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The Basics - tools, capabilities and concepts
Alchemist
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Posted on 08/22/2007 7:29 AM
I really don't consider myself a great builder. But from input I have received, apparently I plan my projects well. I don't have a lot of equipment, but what I do have is good. I am honored by the kudos the Zen I and II roasters have had. What I would like to have happen here with the assistance of David is show just how I go about designing and building a roaster and have it one that most other people could also build.

I think I could expound a lot on the "how" and "why" of what I build, but on 2nd thought, I think the best thing is to let those things naturally come out. On that note, let's jump right in.

David, if you would be so kind to answer these questions, so I know what we have to work with. Generally, all of my building has been done with basic tools, so hopefully you have those or are willing to get them. No lathes are required, but more than a hammer and nail are also needed B)

1) What tools do you have? In particular, do you have the follow:
Drill and "good" bits
Jig Saw
Circular saw
Hammer and screwdrivers
Rivet gun (optional)
dremel (also optional but handy)

2) What metals do you want to work in? I suggest aluminum for the majority of the work. Some copper and brass can also work in the cool "decorative" spots. Thin stainless is possible, but a bear on tools I find.

3) I assume since this started on the Zen I design, you would like some ilk of tilted bed design for the drum. Is this true?

4) Do you want the roaster to be gas or electric? If electric, do you want it to be on a 15 or 20 amp circuit?

That is all for now. Of course, there are tons more questions, but they depend on the answers above. At it's most basic level, this is how I design. Ask and ANSWER a couple questions at a time and then move on. This way the design flows and is not one huge mass of puzzle pieces that may or may not fit together.
 
David
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Posted on 08/22/2007 8:04 PM

Quote

Alchemist wrote:
1) What tools do you have? In particular, do you have the follow:
Drill and "good" bits
Jig Saw
Circular saw
Hammer and screwdrivers
Rivet gun (optional)
dremel (also optional but handy)

2) What metals do you want to work in? I suggest aluminum for the majority of the work. Some copper and brass can also work in the cool "decorative" spots. Thin stainless is possible, but a bear on tools I find.

3) I assume since this started on the Zen I design, you would like some ilk of tilted bed design for the drum. Is this true?

4) Do you want the roaster to be gas or electric? If electric, do you want it to be on a 15 or 20 amp circuit?


Hello, Builder David reporting for duty!!

1) Yes, I have the tools that you listed above.

2) Those metals are fine. I understand about the difficulty of working with stainless steel, like how hard it is to drill. I'm also OK working with galvanized steel, as long as it is not around the beans.

3) I liked the tilted bed because it seemed like it would hold the beans more securely. And, besides, it looked kinda cool, too. It's not essential, though.

4) I would like to have a gas roaster some day, but on this go I would like to have electric. 15 amps or 20? I do have a dedicated 20 amp circuit available, but right now I have to use an extension cord to reach it. The cord is heavy duty, but I'm sure I can't get the full 20 amps yet.
I have an electrician friend who said he will help me out on this, and I have a Kill-A-Watt on order. But, I think that I need to accept that I only have 15 amps available for now. Can we make it to work best at 20 amps, but still be adequate at 15? Or just aim for 15 amps to begin with?

There is one other thing that I thought of. I would like it to be able to tilt over and dump the beans into a cooler of some kind. Could we work that in as well?
 
Alchemist
Top  #3 Print Post
Posted on 08/23/2007 7:25 AM
1) The stainless steel issue is basically that it is "hard to drill" but the learning curve went beyond that for me. "Hard to drill" denotes that it can be done. What I found as a novice is that I kept breaking and wearing out good bits. I just have gone through 1/2 dozen bits and blade on the drum and vanes as I kept dulling them to hunks of metal or snapping them. I have learned that a heavy duty cutoff wheel on my rotary (non-dremel) tool does wonders and is meant to wear away.

2) Galvanized - cool with that too, as you say. Not around the beans.

3) I made the decision to make a tilted bed because of a few reasons. I recalled seeing one like that years ago. I did not and do not have a break to bend my own reducing collar for a tapered snout. And I wanted to have open access to the beans. Once I factored those desires in, an open tilted drum was my only option I saw.

On that note. here is a bit of insight as to the way this design will go. I think of it as a puzzle that may or may not have an answer. In general, I assume there is one until I hit a point that I have mutally exclusive conditions that can not exist in the same roaster (a closed basket style drum and a tilt/dump feature). At that point I decide which is more important, remove the design parameter that is causing the issue and move on. Sometimes noticing that contridiciton is the key.

