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Posted

That's tiny!

0.25 mm is the smallest I've used, and that's pretty tiny. 0.1 mm is incredible for a mechanical, fluted bit. For the imperial guys, that's just 0.004". 

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Posted

That certainly is tiny! You’re not likely to use that one by hand in a pin vise.😬 I managed to drill 0.4mm (0.0157”) holes in some aluminum hinges I made for a Toyota S-800. I mounted my rotary tool in a press stand to do it.

IMG_2363.jpeg

  • Like 4
Posted

I worked in the R & D shop where doing the impossible was the norm. The smallest hole i drilled there was .006" on a miniature manual Levin lathe.

The smallest drill I use for modeling is .013". I'm comfy with my #76 to #73 drills all day long.

The shop I mentioned did drilling in ceramic substrates that were about 2.5 mm thick. They were triangular and about 8 mm on a side.

The holes were as small as .003" and had to be on a tight location. Diamond drills, a mini drill press fitted with a microscope 🔬

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Posted
1 hour ago, bobss396 said:

I worked in the R & D shop where doing the impossible was the norm. The smallest hole i drilled there was .006" on a miniature manual Levin lathe.

The smallest drill I use for modeling is .013". I'm comfy with my #76 to #73 drills all day long.

The shop I mentioned did drilling in ceramic substrates that were about 2.5 mm thick. They were triangular and about 8 mm on a side.

The holes were as small as .003" and had to be on a tight location. Diamond drills, a mini drill press fitted with a microscope 🔬

Probably the only way to successfully drill with the 0.1 mm would be with a computer-controlled drill.

  • Like 1
Posted
1 minute ago, Big Messer said:

Very interesting!.

Tom lipton has a YouTube channel, the guy's a walking encyclopedia of knowledge on machining. He's got a couple videos working on small problems with superconductor magnets and did a collaboration with another channel giving a "tour" of Berkeley labs. He's a bit long winded, but a true craftsman and master of his trade.

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Posted

I was recently working on a project and wanted to drill some very small holes. A 0.15mm hole in a piece of 0.6mm hex shaped piece of plastic was the target. The 0.15mm hole was needed to feed a piece of 0.1mm brass wire through.

I sourced some of the common Chinese carbide PCB drill from amazon and gave it a try just to see if I could indeed manage the task.

After a bit of fussing and working my way down in size from 0.4mm, I did in fact manage to make my 0.15mm hole and just to prove to myself that it was no fluke I repeated the task several times.  Admittedly, I did break three 0.15mm bits, one in use and the other two from just being careless.

Best holder for these style of drill bits having a 1/8" shank is the holder of my Starrett 70A scriber. Used only the weight of holder and bit with the index finger of my left hand steadying it vertically and carefully turning with the fingers of my right hand. 

Holding the piece to be drilled is vitally important. You are doomed to failure if you try to hold it in your fingers or loose on the bench.

 

image.jpeg.763d00c2fb66c2f1869456f2733aa963.jpeg

Piece with hole and 0.1mm brass wire through that hole:

image.jpeg.058411bf93e4a642572e0163501cb163.jpeg

Tamiya markets some 0.2mm high speed steel (HSS) bits that work very well and are not as easily broken as these carbide bits. I never broken one but I have lost one by being careless when putting it down on the workbench where it simply vanished into the clutter never to be seen again.

cheers, Graham

 

 

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Posted
43 minutes ago, ColonelKrypton said:

Best holder for these style of drill bits having a 1/8" shank is the holder of my Starrett 70A scriber.

I have the same scribe,though yours is in much better condition. Mine was a 1.00 dollar swap meet find. Fits carbide drills perfectly. 

  • Like 1
Posted (edited)
2 hours ago, ColonelKrypton said:

Tamiya markets some 0.2mm high speed steel (HSS) bits that work very well and are not as easily broken as these carbide bits. I never broke one but I have lost one by being careless when putting it down on the workbench where it simply vanished into the clutter never to be seen again.

