PeetsFan wrote:How do you build and sell. one for only $100? Sure, if I were building 250,000 or even 50,000, I might be able to do that. But 100 or 200? No way. Each component will cost top dollar. And if I want a temperature display instead of just a temp output for a Fluke meter, then I'd program an FPGA and it would output to a little numeric LED/LCD display. It's inexpensive, but at quantity 100 or 200, DigiKey will charge you $10 here and $15 there and soon your part cost is already $100, plus labor, and shipping, development time, and then returns because somebody says your pinhole is too big, or too small, or the temperature is 1/100000th of a degree wrong, or it's the wrong color... You'd lose money.

I wouldn't try to bundle a meter. One can get a cheap multi-meter with ability to read thermocouple for $20 from Amazon.
I doubt the following items cost more than $10 combined:
- cheap basket
- thermocouple (doesn't need wide range, just some linearity near 80-100C)
- small amount of JB Weld or something similar
- something to slow down the flow
- clear instruction on how to calibrate, what to expect, etc.

Calibrating an inexpensive orifice to flow consistently across 100 pieces is not a trivial problem. More commonly done with something like a very fine needle and then trimming the length to calibrate the flow. I believe the Scace uses a piece of porous ceramic to mimic the heat capacity of a coffee puck and then has some sort of calibrated orifice below to set the flow. He charges enough he could use a ruby or some other hard material with a custom drilled hole. I've never cared about having a Scace to try to make one, but f I was to try today I think I'd start with a fine syringe needle and if I could get one to work perfect by trimming, I'd take the next bigger one and devise a way to very very gently squish it to reduce the flow.

Ira

From my memory of using one.. I think the nut on the bottom is adjustable for flow.. there is not a precision single hole as you might want to calibrate for different types of extractions.

Peppersass wrote:I believe a #80 bit is the correct size to mimic the "standard" espresso flow rate of ~70ml in 30 seconds at 9 BAR, but it's somewhere between difficult and impossible to drill a clean and precise hole by hand with a bit that thin. It probably can be done with a very carefully aligned drill press, though I don't think a typical drill press chuck can securely hold a #80 bit. So it might require securing the bit in something else, like a hand drill designed for use with tiny bits, then securing that in the drill press chuck.

I just built CM's design portafilter thermometer. I used a Foredom handpiece in their P-DP30 drill press which holds those Amazon cobalt mini-drills very solidly. It drilled through the brass cap easily. Smallest drill I had on hand was 0.43mm,which is a tad bigger than a #80. 100ml through the filter in 30 sec at 8-9bar, so I will order some smaller ones. 0.35mm should be close to #80, but I'll do some tests with the 0.43mm hole for now. It should be extremely consistent. Cost of fitting < $15. I had an old single basket and the necessary tools in my basement shop) and about 20 minutes of work time. I'm using an $18.50 digital thermometerI got from Sweet Marias.

Actually I'm thinking of making a few extra caps with different hole sizes, e.g. 0.25, 0.35, and 0.45 (0.43 is close enough) to mimic different extraction flow speeds. I'm still thinking of finding a medium, probably fine glass beads, to fill the cylinder but I'm really not sure that's needed for assuring temperature stability. Great idea, CM! IMHO it's a Scace Slayer!

Thanks for the update on the drill bit sizes. My order from Amazon is scheduled to arrive tomorrow. I'll see how it goes.

I ordered some micro drills from Amazon yesterday and they should arrive tommorow. the smallest available was 0.1mm and they go up from there in 0.1mm steps. I'll drill a few caps with 0.1, 0.2, 0.3, and 0.4 holes. My first attempt with a 0.43mm drill (it was marked 0.45, but it measured 0.43 on my Mitutoyo) discharged 100gm of H20 in 30 seconds. One of the caps should give me 30gm to 35gm in 30 seconds, which would match common espresso extraction flows. I'm still looking for some media to mimic slowed flow through a puck. I understand the Scace device uses a porous ceramic disk in place of a puck, but given the rate of flow through a small orifice under pressure I doubt temperature measurement will suffer from lack of a puck-replacement medium.. I don't see any problems with this setup being able to mimic Scace repeatability, but I'll get back and let folks know what I find out.

As I mentioned in my previous post, using a Foredom type rotary handpiece (look them up on the Internet) with Foredom's simple but very solid drill press works extremely well for drilling these very small holes in brass.

Pressino wrote:Foredom

Oh no!!!! The flashback of my dentist visits!!!

I learned 2 things this evening.

1. My micro drill bit set arrived and upon closer look, the smallest one 0.3mm seems too thick. I went ahead and did the hammer trick on the drilled brass surface, meaning that I smacked it a few times to close the hole little bit. Well, now it got too small so I had to use a needle to enlarge the hole little bit. It works but the water flow rate is about 60 ml for 25 seconds. I may have to try a different hole boring method next week.

2. This whole assembly has some metal mass and holds the heat. I'm not sure if it's a good thing for this purpose because out of 7 measurements I just did, the first 4 was showing a few degrees lower temp than the last 3 as if the water in contact with the metal part is affecting the measurement. Inside the basket of the real Sace has a non-metal filler. I'm wondering if I need to do something like that for this cheapskate "Scace".

Capuchin Monk wrote:
2. This whole assembly has some metal mass and holds the heat. I'm not sure if it's a good thing for this purpose because out of 7 measurements I just did, the first 4 was showing a few degrees lower temp than the last 3 as if the water in contact with the metal part is affecting the measurement. Inside the basket of the real Sace has a non-metal filler. I'm wondering if I need to do something like that for this cheapskate "Scace".

Are you fully preheating the pf/device before attempting measurements? With the Scace Greg recommends leaving it locked in for an hour on a machine that is fully up to temp (on for 2 hours?).

Thanks for the info. I'll try again with longer warm up time.