One other point I want to bring up is the phrase "form follows function". I have learned multiple meanings of this phrase (thank you Dan) and the two I like best and live by are "The appearance (form) of the item naturally grows (follows) from the task it is asked to perform (function). Keeping that in mind, there are a couple other interpretations that although not strictly correct, make good addendums. "The form (appearance) comes after and the function in importance". This is true of my Zen II. Works but is not highly aesthetic. Finally, IIRC, the way it was intended, was simply placing the order of appearance, i.e. "let's make it work, then we will make it pretty". What it does NOT mean IMO is let's totally build it for functionallity and THEN think about looks and design that in. That is a road for trouble. Appearance IS part of the design and has to be planned accordingly, which is why I think the Zen I was received so well (it has particular angles that I found aesthetic, colors and even a label).

So, tilted drum. fine. Let's go with that for the moment and see if you like the conditions it imparts.

1) There will be energy lost. Can we meet your 15 amp and 1 kg requirement. Experience tells me probably. Good insulation and efficient transfer of energy to the beans will be the keys. ( I have a design thought in my head about a recirculating convection pathway that I think will ensure this).

2) We will need an open ended drum. The drum I have found it THE KEYSTONE to this kind design (drum roaster). Decide on that and design around it. We will talk more on this.

3) If we DON"T go with an open ended drum (tilted or not) then either we have to design in some ilk of flap and tolerances for the drum or have to give up the tilt feature.

Overall, I like the tilt feature and think we can make the tilt work, so I would suggest locking in that design feature (tilted open drum, [optional closing maybe]) and proceed to spec out the drum (Keystone). One thought I do have is going maybe a bit more subtle. I have probably close to a 30 degree angle on the Zen I. The beans are not going to just jump out the front for no reason. I think 5 or 10 degrees may suffice and make the design easier to build. Just enough to shunt them to the back. We can prototype that and test it.

Finally, 15 amps. Done. I say that simply because there is no reason NOT to go with it. You have it. It's common. 20 amps are difficult. IF we find that the finished roaster can't do a kilo of beans, in my mind, that is that. As it is, it will roast what it can roast. 15 amps is more important than a kilo IMO.

So, I think we have the following:

1) Tilted drum (most likely open)

2) Tilt and dump feature (I am thinking a hinge at the roaster chamber and frame in the front, instead of tilting the whole roaster) (side note to think about, we either have to attach the motor to the roast chamber (my choice) or use a gear system that can uncouple (difficult due to availability, scale and complexity to the design, elegant as it is).

3) 15 amps (with safety margin 10%, or maybe just 1 amp)
 
David
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Posted on 08/23/2007 10:55 PM

Quote

Alchemist wrote:
So, I think we have the following:
1) Tilted drum (most likely open)
2) Tilt and dump feature (I am thinking a hinge at the roaster chamber and frame in the front, instead of tilting the whole roaster) (side note to think about, we either have to attach the motor to the roast chamber (my choice) or use a gear system that can uncouple (difficult due to availability, scale and complexity to the design, elegant as it is).
3) 15 amps (with safety margin 10%, or maybe just 1 amp)


That all sounds good to me.

Having the motor and it's belts or whatever attached to the drum sounds like the way we need to go. I don't know of any easily available source for a gear set that could uncouple to allow dumping...and not be too noisy.

So, we'll go with 15 amps, some good insulation, and be ready to accept whatever capacity that will produce.

Roast times are a factor here also. What kind of times to first and second crack do you find desirable?
 
Alchemist
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Posted on 08/24/2007 6:51 AM
Of course roast times are a factor. I like the capability to reach 1 within 9 minutes if I want. That way, even if I want 12 minutes the power exists to modify the profile on the fly. Likewise, control should be such that 2nd does not roll direct from 1 st. I usually prefer 2-4 minutes between the two.

And on both the specifications on both the capacity and roast times, I wanted to be clear that you are not capitulating. In both cases my goal is the most efficient in lieu of a target time and weight. With those in hand, plus the control, you will be able to adjust to your tastes and abilities.

For instance, the Zen II normally roasts 12 oz (good for my life style) in 14 minutes (at no where near 3/4, let alone full power). It can roast 42 oz in 16 minutes if I want.

