Thread: ON line product FAIL

I'm 3D printing some pieces that require the clearing of multiple ~30mm long, 0.4mm diameter 3D printed holes.
About have the hole print fine - I am amaze it can even do this but some of the holes have a blockage.

I've tried clearing the printed holes with a 0.4 mm bit but most times the bit seems to catch somewhere and wander off of its own accord.
Printing the pieces solid and then drilling out the holes even worse, ie bit breaks

My next tack was to go back to clear the holes using the 0.4mm SS acupuncture needle supplied with the 3D printer for clearing the printer nozzle.
This works up to about the last mm of teh 30 mm long hole where the hole exits the work piece, where it's usually blocked enough to need drilling.
There is usually a visible blocked dimple on the exterior surface so you roughly know where to drill.
It's not critical to use a 0.4mm bit just to unblock this hole so I've been using a 1mm bit
The 1mm bit sometime still blocks the hole but pushing the acupuncture needle in the other way unblocks it.
Most of teh time I can o thins without drawing blood by the needle.
Clear as mud?

Handling the small bits in a small (10.5V) Bosch cordless is rather tricky and even the Dremel seems klutzy so I decided to invest in a small hand held drill.
Basically its a teeny chuck on a stick here it is.
Drill.jpg
All for the princely price of $6.88 delivered.
All Black Anodised Al, and steel jawed chuck can even easily hold a 0.2mm diameter SS acupuncture needle nice and firmly.
Absolutely no complaints - it does the job very well.

Now the drill comes with a set of 20 different size HSS bits ranging from 0.3 to 1.6mm in diameter (in 0.05mm steps up to 1mm an 0.1mm thereafter)
BitSize2.jpg

I had no need for these bits because I have a nice set of 0.4 -3.2mm bits that really work well.

Just for fun I decided to measure the bit diameters and this is what I found.
There's 6 of 0.64 mm, 6 of 0.75mm 5 of 0.98mm an 3 of 1.46mm
BitSize.jpg

To ad a bit more insult m have a look at how the tips are ground.
Drillbit.JPG

Basically they are rubbish but I wasn't expecting much given the price.
Now I'm not worried because the drill itself is OK and as I said I have other bits.
But I have let the seller know that they are not supplying what they are advertising.

Hi Bob, Guys,

I'm not at all surprised at your findings ! I see a lot of these "Micro Drills" in hardware stores for ridiculous prices.

I acquired mine in the same way you did, the hand drill is fine though. Mine is made from brass and not plated, its has three steel jaws and will grip a 2.5 mm drill, which for me is a downside because most all my very small drills, the carbide ones are 4 thou and up to 250 thou (1/4" inch) are on 1/8"th inch shafts.

Originally Posted by BobL

I decided to invest in a small hand held drill.
Basically its a teeny chuck on a stick here it is.

Technically a pin vice. Very handy for all sorts of jobs. I use mine for enlarging the holes in PCBs to accept solder pins.
I have a set of those drill bits. I must go and check them.

Originally Posted by jack620

Technically a pin vice. Very handy for all sorts of jobs. I use mine for enlarging the holes in PCBs to accept solder pins.
I have a set of those drill bits. I must go and check them.

Thanks for reminding me about the name and the tip to use them in electronics.
The ebay ad called it a " Pin ausell"?

I have a pin vice that uses collets but it only has a few sizes an only goes down to about 1.2mm.
SWMBO has a carbide set like BaronJs for her jewellery stuff but they are very fragile and don't like using them.

BTW I got a quick reply from the vendor and they are refunding me 50% of cost ($3) so that is something

Hi Bob, Guys,

Carbide PCB drills are really delicate and not very suitable for hand drilling, even a Dremal on a stand can have enough vibration to break a fine carbide drill, HSS is far more robust for hand drilling. They are very good in a sensitive drill holder mounted in the lathe tailstock.

An ER11 collet chuck used as a spindle is very good for holding fine drills with 1/8" or 3 mm shanks. They do go down to 1 mm collets.

Reading this I am reminded of wanting to clean out 0.35 mm dia holes in thin stainless, which a magnifier showed had ragged edges.
Challenge: hole count between 200 and 300. The part is an espresso machine coffee filter and I wanted a more consistent filtering action, not helped by inconsistent filter hole sizes due to factors such as ragged edges on some holes.

Tried doing it with an Eclipse pin vice, hand held. This was OK for a few holes despite it being dodgy due to no feed regulation.
Being very low rpm the drill bit would catch on a minute sprag and it wasn't clear if the bit would cut or break. Break it did after a few more holes. I tried the pin vice in the drilll press but with such a tiny bit there was no feel when feeding the drill bit.

