How Micro Drill Bits Are Made [video] | Hacker News Reader

How Micro Drill Bits Are Made [video]

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If you're interested in feats of micro-drilling, I invite you to watch a Japanese game show where a machinist with a micro drill competes against one using an electrical discharge machine to drill lengthwise through a 0.5mm pencil lead: https://www.youtube.com/watch?v=gHR9YQl7ObU

Reminds me of the old joke: A German company manages to create a section of incredibly thin wire - so thin that they don't even have the tools to accurately measure it. So they carefully package it and ship it to a Japanese company, with a letter asking them to measure it.

Two weeks later, they get a package, eagerly open it, and find inside a letter in Japanese and their part. Not being able to see any numbers, they get someone to translate it. The letter reads: "We didn't quite understand what you wanted us to do, so we drilled a hole and cut a thread in it."

Oh! there's Swiss watchmaker joke about a US drill bit manufacturer that goes along those lines too!

Part two starts at 1:20 here:

https://rutube.ru/video/89a3426ca5b80b3363b17f30f976efdc/

I'm afraid the overly-dramatic english dub announcer was too much and I couldn't finish watching. TLDW?

Part 2 is missing anyway, there’s no resolution.

I've seen it before, the machinist defeats the EDM.

It was linked above your comment. Absolutely incredible that the machinist was able to drill the entire length of the pencil lead.

Thanks. It was linked two hours after I posted.

Just when you think there were shows that couldn't be more niche, Japan goes full-on otaku.

One thing that strikes me as odd is 2:48 it says the rollomatic produces 48 pieces per hour, and then at 3:24 a human dominated process for centering the work piece to have it's drill curve cut "take four to five hours".

They surely don't have 200 of these setting jigs. So, are there just lots of blanks made? do they damage that many of the work pieces in the process of setting one up? Are the surplus units used in some other process?

I'm curious because that seems like a complicated piece of machinery to only be operating at a few percent of up time.

They also said that the centerless grinding process is used to reduce the length of the blanks. I'm pretty confident they're doing it to get the finished diameter of the shank.

I find the How It's Made segments to be irritatingly shallow and sometimes grossly inaccurate. You could easily do a 22 minute segment on making these things if you went into more depth.

>I find the How It's Made segments to be irritatingly shallow and sometimes grossly inaccurate. You could easily do a 22 minute segment on making these things if you went into more depth.

It's all well and good until they touch on a process you're very familiar with then 'holy moly, is it always this bad?'

Still one of my favorite shows though...it's eye candy for machine dorks like myself.

absolutely finishing the diameter not the length, was jarring to hear that

That "four to five hours" didn't make any sense to me either. Perhaps they meant that doing this for a batch of bits takes that much time?

It also struck me as disappointing that the actual grinding of the flutes was not really shown. I'm sure it would be hard to photograph as it's likely completely bathed in cutting fluid, but perhaps they could have done a run without it just for the video?

The "four to five" hours they mention is probably the time required to setup the grinding center, maybe dress the wheels, do some fine adjustments on the grinding process. Once the machine is setup, grinding each drill is just a few minutes.

The grinding machines they are using seems to require quite a bit of manual handling, but cnc grinding center where everything is automated also exists.

Actually, the grinding of the flutes is shown very briefly around 3:35. Filming this operation on such a small scale is difficult because of the geometry of the system and the grinding process: the drill blank is supported from below to prevent the carbide from snapping under the load, and the wheel grinds from above. The grinding wheel is order of magnitudes larger in diameter than the diameter of the drill it is grinding. Also, everything is flooded with cutting fluid.

There are hundred of videos showing the process on youtube if you look for "cnc grinding drill".

It really depends on the workflow and scale of operation the cutting tool manufacturer. Some focus mostly on small batches of very specialized tools, and some focus on producing huge volumes of standardized cutting tools. And anything in between of course.