I fully expect this roaster to do a lb, and a kilo I don't foresee any problem with.
 
Alchemist
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Posted on 08/24/2007 7:20 AM
OK, jumping straight into decision points for you about our Keystone.

Do you have any feeling or desire for the drum? Let's start with material.

1) Wire mesh. Pro's: Great air flow. Great chaff removal (but have to design chaff system), great ability to change with ambient temp. Cons: Some people do not like the direct heat scorching possibility. I feel that is user control.

2) Perf drum. Pro's: More rigid. Depending on material, harder to work with. Ditto on chaff. Con's: possibly harder to work with.

3) Solid. In many ways I like the thought of a solid drum, but chaff may be a problem. I small slit (as appropriated from the roaster contest) may take care of that. Pro's: Generally rigid construction. Many items around that could be used (with mods). Beans will not see wide fluxes in temperature. Con's. Slower to respond profile changes.

I should mention, I said we will design the roaster for maximum capacity. That was in regards to general power and efficiency of design. We do need that maximum target for sizing the drum. I looked and don't see how much you wanted. Seems it might have been a kilo? 2.5 lbs?

So, do you have a drum in mind? Mod or build from scratch? Aluminum or stainless? This is the one area many people like SS and with work and patience we can do that also.

Once you give me a weight target, for our viewer's benefit and documentation I will run though the drum dimension vs bean volume calculations (unless you would like too).

Oh, side tool question. Any chance you have a brake and/or a table saw? (just thinking ahead).
 
David
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Posted on 08/24/2007 8:09 AM

Quote

Alchemist wrote: And on both the specifications on both the capacity and roast times, I wanted to be clear that you are not capitulating.

I'm not. Thank you for double-checking.
(Not to worry, you can count on me to speak up. Just ask anybody.)

Actually, I am quite pleased with the specifications so far.
I know we haven't made all of the decisions yet, but I have liked the kinds of questions that you have asked so far. It gives me confidence that we will get to something that both of us are quite pleased with.

I also appreciate your musings, meanderings and thinking aloud.

Rock on!
 
David
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Posted on 08/24/2007 9:38 AM

Quote

Alchemist wrote:
The drum.
1) Wire mesh.
2) Perf drum.
3) Solid.


I don't think I'm quite ready for a solid drum.

Perf is OK.

Wire mesh I wouldn't have considered until a couple of days ago when my wife brought home from the thrift store a wire mesh drum. I think it is the "vegetable tumbler" from a Big George Foreman Rotisserie (by Salton).

I think I would like to use this basket, but there are some considerations.

First, the picture.
 
David
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Posted on 08/24/2007 9:40 AM
Here is the basket. I think it is a George Foreman. Note that it has two holes in the end (on top here).
David attached the following image:
basket[470].jpg
 
David
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Posted on 08/24/2007 9:43 AM
Now here is the basket from the GF manual, with the part number. I notice that in the drawing there is only one hold in the end. I am guessing that the drawing is not correct, but I don't know. It makes more sense to have two holes for torque and to fit on the skewers.
David attached the following image:
GeoForemanBasket2[471].jpg
 
David
Top  #11 Print Post
Posted on 08/24/2007 9:51 AM
The considerations:

Suitability - to me it looks sturdy enough to get the job done. And it has some stubby vanes in it already. They coud be the basis for attaching some straight or angled vanes, if we decided to do that.

Availability - Do you have a similar basket available to you? Can our readers get these?

The Big George Foreman Rotisserie itself has been discontinued, but these baskets can still be found. If you like it, I'll give you a source.
 
David
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Posted on 08/24/2007 10:15 AM

Quote

Alchemist wrote:I should mention, I said we will design the roaster for maximum capacity. That was in regards to general power and efficiency of design. We do need that maximum target for sizing the drum. I looked and don't see how much you wanted. Seems it might have been a kilo? 2.5 lbs?


I would love to have a kilogram of coffee at the end of the roast. I will settle for less as this may be too ambitious on 15 amps within 15 minutes, unless we have some really super heat-containment strategy. I have done a couple of pounds in my current TeaKettle roaster, but the roast times are too long for me (around 20 minutes). I know adding insulation around the vessel would help, but it's too pretty to cover up. So, I stick to 16-20 ounces in 12-15 minutes.
 
