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KKTO build questions***FOR SALE***
mkane
Top  #76 Print Post
Posted on 02/26/2020 7:53 PM

Quote

JackH wrote:

Quote

mkane wrote:

I pondering over the idea of some kind of bearing for the shaft
https://www.mcmas...-bearings/
to pass through on the outer pot. Thoughts?



Those look good. I wish I did that for mine. What shaft diameter are you going with?


1/2" When I gather all my parts I'll start a build thread.
Edited by mkane on 02/26/2020 8:14 PM
Always learning
 
mkane
Top  #77 Print Post
Posted on 02/26/2020 8:16 PM

Quote

Koffee Kosmo wrote:

Quote

mkane wrote:

I pondering over the idea of some kind of bearing for the shaft
https://www.mcmas...-bearings/
to pass through on the outer pot. Thoughts?

Those look good. I wish I did that for mine. What shaft diameter are you going with?


Yes that will work fine
The most crucial area is the perforated plate - so I would put one there as well


ThumbsUp

KK
Always learning
 
Alaroast
Top  #78 Print Post
Posted on 02/27/2020 8:59 AM
Installed false bottom with about 1.5" thickness of the ceramic insulation. I decided against using the full 2" thickness since this stuff is pretty dense and would have taken a lot of compression and pressure while sealant was curing. I used the copper silicone stuff since it had a little higher heat rating than the red. I found an old aluminum cake plate at the thrift store for $2 which was easy to cut to size with a jigsaw and file for the false bottom. I filed down edges to allow for about .040" clearance around all sides after cutting with saw. After setting bottom in place with sealant, I smoothed out the fillet with my finger and then placed a 1"2 roll of tape on bottom, inserted the inner pot and place a gallon jug of water in there to provide weight while curing. Make sure all holes through false bottom and pots are properly aligned before sealant starts to set up. Should be good to go in 24 hours where I'll do a lengthy heat burn in. Don't want silicone fumes in my coffeepouring

Thanks KK for the pictures of how you went about this; it helped out a lot as I did mine.
Alaroast attached the following images:
fb3.jpg fb2.jpg fb1.jpg fb4.jpg
Edited by Alaroast on 02/27/2020 9:06 AM
Fiorenzato Bricoletta Espresso Machine, Obel EB Grinder, USRC 3kg roaster
 
Koffee Kosmo
Top  #79 Print Post
Posted on 03/03/2020 7:12 PM
Well done Alaroast ThumbsUp

For ease of use and easy electrical connection to the drive motor it?s best to fit a female connector plug for the wall wart 12V power supply

Something like this

i.postimg.cc/23Pc7Yr4/407-CBB0-A-1-AF8-40-F4-B5-B1-A31-C32-F204-D4.jpg

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
Alaroast
Top  #80 Print Post
Posted on 03/04/2020 7:47 AM
Thanks! About the drive motor connection; I'm using a 120V motor so I just have it wired in directly to a standard 2 prong plug for house power. I am still trying to figure out roast times and temps though. On my old SC/TO roaster, the roasting chamber space was much smaller and so heat was easier to manage and usually roasts were completed in 12-15 minutes to beginning of 2C. I'm finding that I need to preheat the KKTO at least 10 minutes until I get it up to about 480F. Once I drop in beans, it takes a while to recover in temperature and my last roast took nearly 25 minutes. I think with added insulation and correct preheat times, I'll be able to get that time down to about 15 minutes. My last roast was also 800 grams so I may need to back off to about 650 grams.
Fiorenzato Bricoletta Espresso Machine, Obel EB Grinder, USRC 3kg roaster
 
renatoa
Top  #81 Print Post
Posted on 03/04/2020 8:29 AM
If possible, try to measure the real power of the bulb heater.
There is a big spread in the supply sources the chinese are using to build these lids.
Was surprised one day to have a lid that requires 80% level to bring 250 grams into FC in 10 minutes, while my regular workhorse needs only 64% for same task.
Measured, and the new lid was been found having 900W !!!
 
