Author Topic: Small diameter drill bits  (Read 631 times)

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mike_lawyer

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Small diameter drill bits
« on: March 14, 2019, 08:53:34 PM »
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I am looking to purchase some small diameter drill bits in sizes from 60-80.  I had a set I purchased from Micro-Mark years ago, but many have broken over time.  I was wondering if there is a particular set that anyone could recommend that would last a long time.  I don't mind paying a little extra for a better set.

Chris333

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Re: Small diameter drill bits
« Reply #1 on: March 14, 2019, 09:03:34 PM »
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I get the set with the little round base and clear cover. Go through about 1 set a year.

jnevis

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Re: Small diameter drill bits
« Reply #2 on: March 14, 2019, 09:10:27 PM »
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Drill Bit City  I get a set of their MRR bits and #75 bits every couple years.  https://drillcity.stores.yahoo.net/restool.html 
Can't model worth a darn, but can research like an SOB.

PiperguyUMD

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Re: Small diameter drill bits
« Reply #3 on: March 14, 2019, 10:18:15 PM »
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This is the place you want! They cater to machine shops, so their bits have a larger chuck that work great in pin vices. Plus, they’re cheap!

https://www.drillbitsunlimited.com/

peteski

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Re: Small diameter drill bits
« Reply #4 on: March 14, 2019, 10:44:29 PM »
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This is the place you want! They cater to machine shops, so their bits have a larger chuck that work great in pin vices. Plus, they’re cheap!

https://www.drillbitsunlimited.com/

Those are 1/8" shank Tungsten Carbide (TC) drills used for drilling PC boards.  They also have split-shank points, and will cut through most materials like through butter.  Extremely sharp, hard, and very fragile.  I use TC bits very often, but they break very easily when drilling by hand. I usually use them iin a drill press. For hand drilling (in pin vise) regular High Speed Steel drill bits are much more robust.
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ednadolski

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Re: Small diameter drill bits
« Reply #5 on: March 14, 2019, 11:25:17 PM »
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I am looking to purchase some small diameter drill bits in sizes from 60-80.  I had a set I purchased from Micro-Mark years ago, but many have broken over time.  I was wondering if there is a particular set that anyone could recommend that would last a long time.  I don't mind paying a little extra for a better set.

its more a matter of how you use them then the strength or quality of the bit.  it's important to keep your hans and the work as stable as possible.

fwiw you can order even the really small ones on amazon: https://www.amazon.com/HSS-Jobber-Length-Drills-0071/dp/B00I2CBP8E/ref=sr_1_fkmrnull_14?keywords=.0071+drill+bit&qid=1552619929&s=gateway&sr=8-14-fkmrnull

ed

mmagliaro

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Re: Small diameter drill bits
« Reply #6 on: March 14, 2019, 11:31:30 PM »
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Those bits from DrillBitCity and DrillBitsUnlimited are tungsten carbide, and while they are sharp and hard as the dickens, they are extremely brittle (as Peteski pointed out).  In sizes like #78 - #80, they are an exercise in futility trying to drill holes with a hand-held pin vise without breaking them off.

That set Chris333 alludes to, with the black plastic base and the clear domed top, is pretty good.  I've had a set of those in the past.

But for my money, the only drill bits I will buy now are individual sizes (not a "60-80" set), as new old stock (NOS) from old-school American drill bit manufacturers.  My favorites are Precision Twist Drill, Cleveland and Union,  but there are others.  Many of these went out of business or were gobbled up by companies in China and the quality isn't what it once was.  Others, like Precision, got gobbled up (I think Dormer owns them now), and they still make good bits, but the prices are horrid ($5 - $10 per bit).

So I troll eBay looking for old stashes of these bits, and I hoard them.

And now that I've told you this, I will have more competition.   ;)

Seriously, an old pack of Precision Twist Drill #80 bits will drill clean holes through steel or brass so much easier than any hobby bit.  They can be had for about $1 per bit on eBay.  I buy lots of the smaller sizes that are more prone to breakage.

That's what I'd do.  Forget trying to own a complete set.  Buy multiples of the sizes you use a lot.
And avoid tungsten carbide bits except for sizes around #70 or bigger.  For hobby use, the smaller sizes break too easily.  Stick with high speed steel (HSS).
« Last Edit: March 14, 2019, 11:33:29 PM by mmagliaro »

narrowminded

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Re: Small diameter drill bits
« Reply #7 on: March 15, 2019, 05:36:49 AM »
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Those are 1/8" shank Tungsten Carbide (TC) drills used for drilling PC boards.  They also have split-shank points, and will cut through most materials like through butter.  Extremely sharp, hard, and very fragile.  I use TC bits very often, but they break very easily when drilling by hand. I usually use them iin a drill press. For hand drilling (in pin vise) regular High Speed Steel drill bits are much more robust.

