It's an Illy can, aluminium is my guess. The rod is a steel m8 rod and is connected at the back using some 'nut' I found at the local DIY store. It accepts m8 and is likely designed as something for constructing wooden cabinets or the likes. I used the holes to rivet it to the bottom of the can and added some fins. Only drawback is that the hole in the front is bit large causing beans to fall out every now and then. Most roasts are very even and the result is good enough not to order any roasted beans.

You're right, it makes more sense that a disposable can would be aluminum. So the thread rod does not extend into the can? I've always preferred running the rod through the can so that the load can be supported on both ends. That also gives you a place to attach a lid. How did you attach the fins?

In MkI I attached the fins to the threaded rod but in this one the fins are one big strip of metal bent into a U, it rattles a bit without beans but with beans it works pretty well. Hardly any beans get stuck and I do not see tipping or scarring at the right rpm (somewhere between 40 and 60 rpm is ideal). It holds approx 125g of greens.

I thought of a two ended support, but the can with greens is still so light that I hardly feel it when holding the cordless drill. Made a support this weekend as it just takes too long for comfort (usually hit FC at 6-7 minutes)

Went back to Mk and I think the size of the hole in the lid is key to the performance. Was getting underdeveloped quick roasts in MkII but now the overall times are the same but the beans are bigger and smell much better, basically a no brainer to get a good raost whereas with MkII I kept chasing things and got a lot of woody and acidic roassts.
Yesterdays Peru Tunki was great as a ristretto, about 15,5 in, guess some 20-25 out in 45 seconds, sweet, deep, spicy with chocolate and depth...

Which version has a larger opening? Did you have too much airflow, or too little?

I might want to think about the airflow on my 230g roaster. I am getting better development now that I raised the flame up closer to the drum, but I've sometimes wondered if I should enlarge the drum perforations. Reminds me, I should probably post some better pictures of that roaster now that I'm using it again...

Well flow....it's more like a sample roaster, it has an opening on one side in the middle of the lid and for MkII I made it a bit larger (used the wood drill size I have that came closest, in Mk I I drilled a lot of tiny holes so it has a jagged edge, but that was the proof of concept model )

I just hold it over the flames of the stove so no real airflow etc and the height over the flame is managed by hand-eye coordination...all very crude and basic but the handicap is that the results are so good that I do not to making the 500g roaster for which I have parts lying around (minus some machining that still is to be done)

I don't really understand how airflow in coffee roasting works, especially with stovetop roasters, but if you're saying that the hole size made the difference, then I think airflow is most likely the significant variable. I wonder if the temperature difference between the drum and the outside air is the reason roasters like ours don't need fans. Maybe we get a lot more airflow than we think just from the hot air expanding out of the drum?

Indeed, the airflow due to steam escaping and the rotation of the drum will be plenty, and is probably just too much quite Soon.
In the beginning I did some IR temperature measurements but quit doing so as I need three hands, but the temperature shown often apppeared to be the temperature of the escaping steam rather than bean temp.
As the roasts are quite repeatable (that is without wind) I quit bothering and only keep track of time and pull small samples to look at color, size etc every now and then.

Interesting roaster. Are you roasting indoors? Is tin safe for roasting? I built a stainless steel roaster from a steam pot, normally found in a restaurant. This roaster is fired by any blue flame device, I prefer the camp stove and roast in my garage. The roaster can do 300 grams nicely. I added a bimetal thermometer to the roaster the next year and it allows me to control my profile within seconds. I get beans to 350F by seven minutes, then 400F by ten minutes. First crack occurs at around eleven minutes, and allow a two minute first crack, a pause of 20 seconds then crank the heat to 10,000 BTU for second crack. I don't roast beyond the start of second crack.

Hey, I think I recognize that one. Did you post it somewhere a couple years ago or so? It looks really sharp. If it's the same one I'm thinking of, that one inspired me in building my bigger roaster. Instead of a metal frame, though, I'm using wood boards, and my burner is mounted inside the frame. And the drum is an old LP bottle. I keep meaning to put some pictures up, maybe another week...

I roast indoors when I use this particular roaster. At 85 grams, it's not enough to need to worry too much about ventilation. If it's warm enough, though, I always roast in the garage with my half pound roaster.

Food cans come with a plastic lining, I burn that off and then clean the residue out as best I can before roasting any coffee. Besides that, I'm not aware of any health concerns with using it.