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Excali-weenie, Slayer of Burnt Hot Dogs, Bane of All Over-Roasted Marshmallows!

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My wife, son, and I like to spend a dinner or two month during the spring time before it reaches nuclear heat levels of 90-110 deg F eating dinner outside by our fire pit area we lovingly call the "fire bowl" (Click to see a video of what the fire bowl looks like).  The rabbits, pheasants, bull snakes, stars and the occasional great horned owl are our eating companions. And hotdogs and marshmallows are often on our dinner menu.  My son is 4 years old, and I am his big kid equal.

During the last weenie/mallow roast excursion to the fire bowl, I had a small epiphany.  Our roasting sticks drove me nuts, and having access to my prototyping lab for my business (Past Primitive™) I run with my wife, and being a product designer and all, I thought... why not do something about it? Surely there was a better roaster to be made for my family.  It's not that I don't appreciate the simplicity of the traditional roasting sticks, simple, pokey, allows me to hold food over flame without burning my hand... But with all this technology that I love always and forever almost as much as I love my wife always and forever, I thought there were improvements that could be made.

And what  I really wanted/needed was a roaster to end all roasters, and thus... Excali-weenie slayer of burnt hot dogs, bane of all over-roasted marshmallows was born. Who knows out of what ethereal mist this design came to me from, perhaps from the Lady of the Lake, perhaps not, all I know is I really like it. Let us begin our journey of inception, fabrication, and assembly! And don't forget your coconut shells ( let's see who gets that reference).

Also I realize this may not be a new idea, but it's new to me.  One of my rules when I design a product is that it has to be something I am excited to use myself.  I find it keeps me happy through the entire process.  Also, I would cite the numerous other products that have found outrageous success many years after their first incarnation; however, whether this process leads us to a successful product deployment or not, it's hard to say... But I had a lot of fun creating it!

Here's a demo of what it can do.  I know it's not over a fire, but I promise it works there too, in fact even better.
 
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Step 1: The Problem

So I am going to make this real simple.  I had four major issues with the traditional roasters I have used which I will discuss in length. 
  1. Too Short
  2. Too Flimsy
  3. Difficult to Turn
  4. Not Awesome Enough
Too Short... I realize a short roasting stick provides lightness, maneuverability (important for not smacking your mallow or dog into the ashes) and would be just fine if you had a small fire... That being said, I usually roast on family camping trips, in the back yard, essentially I am always with people.  Most of the time it's done in the evening, and it's cool.  Cool temperatures often means cold people.  Cold people means the fire is kept blazing hot and large.  Short roasting stick + large hot fire + hunger = burnt arm hair and or possibly singed eyebrows (although I haven't done that yet).  Also burnt arms is definitely not a proposition my four year old is willing to bare. So while a short roaster is fine for small fires, a small fire seems to remain a quaint idea that always loses the "it's cold, put more wood on the fire!" battle.

Too Flimsy... I'm not to sure why most commercial roasters seems to be constructed in such a way that you would think rubber would have more rigidity than the steel wire setup they often utilize, but I am assuming it's much like the potato peeler example.

Oxo the brand of kitchen wares many years ago released a redesign of the simple traditional potato peeler, which traditional peeler now is not very common anymore. Perhaps you remember the traditional one.  I know my hands do.  It was constructed from a steel band for the handle, and was really obnoxious to grip.  If you have watched the documentary Objectified (a link to the trailer) it talks about the designers inspiration behind the redesign. His wife had arthritis and complained about the difficulty of gripping the potato peeler.  And so he had the thought to enlarge the handle and rubberize it. It was a raging success of a product.

My point being that some poor designs keep getting used not because someone thinks that it's a good idea, but because no one has taken the time to think of something better. Much like the potato peeler, the roaster remains likely unchanged because it serves it's purpose, and most people get along fine with it.  

Difficult to turn... Burned campfire hot dogs and marshmallows are a staple of our family campouts.  Mostly because of impatience to roast the food.  You stick it close to the coals because you're hungry, and then a few seconds later when you check on it, you have a lovely charred black skin on your food. Mmmmmm, delicious.  Of course you could solve this by slowly rotating your roaster which would allow it to remain close to the coals, not burn, and be cooked through quickly.  However, most roasters I use have rectangularly shaped handles.  I've even use some rounded handles.  And while it's possible to rotate both in your hand, it's difficult to remain concentric in your rotation, while making it difficult to avoid ash, or flames, and making the prospect of roasting food that much more obnoxious.  

