Feedback sought: New corretto/KKTO build

[260zman]

I've used the coupling from a breadmaker fitted into the bottom of my insert so that I can remove it all to dump the beans in the cooler. The windscreen wiper motor shaft was very similar to the original bm shaft. So only required minor mods to fit the coupling. Combine this with using the bm element and I often do a full kg roast batch.

[Koffee_Kosmo]

Nick - Regarding the motor speed - the drive motor speed ratings manufactures put on there motors is free spinning, they all go slower up to 30% with weight to push
The higher weight push rating the better the motor will be able to push at the rated free spinning speed

ReaderAl - I have sent you plans of two bean coolers, one with an exhaust fan, one with a vacuum

KK

[Mono]

Not sure if this is helpfull but on my current build i am using a car wiper motor powered by a modded computer transformer. I screwed a nut to the shaft of the WM, a socket sits on that held there by silicone [high temp] then KK's agitator shaft fits in the 1/4 drive hole. That allows me to pull the colonder and dump the beans into the cooler

[nikko.the.scorpio]

Ok completely backflipped on my design to using the breadmaker motor, bummer I've already ordered the other motor but no big deal. Reason for the flip is I think I've come up with a design that will be a lot simpler and require less connections etc using the breadmaker motor as the basis for it.

Hard to describe but essentially I've cut the bottom out of the breadmaker's baking tin (as shown in post #25 of this thread), this just sits in it's slot and can be lifted out very easily - it's driven by the motor connecting to the flywheel below it - this has the D-shaft spindle that the paddle used to mount onto. So I've ordered a 8mm to 10mm Coupler - now these are specifically designed to allow easy and efficient connecting of different drive shafts/connections. So one of these will be screwed on to the D-shaft of the breadmaker's paddle mount and I then just have to find suitable 10mm drive shaft to put the agitator etc on.

The real beauty of doing it this way is that I plan to actually glue/screw etc the entire piece of breadmaker tray base to the bottom of the exterior pot - worst case I could just use high temp silicone glue and then add a few small screws for extra strength. A hole is drilled in the base of the pot to allow the d-shaft to come up into the pots. I then use the Coupler to connect this to the drive shaft. So this is going to be all one connected and contained unit that can very easily be lifted off the old mounting point (and in some karmic luck it fits next to the exposed electric motor with around 10mm gap between them - which will be enough to make some kind of insulating cover/top for the motor to keep it out of the way etc.

But the Coupler's really are a VERY handy thing to get - I didn't know what they were called and went to Jaycar as another person on here used something from there to act as one (though I think it was an audio cable joiner) - but this is the real thing that is specifically for motor drive shafts etc. Very easy to find on Ebay, my 8mm to 10mm one was ~$3.

Also ordered a packet of copper washers, both for spacing/raising and also to ensure steel isn't rubbing on steel or aluminium etc. Around $4.50 for 20. 12mm internal diameter ones.

I'll try and bung up a KK-special drawing of what I'm envisaging a tad later as I'm sure the above ramble comes across as clear as mud. ;-)

[readeral]

Sounds pretty good. You're not worried about the BM motor fittings shifting due to constant exposure to heat/accounting for flex of the bottom pot? The motor itself should manage the heat right, given it was inside the bread maker...

[nikko.the.scorpio]

Sounds pretty good. You're not worried about the BM motor fittings shifting due to constant exposure to heat/accounting for flex of the bottom pot? The motor itself should manage the heat right, given it was inside the bread maker...

Hi Al,

Ah it's still very bodgy BUT there's a bit of a clearer path now, whereas before I was still stuck with a big question mark over a bunch of stuff.

The BM motor fittings etc where the old bottom of the tin slots/slides into this recess which then drives the d-shaft is all steel with the thicker parts being a cast alloy. It's very solid and I've no concerns at all about it handling any heat that is conducted down through the base of the outer pot etc. The outer pot has a 3-4mm extra thick base so no issue at all with that flexing.

