# Drilling really tiny holes



## Kludge (Aug 17, 2008)

Somewhere there was a discussion about drilling small holes with carbide drills and the discovery that they break rather easily plus aren't really happy with some materials. Most of the comments offered suggested that carbide bits like to go real fast, which they do, but no alternatives to carbide.

First of, the tiny carbide drill bits are extremely brittle and will break if you look at them too hard. On the other hand, they can go through drill rod without a second thought. To do so requires equipment that has almost no runout - a watchmaker's drill press or lathe (both rated around .00005") or something along the lines of a Sherline (rated at something like .0005"), as examples - to minimize the flex and breakage. But not everyone has anything like that. In fact, from what I see here, the vast majority have "big boy toys" instead.

All is not lost. Waiting in the wings are two other flavors, HSS twist drills and spade drills. Neither one demands a lot of speed and both have enough flex that normal shop tools (lathes, mills, drill presses et al) can handle them. Chucks are available that go in a regular Jacobs or equivalent chuck that go down to 0" that can hold both types quite nicely. 

The twist drills are available through any number of places, Micro-Mark being a decent source. Spade drills are a bit more tricky. I've already mentioned Dashto as a supplier of watchmaker's tools. Tom - a really nice guy, by the way - has a variable inventory since it's mostly from estate or bought out watchmaker's shops and some items go a bit more quickly than others. Periodically he'll have drill bits, many of which are spade drills and some are in sets that start at .004" and go up in .002" increments. A #80 drill is .0135" which is close enough to .014 that the difference shouldn't matter. These sets are designed to drill watch jewels so should be adequate for most tasks we come across. 

I know I've seen number sized spade drill bits somewhere but I cannot remember where. If I can find them, I might swap out my HSS bits for them for normal use. They like to run slowly and don't load up with chips as badly as twist drills do.

One other type of drill bit sometimes used is a D-bit. These are used, among other places, for making bagpipes although they do have legitimate use as well. ;D An example can be found at http://www.bagpipeworld.co.uk/MakingBagpipes/Drill.htm which includes a reamer used for the same purpose. These are single flute drills and have been used in the past as gun drills and pretty much anywhere a deep straight hole is needed. The cool part is that it's not really necessary to need a deep straight hole to have need for one of these. They also like to run S-L-O-W and don't load up with chips quite as quickly as twist drills. The smallest I've seen on the open market is .05" or so but I wouldn't doubt that smaller ones are available. 

Side note: Just for grins 'n giggles once (and to prove a point), I drilled a piece of .5mm brass rod along with a piece I could have silver soldered to it far more easily using a .004" (.1mm for all intents and purposes) spade bit. Then I used .1mm diameter pins (originally used to hold wristwatch hairsprings in place) to hold them together. After that, I sent the whole thing to someone who doubted I could do it. I never heard from him again - or got my piece back, for that matter.

As a second side note, I wasn't all that sure I could either until it was finished. 

Best regards,

Kludge


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## Dhow Nunda wallah (Aug 18, 2008)

Hi Kludge
I'm a newb to this site myself, but have experience with small carbide drills, hope the following is helpful.

I've drilled holes in brass, aluminium and 316 SS, down to 0.010", in my 9 x 20 lathe, with carbides.
Just "touch" the part with some sharp tool in your tailstock (I use a carbide 60° V burr), to find centre then back off and stop there.

I have a pin-chuck with removable cap to store spare collets. Remove the cap, remove the collets.
find some piece of rod/bar that is a sliding fit in the back of the pin chuck then chuck that piece in your tailstock.
Select the appropriate (usually 1/8") collet for your pinchuck and secure the required size (carbide) drill.

Slide the hollow tail end of the pinchuck over the bar in your tailstock chuck, slide the tailstock up close to the job.
Crank up the headstock to highest speed and gently peck drill, backing off frequently.
Critical here "gently" and "frequently".

A little bit of slop in the centreing bar/pinchuck fit is all to the good, it allows some self-centreing of the drill.
And since you are hand holding the pinchuck, you will immediately feel any tendency to grab. Even in brass, which is a ***** for grabbing. If you feel any "grab" or roughness, you can back off the drill and/or allow the pinchuck to spin in you fingers.

Hope this makes some kind of sense.
Rgds, Lin


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## Kludge (Aug 18, 2008)

Dhow Nunda wallah  said:
			
		

> I'm a newb to this site myself,



Welcome aboard! Keep in mind that _everyone_ was a newbie here at some point or another, the folks who created the board being the most senior of them. I'm still a newbie (despite the "advanced" rating and the karma - neither of which I have yet puzzled out), both in time aboard and, in comparison to many here, in machine shop practices. 



