and ended up moving the stack to the top of the chamber to fix the issue.

Also, your picture shows you decreasing the size of the exhaust at the top. Not sure I would recommend that as it will increase the air velocity and mess up your airflow. Think of a water hose that you put your thumb partially over the end.

That’s good to know. Thanks. I’ll see how my temps end up. Do you have a link to that thread? I'd like to see the differences between mine and his. I have tried to model mine after a very standard, traditional Texas offset.

That picture shows both the 8” stack and the 6” stack to show the difference in height between the 2. I will either do the 8” or the 6”. Not a stack with decreasing width.

[Big T]

I remember the guy having temp issues but I don't recall the name of the build thread, it was a RF not a traditional offset. You can increase the length of the 8'' stack a little bit and put a damper on it to slow the draw if you need to.

[dacolson]

Lots of folks have different experiences w rack level stacks. Here’s the thread where Rollinsmoke moved his stack:
https://smokerbuilder.com/forums/viewto ... 148&t=7265
I have an RF and a standard offset. Both with rack level stacks. Temp control is not an issue at all on either. Follow the calculators. Err on the larger side and manage w fire size and dampers like Big T says.

[tinspark]

There was a Mack build on this site with a fold down stack. Looks to have a pivot point at a flange, gasket, a few bullet hinges, and a latch. This way the OP could get his rig out of the elements
Here is the build:
http://smokerbuilder.com/forums/viewtop ... k&start=25

[thejm]

I remember the guy having temp issues but I don't recall the name of the build thread, it was a RF not a traditional offset. You can increase the length of the 8'' stack a little bit and put a damper on it to slow the draw if you need to.

Its good to know that it was a RF and not a traditional offset.

After thinking about it for a while and playing with some designs, I am almost positive that I'm going to switch to an 8" stack. I actually already have a 6" sch. 40 pipe but im going to try and exchange it for an 8" sch 40 pipe. I just can't find a design for a folding stack that i dont hate lol.

[thejm]

Here is one that uses a folding stack, not sure if it will help or not, but it might give you some ideas. Its the Mack Upgrade thread, on page 2.

viewtopic.php?f=11&t=7297&start=25

That smoker came out looking really good!

[Rodcrafter]

I just made a removable stack so I could use normal grill covers on my backyard cooker.


https://imgur.com/IFTz99k

[Big T]

I just made a removable stack so I could use normal grill covers on my backyard cooker.


https://imgur.com/IFTz99k

I'm glad to see you back on the Forum RC! There's not many of the original guys on here from years back when I first joined.

[Pete Mazz]

Yea, we miss you buddy!