The motor will in theory have some sort of a non-conductive cover over it to mainly protect from electricity and also chaff/dust getting into it - at the very easy end of the spectrum something like an over turned flower pot or wooden box. I don't think very much heat will be radiating horizontally over to it even if it was uncovered as the outer pot will have ATLEAST ~6 layers of fire blanket wrapped around the entire outside of it (a single 1m x 1m blanket was a very good fit when folded up multiple times).

One of the benefits of this is that the BM motor is definitely massively overspecced for the torque needed to stir even the largest roast of beans the entire pot would hold. The RPM's should also be right about where KK had envisaged.

If/when the motor(or part of it that can't be easily replaced) goes pop I've another near exact spare I can slot in and then I think I could easily enough modify whatever I end up with to use the direct drive motor. I still think this is a great way to do it for most people but it was going to get a tad tricky with that design & getting a really nice removable top section - whereas the BM bits in theory I believe will give me a superior working outcome. Haha but we'll see. :-)

[nikko.the.scorpio]

Dribs and drabs of bits and pieces for the KKTO have been coming in via mail and also from trips to Bunnings. Since the last post I've received/acquired:
- Silicone tubing for rim of top roasting section: that arrived yesterday, fitted it this morning by marking a straight line along it and cutting with a razor blade - got to be careful but worked very well. 73cm circumference, holds itself in place nicely - I ordered the 5mm internal diameter stuff - very good quality. When I am sure it's there to stay will put a few tiny bits of silicone glue to hold in place at a few key spots.

- Large thermocouple probe: This is the large one thats the same as that used in several builds by KK. This is VERY good quality but I'm not sure if I'll actually end up using and if I do where to best place to get meaningful data from it. I'm not really one to log data and graph curves etc so isn't the end of the world if I don't use it (as I can certainly find a use for it with my charcoal Weber kettle slow roasting pulled pork etc) but great quality item.

- 1m of 10mm aluminium tubing (Bunnings): This was about $2.30. It's 10mm thick and has 1mm thick walls. It seems strong enough to do the job required and I was having a real PITA fining stainless steel shafts, plus drilling that would have been a tad trickier. The plan is to try this, I've made sure to use quite small screws for securing the holding plates for the agitator so that minimal metal has to be removed - and I feel it will still be up to the job. If not I will order some 10mm solid aluminium rod instead.

- M3 x 25mm SS 316 screws: these are to hold the plates in place to the drive shaft and also secure the bread maker's connection/try bottom to the base of the pot.

- Round foil tray: from WW, am going to replace the foil with this.

Haha doing another 'manually' agitated roast today - going with 500g (60% Peru, 20% Rwanda, 20% Sumatra Mandheling). Will try and draw out roast a tad more and want to stop earlier this time. Will wait until I have all the bits before commencing drilling etc.

[readeral]

How'd your manual agitation go this time?

Lots arriving in the mail for me. I'm still waiting for some (essential) pieces to arrive - but as soon as they do I'll be putting mine together!

I'm curious what foil tray you got from Woolworths - is it those large oval shaped ones?

I'm pretty keen to make this system as efficient as possible to allow some decent control without needing the TO on 100% for the whole roast. I guess the ideal would be turning it down gradually if I can reduce the heat loss in the system.

[nikko.the.scorpio]

Hi Al,

It went a lot better. 500g this time. Prewarmed for around 5min at 175c. Then gave it around 10min at 175. Moved to 200 for about 5min, 1C occurred and burped at this point. Kept at 200c for about 4min for after rolling 1C and then gave it a minute or so of 225 and dumped - didn't hit 2C. Perhaps ended up going a tad lighter than desired in an overcorrection but MUCH more even roast with only 2 burnt beans.

FWIW I realised how these beans had gotten SO BADLY burnt the first time around.....I'd been what i thought was pretty lightly flipping the pot to try and ensure the beans were rotated and not just sliding around and some of the beans must have gone up and over the heat shield, they burnt to a crisp in the few seconds they were up there. MUCH more conscious of that this time around hence only around 2 beans burnt (and tossed).