Koffee Kosmo
Top  #82 Print Post
Posted on 03/04/2020 5:10 PM

Quote

Alaroast wrote:

Thanks! About the drive motor connection; I'm using a 120V motor so I just have it wired in directly to a standard 2 prong plug for house power. I am still trying to figure out roast times and temps though. On my old SC/TO roaster, the roasting chamber space was much smaller and so heat was easier to manage and usually roasts were completed in 12-15 minutes to beginning of 2C. I'm finding that I need to preheat the KKTO at least 10 minutes until I get it up to about 480F. Once I drop in beans, it takes a while to recover in temperature and my last roast took nearly 25 minutes. I think with added insulation and correct preheat times, I'll be able to get that time down to about 15 minutes. My last roast was also 800 grams so I may need to back off to about 650 grams.


I use this method for blended beans to equalise the moisture content but will also work on any single origin
Run the beans normally on the lowest temp setting for up to 10 minutes
Then ramp up the heat to full and start time on the roast proper for the duration of the roast

The sweet spot for the roaster is 600gr to 750gr
But as ones roasting experience develops after several hundred roasts - and with some modifications to the TO like deflector mod and thermostat you can roast up to 1 kg

The ideal TO is one that operates at 1400W as that is matched to the roaster volume
If the TO is lower wattage then the volume needs to be reduced lower to compensate

So take baby steps and learn the capabilities of the design
Don?t follow any other roaster profile - make up your own to your personal taste in coffee

I personally prefer the older roast methods to bring out the full flavour of coffee
So experiment with roast times to FC and SC ( no right or wrong here ) and choose the ones that your tastebuds love

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
mkane
Top  #83 Print Post
Posted on 03/04/2020 6:36 PM
Does someone know what steps need to be taken to bypass the Supentown's thermostat. Is it a simple resistor change or is it more complicated?
Always learning
 
renatoa
Top  #84 Print Post
Posted on 03/05/2020 1:43 AM
Check back in the thread, first page, the repair video link in post #5.
When the guy detach the plate with bulb from the glass lid, you see the thermostat hanging in two wires.
Unplug thermostat from those sockets and use the terminals to connect the SSR.
Or short them if you want to connect SSR in other location.

Tip: before going further with electronic control, you could try the diode trick, is much simpler and effective, but sure, not allowing Artisan connection and profiling.
 
Koffee Kosmo
Top  #85 Print Post
Posted on 03/05/2020 6:24 AM

Quote

mkane wrote:

Does someone know what steps need to be taken to bypass the Supentown's thermostat. Is it a simple resistor change or is it more complicated?


Try this thread and see post 47

https://forum.hom...owstart=40

KK
Edited by JackH on 03/05/2020 4:35 PM
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
renatoa
Top  #86 Print Post
Posted on 03/05/2020 6:43 AM
i.e. this post: https://forum.hom...post_58787
 
JackH
Top  #87 Print Post
Posted on 03/05/2020 4:45 PM
My Turbo is an older model Sunpentown with the solid electric element like a stove. Most of the newer models are wired differently and some use Halogen bulbs as the heat source. It is hard to document this because of so many variations in wiring and wire colors.

With the thermostat bypassed it will run "wide open" so it needs to be controlled and monitored so it doesn't burn your house down. It is probably a good idea to leave the built in fire safety fuse intact.
---Jack

KKTO Roaster.
 
mkane
Top  #88 Print Post
Posted on 03/05/2020 5:05 PM
And the unit I bought is only 1200 w. Seems 1400w is hard to come by so vessel size is of utmost importance.
Always learning
 
JackH
Top  #89 Print Post
Posted on 03/05/2020 6:09 PM
The Galloping Gourmet Perfection-Aire, Model# 707 was the Poppery I of turbo ovens. I believe it was 1400W. If you can find one.
JackH attached the following image:
oven.jpg
---Jack

KKTO Roaster.
 
mkane
Top  #90 Print Post
Posted on 03/05/2020 7:44 PM
Thanks Jack. Found one in nice shape. 1470W. At this rate I'll have enough parts to build 2 units.
Always learning
 