"Ditto"  Really! 8)  And I too have satisfactorily used https://www.drillbitsunlimited.com/.  He's located near me.
« Last Edit: March 15, 2019, 05:47:07 AM by narrowminded »
Mark G.

Chris333

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Re: Small diameter drill bits
« Reply #8 on: March 15, 2019, 05:46:30 AM »
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I'd break those tungsten drill bits in water.

Lemosteam

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Re: Small diameter drill bits
« Reply #9 on: March 15, 2019, 06:35:32 AM »
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If you decide to go carbide, these prices cannot be beaten for a pack of ten in a protective case:

https://www.ebay.com/itm/10Pcs-1-8-Shank-Spiral-Flute-Tungsten-Carbide-Micro-PCB-Drill-Bit-0-2-0-9mm-Tip-/262902302178?var=&hash=item3d3632c5e2

Sometimes, on the smaller diameter bits I break the bit off leaving about 1/8' and "resharpen" it using my cutoff disc, holding the bit at ~60 degress to the disc while rotating.  This makes the bit less prone to breakage (less deflection) during hand drilling.

It really does not matter if the sharpening is perfect, but try to get the resultant point in the center of the bit.



mike_lawyer

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Re: Small diameter drill bits
« Reply #10 on: March 15, 2019, 09:34:27 AM »
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Thanks guys for all the recommendations.  Sounds like high speed steel (HSS) would be best for my uses, which is using the bit with a pin vise to make precise holes when scratchbuilding.  What I might do is pick up one of those sets with the plastic cap on it to get me started, then buy individual HSS bits as I find them.  That looks like my best bet to at least get started with an assortment of bit sizes.

peteski

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Re: Small diameter drill bits
« Reply #11 on: March 15, 2019, 09:34:53 AM »
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If you decide to go carbide, these prices cannot be beaten for a pack of ten in a protective case:

https://www.ebay.com/itm/10Pcs-1-8-Shank-Spiral-Flute-Tungsten-Carbide-Micro-PCB-Drill-Bit-0-2-0-9mm-Tip-/262902302178?var=&hash=item3d3632c5e2

Sometimes, on the smaller diameter bits I break the bit off leaving about 1/8' and "resharpen" it using my cutoff disc, holding the bit at ~60 degress to the disc while rotating.  This makes the bit less prone to breakage (less deflection) during hand drilling.

It really does not matter if the sharpening is perfect, but try to get the resultant point in the center of the bit.

Wow John!  If you can resharpen small TC bits (#70-80) without some serious magnifications then you are pretty darn good!  I also didn't know that you can grind Tungsten Carbide using standard abrasive cutoff wheel.  I thought that the green Silicon Carbide grinding stones were needed for this task.

Also, those bits have split point geometry, which is a big reason why they drill so well.
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Lemosteam

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Re: Small diameter drill bits
« Reply #12 on: March 15, 2019, 09:47:23 AM »
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As I said it's never perfect, but it will work.  there is not "back taper to the cutting edge, but it really does not matter all that much in plastic and soft metals.

If I see sparks, its cutting.

garethashenden

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Re: Small diameter drill bits
« Reply #13 on: March 15, 2019, 09:54:04 AM »
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I find McMaster Carr a great source for this sort of thing. They’re an industrial supplier so things tend to be good quality. There have a very extensive catalog which is quite easy to use. Just be aware that th only shipping option is overnight Fedex, so don’t order just one drill bit...

mmagliaro

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Re: Small diameter drill bits
« Reply #14 on: March 15, 2019, 04:13:58 PM »
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https://www.kaufmanco.com/itemdetail/PTD%20090161

This is a #60 - #80 set made by Precision Twist Drill for $29.95.
That isn't cheap, but it's a great price for PTD bits.  And these are seriously good HSS bits.

It says "ships from factory", which means they are out of stock and they have to get them from PTD to fill your order.    I have ordered from Kaufman with a case like this before.  It's best to call them and order on the phone, because they can tell you how long it is really going to be before you get your order.  It kind of depends on when their next shipment from PTD is coming in, if PTD has a back-order on it, etc.  Call first.

But they have the best prices for new PTD bits I have found (aside from finding NOS on eBay)

Here are separate #80's  for about $1.60 each
https://www.kaufmanco.com/itemdetail/PTD%20018680