Metric drills

[cheechi]

Apologies if there is a thread I have somehow missed. I did try searching but with two really common words the SNR was pretty low.

What constitutes a 'complete' drill index for metric drills?

Some I have seen are 1-6 or 1-4mm in 0.1 increments

Some I have seen are 1-12mm in 0.25 or 0.5 increments

I'm not looking to have a '100% of everything' type index just more wondering how is the right way to look at it. With most standard sets come up to 1/2 in 1/16 steps, some do 1/32, some have only 'common' 32 steps but mostly 1/16 steps. And I have a chart that I could tap common metric threads with existing drills.

Do most machinists no matter where they are have a 'full' metric index in addition to inch, wire, letter, etc? Or is it not common in the US to have more than a few, if any?

At the end of the day it's not something I need but one that I have wanted for a while. I do measure more and more in mm since I got a new tape measure, but I'm not going totally crazy.

 

[T45]

the 1/16 to 1/2 by 1/64ths type set in sae is 29 pcs
in metric, its 1.0 to 13mm in 0.5mm =25pcs

To FIRST APPROXIMATION, the other sets are basically letter (6-10mm by 0.1mm) and wire (1-6mm by 0.1) equivalents

 

[bcradio]

I never knew they had metric drills. I usually just put my bits in whatever drill i have handy.

 

[Bangkokian]

Are you going to be tapping? The increments are important then.

Sent from my SM-T805 using Tapatalk

 

[bcradio]

The technical name for a "drill bit" is actually just "drill"

I prefer to use the same approach as Wikipedia and just call it a bit for clarity

 

[T45]

I prefer to use the same approach as Wikipedia and just call it a bit for clarity

You're being both wrong and pedantic at the same time

viz...drills, countersinks, counterbores, reamers etc

 

[John in OH]

Our craft millwrights usually seemed to use the terms "drill bit" and "drill motor". When the two are assembled you have a "drill". May just have been a local thing.

 

[John in OH]

Apologies if there is a thread I have somehow missed. I did try searching but with two really common words the SNR was pretty low. ........

Yeah, the search function here on GJ *****. I've found the best way to search GJ is actually via Google. On the Google search line, type in:

site:garagejournal.com - subject of interest

For example, site:garagejournal.com - metric drills

 

[vavet]

For perspective, 1/32" is 0.8mm. If you feel like 1/32 is sufficient resolution, a drill index with 0.5mm increments would be even finer.
I can see if you were doing really small work (like watches) you might want even smaller increments, like 0.1mm.

 

[Dave455]

The standard sets in metric are 1 - 10mm in .5mm increments, 1 - 13mm in .5mm increments, 1 - 6mm in .1mm increments and 6 - 10mm in .1mm increments.

The first two are fine for general purpose workshop or woodworking use, though I tend to think in inches, especially when woodworking, so prefer a fractional set.

The second two ranges are geared towards engineering use where you need tapping drills. Personally, despite thinking in inches mostly, I find that it's much easier to use metric drills rather than number and letter drills, and my sets of the latter have either been retired or kept for special jobs! Obviously, you use the metric drills as tapping drills for metric and imperial threads!

I do have a 'full' set of metric drills, in that I own both sets of .1mm increment drills, but the set of larger drills was costly, and gets used rarely. Most times you can get away with 1 - 13 mm in .5mm increments and 1 - 6mm in 0.1 increments. Maybe add a couple of tapping drills in the larger sizes!

 

[pi_guy]

I have a few sets of fractional & number and letter drill bits, I buy the metric ones as needed.
Just have not seen a reasonable costing complete metric set.
What I am wondering about is metric gauge pins, use often for measuring clearance would be of use. Verses finding the decimal equivalent pin and using that.

 

[nbpt100]

It all depends on how you are using them.

Are you a machinist who needs precision or a mechanic that may need to re-tap something metric on occasion?

If you are doing tape measure work, as you said, then the precision does not warrant a metric set. You can usually find something close enough with a letter, number or fractional drill size.

I would look at the common metric threads that you encounter and make sure you have at a minimum those tap drills covered. If that is what your applications are?

If you share a little more about how you need/wish to use them then I think you will get some better answers.