Alaroast
Top  #91 Print Post
Posted on 03/06/2020 11:45 AM
I have 2 variations of Sunpentown's ; one is digital and one is regular dial for thermostat and timer. What I found with both of these ovens after using a thermocouple to check chamber temperature is that they will not get hot enough even turned up wide open. Once they get near temperature of 480F, they begin cycling on and off to maintain temp and don't quite get there for a KKTO setup. I'm using older 1200W Savoueux TO that has the solid heating element. It passes 520F if I'm not careful. The thermostat knob shaft broke off several years ago so I inserted a long screw through the broken knob to act as the shaft and it works great. Maybe this allowed knob to go past the recommended setting.
Fiorenzato Bricoletta Espresso Machine, Obel EB Grinder, USRC 3kg roaster
 
mkane
Top  #92 Print Post
Posted on 03/06/2020 5:05 PM
So If I'm going to use the Supentown the thermostat needs to be bypassed or I'll use it to cook something.
Always learning
 
renatoa
Top  #93 Print Post
Posted on 03/07/2020 1:43 AM
I wouldn't say it needs to be bypassed, as mandatory...
480F = 248C, if true convective air temperature, in the center of the oven, is good to do a medium roast.
I did light roasts even with 236 C.
+400F are required for SC roasts, perhaps, but I am not that kind of coffee guy.
Also. modding the thermostat, to translate scale by 10 or 20 degrees, is not a difficult job. Just a screw rotation.
 
mkane
Top  #94 Print Post
Posted on 03/07/2020 10:54 AM
I'll take it apart and find that screw. I could also use a lower volume pot set and use less beans to get the inside temp up there? Problem doing this is pot diameter might not match up well. As it is 10" diameter is on the verge of too small.
Always learning
 
renatoa
Top  #95 Print Post
Posted on 03/07/2020 11:28 AM
Ikea steamer insert is 23 cm - 9"
Requires welded handles removal though.
 
mkane
Top  #96 Print Post
Posted on 03/07/2020 5:27 PM
Of all the insert's I've tried the handles are in the way. I have another double boiler on the way and I'm sure the handles will be in the way also. I'll bend em' or break em'. TO has to fit one way or the other.
Always learning
 
Koffee Kosmo
Top  #97 Print Post
Posted on 03/08/2020 3:16 AM

Quote

mkane wrote:

Of all the insert's I've tried the handles are in the way. I have another double boiler on the way and I'm sure the handles will be in the way also. I'll bend em' or break em'. TO has to fit one way or the other.


I had earlier posted that the OP had the same issue
My answer was - the steel handle will bend, just put it in a vice and push
You can also put some heat to it to soften it up first

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
Koffee Kosmo
Top  #98 Print Post
Posted on 03/08/2020 10:12 PM
OK after careful deliberation on the thermostat
I have found an easy solution
This applies to the halogen turbo ovens but any that have an exposed heat sensor

No need to dismantle the TO
On the photos below you will see a rectangular piece of metal that expands with heat
When that heat is reached it trips the heat cycle

Speaking manually - if you press it down it will switch off the heat

So the easy fix to modify the thermostat is to use a fine screwdriver and lift the metal slightly over to the side so it rests or wedges on the side metal

The heat won?t cycle any longer

But it comes with a WARNING
Don?t leave the roast alone as it will get away from you and may catch on fire

So it may be best to leave it standard if you can?t devote your time on the roast

i.postimg.cc/TLVH8gwJ/9-A2-A58-D6-F878-4-A1-D-A34-A-BD4-FD3-BC0432.jpg

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
renatoa
Top  #99 Print Post
Posted on 03/09/2020 2:46 AM
Very strange piece of metal there... and big doubts I have it is the temperature regulating thermostat.

Why I say this... because that piece is not in the right location to be actuated by temperature knob.
All mechanical thermostat models I moded have the thermostat placed on same vertical as the temperature knob, because they are mechanically coupled.
Also, the thermostat is placed in the second stage/compartiment, under the bulb plate, to protect it from oils that could cover the contacts and clog the thermostat.

I seen stuff in that location only for electronically controlled lids, but they are thermocouple sensors, not thermostats. Not that kind of thing you can make not operational with a screwdriver only.
That rectangular piece of metal could be a sensor cover, just a guess...

Could be also a safety bimetal, the last chance against fire when everything else fails, which trips at +250C or other high temperature, out of normal oven cooking range.
 
Koffee Kosmo
Top  #100 Print Post
Posted on 03/09/2020 6:28 AM
It?s kinda springy
When I press that metal IN while the oven element is ON - it clicks and switches off the element OFF

So I thought it may be a heat sensitive metal thermostat

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
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