The foil tray is a large round one, WW branded - worked well enough, I cut IIRC an 18cm hole in the absolute centre of it then I gradually scrunched it around the edge of the TO lid. It was perhaps 2cm too short in total circumference so I cut it in half and then overlapped the two sections at a joint, this left a 3cm or so channel that is the window. I had thought I'd have to cut the edges (which were formerly the sides of the tray) off but as it worked out they can be really handy on the top of the lip both to hold the underneath stuff in place and also as a double layer of the foil! It's no work of art but should be very effective.

FWIW I've actually used the TO to cook a few other things (back in it's proper glass base - which I lined with foil as well) and having the foil lid really helps it cook quickly/efficiently! Did a really nice simple bread to eat with some homemade hummus! Haha so it's not just a one trick pony!

I've added a few dabs of silicone glue, clamped to hold them in place so the foil is anchored in place - it's REALLY secure and much stronger than the alfoil layers. Bit of a PITA to do but you just have to take your time and scrunch it up around the lid, if you do it well it'll all but hold itself in place. No vents are blocked and it should last a very long time and wipe clean very easily as well. Here's a pic (heat shield is only off as I was glueing):

IMG_0107 by NG

IMG_0108 by NG

I agree with you 100% - an efficient system will mean less heat needed to achieve a set level of roast and this is universally regarded as a good thing for the beans - as well as less stress/wear on the rest of the roaster's components - so if the tweak/mod is cheap/simple then I think it's only got to have a small benefit to make it viable/worthwhile IMHO anyway. :-)

[readeral]

Nice work!

In my looking through WW I've only spotted oval shaped aluminium trays so far - will keep looking! I can see them in their web app. The other option is to pick up some similar thickness aluminium sheet - if I could work out how thick it was. Without the ridges in the tray, could be easier to manipulate?

I went to buy one of the Lumina TOs today, and ALDI have rotated them back off the shelves, which is a bummer. Missed the window, but they'll be back. From what I can tell though they're exactly the same as the ones Kmart has on offer for $39... just didn't get back into an ALDI in time. It's hilarious finding ALDI TOs on gumtree for $80.

[nikko.the.scorpio]

Nice work!

In my looking through WW I've only spotted oval shaped aluminium trays so far - will keep looking! I can see them in their web app. The other option is to pick up some similar thickness aluminium sheet - if I could work out how thick it was. Without the ridges in the tray, could be easier to manipulate?

I went to buy one of the Lumina TOs today, and ALDI have rotated them back off the shelves, which is a bummer. Missed the window, but they'll be back. From what I can tell though they're exactly the same as the ones Kmart has on offer for $39... just didn't get back into an ALDI in time. It's hilarious finding ALDI TOs on gumtree for $80.

Thanks mate - like I said no Australian design awards for it BUT it should do what was intended and cost all of $3.50 with very little effort to get in place etc.

You might be right about the sheeting BUT the only thing I'd suggest is that even for me I was aware that it probably didn't make a huge difference for the coffee roasting - whereas it would much more if I used the TO in it's normal glass bowl/bottom. Reason for this is that the centre/element of the TO is 18cm across (mine is the Aldi one but I'd imagine most of them are pretty similar). Now my pot is ~21.5cm in diameter....so really only 3.5cm or so of the nicely aluminium covered lid is actually reflecting heat from the cooking enclosure back down into it. So in % terms I'm not kidding myself that this is going to make a huge difference to the overall efficiency.

To be fair most folks will be using larger pots, as mine was towards the smaller end of the spectrum but it's something to take into account before you go to too much trouble modding your lid. Alternatively if it makes it any easier you could just line the inner 3-5cm of it so that it matches up with whatever actual pot diameter you're planning on using. So that could make things easier for you and should in theory be just as efficient.