As a side note: what's been frustrating me lately is that you typically only encounter fractional drill bits or sets at hardware stores. I have been looking for some number and letter drills to have on hand for tap drills and they are not as easy to find in a hardware store as you would think. My local True Value, Lowes and HD only have fractional drills and some random metric sizes. Everyone must be buying these on line now and they refuse to carry them in the store.

 

[bcradio]

You're being both wrong and pedantic at the same time

viz...drills, countersinks, counterbores, reamers etc

I guess Wikipedia is wrong also and you all are right.

 

[vavet]

It all depends on how you are using them.

Are you a machinist who needs precision or a mechanic that may need to re-tap something metric on occasion?

If you are doing tape measure work, as you said, then the precision does not warrant a metric set. You can usually find something close enough with a letter, number or fractional drill size.

I would look at the common metric threads that you encounter and make sure you have at a minimum those tap drills covered. If that is what your applications are?

If you share a little more about how you need/wish to use them then I think you will get some better answers.

As a side note: what's been frustrating me lately is that you typically only encounter fractional drill bits or sets at hardware stores. I have been looking for some number and letter drills to have on hand for tap drills and they are not as easy to find in a hardware store as you would think. My local True Value, Lowes and HD only have fractional drills and some random metric sizes. Everyone must be buying these on line now and they refuse to carry them in the store.

Harbor freight carries a few sets with the fractional, letter, and number sizes.
I can't speak to the quality.

 

[Dimitri]

Honestly I buy drills based on need other then the basic set that goes by 0.5mm.

For common metric taps.

• M3x0.5 - 2.5
• M4x0.7 - 3.3
• M5x0.5 - 4.5
• M5x0.8 - 4.2
• M6x1.0 - 5.0
• M7x1.0 - 6.0
• M8x1.0 - 7.0
• M8x1.25 - 6.8
• M9x1.25 - 7.8
• M10x1.0 - 9.0
• M10x1.25 - 8.8
• M10x1.5 - 8.5
• M12x1.0 - 11.0
• M12x1.25 - 10.8
• M12x1.5 - 10.5
• M12x1.75 - 10.2
• M14x1.25 - 12.8
• M14x1.5 - 12.5
• M14x2.0 - 12.0

Etc.

Really, If I did my numbers right, you only need to stock less then 50 sizes for metric to get everything from M3 to M14 holes, taps (19 in total including ISO/DIN, JIS, sensor, and spark plug sizes), reamers, counterbores and clearance holes including the 0.5mm spacing general purpose bits.

The SAE equivalent of that, Fractional, Letter and Number sizes to cover roughly the same range, doesn't even fit in the 135 sets that they sell, as you still need to extend it out to 5/8" sizes to compare it to M14, and you need 20 taps to cover the same NC/NF range with no special threads.

Dimitri

 

[Dimitri]

Everyone must be buying these on line now and they refuse to carry them in the store.

It's because you don't need all of them. You need 22 drills to cover the range between NC/NF taps for SAE threads between a #5 and 5/8", to cover a standard commonly found Metric M3 to M14 threads.

The sets comes with 86 letter and number sizes that you don't honestly need all of them. And many people buy just the sizes they need for tapping. Everything else can be handled by a standard 1/64" fractional sizes.

Dimitri

 

[454ragtop]

It's because you don't need all of them. You need 22 drills to cover the range between NC/NF taps for SAE threads between a #5 and 5/8", to cover a standard commonly found Metric M3 to M14 threads.

The sets comes with 86 letter and number sizes that you don't honestly need all of them. And many people buy just the sizes they need for tapping. Everything else can be handled by a standard 1/64" fractional sizes.

Dimitri

14MM is closer to 9/16", and 5/8" is an almost perfect match to 16MM, just sayin'.

 

[T45]

I guess Wikipedia is wrong also and you all are right.

are you still arguing this?

 

[bcradio]

are you still arguing this?

Are you still worried about it?

 

[Monte]

the common drill bit sets over here are 1-10mm and 1-13mm both in 0,5mm increments.

 

[Dimitri]

14MM is closer to 9/16", and 5/8" is an almost perfect match to 16MM, just sayin'.