Then I remembered having a tiny little drill chuck with a manual feed adapter. To see how it works see the Ausee website:
Micro Drill Adaptor JT0 - 1/2" Shank
No, I don't know the owners and they don't reward me for mentioning their wares.

small drill chuck 1a.JPG
Photo above shows an espresso filter, and my 0.3 - 4mm capacity drill chuck on its manual feed adapter, which allows direct feed by your fingers pushing down on that knurled ring (which is mounted on a ball bearing). With my bench drill running at a few hundred rpm I was easily able to sense the feed pressure and the drill advancement when drilling. The adapter is spring loaded to retract when you release the knurled ring. Result: no more drill bit breakage, and a noticeable (though not dramatic) improvement in the consistency of my espresso.

Bill

Interesting what you say about the basket holes,.
I've tried a suppose pro level PF basket (holes good to 0.02mm) but could not tell the difference taste wise but I should note my taste buds are not very sensitive. Nothing's quite smelled or tasted the same since I totally lost my sense of smell for ~6 weeks in 2002 from working with MDF. My sense of smell came back different and it also affected my sense of of taste.

The holes I was drilling were for a similar coffee geeky path, Weiss Distribution Technique (WDT) tools shown in the photo below.
I've printed over a dozen of WDT handles and stands for friends etc.
The long thin wires are acupuncture needles.
#3 was made by a mate of mine using 8, 50mm long x 0.35mm needles
The purple and black ones (1 & 2) are from a Thingiverse plan by the Espresso Aficianados Discord each use 9, 75mm long 0.4mm needles
The white one (#4) uses 5 needles same as #3
4WDT.jpg

These are printed with the needle exit holes face down on the bed of the printer and about 1/2 of the holes end up blocked.
Holes.jpg
To see what they're for, interested persons can search for WDT espresso tools, they've been around for over 15 years.
FWIW I cant really tell the taste difference with these either - but the so called "pour" looks more even.

BTW your little pin vice looks like a beauty.

Originally Posted by BobL

... I've tried a suppose pro level PF basket (holes good to 0.02mm) but could not tell the difference taste wise.
.. The holes I was drilling were for s similarly coffee geeky path, Weiss Distribution Technique (WDT) tools shown in the photo below

Thanks for that Bob,

There being so many ways to make a bad espresso, I found it hard to know which aspect to work on, but my results have slowly improved over time. I found learning to load the filter basket for a consistent and effective outcome was a long slow path, and admit that I have not really looked into the Weiss technique, but things that have helped me so far are:
a) an even, controllable grind: needs a good grinder with accurate repeatable grind setting, which is lots cheaper if your arm is the motor,
b) a good filter basket: a 'competition' filter basket did make a difference compared with my redrilled one,
c) a distribution tool (it's not a precision instrument so for me cheap is good) which distributes and settles the coffee in the filter, and it works better if adjusted for compaction depth,
d) scales for weighing the coffee dose to be ground - should read to 0.1g, and
e) good care in the process of distributing and compacting of coffee after loading into the filter (see below).

Expanding on e) above
If I follow all the steps below the results really are better. And occasionally I score a really nice cuppa!
After weighing the dose, grinding it and loading the filter basket, the pile of coffee in the basket is gently smoothed level (finger works fine), then further settled by tapping the portafilter ("filter carrier") on the bench. The distribution tool is then slowly lowered (while rotating it) into the basket until it reaches the depth I have set on the tool, leaving only a mm or so for final compacting with the tamper. My shed made tamping tool, diameter about 0.05mm less than the filter ID, is applied and I push down quite hard (probably at least 15kg). I learned this after seeing a comment somewhere that above a certain packing pressure the flow resistance of the coffee pack becomes quite insensitive to extra packing pressure, and it seems to be the case. I find that using the higher packing force gives much more consistent results than a slightly finer grind and a moderate packing force(say 5-10 Kg).

Forgot to mention that I use a bottomless portafilter (base of the filter basket is not covered) which actually lets you see how evenly the coffee is packed by the way it comes through the filter. If not evenly packed it's obvious, and in an extreme case you will see weak coffee squirting from one small area while the rest releases only a few drips.

Cheers,
Bill

Originally Posted by WCD

Thanks for that Bob,

There being so many ways to make a bad espresso, I found it hard to know which aspect to work on, but my results have slowly improved over time. I found learning to load the filter basket for a consistent and effective outcome was a long slow path, and admit that I have not really looked into the Weiss technique, but things that have helped me so far are:
a) an even, controllable grind: needs a good grinder with accurate repeatable grind setting, which is lots cheaper if your arm is the motor,
b) a good filter basket: a 'competition' filter basket did make a difference compared with my redrilled one,
c) a distribution tool (it's not a precision instrument so for me cheap is good) which distributes and settles the coffee in the filter, and it works better if adjusted for compaction depth,
d) scales for weighing the coffee dose to be ground - should read to 0.1g, and
e) good care in the process of distributing and compacting of coffee after loading into the filter (see below).