[nikko.the.scorpio]

Progress has kind of ground to a temporary halt due to waiting for bits and pieces to arrive on the proverbial slow boat from China. But the vast majority of the essential ones are now here so it's just a matter of seeing how they can possibly be best implemented into the still slightly variable design.

Below are a few of the more recently arrived bits. From left:
* copper washers (not as big as KK's ones but suit the size of the bits I'm using & hopefully work just as effectively).
* Top is 10mm aluminium tubing from Bunnings - it's very strong but I have slight concerns about when I drill multiple holes in it though I suspect it'll still be fine if I do minimal sizes. Will order solid one if it's an issue, plus I have 1m of it so can trial a few different bits and redo, as only need around 10cm of it!
* In it's plastic wrapping is a K-type thermocouple, with the screw in type probe head - unsure if I will use this - if I do it'd be put in through the side wall but I don't know if it's limited depth into the bean mass would really provide much handy info. Plus hassles when removing liner etc.
* Inline on/off power switch for modding of breadmaker motor. There's a very well regarded guide on this and apparently it's as simple as inserting this in one of the power cable's sub strands. Suffice to say I will be uber careful but is meant to be completely safe.
* Larger probed k-type thermocouple, again unsure if I will use this as I suspect the mounting options will limit the amount of handy info I can get from it as hard to mount in a good spot with the rotating agitator etc. No loss if not as will be great to use on my Weber charcoal kettle etc.
IMG_0112 by

Next this is the internals of the large/outer pot, shown is the 3 screws through it's base holding the old breadmaker tin's base bit on, it's 40mm or so drive shaft is up through the base of the pot and I've got an 8mm to 10mm drive coupler on top of that (it's just sitting on at present, there's 2 hex head screws to tighten/secure it on either end, it's made of aluminium) - the 10mm drive shaft that goes into the inner liner and will have the agitator etc attached to it will sit in this and be secured by the 2 top screws (I will probably drill very small holes so the screws can go 'through and into' the shaft for better grip).
IMG_0113 by

And this is the same fastening of the old breadmaker drive mounting on the bottom of the pot. Was an easy job and it sits perfectly flush and super tight. Used quite small 316 SS dome head screws, which I'll also use to attach the agitator.
IMG_0114 by

I'm still unsure on the exact agitator design to go with - either the 4 strands of SS wire from a whisk or I'll cutout some aluminium or ss sheeting with a dremel and make the curved wing design that KK evolved to - am just trying to get feedback from KK as to which one of the two is the more efficient turner of the bean mass.

Also need to knock up some MDF or ply into a small inverted box/platform to put the old breadmaker's internal chassis (as shown in earlier posts) onto or into (might put it inside and use brackets to mount it as was done by 'Burnsy' in his build. But it's just deciding that kind of stuff thats holding it up as otherwise I could finish it today if desired as everything needed for any option is in my possession. So not a bad problem to have. ;-)

[nikko.the.scorpio]

Seems I've hit a major snap in my design. Was rewiring the breadmaker motors this morning and through doing this found that my preferred one (which is older) doesn't have the grunt to turn the mount for the KKTO's drive shaft. I found this somewhat surprising but tried multiple different variations of the wiring (start capacitor on and direct into motor) and nothing made much difference.

Now I have another newer breadmaker's internals from another Breville and the motor on this is a LOT bigger and it was easily able to drive the KKTO's shaft BUT and this is the thing - the motor is so much bigger than I can't properly fit the pots into the holding slot - as they're literally pushing right into the edge of the motor - and even though I could cut some metal casing off the motor and even bash in the pots this would still be rather dangerous.

So I'm going to have to either reconsider using the 12v motor (which still hasn't arrived from China! Bought on 13AUG) or come up with some way to extend the drive shaft from the breadmaker's internals up and put the cradle/slot up higher - this probably sounds hard to picture but it might be possible, my head is currently just buzzing from the stress of playing around with 240v (not something I'm overly fond of though I took extreme safety actions and read up a LOT before doing any of this). Bit of a bummer......

