readeral's KKTO

[readeral]

N.B. This is a design entirely developed by Koffee_Kosmo, merely partially implemented by me.

With much thanks for help from KK and prompting from nikko, here's a new thread for my new KKTO build I've been putting together.

As my frankenpopper has been a fun experiment, but no where near consistent enough for my needs - the KKTO was a necessity for keeping up the newly formed home coffee habit!

I managed to score the correct pot set (Metal handled Arcosteel) on scumtree for $30 and so it all started.

KK sent me a purpose-manufactured motor, drive shaft and washers, agitator materials, insulation and false floor.

I purchased from fleabay some hi-temp hosing, a DMD and thermocouple.

Still to get is the TO itself (hopefully it'll come back into ALDI, otherwise I'll get a Kmart one, they're the same), a power 12v 2.5A power supply for the motor, a silicone gasket maker, and materials for the pot platform.

What follows are some pictures of the build so far.

This is the pot set recommended for a 'standard build':


This is the fitted silicone. Note that the top tube (green) has been split carefully down the middle to sit over the lip. The bottom tubing has been attached with a 2mm tube connector from Bunnings (I had to trim the connector down to make it sit flush against the pot as it's square). It sits above the small lip, and will fill the gap made between the two pots when they're put together.


This is a photo of the black tube filling the gap between the pots. I will later use some silicone gasket maker to hold it firmly in position.


I had to drill my own pots, so I used the following method to find the centre, as I wasn't willing to trust the rings on the pot itself. Note the lines drawn to intersect the pot edge at two points. I then found the centre of this line and drew a perpendicular line across and through the centre of the pot. I did this 3 times and approximated the meeting point. It was very slightly different to the lines already on the pot.


This is the resulting drilled hole. 18mm in diameter, which is good as the hole ended up having drifted 1mm off centre once we'd finished.


The insert was also drilled at 14mm, but we just had to go with the already present drainage holes as our drilling guide.

More to come...

[readeral]

This is the drilled insert with the drive shaft fitted, one washer between the drive shaft collar and the insert


This is the shaft from the inside, another washer between the holding plate and the insert


This is the wire that will be agitating the beans - it's been marked to correct length so that the wire can be bent at 90 degrees to insert into the drive shaft.


Here's the bent wire:


Here's one of the wires inserted before the holding plate is put on:

[readeral]

Here's the agitator wire inserted with the holding plate attached (backwards - so it would still hold the wire but not get in the way of bending the wire. This cup was my guide for getting the curve correct


The finished bent wire agitator. Not perfect, but good enough.


The finished bent wire agitator from another angle. I will probably trim off the excess wire at the top, and will probably bend the bottom wire back on itself and attach a metal spring for a bit more heft to move the beans around at the bottom.


So what's next?
At the moment I have to make some adjustments to the aluminium false floor that I have, and then I will be using the gasket maker to seal it in place at the correct depth, with gaskets made for the drive shaft on the external pot (reduce that 18mm hole) and the aluminium false floor (in my instance, 16mm hole)

After that, I'll need to build a platform for the pots to sit on (and some centring posts) as my drive shaft protrudes by 46mm. I'm planning to sandwich 3 sheets of MDF together, and the motor provided by KK will be attached to the bottom of this MDF.

I'll then likely put some castor wheels or legs on the bottom.

Updates as it moves forward!

[adifoto]

It comes together quite nice.
Thanks for the photos.
Adi

[readeral]

Thanks to adifoto for doing the drill holes in my pots!

[nikko.the.scorpio]

Nice work Al! Bloody heck I look at how quick and nicely thats come together for you and I think there's REALLY something to be said for buying the pre-made perfect bits from KK instead of putting together from this and that as I've done.

Looks great and look forward to seeing how you finish it off.

[readeral]

As I said to Paul yesterday, I measure thrice cut once :P But as you say, all credit to him for the excellent drive shaft and agitator.