Not awesome enough... Roasting sticks are boring, I think a pointy wooden tree branch is more interesting than most roasting sticks I have seen. If I am going to put down some money for a dedicated roasting utensil, I want it to have some awesome-looking features.  It makes me feel good about the money I spend when the product is not just functional but aesthetically pleasing. And a roasting stick for me represents frivolity and fun.  Of course I can microwave my marshmallows for smores (kind of gross though), and I could roast my hot dogs in the oven.  But that isn't nearly as fun as having a camp fire, and spending some time outside with my beautiful wife, and ridiculously silly kid in the great outdoors of our backyard. Therefore there must be more awesomeness and attractiveness added to the traditional weenie roaster setup.

The theoretical solution (at least for me)... The perfect roaster would be stiff, collapsible, easily rotated, and long enough to have a warm fire, but not so long that you have to let go of the handle to reach the tip.

Step 2: The Non-Theoretical Prototype Plan

Picture of The Non-Theoretical Prototype Plan
Now, I realize it's easy to criticize any given product or piece of technology.  But as I have often exprienced in my design work, many flaws of designs have trade-offs: mass manufacturing difficulties can arise, certain features that provide a great solution in one area make for a horrible experience in another. That being said the following prototype was the best I could execute on my theoretical "perfect" roaster given my resources of time, money, and proof of concept goals.  

The Plan of Action

Problems & Solutions:
  • Too Short - Increase the length of the roaster.
  • Too Flimsy - Use thicker gauge steel wire for roasting stick to prevent flex.
  • Difficult to Turn - Motorize the roasting stick with a small DC motor and switch. Gear the motor down with an extremely high gear ratio of around 1:200 - 1:500 to give it enough torque to rotate a average hot dog. House the motor, batteries, and switch in roasting stick handle. 
  • Not Awesome Enough - Make the roaster in the loose form of a sword.  What kid (kid adults included) wouldn't love the fun of pretending they are some ancient night skewering evil hot dog monsters and ghost marshmallows. I know I do.
Concepts Needed Proving:
  • Can a small DC motor be geared down to a reasonable size and last long enough on a few AA batteries to rotate a an average 2oz (+/- 55g)  hot dog for a total of 30 minutes to an hour of roasting time.

Once I had those goals in mind, I set off on the nitty gritty of the prototype build.

Research Phase:  

The Motor & Transmission: I researched motors and found a commercially available dc motor for purchase from a manufacturer with an attached transmission with my target ratios.  The dimensions of the motor were also within my design intentions for the form of the handle.  I did of course not end up purchasing those motors, since the minimum was 500 and I did not want to to take the time or expense to get a sample, or track down one for purchase from a retail location.  But knowing the existence of the motor in the correct specs answered my question as to whether or not I could eventually manufacture the roasters at an appropriate price point. So I turned to my boxes of collected DC motors and plastic gears harvested from many a derelict inkjet printer.  They're free, and most importantly I could start my build immediately.  I find it best to strike while my inspiration is hot.  

The Business End of the Roasting Stick: My first issue was I was unsure of how to get a source of cheap straight steel wire without buying expensive steel rods.  I was all ready to devise a machine with a series of pulley's that would replicate the industrial machine for straightening wire. If you have read my previous intstructable "Serious Homemade Manufacturing Equipment on a Shoe String Budget" you'll know I have no fear of getting all homemade on traditionally industrial manufacturing tech. Fortunately for me Instructables.com is there to save me from my eagerness. Thanks to rimar2000's  instructable I learned an amazing trick on how to straighten wire.  Even thick gauge wire. It can even be done fast enough to be a viable cottage manufacturing solution for my weenie roasters. Once that was learned, I went for a spool of old 3/16" thick steel wire left over from a previous project.  We'll talk more about the details in the welding step of this instructable. 

Now we are on to drawing up the designs and fabricating the parts. 

Step 3: CNC Fabrication

I have a CNC router in my prototyping lab.  I love it.  I really, really love it. Should I say that again?  I wish everyone could have access to CNC machines!  They really are the bee's knees for being able to quickly prototype parts that stay close to your design intention.  And it just so happens that a wood handle shaped like a sword is the perfect fit for a CNC router.  Using VCarve Pro, the included CAD/CAM software with my tool, I designed up the handle, which would also house the motor, batteries, and switches.  I also designed the transmission case that would hold all the appropriate plastic gears in place and at the right height to gear down the motor so it would have enough torque to rotate a hot dog 2 feet out from the drive shaft of the tiny motor.

One issue that I thought turned out nicely was that my scaling up the size of the handle to match the transmission case really helped the oversized transmission case and handle communicate a sense of fun and frivolity.  Which was my intention for the form of this roaster.  So even though in future prototypes the handle will be scaled down most likely once I secure the small motor with micro transmission pre-attached to be somewhat more manageable and storable for the purposes of my family, we will enjoy the silliness of the oversized handle.  Plus it does communicate a certain sense of... "I have the baddest roasting stick around!"