> but have experience with small carbide drills, hope the following is helpful.



It's very helpful! Thank you, Lin. Pin chucks (or pin vises as they're sometimes known) are inexpensive and widely available so even making a custom tool using one isn't a major issue.

It also gave me an idea for a similar tool (which hasn't fully formed in my mind but will given sufficient Jamesons in my coffee) that can be headstock or chuck mounted in a mill or drill press for those pesky situations where drilling using the tailstock isn't practical. 



> I've drilled holes in brass, aluminium and 316 SS, down to 0.010", in my 9 x 20 lathe, with carbides.



Hmmm ... that's somewhere around #83 or 84, isn't it? I used to have a chart that went past #80 to somewhere beyond #90 but it seems to have gone adrift. I think it would be ubercool to have an even tinier set of number size drills than I already have someday. My watchmaker's spade drills go to .004" (effectively .1mm) and being able to get there by other means would fill in a few gaps no one but me would notice. 

I'm surprised no one from across the ponds jumped on the comment about the bagpipes. The Irish in me was dying to comment, the Scotsman was daring him to do so and the Welshman hadn't gotten the joke yet. The other nine (known) nationalities decided to sit this one out since they have enough problems between them as it is. ;D

BEst regards,

Kludge


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## Dhow Nunda wallah (Aug 19, 2008)

Hi again Kludge.
Noticed the bit about the pipes, being of Scots heritage myself 
Even played in a pipe band for a while (as a drummer!)

Hope I don't upset the applecart here if I mention a business name?
No connection, just a satisfied customer, etc.....
An outfit called drillbitcity, in the USA, supply micro-carbide resharps. Both drills and router bits down to about 0.006" as I recall. Sorry, I've never used number/letter system.

I can't find the bookmark but google will find em.
First class service and prices and the resharpened drills work just fine. I've used em on anything from PCBs to oil burner jets.

Have another Jameson's while I dig out the Laphroaig.

Slainte!
Lin


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## Kludge (Aug 19, 2008)

Dhow Nunda wallah  said:
			
		

> Noticed the bit about the pipes, being of Scots heritage myself



Irish, Scots and Welsh form 1/4 of my known bloodline. Another 1/4 is Scandanavian (Danish, Swedish and Norwegian), and the other half has Eastern Europe pretty well tied up. Between the lot, I've got a couple built-in skirmishes. border incidents and outright wars which gets to be interesting sometimes. 



> An outfit called drillbitcity, in the USA, supply micro-carbide resharps. Both drills and router bits down to about 0.006" as I recall.



From my bookmarks: http://drillbitcity.com/

And, yes, they are a pretty neat outfit. I've bought a few items from them and need to go back to fill in a few gaps here and there.



> Sorry, I've never used number/letter system.



I use number/letter. I use metric. I use fractional. I use decimal. Basically, I use what gets the job done. Sometimes taking time with a size comparison chart helps me decide which bit to use which means I have holes using several systems in the same project. This in turn makes trying to draw the projects so someone else can duplicate them somewhat confusing - especially when half the time I don't remember what I used. Of course, it might help if I sketched them out ahead of time somewhere other than between my ears ... ;D



> Have another Jameson's while I dig out the Laphroaig.



A fair to middlin' single malt - definitely too good to drown coffee with.  

One of the down sides to living outside the UK is we don't get the Good Stuff. Silly folks keep all that for themselves! And US law requires that Guinness not be much more than flavored water. I really do need to find somewhere to get more ... um, user friendly beverages.



> Slainte!



Slainte 

Kludge


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## mogogear (Aug 29, 2008)

Kludge  said:
			
		

> I
> One of the down sides to living outside the UK is we don't get the Good Stuff. Silly folks keep all that for themselves! And US law requires that Guinness not be much more than flavored water. I really do need to find somewhere to get more ... um, user friendly beverages.
> 
> Slainte
> ...



I solved my single malt desires ( and not able to move to Scotland) by using ebay for the purpose of buying a copper still from near the Appalachian Mountains. I found a great website called *www.homedistiller.org* and learned to distill my own!! Going for 6 years now and it is easier than making beer!! It is not as good as any generations old master distillers product-- but I have sure had fun making my 5 bottle batches... Like we all need another fun hobby!! ;D Luckily the wife likes single malt as much as I!! I have a Scottsman that lives next door- He is valuable as a sounding board- and he likes the pay!! :big: :big:-

Oh - well-- didn't mean to hijack your thread- sorry


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