My biggest problem is how to mount the motor. It just seems crazy to join 3 pieces of MDF together, but I can't think of anything else that would be as stable!

Picked up a round file today and some RTV gasket maker - so all the internals will be done this evening. Leaves mounting, electrics and the TO to go.

[readeral]

Think I've found a possible low effort solution, but not the cheapest if talking raw materials... but my time is worth something too, and right now with an erratic popper, I'm back to buying beans from my local roaster.

This chopping board from Wiltshire ('Wiltshire Gourmet chopping board') is 45mm thick - only 1mm from my needed thickness. I'll just drill it, and then test it for suitability. If need be, I can cut a 1mm thick plate of aluminium to go between the motor and the chopping board to make up the extra distance, but my hunch is I might have enough room in my measurements. We'll see!

[GreenBeanGenii]

Necessity being the Momma of Invention again!!!

Grand thread about your journey,readeral.

Thanks for posting everything.

[Koffee_Kosmo]

Glad to see that it's all coming together nicely for you, and my instructions were easy to follow @readeral

KK

[readeral]

Glad to see that it's all coming together nicely for you, and my instructions were easy to follow @readeral

KK

The breadth of your documentation is sensational!

[readeral]

I adjusted the aluminium floor to be a little more centred with the round file - I had issues with the drive shaft rubbing, but they've now been eliminated and everything sits nicely.

Next I used a pacer pencil to draw little markers through the internal pot to the outer pot, so I could know exactly how deep the insert pot sat.

These lowest holes were 15mm up the side of the insert, so I measured 15mm below this line for the bottom of the insert. My drive shaft collar sits 10mm further under that, and I wanted to have 5mm gap between shaft collar and the false floor - so I found the point 30mm below my markings by inserting my false floor, and using a set square I levelled it out at 30mm below my marks.

Then I took a sharpie and drew this line around the insert and pulled it all back out again.

Then I went to work with the Permatex, placing a ring of silicone around my drive shaft exit hole from the inside of the outer pot.

[readeral]

Next went down a layer of insulation, and Permatex was placed on this layer, along with another ring around the exit hole. I kept doing this until all the insulation was in place.


After that, I wrapped some aluminium foil around a pen and pushed through the hole, just to make sure that all the strands of insulation were neat against the side and that the hole was clear for the drive shaft. This didn't work as well as I had intended, but was ok.

Finally the aluminium false floor was placed back in, and levelled up to my pre-drawn line and checked with a spirit level, and then I ran a ring of Permatex around the outside (This was freakin' hard by the way, this stuff is stiff and also in a metal tube, you need strong hands if you want to make it all the way round (I didn't)). I then used the edge of a display folder cover that I'd cut up to smooth it out (the folder had a nice curve on the edge) and I was done.


Tomorrow once all is set, I'll probably turn it over and add another ring of Permatex at the bottom to try and centre the drive shaft, as the hole is 5mm larger than the shaft is.

Thinking it through, if I had to do it again, I probably would put a ring of Permatex just below my drawn line before putting the insert back in, as that would mean it was supported from the underside, not just being upheld by the stuff I added from the top. However, I did have a small gap down between the wall where it may have seeped through - so here's hoping it holds ok.

Anyway - that's it for today!

Online, I purchased my chopping board to mount the motor on the underside, and for the pots to sit on. KK has warned against using this type as it's construction in blocks may mean it could be at risk of warping. Don't take this as my recommendation, but I'll take the risk I think, as it's already ordered. Instead of using aluminium to make up the 1mm distance (if even necessary) I think I'll use a thin amount of rubber, with the idea of isolating the motor to reduce vibration noise, but also protect it from any potential damage if the board does eventually warp out of shape.

[readeral]

I also placed a ring of permatex on the aluminium false floor just inside the drive shaft hole - but unfortunately it didn't take (I put in the shaft, and it gripped to the shaft and came away from the aluminium.)

