Feedback sought: New corretto/KKTO build

[Koffee_Kosmo]

By the end of this endeavour, it would be easier and close to same cost to purchase a shaft from me
I can guarantee less headaches and a quicker finish of your project

KK

[nikko.the.scorpio]

Surely your motor (or the advert you bought it from) stipulates the recommended ampage?
Sounds like you've got the socket idea worked out. I can't picture it because I've no idea what the socket fitting looks like.. But if it stays when yanking your pot, you're all good!
For reference - KKs drive shaft design is twice as thick as your socket extension bar. I can't foresee you having any issues providing:
1. You can eliminate any sideways movement of the shaft (drill your holes small, or attach some washers somehow to reduce your preexisting hole size)
2. Have a plan to attach your agitator that doesn't require drilling holes in the socket extension.

Hi Al,
Ah well the exact motor I bought didn't stipulate the amperage in the listing but I've just searched for it in another similar listing and sure enough I found that it's 'Rated Current' is 1.04A. So in a perfect world given the sometimes generous overratings by Chinese makers on powerpacks I would use a higher than 1A power supply, as recommended by KK - but I'll use this until I'm able to locate another one. I won't be roasting more than ~500g of beans at once so really pushing the motor shouldn't be a huge issue.

I hear what you're saying RE: the thickness of the socket extension - I've had the luxury of viewing one of KK's pre-made shafts in person and they're excellent quality. From memory they appear to be solid aluminium with a nice gauge on them.

And yes you're right this is the one thing thats really becoming a fly in the ointment - that being that you need to have some type of a easy, removable connection - but that the shaft needs to be able to be drilled into etc for the backing plate/agitator.

But alas these two problems have very different 'easy' options....as something involving a socket set type attachment is the stand out choice for the easy in-out connection but the extension bars for these are all made of steel and drilling multiple home in this for putting the backing plate screws & wire agitator holes would be a major challenge without a dress press. I've got a bench vice & a couple of reasonable drills but I still don't know if they'd be up to the task.

I had 'planned' to put the 1/4" socket extension in the vice and then use the angle grinder with a grinding disc on it to make a 3-4cm 'flatish' section that would be easier to drill into but even then it seems like it'd be tough going. haha I think there's a good reason KK used aluminium instead. ;-)

I might try taking a very small 1/4" socket extension, cutting its connector ends off. I could then use either one of these to be forced into the hollow middle section of the 10mm aluminium pipe I got. The 1/4" extension bar is VERY close to fitting inside it and if I was very lucky I might be able to get it to fit very tightly - might be a bit of a long shot as chances are the aluminium pipe splits instead BUT if I chamfer back the extension bar just a tiny amount it might work.

I've ordered another servo coupling from China...6mm to 8mm, which will enable the motor to be connected to the drive shaft.....but further than that is still to be decided.

Absolute worst case scenario I know I could connect it up like this BUT it'd be a real PITA to fit underneath the roasting platform due to the multiple connections but it would be:
electric motor (6mm)->6mm to 8mm coupler->1/4" socket square end->1/4" socket round end->8mm to 10mm coupler->10mm aluminium tube

The socket connections are screwed into the couplers & I already have the needed socket bit, aluminium tube (which should be much more easy to use to drill into etc for the agitator etc) and the 8mm to 10mm coupler. Would be about 65mm of vertical connections though! But I know already that it'd fit perfectly ....anyway I will likely cut the extension bar and see how it looks vs inside the aluminium tubing, if thats not viable I'd likely go with the multi-connection option with the 2 couplers. I don't really see many other alternatives and all the vertical crap should be able to be hidden away 'inside' the inverted box/platform.

Haha I read your build and almost cry at how straight forward it's been .....haha but anyway. :-)

[Koffee_Kosmo]

Any motor that pushes a heavy load also needs a strong power supply
I always recommend a 2.5 amp power supply
Using an underpowered power supply will result in burnout

KK

[readeral]

Surely your motor (or the advert you bought it from) stipulates the recommended ampage?
Sounds like you've got the socket idea worked out. I can't picture it because I've no idea what the socket fitting looks like.. But if it stays when yanking your pot, you're all good!
For reference - KKs drive shaft design is twice as thick as your socket extension bar. I can't foresee you having any issues providing:
1. You can eliminate any sideways movement of the shaft (drill your holes small, or attach some washers somehow to reduce your preexisting hole size)
2. Have a plan to attach your agitator that doesn't require drilling holes in the socket extension.

[nikko.the.scorpio]

@kk, understood and have changed tact to that plan from now on. 12v motor finally graced me with it's presence today!