True but I never needed a 9/16" tap. After M12 or 1/2" I always seem to jump to M14 or 5/8" threads.

Dimitri

 

[dr_clyde]

I only have the sizes that correspond with a metric tap. If all I need is a clearance hole, the few thou difference from a fractional drill will work fine.

Fwiw, I call them twist drills most often, sometimes just drills. I usually only hear them called drill bit by mechanics. The manufacturers call them twist drills and the sellers call them drill bits. It really doesn't matter, everyone knows what you mean when you say either.

 

[cheechi]

The standard sets in metric are 1 - 10mm in .5mm increments, 1 - 13mm in .5mm increments, 1 - 6mm in .1mm increments and 6 - 10mm in .1mm increments.
...
despite thinking in inches mostly, I find that it's much easier to use metric drills rather than number and letter drills
...
Most times you can get away with 1 - 13 mm in .5mm increments and 1 - 6mm in 0.1 increments.

This is more or less what I assumed and I thank you for letting me know. I was hoping to hear from someone in Europe/UK. My thought was that a metric set might make more sense than the number/letters to me at least, since I'm not a machinist and only ever get one of these when it's the next size up or down on the chart.

For perspective, 1/32" is 0.8mm. If you feel like 1/32 is sufficient resolution, a drill index with 0.5mm increments would be even finer.

This is a good point and one of the things I wondered, with a lot of metric being x.25mm sizes, whether a x.3mm or x.2mm drill would be truly the number it says or if it's a common shortcut or shorthand one way or the other. This is why a I assumed set that includes 'some' 0.1mm increments but 'mostly' 0.5mm increments might be the 'common' sizes for the lay person who 0.05mm wouldn't matter.

I have a few sets of fractional & number and letter drill bits, I buy the metric ones as needed.
Just have not seen a reasonable costing complete metric set.

This was another reason for my question, I assume someone would have a set in a mid range price/performance point if it was really going to be needed. You know Irwin, Dewalt, both brands that sell taps & dies so even if they are not great I was expecting a set from either or both.

I mean there is the Snap-On set 1-13 in 0.5mm, Norseman makes metrics but without looking at every single pdf on their page I didn't see a set in the few I did go through.

It all depends on how you are using them.
...
If you share a little more about how you need/wish to use them then I think you will get some better answers.

That's the issue. I don't really 'need' them as I am neither a mechanic nor machinist, but much of what power tools & machines I buy are metric. I was looking at my decimal equivalents chart and pretty much have (according to it) what drills are needed to tap the metric holes that I have taps for anyway, but my thought process was whether these are 'close enough' or the actual size a US machinist would also use in tapping a metric hole.

short answer, I don't need any. This was a question mostly out of curiosity, but since I do have a lot of metric taps, (at least I consider it a lot for a US non-machinist) at some point cleaning or fixing something it's realistic that I may use one or a few and need the appropriate drill. Plus this website is hoarders anonymous what's one more drill set, maybe I was just looking for an enabler to justify me buying a set.

Harbor freight carries a few sets with the fractional, letter, and number sizes.
I can't speak to the quality.

I can. The Cobalt coated 'full' index are very nice although I'm sure you could find a dud every drill I have used from my set has been sharp and run cool. This is my only set of letter/wire gage drills.

 

[dnschmidt]

Norseman makes a nice metric set. Just bought one from EMI Supply, Inc. which had the best online price. Came in a nice Huot like box, don't think it's genuine Huot but it works. Norseman makes great drills and their sort of cool looking as they have Pittsburgh Steeler colors (Black and Gold).

 

[T45]

Honestly I buy drills based on need other then the basic set that goes by 0.5mm.

For common metric taps.

• M3x0.5 - 2.5
• M4x0.7 - 3.3
• M5x0.5 - 4.5
• M5x0.8 - 4.2
• M6x1.0 - 5.0
• M7x1.0 - 6.0
• M8x1.0 - 7.0
• M8x1.25 - 6.8
• M9x1.25 - 7.8
• M10x1.0 - 9.0
• M10x1.25 - 8.8
• M10x1.5 - 8.5
• M12x1.0 - 11.0
• M12x1.25 - 10.8
• M12x1.5 - 10.5
• M12x1.75 - 10.2
• M14x1.25 - 12.8
• M14x1.5 - 12.5
• M14x2.0 - 12.0

Etc.

