DIY: Introducing the only 'Shorty' version of the Oklahoma Joes Bronco Drum Smoker in existence

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The Problem: I wanted a decent sized grill/smoker that was relatively portable, but would still fit under the tonneau cover on my truck (max height 18.5"). After looking at nearly everything available in that size, I decided to go with a 'shorty' version of the Oklahoma Joes Bronco drum smoker. I already own one and love it, but it is much more heavy than is feasible to easily move around (since the full-size 18" Bronco is around 138+ lbs.).

The Solution: I took the regular OKJ Bronco (in the smaller size with an 18" grill grate), added a metal plate at the bottom, an UDS style sliding intake from Lavalock, and a sliding top vent (since the stack would have been too tall for the bed of my truck under the tonneau cover). Thus, the 'shorty' was born. I've only done the initial burn-in, but performance is good so far. It can sustain up to 700 degrees with the lid closed, but when the intake and exhaust is choked down, will sustain around 235 degrees on lump charcoal (without a water pan). I've provided a few pictures of my build.

 

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More pictures. Please let me know if you have any questions.

 

[JLeonard]

Well thats cool. What do you plan on cooking on it?

Jim

 

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I plan to cook just about anything on it, from grilling to smoking. My plan is to construct an ash pan and charcoal basket which is much lower profile to allow space for a water pan for indirect smoking. I also have an El Charro rotisserie which I plan to also use on this 'shorty'. Here's a picture of how I use my El Charro on my existing OKJ Bronco. My El Charro will run off of batteries and this would make for a lot of fun tailgating. I've also done pizzas on my existing Bronco and figure I can do high heat searing or pizzas as well on this 'shorty' version.

 

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Also, just for fun, I signed the bottom with the angle grinder. It's only visible when carrying with one hand. It isn't too heavy overall. I estimate it weighs around 40-45 lbs or so. It isn't too awkward to carry with one hand with the lid against my body.

 

[02ebz06]

Nice mod.

 

[Meniscus]

Update: Here's the plan for the ash pan and charcoal basket, as eluded to on a previous post.

As shown in this picture, a 1/2 size steam (hotel) pan is a good size to sit in the bottom of the Shorty. The plan is as follows (from the bottom-up):

• 1/2 size steam pan with small bolts through the bottom on all 4 corners (this will raise the ash pan up off the bottom plate by 1/4".
• In the ash pan, I plan to place an extruded metal charcoal basket (see second picture as an example of what I mean). The charcoal basket will have 1" bolts as risers (to allow ash to fall into the pan below) and the basket itself will be around 4.25" tall. Based on the 2.5" tall ash pan, it means the charcoal basket will extend above the top lip of the ash pan by 1.75". I may choose to also drill holes in the top sides of the ash pan to promote airflow, if necessary.

The charcoal basket could be taller, but I'm trying to limit to just 4.5" overall from the bottom plate to the lower grill grate height (see brackets in the first picture). That will make it easy to place a water pan on the lowest level of the grate. The alternative is to run long bolts through the side of the drum at a higher height for the bottom grate. I will have to see what works and is feasible. Even if I don't add bolts through the side, I can imagine that a suitably sized water pan would sit on the square charcoal basket and would allow the charcoal basket to be taller. That approach would also allow for the water pan to be on one side (or to the back) and allow for 2-zone setup (like a kamado or kettle).

As another option, I could use the deflector plate that comes with the OKJ Bronco and set it directly over the top of the square shaped charcoal basket. That would work as well.

Overall, the entire goal of implementing a different ash pan and charcoal basket is simply to increase the amount of space available inside the grill/smoker. This should provide a lot of flexibility moving forward and would also facilitate low and slow cooks in the field.

 

[Meniscus]

Over the weekend, I constructed the charcoal basket with the half size steam (hotel) pan as an ash pan. The ash pan has bolts in the bottom to keep it raised off of the bottom plate and the whole assembly sits nicely under the lowest grill grate height. This allows for direct grilling/searing down low or to employ a water pan for indirect cooking. The charcoal basket itself is a friction fit and the bottom sits roughly an inch above the ash pan. Let me know if there are any questions. :)

 

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Update on the effectiveness of the new charcoal basket and ash pan:

• I started the Shorty by using about half of a smaller Weber chimney of lump charcoal. After the lump was fully ignited (in roughly 10 mins.), I poured into the side of the charcoal basket, closest to the front sliding vent (intake), and closed the lid. Starting with the exhaust vent at roughly half open and 3 rows of holes on the sliding vent, the Shorty came-up to around 200 degrees in another 10 mins.
• Then I closed the sliding intake vent to just 2 rows of holes and despite opening the Shorty several times over a 6-hour period after, it happily sustained around 225 degrees without any fuss. It was still going strong when I closed the vents to choke the fire.