Grabbed an old 12v 1A wallwart power supply - added some connectors on the end of the cables and it powered up the motor nicely. From what I've read these types of motors consume well below 1A (generally 0.3-0.5A) so should be more than ample.

Now just need to give some thought to the drive shaft etc. The motor has a 6mm d-shaft on it.....and I'm leaning towards the well trodden path of a socket extension (probably a shortish 1/4" one) as the drive shaft. So the trick is HOW do you connect the two of these?

My initial thought is as follows. Use a 6mm to 10mm servo coupler to connect to the motor's 6mm shaft (see generic pic below)
http://i01.i.aliimg.com/wsphoto/v0/3...-b-Coupler.jpg

Then in the 10mm end of the coupler I put in a small socket fitting (I've checked on the 8mm to 10mm coupler I bought earlier (which is no good for this)) and a small socket will fit into the 10mm coupler fine.

Screw and loctite on either end and you've then got a pretty efficient all in one connection on the motor end that can easily be pulled out when it comes to dump the beans with damage to the setup.

Any better ideas would be greatly welcomed......?

I'm figuring that a 1/4" socket extension bar is amply thick enough to act as the drive shaft....plus all my existing sockets fit it so seems logical.

[readeral]

My new KKTO thread found here: http://coffeesnobs.com.au/roasters/4...rals-kkto.html

[Koffee_Kosmo]

The reason for using a 12V drive motor was safety so no one gets electrocuted
And it can be used world wide
So my advice Nick is to stick to 12V ( sometimes stuff posted free from China takes 30+ days )

@ readeral
Bean temp readings are all you need
However after a while you will just let the roaster do its job and not be overly fussed about it

To the burping question
This method is used for smaller roasts 500 / 600 grams or under (bean dependant)
All roasts over 500 / 600 grams don't need to be burped unless it's absolutely nessesary

KK

[nikko.the.scorpio]

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?

Hi mate, haha I was looking forward to hearing about your build so much that you should christen it with it's own thread - gawd my build is a bit of a mess at present but you're very welcome to pop yours in here as well gawd knows I think it'll elevate mine through it's sheer presence alone! ;-)

Yup, definitely the right voltage - it's a straight 240v into the motor one with some splitting of the leads into the motor off to the starter capacitor. I think it's just got a lot of miles on the clock (was previously used in the corretto). Anyway losing it in itself isn't the end of the world.

As mentioned the other Breville BM motor, which is from a newer one and is MUCH more powerful is an option BUT I'd have to be a bit tricky to be able to use it. It's hard to explain but it might be possible BUT my slight concern is that when I tested it yesterday (as I'd not run this motor at all) it appeared to have considerably above the ~70rpm that KK recommends. Nothing crazy but I'd say ~100-120rpm. So the extra dicking around + this has me thinking I'll give the 12v motor first crack instead.

My challenge with that is finding a way to attach its little drive shaft/mount to another drive shaft up into the roaster in a manner where it can easily, safely & without damaging any part of the roaster allow the top roasting section to be lifted up & off when it comes time to dump/pour out the completed roasted beans. The really only viable option I can see is the most commonly used one - that being a socket extension bar & a socket/adapter to connect to the motor.

Anyway I'll have to wait until the motor arrives - then I should be able to try and piece together the best option. Shouldn't be too hard and going with the 12v motor is likely the overall best option anyway in the long term.

Yes, I followed up with the seller yesterday - usual type cut and paste response but he added a bit more that made me think there was actually a human there and his response was helpful - I'll give it until MON and if not here he'll give a full refund.

@dimal, much thanks for the recommendation - that one's RPM rating is a tad slow BUT I'll secure something like that if the mail order one doesn't show. Thanks :-)

[Dimal]

Regarding geared motors...

Have you given any thought to something like this (from within Oz), or maybe even a small window winder/windscreen wiper motor from a wrecker?

Mal.

[readeral]

I also cut the spades off my thermocouple today and soldered on some banana plugs. The Thermocouple isn't as fast reading as I had expected (not sure why I expected it to be faster than it is...) - but once up to temperature, it's happy to make the degree or two change per second reasonably well..

BUT this leads me to think that in order to measure the changes properly, a preheat of the roasting chamber for the benefit of the thermocouple alone will be required. Aside from best practice of preheating to keep the drop temperature higher and extend development.

Another thought I had (related to the exhaust question above) is a bean drop mechanism to avoid heat loss.. but given the glass lid, I'm not sure it's possible.

[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?

[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.

[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......

[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]

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.