Really, If I did my numbers right, you only need to stock less then 50 sizes

This is true, but 50 drills is like two 25 piece sets, and maybe $200+ depending on the distribution of sizes. And then you may want drills shaped and coated for aluminum vs stainless steel vs regular use.

So its not a $35 dollar purchase at home depot at that level of abstraction.

The other consideration is that unless using a drill-press, the perfect size for a tap is sometimes undersized a bit (because hand-drills wobble). So that's another factor to consider..

1) standard thread
2) fine thread
3) hand held (1-2) =4
4) Alloy drills (1-4)
5) m42 drills (1-4)

That yields 4-8-or 12 unique drills per single tap size.

 

[Dimitri]

My 50 size guesstimate includes 2.5mm to 15mm by 0.5mm steps. It also includes the above sizes for the metric taps. It also includes the sizes required for M3 to M14 reamers and counterbores as well as clearance sizes for the fasteners.

Variations on materials and coatings are not a factor, not one to compare metric to SAE. Both will cost someone a pretty penny. But if doing general purpose drilling not in a production setting a single set of M42 drills is all one needs.

Dimitri

 

[PelicanPines]

M5 M8 M10 M14 are the only taps I have needed so far. With a mix of thread pitches... I need to get the correct Drill Bits for those sizes. I am interested in what you end up with.

 

[bwringer]

I once walked into a hardware store in a tiny town in Kentucky and asked for a "drill". I was in a hurry to get my motorcycle fixed, and I needed to deal with a snapped bolt. I needed a cheap drill, some drill bits, and an extension cord, figuring I'd just give them away when I was done.

It was one of those ancient places with random **** piled everywhere, so you had to wait for help; there was no way to find anything on your own. After waiting absolute ages for the elderly proprietor to finish chewing over the latest local manure spreading gossip, he led me to a dusty display containing a few leftover drill bits in odd sizes.

What ensued was a solid five minute re-enactment of "Who's on First?", except with the elderly fellow insisting on the "proper" usage of "drill" to refer to what I knew as a "drill bit", and pretending to not even understand what I meant by the words "drill bit" and "drill".

I was completely confused -- I had never in my life heard of any other usage than "drill bit" for the poky thing and "drill" for the thing to turn the poky thing. Perhaps it was a regional thing -- I was from the exotic northern land of Indiana.

Finally, I was at the point where I said "look, sell me a thing to make a hole and something to turn that thing, and call them whatever you want." After a while, he said "You mean a drill motor?" I had never heard of such a thing, but agreed to take a look -- he then led me to another display containing a dusty, crumbling Black & Decker box that clearly said "3/8" Drill".

Anyway, pedantry is pointless and pisses people off. It's useful to know that usage varies, but it's better to just leave it at that and verify when you need to.

 

[T45]

My 50 size guesstimate includes 2.5mm to 15mm by 0.5mm steps. It also includes the above sizes for the metric taps. It also includes the sizes required for M3 to M14 reamers and counterbores as well as clearance sizes for the fasteners.

Variations on materials and coatings are not a factor, not one to compare metric to SAE. Both will cost someone a pretty penny. But if doing general purpose drilling not in a production setting a single set of M42 drills is all one needs.

Dimitri

$220/shipped and hss not m42, but the setup seems pretty efficient.

 

[Cope]

I bought a 25 pieces set on eBay a few years ago. No idea who made them, but they came in a Huot index. Sizes 1-13 in 0.5mm increments.

 

[rob67]

1-4mm in 0.5mm increments plus 5-12mm in 1mm increments will get you very far. 3.3 for M4 is pretty useful, too. Next I would add 8.5 for for M10 and maybe 6.8 for M8.

I'd rather go bigger than 12mm than fill in more 0.5 increments.

This is from my experience as a hobbyist, not as a professional.

 

[nbpt100]

It's because you don't need all of them. You need 22 drills to cover the range between NC/NF taps for SAE threads between a #5 and 5/8", to cover a standard commonly found Metric M3 to M14 threads.