Other Modifications (top mount thermometer):

• Since the thermometer that comes with the OKJ Bronco does not have a long stem, it doesn't read as accurate in the Shorty version. This is not the thermometer's fault, it is the inherent airflow inside the shorty. Rather than to drill a hole in the top of the Shorty, I decided I might try a low-profile solution (again, keeping the overall height down so that it fits under my tonneau cover for transport).
• Using a Tel-Tru BQ100 (1-3/4 inch dial, 2.13 inch stem, 150/700 degrees F) through one of the pre-drilled mounting holes meant for the exhaust stack that comes with the OKJ Bronco, it quickly provided easy and accurate readings of the grill/smoker environment inside (confirmed with several digital probes). See picture.

I'm sure someone will be curious about how much lump charcoal was used, so the final picture in this post shows the remaining charcoal after 10 mins. (starting in the chimney), 10 mins (to come to 200 degrees), and an additional 6.5 hours burn time. You'll see it would have probably gone another couple hours without consolidating the burning embers/lump.

 

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Future Mods:
Recognizing that I now have an easy method to monitor the Shorty's temperature, the oversized OKJ thermometer is no longer needed. As such, I discovered that the hole size and thread of the front mounted thermometer is 1/2" NPT. I ordered a set of three 1/2" NPT stainless plugs. The plan is as follows:

• When I want to close off the open thermometer port, I'll just hand tighten one of the 1/2" NPT plugs.
• When I want to have more data or monitor the environment in the Shorty with a digital thermometer, my plan is the drill a small hole, the same size as the digital thermometer probe that connects to my various wireless thermometers.

I believe this solution will be much easier than trying to manage a grate mounted thermometer probe and keep the probe away from the meat which can also skew the readings. It will also be easily swappable to choke the fire when done cooking. Also, since the longer digital thermometer probe will just slide into the small hole I'll drill, it will be easy to slide out if I want to remove the grate when it is in the lower position (below where the thermometer port is).

I'm open to any other ideas on mods that anyone may like to suggest. I've considered a few different options for folding legs, but haven't settled on anything I like yet. As a bonus, I did use a laser thermometer on the bottom plate on both the original test (to 450+ degrees) and the latest test (up to 225-235 degrees over 6+ hours). With the original charcoal basket that comes with the OKJ Bronco and my DIY version of a charcoal basket and ash pan, the bottom remained cool enough to touch for up to 4-5 seconds. The question remains how hot the bottom plate will get when using the DIY basket and the raised ash pan at higher temps. We will see.

If someone expresses an interest in what options I've been considering for legs, let me know and I'll share some pictures of what I was thinking. Again, I am limited to the overall height of just 18.5" to fit in the bed of my truck under the tonneau cover, so any solution will need to be fairly low profile. For now, I have the portable folding grill grate as shown in the original pictures of this thread.

As a final thought, I've also been toying around with how to employ a TipTopTemp for the exhaust vent. I'm not sure that it is necessary since the Shorty holds such consistent temps without intervention and I'm also not sure if it would exceed my overall height restrictions, but I am still thinking about it some more.

 

[Meniscus]

Drilled through the 1/2" NPT Stainless plug last night and it fits all three styles of my digital thermometer probes without any play. IMHO, this is a great mod for any OKJ Bronco Drum Smoker. I'll likely drill another one for my full-size OKJ Bronco. If anyone is interested, here is the Amazon link for the set of 3 plugs I purchased for $9: https://www.amazon.com/dp/B07DMYX3BZ?psc=1&ref=ppx_yo2ov_dt_b_product_details. Just be certain you are ordering the 1/2" size since there are several sizes available in the link provided.

As you can see from the second picture, the digital probe extends much further into the Shorty and sits conveniently between the lower and upper grate positions. It should read temperatures much more accurately than the provided analogue thermometer and not have an issue with proximity to the meat as is typical with putting a digital probe on the grate.

As stated previously, I purchased a set of three plugs so I still have an intact plug when I choke the fire or when I'm not using a digital thermometer probe.