Whatever the grinding machine that is used, there is always a necessary setup step before the production run. The setup involves installing some equipment on the cnc machine, heating up to operation temperature, calibration, dry run to check for possible collisions and grinding a few pieces and check that they are within specs.

The name of the game is then, given typical customer order or target market, to find the right balance between the utilisation of the different machines, human intervention and automation while optimizing for cost and cutting tool quality.

In the video, it look like it is a pretty small manufacturer doing small specialized batches. In this case most of the time is spent doing machine setup and quality control, and the drill value doesn't justify the investment into a more complex or automated system.

I think the "four to five hours" is to set up the process; once set up, it can machine multiple bits.

The smaller the drill, or milling bit, the smaller the run-out tolerance. For these size bits, you're going to need to make very certain the run-out is on the order of a few microns.

This video seems to be unavailable in Canada, unfortunately.

Funny as How its Made is shot in Canada

https://en.wikipedia.org/wiki/How_It%27s_Made > Canadian documentary television series that premiered on January 6, 2001, on the Discovery Channel in Canada and the Science Channel in the United States. The program is produced in the Canadian province of Quebec by Productions MAJ, Inc. and Productions MAJ 2.

https://www.dailymotion.com/video/x7zlack

When you cut metal, either with a lathe, end mill, or drill bit, there's a recommended speed that the cutter's edge moves across the metal. When you're drilling something with a tiny drill bit, the RPM necessary to achieve that speed becomes incredibly fast.

Cutting tools are like F1 cars: they work best when you run them at the right speed, and that speed is a lot faster than you're going to be comfortable with!

“This video is not available in your country”

Anyone have an alternative link?

https://yewtu.be/watch?v=gHR9YQl7ObU ..?

That’s a different video, the one linked in the post is an episode of How It’s Made. Here’s another link to it: https://www.dailymotion.com/video/x7zlack

BTW: Making small spade bits is completely doable if you have a lathe, stone, and screwdriver sharpening jig.

I've done it myself down to 0.5mm but that smallest one was just an exercise...if I valued my time, it was a $100 bit of much lower quality than what's easiy bought for MUCH less.

Clickspring has an excellent video on simple shop-made drills:

https://www.youtube.com/watch?v=N1aj_3tlQhU

You don't need the lathe (though he uses one to rotate it for easy sanding, a drill chuck would work just as well), merely a stone, a torch, and some stock of appropriate diameter...you only need the lathe if you're starting with a shapeless chunk, and this isn't the stone age anymore!

https://www.mcmaster.com/metals/hardened-undersized-high-spe...

I will check it out; thanks. I've seen some of his videos and he does lovely work.

For anybody who wants to try this themselves, or wants to sharpen drill bits generally, getting the concentricity of the point and the shank accurate is absolutely key.

For normal-sized drills, at best you're going to drill an oversized (and likely tapered) hole. When you get into the smaller sizes, you're going to break bits left and right.

For normal-sized drills an everyday drill sharpening gauge should do the trick. That'll stop being useful long before you get down to 0.5mm.

If you're drilling wood or some other soft material, and you've got bar stock of the right diameter around that isn't hardened (i.e. a nail), you can sometimes get away with clipping the end of the nail off with a pair of diagonal cutters and peck drilling. You have to peck because the shank fills the hole so there's no way to clear the chips.

If the point angle looks symmetrical and the flute lengths look the same, then it's usually fine/close enough for most fab work.

I have been wondering about micro drilling in dental context. Is there any reason why root canals don't use microscopic drills instead of the current drills that make teeth weak, and need crowns for support?

> Is there any reason why root canals don't use microscopic drills instead of the current drills that make teeth weak, and need crowns for support?

...Because the very act of removing material leaves a void that makes the tooth weak? The method of making something hollow doesn't make it any less hollow.

-Emily

Fluting process should be done on CNC Rollomatic in "one install" (as drill bit already centered after grinding process).

What is the smallest drill bit one can buy?