That was a bummer - doesn't bode well for the rest of the permatex (without the support from underneath - see previous post) but maybe it will be ok. What I'll do is rough up the aluminium with some coarse sandpaper and put some more down.

[readeral]

Ok, time for an update - been two weeks and I've just managed to pull almost everything together.

Firstly - I didn't go ahead with the chopping board posted above. Two weeks after ordering it, I contacted the business I bought it from.. turned out it wasn't in stock. Not to worry, I went with another Wiltshire board, this time the 'Chop Chop' medium size, also 45mm in thickness. Ordered it from Harvey Norman online and arrived a few days ago.

I must say - drilling the holes was a gigantic pain in the ass. Again I had help from adifoto to drill these holes. The thicker the material, the greater the possibility of not drilling straight down. Unfortunately the press drill was not big enough to reach the centre of my chopping board, and so we needed to use a wireless drill. I recommend getting access to a press drill the right size if anyone is following this up.

The other recommendation I had from KK was instead of going with a 45mm thick board, to have a thinner platform and raise the pots up from the platform. This would have saved us the headache of less than straight holes - and I could have used some 20mm ply. Anyway - in my optimism for managing the thicker board, we went ahead. I just recommend considering this more carefully than me! Can be done, you just need some way of guiding your drill straight down.

I don't have any photos of the drilling, but we drilled the shaft hole first, and after doing that, lined up the motor and drew with a pacer, the positions for the screw holes. I tapped a screw into the wood for a drill guide to start each hole and we got to it. This was our second mistake..

What we should have done, was mark out and drill the first hole, screw down the motor with this one hole, ensure the shaft hole and the motor socket lined up perfectly, and then marked and tapped a drill guide for the second hole, repeating the process for each hole. Instead, we drilled 3 holes (having tapped a start for all 4) and realised the final one was going to be out of alignment. We needed to re-drill all our holes a little bigger to compensate.

This wasn't the end of the world, as with the addition of countersinking our holes and KKs supplied washers, we could screw it down tight enough to secure the motor in proper alignment with the shaft hole and not move. Well... might need re-tightening in the future cause it's not guaranteed not to slip.

KK did supply some bolts that were suitable for his manufactured base, but as I didn't have one of those, I went and bought some 50mm bolts with the correct thread.

Here's the end result (yes I chose to put 'chop chop' top side up, because the board has built in handles that don't function upside down):


So with all that securely in place, we then drilled some holes in a random bracket I had sitting around. Some sort of alloy, bent a bit under the pressure of the drill but didn't matter - we took to it with a hammer. Having drilled a hole, I then secured a 2.1mm DC socket to it, and we screwed it to the bottom of the board. I had grand plans for drilling holes through the board and securing the plate up the other way (as per an approach by KK on another forum) but by this point we'd been wielding the drill for 3 hours and couldn't be bothered anymore. Here's the result:


Finally, I spend $9 on some clearance (ugly) furniture legs from Bunnings, got some wood glue and glued them to the bottom of the chopping board, let it set under pressure for 12 hours, and the foundations were complete!


My wife soldered my motor to the socket (I'm _not_ an electronics guy) - we plugged in the 12v 2.5A power pack and gave it a go to test the alignment of the shaft hole. This youtube is the resulting effort.

This second one is shorter but easier to see what's going on.

I do have a bit more to go:
- I've clamped my cable to the board using those little cable clips you can get from bunnings - but I want to cover the motor and the socket wiring with some sort of plastic casing (probably from Jaycar) so they can't get knocked around.
- I've got a fire blanket I need to sew and cut holes in for the pot handles and use my cable ties to secure. Eventually I'd like to secure it with velcro (like a rectangle with velcro at each end, holding the fire blanket tautly to itself) but cable ties will do for now.
- I need to put auto-centring guide to ensure my pot set does not shift and put pressure on the motor. In this regard, having a 45mm board is helpful as the risk of lateral pressure on the motor is lower. I'm considering either nailing down some leftover silicone tube I have from the build, or using wooden blocks.