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Topic: Update: Not so ugly roaster development (19 msgs / 494 lines)
1) From: Derek Bradford
Hi All,
Thanks for all your help with the vanes issue.  I've decided to go
with 4 vanes, 2.5cm high.  I considered 6, but it seemed like the
beans would tumble from vane to vane without contacting the drum at
all.  I have a drill now, so if I decide 6 is better, I can drill out
the pop rivets.
I spent much of the day working and scrounging for parts, hence the
lack of emailing.  Like I said, I bought a drill--the very best Black
& Decker had to offer for 30 bucks.
Anyway, I have a new question to ask everyone.  I'd like to have it
motorized...as you know, the last one was hand-cranked, which was
fine, but since I'm completely rebuilding, why not motorize?  Also,
since I'm going to have this wonderful sample hole, it'd be a shame
not to get to use it effectively.  So...on to my question:
I have access to about a million fans (room fans).  They're free, and
they all come with great motors, except that they turn far too fast. 
Can anyone think of a simple way of lowering the rpms?  As for
transformers, I can get cheap PC power supplies that supply 12 volts,
but I'm not sure the motor would even turn at that voltage.  Can
anyone offer some suggestions?  I know there're lots of engineers
here, even some electrical ones, so here's your chance to shine!
Cheers,
--Derekhttp://uglyroaster.blogspot.com

2) From: Alchemist John
I am going into this a little late, but I wanted to say good 
job.  Same thing, you have decided on 4 vanes, but as food for 
thought, my drum technically has 6 1" vanes, except they are not full 
vanes.  2 are in the in the 12oclock position.  Each is one third the 
length of the drum, one being at each end, the center open.  There is 
a set just like that at the 6 o clock position, then there is one 
vane each at 3 and 9, right in the middle of the length of the 
drum.  The effect, even at very slow rpms is constant cascading 
mixing in and out and back again.
All I can say is the right tool for the right job is so helpful.  I 
used a pop rivet gun for one roaster and it was ok, but on my current 
one I use it is nothing by sheet metal screws.  Makes modifications 
and repairs very easy - no drilling out.
As for your current question - I have a question back - do you have 
access to free or cheap bike parts?  Instead of slowing the fan down 
with voltage, why not consider doing it with gears.  With just 2-3 
gears of different sizes you can slow it down almost to a stand 
still, but still have the full fan power to drive it.  And that is 
assuming the fan motors can even drive it - all the ones I am used to 
stop with the slightest friction.
At 06:25 8/27/2005, you wrote:
<Snip>
John Nanci
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/

3) From: Pecan Jim Gundlach
On Aug 27, 2005, at 8:25 AM, Derek Bradford wrote:
<Snip>
Put a large pulley on the drum shaft and a small one on the motor.   
Connect with a belt or chain, depending on the kind of pulley you  
use.  This not only allows you to set the speed but moves the motor  
away from the heat.
   Jim Gundlach
"The espresso machine is an accessory to the grinder, not the other  
way around."

4) From: Derek Bradford
On 8/27/05, Alchemist John  wrote:
<Snip>
I'm using a combination of screws and pop rivets.  I used the pop
rivets for the drum, but for most of the housing I expect it will be
screws; it has been so far.
<Snip>
Bike parts: I can get them.  I think it would be a lot of work to
align the gear assembly.  I've done some robotics competitions (race
ones with only a day to build), and my experience has been to avoid
gears--too flimsy and not dependable in the long run.  But this is
leading into other stories...
As for the motor stopping, I had completely overlooked that.  I'm
using a fan for cooling, and just figured, hey, there's a cheap motor
source.  I think you're right, though.  There is always the option of
using geared-down turning area of the motor at the back of the fan
motor (you know, the one that turns the fan assembly itself?).  It's
got to be able to handle some resistance, since it turns the fan,
which is as heavy or heavier than a drum.
Any other thoughts?
<Snip>
tings
<Snip>
ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip>
-- 
Check out my blog--catch up with me on YOUR schedule, not mine.http://novernae.blogspot.com

5) From: Alchemist John
Weight is not resistance - The fan blades could be 10 lbs and once it 
was going, there is only air resistance to slow it down.  Your drum 
is going to be bottom weighted (beans there) and have contact 
friction from the two support sides.  The bottom weight is your most 
pressing force to overcome.
In regards to robotic gears and this kind of gearing, having worked 
with both, it is day and night.  This is gross macro gearing and I 
found it to be pretty easy in comparison.  Micro gearing almost drove me crazy.
At 07:09 8/27/2005, you wrote:
<Snip>
John Nanci
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/

6) From: Michael Wascher
Could your new drill be the power source for your drum?
On 8/27/05, Derek Bradford  wrote:
<Snip>
-- 
"Not all things that are countable, count, and not all things that count,=
 
are countable". Albert Einstein

7) From: Tom Ulmer
I can never seem to find stainless sheet metal screws when I'm looking.
Everything I see around here are zinc coated.