 

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Reconfigured the exhaust vent arrangment to accommodate the thermometer and also added a spacer so the thermometer sits flat.

 

[jaxgatorz]

Looking good !

 

[Schwarzwald Metzger]

The Problem: I wanted a decent sized grill/smoker that was relatively portable, but would still fit under the tonneau cover on my truck (max height 18.5"). After looking at nearly everything available in that size, I decided to go with a 'shorty' version of the Oklahoma Joes Bronco drum smoker. I already own one and love it, but it is much more heavy than is feasible to easily move around (since the full-size 18" Bronco is around 138+ lbs.).

The Solution: I took the regular OKJ Bronco (in the smaller size with an 18" grill grate), added a metal plate at the bottom, an UDS style sliding intake from Lavalock, and a sliding top vent (since the stack would have been too tall for the bed of my truck under the tonneau cover). Thus, the 'shorty' was born. I've only done the initial burn-in, but performance is good so far. It can sustain up to 700 degrees with the lid closed, but when the intake and exhaust is choked down, will sustain around 235 degrees on lump charcoal (without a water pan). I've provided a few pictures of my build.

Oh nice.

 

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Today's test with the El Charro on top.

 

[jaxgatorz]

That is really cool !

 

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After the meat was done on the El Charro, I put in the deflector plate and smoked a whole chicken at 225F and then 375F for the last 15 mins. It turned out very good. Just like the full-size OKJ Bronco, the Shorty is able to maintain very consistent temps without having to fiddle with the intake and exhaust vents.

 

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A couple quick pictures. From the 3-day weekend, did a quick pizza on the shorty. The next day, I did 2 racks of hanging baby back ribs, cut into thirds, plus some sausages hanging on a Pit Barrel Cooker 10" hanging skewer (meant for hanging a chicken).

Overall, performance is still quite good. However, I had to crack the lid open slightly with a smaller fire since the top vent doesn't have the full flow needed in cooler temps. I'll be revisiting the top vent when I have time, but in the meantime, it does just fine with a larger fire. I believe the biggest issue was inherent to the wind that blew across the shorty when closed (avg 10mph). I think that an exhaust vent with more open areas would have resolved this issue. The other alternative would be to run a larger fire. I never expected this 'shorty' version to be all things, but it certainly does everything I need to do in the field.

As a final note, the probe port with the longer digital thermometer probe reads temperatures within approximately 8 degrees of the small TelTru thermometer on the top at the exhaust vent.

 

[Meniscus]

Here is an update concerning the exhaust vent. After an extensive search, I found a bulkhead fitting which has 2" NPT female threads inside. This allows me to use a 2" ball valve as the exhaust. Again, I'm limited to just 18.5" of height to fit under the tonneau cover on my truck and with the ball valve installed, it is too tall. However, by using this bulkhead fitting, I'm able to use a 2" plug when transporting which is only hand tightened. When I get to where I'll be grilling/smoking, I spin out the plug and spin on the ball valve.

The other benefit is that I can now have a taller exhaust stack by simply using a length of threaded 2" pipe. Will be trying that next and playing around with the height of the stack to find something optimal.

Obviously, I'll put the other bolt in which will be no problem. Luckily, the same Tel-Tru thermometer will fit alongside. Before anyone asks, the seal on the ball valve is rated for 700 degrees Fahrenheit, but if I do decide to run the shorty wide open for higher temps (like for pizza or high heat searing), then I can simply unscrew the ball valve and I still have the option to screw the stack directly into the bulkhead fitting if I want.

I'm very pleased how this solution came out and it is simple. It is important to note that this solution could be used on any OKJ Bronco and would allow for a taller smoke stack than it came with from the factory. There are no modifications to the lid that would need to be done. You'd just remove the existing stack and replace with this solution. As an added benefit, the smooth pipe stack (not pictured) would also make it easy to adapt to things like the TipTopTemp if someone wanted to employ a passive temperature management on the regular OKJ Bronco. Let me know if there are any questions.

 

[Meniscus]

I've now completed a trial run of the Shorty with the revised exhaust vent. It is now much easier to adjust and dial in Temps. The flow is also smoother and it allows me to open a little more and close down the intake for a better draft. It seems to have even temperature across the top grate position and the pork loin I did turned out great.

Next, I plan to try it with a short stack around 10", but the pipe hasn't come in yet. I will update later, but the proof of concept and initial results are much improved from the previous flat exhaust vent. Happy new year!