David
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Posted on 08/24/2007 11:22 AM

Quote

Alchemist wrote:
So, do you have a drum in mind? Mod or build from scratch? Aluminum or stainless? This is the one area many people like SS and with work and patience we can do that also.

Oh, side tool question. Any chance you have a brake and/or a table saw?


As much as I am recently enamored with my George Foreman basket, I am certainly open to fabricating a drum. I can get perforated stainless steel at the specialty hardware nearby.

No, I don't have a sheet metal bending brake. I know how to use 2x4's as shown in the video here. I could also pick up a proper brake for under $30-40 at a local tool store. I'm willing to get one if we need it.

No. I don't have a table saw either. This might be the excuse I have been looking for, though.
 
Alchemist
Top  #14 Print Post
Posted on 08/24/2007 12:39 PM

Quote

David wrote:
The considerations:

Suitability - to me it looks sturdy enough to get the job done. And it has some stubby vanes in it already. They could be the basis for attaching some straight or angled vanes, if we decided to do that.

Availability - Do you have a similar basket available to you? Can our readers get these?

The Big George Foreman Rotisserie itself has been discontinued, but these baskets can still be found. If you like it, I'll give you a source.


I have the source, and a couple of these already. The version with with the rods attached is what I use for the Zen II. The vanes do a great job as is. If you have the source handy, how about posting it for our viewers.

I agree, this should work fine. I already have a few modification ideas for making it open snouted for this project. I will see if I can put a couple quick drawings together.
 
Alchemist
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Posted on 08/24/2007 12:41 PM

Quote

David wrote:

Quote

Alchemist wrote: And on both the specifications on both the capacity and roast times, I wanted to be clear that you are not capitulating.

I'm not. Thank you for double-checking.
(Not to worry, you can count on me to speak up. Just ask anybody.)

Actually, I am quite pleased with the specifications so far.
I know we haven't made all of the decisions yet, but I have liked the kinds of questions that you have asked so far. It gives me confidence that we will get to something that both of us are quite pleased with.

I also appreciate your musings, meanderings and thinking aloud.

Rock on!


The musings and thinking aloud are a major portion of what I want to do here. I really don't want to just present how we did it, and here are the blueprints. I want people to see how and why the design progresses the way it does and how we get over the humps and bumps.
 
Alchemist
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Posted on 08/24/2007 1:13 PM

Quote

David wrote:
Now here is the basket from the GF manual, with the part number. I notice that in the drawing there is only one hold in the end. I am guessing that the drawing is not correct, but I don't know. It makes more sense to have two holes for torque and to fit on the skewers.


There is only hole if memory serves. The "rod" is square and fits tight.

My thought on this is that in lieu of a rod all the way through for the basket (DRUM ;) ) to ride on, we mount a stubby rod on the motor end, held in place by a couple of lock collars. The other end we cut our dump/load hole. We then mount there metal plates. The first is so the wire (more in a moment) doesn't rub the drum, the 2nd (smaller than the first) creates the groove for said wire, and the third completes the groove and keeps the wire(s) in place. The drum will then ride on a wire (maybe one on the top also to keep it in place) and hopefully be very quite.

Does that make sense?
Alchemist attached the following image:
meshdrummod[473].jpg
 
Alchemist
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Posted on 08/24/2007 2:03 PM
Upon a little more thought, I think four guide wires would be better and more secure. Keep it better centered.

Oh, and for an inside view to my thinking, this sandwich of sheet metal to make the groove is a direct result of keeping it simple. Those who could would just do a bit of lathe work. NOT HERE! s:3
Alchemist attached the following image:
wiremount[474].jpg
 
David
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Posted on 08/24/2007 10:45 PM

Quote

Alchemist wrote:There is only hole if memory serves. The "rod" is square and fits tight.


Not on mine. So we either need a variation on the drive-end fastener or I need to get one like yours.

Quote

The drum will then ride on a wire (maybe one on the top also to keep it in place) and hopefully be very quite. ?


Quote

Upon a little more thought, I think four guide wires would be better and more secure. Keep it better centered.


Quote

Does that make sense?


I believe so. It looks like you have fabricated a pulley.
The four guy wires fit in the groove to stabilize it (rather than to turn it).
 
Alchemist
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Posted on 08/25/2007 3:23 PM
Mine looks like the one in the drawing - one square hole. But I see your looks like there are two holes. Are they round or square?

As it is, I can't find mine right now, but found the invoice in my files, so could order a pair (one for you and one for me, per our conversation).