8) From: Alchemist John
I am not sure what mine are, but I think they are SS - does not 
really matter in my case - they are all outside and not exposed to heat.
At 08:45 8/27/2005, you wrote:
<Snip>
John Nanci
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/

9) From: Robert Avery
John ... weight is resistance when it comes to mass acceleration effects  
... A small motor could swing it ...agreed ... but getting it there might be 
a problem ... of course it could take a long time to stop it as well ... 
Just wondering ???
<Snip>

10) From: Robert Avery
Tom ... most ACE Hardware stores carry stainless screws and bolts ... I know 
the have stainless sheetmetal screws ... you might want to give them a try. 
My resource dried up after I retired .. so ACE is the Place !!!!
<Snip>

11) From: Derek Bradford
I've thought about that.  With the current trigger, it's not sensitive
enough.  It'll run at a low rpm, but not stably.  I'd have to rewire
it with a more sensitive dial switch to regulate the rpms.  It would
be a fun project, but to be honest I have no idea how to go about it. 
I suppose it would really just be a matter of rerouting the wiring
through the new switch.  That said, in my last robotics competition,
we used dremel shafts on 12 volt circuits to power various things.  I
wonder if I could cheat a bit and just wire it up directly to 12
volts?  That might also overcome the undersensitivity of the trigger. 
Thoughts?
On 8/28/05, Michael Wascher  wrote:
<Snip>
 
<Snip>
-- 
Check out my blog--catch up with me on YOUR schedule, not mine.http://novernae.blogspot.com

12) From: Philip Keleshian
Hi Derek,
Fan motors are typically AC induction motors. They will not run on DC.  =
The speed of an induction motor can be controlled but they aren't the =
first choice for speed control.  To maintain torque at the various =
speeds the controller should vary frequency as well as voltage. For use =
driving a fan phase control (lamp dimmer) can be used with some success. =
 I have done it and I have a range hood which uses that approach.
To get to the speed which you want to turn your drum and maintain =
sufficient torque I would think you will need some sort of gear or =
pulley arrangement at least for some of the speed reduction.  With the =
torque multiplication you will get with the pulley setup the phase =
controlled fan motor may work.
Phil

13) From: Derek Bradford
Hi Phil,
Thanks for the reply.  I decided to keep it simple, and I'm using the
shaft that moves the fan from side to side.  It turns at 20rpm, and is
perfect for my drum size.  It didn't require much modification, and I
think it will work fine for quite a while.  My shaft is a whole other
matter, but I've made improvements to it as well.  You can see
pictures of the motor assembly on my blog
http://uglyroaster.blogspot.com).Cheers,
--Derek
On 8/30/05, Philip Keleshian  wrote:
<Snip>
he speed of an induction motor can be controlled but they aren't the first =
choice for speed control.  To maintain torque at the various speeds the con=
troller should vary frequency as well as voltage. For use driving a fan pha=
se control (lamp dimmer) can be used with some success.  I have done it and=
 I have a range hood which uses that approach.
<Snip>
ent torque I would think you will need some sort of gear or pulley arrangem=
ent at least for some of the speed reduction.  With the torque multiplicati=
on you will get with the pulley setup the phase controlled fan motor may wo=
rk.
<Snip>
ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip>
ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip>
-- 
The Uglyroast Coffee Roaster.  ...Now 40% less ugly!http://uglyroaster.blogspot.com

14) From: Philip Keleshian
Hi Derek,
That looks good.
I wasn't thinking of the fans wit the gear box.  When you said fan, I =
was thinking one of those box fans.
Phil

15) From: Robert Avery
Derek ... you might want to look at this item on Ebay as an eg.http://cgi.ebay.com/Bodine-variable-speed-DC-gearhead-motor-w-control-N-R_W0QQitemZ7541449631QQcategoryZ71400QQssPageNameZWDVWQQrdZ1QQcmdZViewItemListed under variable speed bodine motor. Not sure the speed is to your 
liking, but this type of arangement works great and the motors are well 
known for there reliablity. Roaster looks great ...so does the coffee. 
Later, Bob
<Snip>

16) From: J.W.Bullfrog
Belts & pulleys. aka engine fan belt application
Derek Bradford wrote:
<Snip>
-- 
Life in the fast lane ......
It is by will alone I set my mind in motion.
It is by the juice of aribica that thoughts acquire speed,
the lips acquire stains.
The stains become a warning.
It is by will alone I set my mind in motion.

17) From: STephen niezgoda
You should look into rivnuts for the housing applicalation.  The leave a much clearner look and allow for machince screws instead od sheet metal screws and tinnerman clips.
 
Steve N
"J.W.Bullfrog"  wrote:
Belts & pulleys. aka engine fan belt application
Derek Bradford wrote:
<Snip>
-- 
Life in the fast lane ......
It is by will alone I set my mind in motion.
It is by the juice of aribica that thoughts acquire speed,
the lips acquire stains.
The stains become a warning.
It is by will alone I set my mind in motion.---------------------------------
 Start your day with Yahoo! - make it your home page 

18) From: Alchemist John
How are you now detaching the shaft for dumping?  The tryer looks sweet.
At 11:19 8/29/2005, you wrote:
<Snip>
John Nanci
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/

19) From: Derek Bradford
I just pull a pin from the shaft joint (where it meets the actual
motor shaft).  It's much more stable and secure.  It will hold up much
better than the old setup, though still not indefinately.  I'll be
visiting the welder soon enough for a proper shaft.  However, even
after that I'll likely keep a similar joining method; it's really
quite simple and effective.  It's more than strong enough.
If you look at the picture of it on my blog (currently the first
picture), you can see what I mean.  Since the motor is mounted on the
fan base, it bends backward just enough to separate it from the shaft
before I tip.  There's enough play overall that for now, it should
suffice.
On 8/30/05, Alchemist John  wrote:
<Snip>
ttings
<Snip>
ttings
<Snip>
tings
<Snip>
ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip>
-- 
The Uglyroast Coffee Roaster.  ...Now 40% less ugly!http://uglyroaster.blogspot.com


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