If you would like more information about the details of the CNC fabrication process, I will refer you to my other instructable that focuses more on the specifics of CNC fabrication.  My intentions for this instructable is to serve as a specific example of how I executed a design of a prototype, and how I came to use the solutions I did not as much focus on the technical details. 


Step 4: Assembling The Motor Housing

The motor housing was fun to put together.  You may notice from the pictures that the cut out handle does not have rounded edges.  I added those with a 3/4" roundover bit with a manual table router. Just because I have a CNC router doesn't mean It's always most efficient to use.  

For the wiring, I started by soldering some wire to the spring intended to keep the batteries in contact with each other.  Then I hot glued it in place and followed that pattern for the other parts in this order: switch, motor, top battery contact. I used wood screws to keep the two halves together and allow for somewhat easy access to the batter compartment without having to do any other disassembly. 

Step 5: The Transmission

Picture of The Transmission
This was the most difficult part of the build.  The case being the main culprit of difficulty.  None of the plastic gears came as a set from one printer, they just all happened to have the same teeth and give me the approximate target gear ratio I needed.  

The transmission case consists of four parts:
  • Base Plate - The motor mounts to this, as does the handle.  It also provides the correct layout for the gear axels. Made from 1/4" oak plywood.
  • Two Center Spacers - These provide the correct vertical spacing for the gears so they can be placed as tightly as possible without interfering with each other. These insulate the gears from radiant hear from the fire and keep dust out. Made from 0.5" thick particle board.
  • Top Plate - Same as the base plate, except there is no motor mount holes and there is a hole placed for the output shaft that connects the steel roasting stick to the transmission. Made from 1/4" oak plywood.
To design the case, I took out my calipers and measured all the different components that would be used in it.  I recreated them in my 2D CAD/CAM program for my CNC router, and then laid them out in the appropriate places in the program.  After cutting them out on the router, I assembled them together like one big sandwich.  I used two 6/32 machine bolts to keep the layers together and attached the half of the handle to the base plate that would have all the wiring and other components glued into place.

Step 6: Welding The Forks & Straightening The Wire For the Roasting Rod

Okay, first off I have been welding for about a year now and not very much for that time. My welds look attrocious. For my production model, I am going to redesign the steel roasting rod so it will most likely not utilize any welds.  But for my family's use, it was very functional and stiff.

Using the wire straightening method from step 2, I straightened a length of 3/16"  diameter steel wire and some smaller 1/16" diameter steel wire.  I did not take measurements at this point. I felt better to use intuition for the length and see how it felt to use and then to go back in the product model design and make corrections. 

I threaded one end of the 3/16" thick wire with 8/32 threading to mate with the 8/32 threading on the output shaft of my transmission box. On the other end I twisted a section of the 1/16" diameter thick wire  and cut the two tails to length. Using my cheap Harbor Freight Flux Wire Welder I did my best (or my worst) to weld the twisted section onto the shaft.  Was this necessary? Would friction have held the forks on?  I don't know, but it's what I did.  And I won't worry about my forks slipping off now when I've got a precious dog on the end.

Step 7: Celebrate! (Exclamation points are fun! Really fun!)

And that is how I took an idea for an improved hot dog roaster from my mind into reality. Will it change the world? Probably not... Was it fun to make, and do my wife and son love it? Most definitely!

Now to evaluate the whole reason of building this prototype besides having a  fun roasting stick for my family.

Did I prove my concept of using a small DC motor with a few AA batteries would be strong enough and last long enough to roast  an average size hot dog? 

Yes, yes I did.  In my tests I was able to load the roasting stick with at least 6 oz of weight at the end with the roasting stick held horizontal and have it rotate just fine.  An average size hot dog here in the states is about 2 oz or 55 grams.  I haven't tested how long it will last on one set of AA batteries, but I have ran it for at least 10 - 15 minutes so far with no signs of getting tired.  My goal is for it to last at least 30 minutes, hopefully it will go an hour's worth of total roasting time if not more. We shall see.

As far as my original issues with the traditional roasters I have used, did my design solve those problems for me?

Too Short - Yep. I made mine longer, and it allows a more comfortable roasting distance around a large fire. 

Too Flimsy - I stiffened and increased the diameter of the roasting rod and took out most if not all significant flex.

Difficult to Turn - If you consider flipping a switch difficult then I failed, otherwise I passed that just fine.  Although I must say I do have the intention of looking into a wind-up version that would not use batteries.  But for now the DC motorized version is quite fun.  