[readeral]

Ok so feedback on where I'm up to.

I finally have virtually all the parts that I need to make this roaster!

What has arrived:
Pots (finally)
Thermocouple and Victor 86B multimeter (with a new regular style usb cable, handy!)
Motor, driveshaft, agitator wire, insulation, aluminium plate

I still haven't bought a power supply for the motor, nor a turbo oven - waiting for them to arrive back at Aldi, or for Kmart to have a sale (they're literally the same machine, more $$ at Kmart) and haven't yet decided on how to mount the whole pot set yet.

So on the weekend I'll drill my holes and mount the shaft, and have a crack at making my agitator. Once the shaft is in, I'll measure how much of the drive shaft protrudes (so how thick a piece of MDF i need below my pot), and will mount my motor. From there it's just bits and pieces to finish up!

I still haven't worked out how to mount the motor. KK provided me with some small screws to attach the motor I presume to a plate, which I will then further attach to my larger base. Decisions decisions.

Anyway, that's where I'm at.

Further questions I've had (of anyone that answers):
I want to go with two temperature probes - if I use the RoastLogger software (Can't use CS software because it doesn't support Mac OS) I can use my multimeter, and also utilise it's OCR feature to get a second input from a low-fi digital thermometer.

My plan is to have a Bean temp and an Environment temp - my question is: do I want the environment temp thermo to be above the beans (thus getting direct heat from the Turbo Oven) or below the beans (thus avoiding the slightly higher reading the TO will give me). I'm trying to determine how I'll best pick up the type of temperature change that occurs around first crack, without being shrouded by the TO heat delivery. The problem with being below the beans is the fact that heat rises - but with the TO fan running, I'm guessing that warmer air will circulate quite quickly.

Another question I have is whether anyone eventually managed to hook a TC4 up to a Turbo Oven... or if that's just getting ridiculous.

And my final thought/question is whether it's worth building an exhaust mechanism into the whole thing to more accurately do the quick changes to ET that people often do by 'burping'. The whole burping process to me seems like a variable that is just fraught with inaccuracy. Happy to be shot down on that one.

Overthinking? Always.

[readeral]

Seems I've hit a major snap in my design. Was rewiring the breadmaker motors this morning and through doing this found that my preferred one (which is older) doesn't have the grunt to turn the mount for the KKTO's drive shaft. I found this somewhat surprising but tried multiple different variations of the wiring (start capacitor on and direct into motor) and nothing made much difference.

Now I have another newer breadmaker's internals from another Breville and the motor on this is a LOT bigger and it was easily able to drive the KKTO's shaft BUT and this is the thing - the motor is so much bigger than I can't properly fit the pots into the holding slot - as they're literally pushing right into the edge of the motor - and even though I could cut some metal casing off the motor and even bash in the pots this would still be rather dangerous.

So I'm going to have to either reconsider using the 12v motor (which still hasn't arrived from China! Bought on 13AUG) or come up with some way to extend the drive shaft from the breadmaker's internals up and put the cradle/slot up higher - this probably sounds hard to picture but it might be possible, my head is currently just buzzing from the stress of playing around with 240v (not something I'm overly fond of though I took extreme safety actions and read up a LOT before doing any of this). Bit of a bummer......

Wow what a bummer about the motor! Definitely have the right voltage? I rewired my popper fan (twice) the other week and initially used a 12V instead of it's required 18V when it was in circuit with the element, and so it had a slower start up. We've wired in 19V now, so although the motor won't last as long, it's definitely got the power it needs to move the beans inside the popper.

Also sucks your Chinese motor hasn't arrived. I'd be inclined to follow that up and just go straight to that one, rather than the other breadmaker one. Alternatively, could you use the newer breadmaker and instead of cutting the motor, increase the holding slot for your pots so it sits higher?