Hi, all; introducing myself as a newbie. As someone with no real prior interaction with this site, please forgive any mistakes I may make.

I'd like to try roasting but aside from what I've read, I don't have a lot of practical working knowledge yet. A Behmor is almost $400 on amazon, and Drgary posted the following on one of my other posts (actually, my first post; this post is my second):

drgary wrote:Walt,

Since you're handy you might cobble together a heat gun/bread machine, which might give you better control than a Behmor and be a fun project. Then maybe consider a Huky or Quest if you decide you're all in.

What I WOULD do for a good cup of coffee!

I didn't really know what a Huky or Quest was at that time, but looked them up and I gather they are around 3x the cost of the Behmor. While that is substantial, its not astronomical as they appear to be high quality. However, to a newbie like me, all I see is a tumbler with a heat source, thermometry, and a variable fan attached, plus small incidentals like chaff bins, tryer chute, loading chute, etc.....all in all, not very difficult to do conceptually and not difficult to make.

I know there are places online where you can just send them files and they will laser cut sheet metal to your specs. It shouldn't be too hard to find people here who are conversant with the software and files needed to have these cut if a design can first be reached and a consensus met. So here it is: I propose an open source design be made by users here so that we can make a roaster that will meet most people's needs, cheaply. I know committee design is one of the worst ways to design anything, but surely so many caffeine addicts can attune their thoughts sufficiently long to design something like a glorified hamster cage with attached hair dryer?

I have a 12x24 lathe and can machine moderately sized parts for assembly, plus welders, press, and a small milling machine. I have access to box/pan brakes for bending and slip rollers for rolling the drum to any size, really, although I think most of us will want something that can do about a 1 lb load comfortably. This will also keep machine size manageable for cost and shipping reasons. Can we do that? We'd probably want to start a specific place for design submissions and perhaps have a moderator in charge? I can do an initial build from the design and make the assembly jigs and do the assembly to make a prototype to submit for testing. I know little about electronics so can't do the thermometry or control circuits to regulate current to heat (if electric, although I would surmise more people would want LP gas in a 1 lb capacity tumbler) or fan. But I think the rest wouldn't be too difficult with off the shelf parts and a bit of fabrication work.

The completed project would be this site's intellectual property and available to anyone who wanted a copy of it, to make for themselves if they wanted to. I'd be fine with assembly/fabrication of the first batch, i'll throw in my labor for free as I'm gaining input from the site and help with making the parts. This would be a group effort in the real sense that there would be no $$ profit from it; its a cooperative effort to make something that would be a benefit to lots of folk who want one. We could ban together into small groups to purchase small batches of sheetmetal, parts, motors, fans etc and each group is responsible for their own finances in order to leverage the group's batch buying power and maybe get better prices for critical components that way, although I suspect evilbay would be a critical player in these parts acquisitions.

comments? or am I just too high on caffeine? Has it been tried before and I'm being overly simplistic?
I could go it alone and just post the results, but I don't have enough experience to know what I want in a roaster. That's where I need the input.

aloha,
walt

Check out the link below it's to a forum where you can find a lot of info on building a home roaster.

http://www.homeroasters.org/index.htm

Thanks, Robert. I checked out that site briefly and to tell you the truth, some of those design elements passed through my head before I did the above post

But, I don't want something cobbled together. A purpose built machine is ok, a cobbled together one may work just fine; but I tend to make things that will still work if you bump it against a pillow, and I'm not afraid of a little work to get there.

I think the biggest issue that you're going to run into is that once you price out all of the materials/off the shelf components/factor in labor you're probably going to exceed the cost of a Huky 500 or Quest M3; especially if you want something that's reliable and repeatable.

The cost only drops as the quantities significantly increase.

If you go down this path, I'd recommend getting a list together of all of the components you want to manufacture, and price out their materials/machining/welding. Then do a cost/benefit analysis to see if it's worth the time and money versus saving for something off the shelf.

I wish you luck.

Nick

I designed a small roaster based off a commercial roaster I purchased. If your interested see my posts, search this site under ripcityman or stainless steel manual roaster (11/23/2013). I can supply you more info if you are interested in this type of roaster.

"I propose an open source design be made by users here so that we can make a roaster that will meet most people's needs, cheaply."

Walt:

Thanks for that good idea and generous offer. Many of us enjoy the tinkering aspects of this hobby, and we're increasingly able to design/spec parts and have them made for us. I'd say there's no harm in trying your idea. The biggest challenge will be making a roaster that's easily controlled for heat and airflow. The drum and its mounting will need precision. Thermocouples are easy, and many of us use Artisan software for profiling the roast. Being able to fine-tune profiles for different greens makes a big difference in taste.