Not Awesome Enough - I think the oversized sword handle shows lots of promise in making the aesthetic appeal of the roaster fun, and the roaster as a whole much more awesome not to mention the coolness of it being motorized!

What's next? - I'd like to add fold-out bi-pod legs to the handle and a flap off the back so you can put a rock on the flap or your foot and not have to hold the roaster with your hands. I'd also like to work on the aesthetic of the steel roasting rod and get the smaller motor with a built-in transmission to allow for more freedom with the form of the handle.  

There's also work to be done to streamline the manufacturing process to meet the target price point we'd like to sell these at.  But other than those boring adult-like things, it's time to have lots of fun camp fires with the family.

So is this product a bit silly and over the top?  I think so, but that's what I like about it. I like how the over-sized sword-like handle makes me feel like a kid when I hold it. I love the over-kill solution of a motorized hot dog roaster.  It exudes fun to me.  At the most, I've added another successful product to our catalog. At the worst, I've made one of the most enjoyable and memorable roasters for my family and I to use.

With that being said, I hope this serves up some more inspiration to you to take the best of the past and mix it up with the awesome of today, to create the amazing of tomorrow!
I didn't mean to put 2 comments lol
Awesome!!!
Awesome!!!
nerd978 months ago
First thing to come to mind at coconut shells:
"Do coconuts migrate?"
Funny and inventive!
Love the various references....
Monty Python <3!
pastprimitive (author)  BrefelanDesigns1 year ago
Good job with the reference! I wondered if anyone would figure that out. It's almost like I need to give you a prize... Wait. I've got a good idea. I have some extra pro memberships from contests I've won, and featured instructables. Would you like one? If so, let me know and I'll get it to you.
Well, I have actually been looking into pro membership, but I would like to try some of the features (esp. badges), before committing... So sure if you don't mind, I would love it! I am actually surprised no one got the coconut reference, it's (to me at least) one of the more "catchy" jokes in Monty Python... of course with "I'm not dead yet..." , "Bring out ye dead" and so many others I suppose it's one that might get overlooked from time to time....
There was a showing of Monty Python and the Holy Grail in Philadelphia over this weekend, but I wasn't able to go.... It's a bit depressing cause here in Dover (Delaware) there is only one movie theater- in the mall... at it's a small theater.... Anyways enough lamenting for the "dead"!
I would appreciate a pro membership, and after trying it out I might be convinced to buy in....
(I've been on here since Summer of 2007, before they had membership, so I actually have some membership benefits, like viewing all steps on one page and downloading PDFs. Though I lack being able to download the e-books and creating badges)
I also looking forward to no advertisements.

Thank you,
~ (DJ) Electfire (amongst many other names)
yoyology1 year ago
This is truly a device of extreme awesomeness. You have a fortunate son!

5 stars and following!
pastprimitive (author)  yoyology1 year ago
Thanks, much appreciated.
heathbar641 year ago
I love it! A couple sugestions:
It looks like you used chip board for the handle. I like to use scraps of composite decking. it's a more homogenous material and finishes up nicely.
for a great transmission, tear apart a lawn sprinkler of the kind that sweeps back and forth. they have a multi stacked planetary gear system that gives a lot of reduction in a very compact space.
I also liked the other suggestions of a thermocouple to power it and an ejector.
pastprimitive (author)  heathbar641 year ago
The composite decking is a great idea, if only i kept it on hand... I tend to have copious amounts of particleboard stocked for prototyping parts, because it cuts so easily and quickly, But I think I will need to get some composite decking to add to my stock pile. I think they use a mixture of HDPE, wood, and some binder resin. Or maybe the HDPE is the binder, and they just heat it up. Either way it's a great idea.
xenor1 year ago
Nice work. Perhaps a solar panel or thermocouple could work to power the turning motor. Plenty of infra red there, but I'm not sure which wavelength most solar panels are designed for.
pastprimitive (author)  xenor1 year ago
That's a really good suggestion. The thermocouple especially intrigues me.
cammers1 year ago
That's very nice.
Have you considered a sausage ejector for the next model? I'm thinking of a lever at the handle that pulls the fork tines out of the sausage when it's cooked.
pastprimitive (author)  cammers1 year ago
I like how you're thinking there.
Very well done.
I started reading and though this needs a motor! Kept reading and was stoked that you included one!
pastprimitive (author)  jdaley997021 year ago
Yeah without the motor it loses a lot of the over-the-top quality that makes it what it is.
ilpug1 year ago
I think this wins my "Over Engineering Of a Normal Object For The Win" award.
Genius and super fun. I'm going to need to make some of these. :D
pastprimitive (author)  jessyratfink1 year ago
Thanks!
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