The sets comes with 86 letter and number sizes that you don't honestly need all of them. And many people buy just the sizes they need for tapping. Everything else can be handled by a standard 1/64" fractional sizes.

Dimitri

I was not even talking about a complete set number or letter set. Although that would be fine. I just wanted some of the most common SAE tap drills. For example I could not even find a single #7 drill for one of the most common SAE Thread sizes. A 1/4-20.

 

[nbpt100]

Harbor freight carries a few sets with the fractional, letter, and number sizes.
I can't speak to the quality.

I have purchases a few of the HF Warrior brand cutting tools and have on a whole been disappointed.

1. I purchased 10 pack of 3/16 TiN coated drill bits to use for pilot holes.
Some were dull and some broke and dulled very easy. The price was cheap so I don't feel too ripped off. Mostly used on Alum and mild steel. I am sure they are fine on wood and plastic.

2. A 90 degree counter sink i bought was dull as a stone. Does not even work good in wood. Again it was cheep so I am not too upset.

3. I later gave them an other shot on a 10 pack of 1/8 TiN coated bits. Same experience as in line item 1.

I did get some Warrior step drills (Uni-bits) that I am happy with. So HF is a **** shoot for drill bits. To me Tap drills are too critical to play around with. I want reliability and quality.

This was my experience. Thanks for sharing your experience.

 

[hoye0017]

I guess Wikipedia is wrong also and you all are right.

I love it when people think Wikipedia is a master reference and is always correct for everything. You realize that Wikipedia entries are edited by anyone who could be just as wrong as you, right? Notice the pencil icon on the upper right in any Wikipedia entry? That's so you can edit them.

Just to prove the point, I edited the "drill" wikipedia post to match T45's take on the subject: https://en.m.wikipedia.org/wiki/Drill

Take a look. I edited the first sentence and I didnt even have to log in to do so.

Try it yourself, then let us know the probability of it always being right.

 

[bcradio]

I love it when people think Wikipedia is a master reference and is always correct for everything. You realize that Wikipedia entries are edited by anyone who could be just as wrong as you, right? Notice the pencil icon on the upper right in any Wikipedia entry? That's so you can edit them.

Just to prove the point, I edited the "drill" wikipedia post to match T45's take on the subject: https://en.m.wikipedia.org/wiki/Drill

Take a look. I edited the first sentence and I didnt even have to log in to do so.

Try it yourself, then let us know the probability of it always being right.

Who thinks Wikipedia is a master reference for everything? You?

 

[Dimitri]

For example I could not even find a single #7 drill for one of the most common SAE Thread sizes. A 1/4-20.

Go to a real machinary store not a construction store masquerading as a tool store.

Otherwise use 13/64". Which at 203 thou, falls between a #7 (201 thou) aka the proper drill and #5 (206 thou) which is commonly used as a secondary tap drill especially when hand tapping.

If hand drilling, the 13/64 and #7 drills will be virtually indistinguishable.

Dimitri

 

[hoye0017]

Who thinks Wikipedia is a master reference for everything? You?

Based on your comments in this thread, clearly you think that. And based on my comments, clearly I do not.

I'm struggling to see how my post could have been construed any other way.

 

[Jazz1]

Are you going to be tapping? The increments are important then.

Sent from my SM-T805 using Tapatalk

That^ is the only reason I have a set that is used rarely

 

[bcradio]

Based on your comments in this thread, clearly you think that. And based on my comments, clearly I do not.

I'm struggling to see how my post could have been construed any other way.

Wrong again. I never said that at all. Good job with making assumptions though.

Is wikipedia an excellent resource? Absolutely! whether you like it or not.
Is it the be all end all? Nope!

Also, I'm not seeing your edit. Better go make the change again

 

[nbpt100]

Go to a real machinary store not a construction store masquerading as a tool store.

Otherwise use 13/64". Which at 203 thou, falls between a #7 (201 thou) aka the proper drill and #5 (206 thou) which is commonly used as a secondary tap drill especially when hand tapping.

If hand drilling, the 13/64 and #7 drills will be virtually indistinguishable.

Dimitri

I know....thanks for responding. It would be nice if a full service hardware store stocked a full array of drill bits.