PCB manufacturers specify their minimum via sizes. Probably that is the smallest usable drill bit size made in quantities. JLCPCB says minimum 0.2mm so there's what you got.

Keep in mind you will need a air bearing spindle that runs at high x10k RPMs to actually use them.

For smaller holes we zap them in the material with lasers.

They go even smaller than 0.1mm. McMaster-Carr sells a 0.051mm drill bit for $25: https://www.mcmaster.com/8904A11/

That's the absolutely small I could find, though I suspect specialty vendors have even smaller ones. You can find MMC's other micro drill bits here: https://www.mcmaster.com/micro-drill-bits/

My only experience with these was in school where we used 0.25mm micro end mills (like a drill bit that cut sideways) to cut our own PCBs. A small desktop micro CNC would just cut the traces out of a blank copper clad board. That's when I learned how easily these bits can break, so even though they're not that expensive you go through them very quickly.

>0.051mm

Holy shucks... How are they even manufactured? I imagine they have really precise grinding tools to make the flutes..

Sphinx uses laser ablation for their smallest drills (0.0030mm is their smallest catalog item, but they've made smaller as special order parts).

They can be pretty small. I purchased this set sometime back. It’s served me well. Gyros® HSS Wire Gauge Mini Twist Drill Bit Set |Includes 20 Micro High Speed Steel Bit Sizes #61 to #80 | with Convenient Clear Dome Storage Case (45-22010) https://www.amazon.com/gp/product/B000SKVF8I.

I frequently use a bigger size for fabricating reinforced epoxy with paper clips serving as rebar. Gyros Micro Drill Bit Set of 25#57 Drill Bits–Small Drill Bits for Jewelry, Plastic and Soft Metal–Mini Twist Drill Bit Set for Pin Vise Hand Drill, Rotary Tool - Carbon Steel Wire Gauge Drill Bits

A #80 tap drill is 3.4x bigger (.343mm) than the one they're showing in the video (.1mm). Which isn't to say they aren't impressive, but they're typically made of HSS, not solid carbide.

.1mm is about 4 thou (.004"), or the thickness of a piece of paper. I'm being a little loose with the numbers here, but they're in the ballpark.

Out of curiosity what do you use the paperclip reinforced epoxy for? Some sort of mold making?

usually it's for repairs of broken things, plastic tabs, random cast models, appliance parts, stuff like that. I'll drill a routing for the paperclip to thread through, then I bend and thread the paperclip through the tunnels, then I backfill the epoxy over the voids. They've usually been pretty tough durable repairs that hold up pretty well.

Sphinx Tools lists 0.03mm (30µm) drills in their standard catalog[1]. IIRC they made the 10µm drill Kern used to demo drilling holes in a hair to show off their pyramid nano CNC.

[1] https://sphinx-tools.ch/en/catalog-products-eshop/drilling-a...

A local hobby shop sold a kit with ten bits, 1.0mm down to 0.1mm, which I bought on a lark several years ago.

The middle sized bits are occasionally useful to (carefully!) finger-drill a tiny hole through a plastic part. They're rigid, very sharp, but pretty breakable if you're not careful.

The 0.1mm bit is so small that it's upsetting even to look at. I've never taken it out of the case.

0.1mm: https://www.aliexpress.us/item/3256801655537532.html

I would not expect you to be able to use bits this small without special machinery.

I've used similar 0.8mm drill bits by hand, and they were fragile enough.

Anyone know how much these cost to buy?

McMaster-Carr sells a 0.051mm drill bit (0.002 inch) for $25: https://www.mcmaster.com/8904A11/

Here's links to other other micro drill bits and micro end mills:

- https://www.mcmaster.com/micro%20drill%20bits/

- https://www.mcmaster.com/micro-end-mills/mill-diameter~0-002...

Nothing against McMaster-Carr, but what is shown in the video is not the same quality.

I used to work for a company that resold products from this company, they sold them for roughly $50 a bit. Pricing was highly dependent on shape, size, tolerance and order quantities.

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