Murphy's Law states that:

1) items will be lost or misplaced until we buy a replacement

2) when trying to return the now duplicate item the receipt will be permanently lost 

3) we will never use the new duplicate item. It will be passed down to our inheritors that will wonder about our sanity when checking all the c r a p we leave behind.

Edited by Big Messer
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Posted
3 minutes ago, Big Messer said:

Murphy's Law states that:

 

number 1 is always true and happens all the time.

number 2, I don't usually return anything and (see number 3)

number 3,  better to have and not need than not have and need. Having something and duplicates of something I never thought I would use but once has gotten me out of a pickle more times than I can count on my fingers and toes.

 

cheers, Graham

  • Like 1
Posted
1 hour ago, johnyrotten said:

Mine was a 1.00 dollar swap meet find. Fits carbide drills perfectly. 

I wasn't so lucky but bought mine on Amazon on sale. Fits any cutting tool having a 1/8" shaft. I also use it to hand hold small burrs for delicate work.

cheers, Graham

  • Like 1
Posted
1 minute ago, ColonelKrypton said:

number 2, I don't usually return anything and (see number 3)

number 3,  better to have and not need than not have and need. Having something and duplicates of something I never thought I would use but once has gotten me out of a pickle more times than I can count on my fingers and toes.

 

cheers, Graham

2) this is how we end with a lot of stuff

  • Like 2
Posted

Here are my smallest PC board drill bits.  I have  no problem hand-drilling using #80 and #85 bits in plastic (I do occasionally break a bit), but I only used the #96 bit in my miniature drill press (and broke few even then).  When I use a drill press, I can drill #80 and #85 holes in metal.  The dimensions in my drill index are in inches.  The #96 bit is protected by plastic tube because it will break pretty much even if you gently brush against it.

TC_DrillIndex01.JPG

  • Like 2
Posted (edited)

0.5 mm dia is the smallest  drill bit I have ever needed to use for my models. I have difficulty imagining where one would use tiny drill bits with smaller diameters than 0.5mm on plastic or resin models.

   Generally I prefer to use normal HSS drill bits than those extremely brittle tungsten carbide PCB bits as the sideways shear  strength is better.

Edited by Bugatti Fan
  • Like 1
Posted
14 hours ago, peteski said:

The #96 bit is protected by plastic tube because it will break pretty much even if you gently brush against it.

Excellent idea. I am going to have to start doing the same.

14 hours ago, peteski said:

I have  no problem hand-drilling using #80 and #85 bits in plastic

Nor do I and even in brass and aluminum with the bit held in a quality pin vice and the work piece held steady and not in my BFF ( Big Fat Fingers ). Carbon steel or high speed steel ( HSS ) wire size number or metric drills are far less brittle than those carbide bits but I do break one from time to time.  #80 is approximately 3.5mm diameter and #85 about 0.3mm.

 

6 hours ago, Bugatti Fan said:

0.5 mm dia is the smallest  drill bit I have ever needed to use for my models.

That is typically true for me as well.  I have a pin vise with a 0.5mm ( i.e. #76 or 0.020") on my workbench and it gets used all the time for making holes for brass wire which I use to pin parts together.

 

6 hours ago, Bugatti Fan said:

I have difficulty imagining where one would use tiny drill bits with smaller diameters than 0.5mm on plastic or resin models.

For a recent project I took up the challenge of seeing if I could reproduce in miniature a small detail which I would normally have not bothered with. One of the issues with researching full size vehicles which you want to build a miniature of, is that the more you look, the more you see and once your see some interesting wee little detail you just have to try and replicate it in scale even if for nothing more than the challenge.

image.jpeg.8b44e76760dec33c9af3bbb4cbafb91c.jpeg

This is the muzzle brake for a QF six pounder gun on a 1/35 scale Churchill tank. The hole in the collar ( actually a counter weight ) is (I think) 0.5mm ( #76), The largish hex bolt head to the left is the bolt which retains the muzzle brake on the barrel after the brake has been screwed on, The retaining bolt's safety wire is that 0.1mm brass wire I described in a previous post.

In the end, not as a difficult a task as I first thought. Nothing ventured, nothing gained was never so true. 

cheers, Graham

 

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