Except for c) which I am still not convinced by, I agree with the rest.

Being of Italian extraction I started drinking stove stop espresso as kid in the 1960's but didn't get my first espresso machine (a second hand Cimbali Domus) until the mid 1990's and that was also when I started really getting into coffee. Although I already knew most of it, in the mid 2000's I did a barista course, followed by a barista competition judges course and also judged a couple of comps. I could do the technical judging OK but didn't think my sensory perception was good enough for judging so I stopped doing that. Also you had to judge twice year or you lost your judges registration and ha to go back and reaccredit and I really wasn't that interested.

Despite this, my coffee shrine has continue to evolve over the years to this.
The machine is a La Cimbali Junior purchase 2004 which I plumbed in for water entry and waste.
It came with a vibe pump but this was replaced in 2018 with an under bench Swiss SS pump (same as what is use on multi group head machines) with small 3P motor and VFD controlled from the Arduino box hanging off the side of the machine. The Arduino monitors temp/press.
The Mazzer Mini also bought 2004 and recently change the burrs holds the real caf.
Grinder on the left is an Iberital for SWMBO's decaf beans, she also drinks tea, hence all the tea paraphernalia.
You can probably see the 3D printer has made a few other bibs and bobs for this obsession.
Shrine2022.jpg

Because Perth water straight out of the taps is so bad I put a lot of effort into water filtration.
CMwater.jpg

Over the years the numbers an $$$ sure adds up but the cost of the hardware is relatively insignificant .
If I'm home I drink at least 4 double espresso shots day and SWMBO usually has 2 so I guess even at $4ea (coffee is expensive in Perth) that's >$150k worth of coffees from this machine alone!

We usually buy our coffee from FiveSenses coffee with beans delivered to us within 48 hours of roasting - preCovid we also used to make lots of coffees for visitors and neighbours.
We've been buying from FiveSenses since the late 1990's and am one of their oldest individual clients. When I first started our monthly coffee bean buy was about $50 and now its about $120 (and that's with a 20% VIP discount!) Averaged over ~25 years that's about $25k worth of coffee

I now justify this because I rarely drink alcohol - If I do its a shot of grappa in the espresso! A bottle of grappa lasts me a year - or more.
That's enough.

Wow! That's a seriously comprehensive setup Bob, and thanks for your detailed presentation.
With only 1/6 of your production rate my setup is minimalist, and it slips away into the cupboard when the lady of the house needs the bench space. The main items are:
coffee stuff.JPG

- a German made Kinu hand grinder with grind settings marked in 0.02mm increments
- a Lelit espresso machine - prodotto d'Italia
- weighing scale
- distribution tool
- tamper

I can understand your reservation about distribution tools. Mine was chosen not only for low cost, but because the three ramps have unusually narrow flats between them.

distributing tool.JPG


Most of these tools, regardless of price, have wide flats which leaves a large central flat (in some cases nearly half the basket diameter) which, even if the tool is rotated, just compresses coffee in the middle of the basket without any redistribution.

I note that Pullman in Adelaide make a "chisel" style distribution tool with only 2 ramps and a very narrow flat at the deepest part - a better design altogther in my view.

Cheers, Bill

Originally Posted by WCD

Wow! That's a seriously comprehensive setup Bob, and thanks for your detailed presentation.
With only 1/6 of your production rate my setup is minimalist, and it slips away into the cupboard when the lady of the house needs the bench space. The main items are:
- a German made Kinu hand grinder with grind settings marked in 0.02mm increments
- a Lelit espresso machine - prodotto d'Italia
- weighing scale
- distribution tool
- tamper

Being able to put the whole shebang away has significant benefits whereas ours takes up about 1/4 of all the kitchen bench space.
It also (usually accidentally) gets left on for hours during the day.
It's about 2kW full power but it has ~8:1 duty cycle so it's more like 250W continuous (solar covers most of it except for the early mornings in winter)

A hand grinder only would probably help slow down my coffee consumption.

We make a lot of coffee to go, ie make two coffees and go down to the Swan river foreshore and chuck the ball for the dogs was our stock covid morning exercise.
OR go and take the horse to the vet. In summer I put two double shots in a thermos full of ice and top up with cold milk every time I go to the tree loppers yard to mill timber.
Same when we go on picnics etc.

I have a similar distribution gizmo like yours except mine looks like it has shallower ramps and slightly wider flats. I don't use it that much.