You might want to buy and try one of the two roasters I mentioned before launching your project. You can always re-sell it. It'll give you a user's experience of a well-tuned, high quality home roaster. There's nothing like that user experience to tell you what's required in an open source version. The Huky has a larger batch size than the Quest. Of course you may like it so much that you abandon your project and go down the home roasting rabbit hole with your Huky.

Gary! Hahahaha, well said. I had actually arrived at the same conclusion, as this post has been up a couple days and although people are responding, the amount of interest shown appears luke-warm at best. While I'm not sure if that's simply a response to the moronic poster or to a silly idea, what is clear is that there is no avalanche of people dying to send me ideas of what they want in a custom roaster.

There is a used M3 in the classifieds that I was thinking of trying to pick up but saw again the hamster cage in disguise behind the shiny stainless and the engineer in me balked.

So saying, I went to Home Depot today and found a small stainless 2 burner BBQ grill for around $99. I think I can use that as a base/heat source to start, and am presently checking ebay for perforated stainless sheet to make the basket from.

I'll try to post the project from start to finish and take pics. Hope it performs well.

the 'open source' part of this project would have been to get someone to do a 3D CAD rendering so that critical and difficult to make parts like the paddles inside the cage could be cut out by machine so that I won't have to do the ol' faithful method of cut-n-try to see if that's the correct shape. Essentially I'd just pay some shop to send me a pile of sheets that I would then simply weld together for assembly. Much simpler. Also someone else could figure out the electronics and the drive assembly for the tumbler.

Still, can't complain as I know I am a completely unknown quantity until I get some serious play time here. But, its not a terribly difficult project, so I'll plod along and see what happens. Not in a rush.

A couple of questions so I can get started; if I want around a 1 lb payload, what are the approximate dimensions of the tumbler? I estimated around 1' long by 8" in diameter? Or should it be wider? closer to 10"? It will be perforated stainless and sitting at a small angle, perhaps 15 or 20 degrees from horizontal. Are such tumblers supported at both ends? is the tumbler always closed off to retain heat? or do some run with open ends with a blower to take out chaff?

walt_in_hawaii wrote:A couple of questions so I can get started; if I want around a 1 lb payload, what are the approximate dimensions of the tumbler? I estimated around 1' long by 8" in diameter? Or should it be wider? closer to 10"? It will be perforated stainless and sitting at a small angle, perhaps 15 or 20 degrees from horizontal. Are such tumblers supported at both ends? is the tumbler always closed off to retain heat? or do some run with open ends with a blower to take out chaff?

Those "couple questions" have me a bit stumped, and that's why I bought a terrific roaster built by someone else! But here are some guesses. I expect there's a little bit of tilt to the drum or the vanes slide the beans toward the front. Otherwise the beans wouldn't exit the roaster when you open the door to dump them. But I'm just guessing. Too much tilt and your beans won't distribute evenly during the roast. Drum size? Got me. Maybe look at the specs of a roaster rated so its sweet spot (75% of rated drum load) is about a lb., so that would be about 1 1/3 lbs., but you won't find that. The closest is a 0.5 kilo roaster, which would give you 0.82 lbs. A good example of that is a Bella Taiwan Mini 500, which is an excellent roaster. The tumblers I've seen are supported at both ends. Sometimes they're perforated, sometimes solid. If your heat source is below the drum and it's made of thick steel plate, that would distribute heat. Cast iron is better but not practical for your purposes. You don't want it closed off in front if you want to drop the beans into a cooling tray at the end of the roast. You probably want some opening at the back so your air circulation also moves through the drum.

By now you'll have seen online that you're not the first to adapt a barbecue drum as a roaster. I'm concerned that the open space around the drum would be too large for easily controlling the roaster, compared to a roaster manufactured for that purpose. I'm conjecturing that the open space around the drum in my North roaster is about half the diameter of the drum in all directions.

As for drum sizes I have built two drum roasters: one of them being a modification of the Stir Crazy / Turbo Oven theme, and the other one a gas drum roaster.

I used an already made perforated "nut" roaster from ebay for my turbo oven grill roaster, and with the proper insulation around it it can roast evenly 13 oz of coffee to 2nd crack in about 15 minutes.

The grill drum I built myself to fit in a 4 burner gas grill. I got stainless steel mesh from a local metalshop, they charged me about $5 a foot for it. You can probably find the material on Amazon. My drum can properly agitate 2 lbs of beans, the problem is that the grill at its hottest can't get those beans to 2nd crack. To much heat escapes from it. I would have to insulate it or something to be able to get a decent roast out of it at that batch size, but I still want to use it as a standard grill, so I'm not quite ready to do that. For now I just dump in my normal 14 oz batch and it acts as an overly large sample roaster that gives me more precise control over my temperature.

If you are looking for general ideas for drum sizing you can get an idea from these guys, who specialize in building grill drums for roasting coffee: http://www.rkdrums.com/