Do both ends on your have two holes?

And yes, basically those are stabilization wires.

Another question. Do you want the controls all on the inside and self contained or can we simply build a stand alone control box? Do you mind a simply variac for power control? Did you say you had one already?
 
David
Top  #20 Print Post
Posted on 08/25/2007 8:20 PM

Quote

Alchemist wrote:
Mine looks like the one in the drawing - one square hole. But I see your looks like there are two holes. Are they round or square? Do both ends on your have two holes?

Both round, both ends. Perhaps it's not a George Foreman, but the clasp looks the same.

Quote

As it is, I can't find mine right now, but found the invoice in my files, so could order a pair (one for you and one for me, per our conversation).

Sure. Just have them sent to my address.

Quote

Another question. Do you want the controls all on the inside and self contained or can we simply build a stand alone control box? Do you mind a simply variac for power control? Did you say you had one already?

I'd prefer self-contained. I have too many dorky-looking workarounds as it is now. I don't need another kludge [Klumsy, Lame, Ugly, Dumb, but Good Enough] roaster. Besides, it wouldn't really be "Zen," would it? ;)

I do have a couple of variacs and this would be a good use for them.
However, I think I'd like to use a triac of some kind. Perhaps like the ones on a kitchen range. They seem readily available. I got one a while back at a used appliance store. Could that be worked into this design?
 
Alchemist
Top  #21 Print Post
Posted on 08/25/2007 11:17 PM
I suspect it may be something else. Do you want to work with it since you have it or get a George Forman with the square bores?

I will touch base with you via PM with shipping, etc.

OK, we can work with self contained. It will make the foot print larger, but that is workable. My thought with an outside control box is not kludge like. It would be a neat and tidy, well labeled control box. ONE. Thinking the variac it is large to fit inside, but doable. Since you are thinking triac, let's talk that a bit.

My understanding is they are basically timed units. You may find you get too much of a temperature flux, but I really don't know. I thought about them at some point but didn't like the lack of fine control.

But in this case, it is YOUR roaster. We can do the triac. Maybe worthwhile to set the design to accomodate both, test both and go with the one you like.

As for "Zen", in my world that means balance. If self contained makes it large and ungainly, then that isn't zen. But that may well be in the eye of the beholder.
 
Alchemist
Top  #22 Print Post
Posted on 08/26/2007 10:05 AM
Just so we are clear, when I said external control, this is the kind of thing I had in mind. Attached, but separate if you see what I mean. Modular more than anything else. Heck, the whole polished look is a nice goal in my mind. It is virtually everything we are talking about.
Alchemist attached the following image:
sampleroaster[475].jpg
 
Alchemist
Top  #23 Print Post
Posted on 08/26/2007 10:24 AM
I know before we started the thread you mentioned using encased heater elements instead of bare nichrome. The more I think about it, there is a lag time anyway with enclosed elements and the triac is mostly built for those anyway. With nichrome, I would say no way, but maybe in this case it would be fine (and definatley cheaper and NOT overengineered). I saw we give them a try.

I may go ahead and test one out with my Zen II since it has two of those elements and I use a variac. I know how it should behave so any differences should be apparent.
 
David
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Posted on 08/26/2007 5:50 PM

Quote

Alchemist wrote:
Just so we are clear, when I said external control, this is the kind of thing I had in mind.


Wow! That sure is red. Shock

I see what you mean about the external control box.
I don't know if I can replicate those embossed letters. ;)
So, I was thinking something more like this. It has the integrated controls. And it's a cool blue.
Note the dump mechanism.
David attached the following image:
Probat[485].jpg
 
Alchemist
Top  #25 Print Post
Posted on 08/26/2007 10:35 PM
Well, it was more the shape I was thinking. But yes, it is red. Personally, I was thinking Purple

OK, I was thinking just that style for the dump mechanism as you call it, except I would put it at the front.

Give me some feedback. I was really thinking the general shape of the red one would do the trick. The main issue I see with the blue one is frankly the compactness. We are going to be insulating the drum quite heavily (1-2" depending on what we need/want) and that is going to bulk it right up.

Is there something in particular (aside form color) that you want to attempt to incorporate into this one, or on the other hand, that you don't like (aside from the color) in the red one? And I would not say the controls are so much integrated as the roaster is sitting on top of one huge control box ;)
Edited by Alchemist on 08/26/2007 10:36 PM
 
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