Metric drill bits

[supton]

Last time I was in HF I noticed an assortment box of metric bolts and nuts. The only thing I have that isn't metric is my lawnmower it seems, maybe the wheelbarrow... Dawned on me that I should get that, and some metric drill bits. I was then a bit surprised that there was no metric bits at HF, maybe China has converted away from metric now, since they export everything to us.

Anyhow, what are some good sizes I should get to have on hand? I'm probably just going to buy some cheapo set off Amazon, but what would be common sizes that I might want to have on hand? I'm guessing 6, 8, 10 and 12mm is going to cover most anything I'd be after. Quick look at the HF assortment shows some 5mm stuff in there. [Whenever I need to thread something, I buy a tap that comes with the appropriate drill already.]

What do our SAE-challenged members use for go-to bolt sizes for random projects?

 

[Chris142]

Don't the bigger drill kits come with a bunch of sizes? I'm sure there is a metric equivelant in there.

 

[supton]

Originally Posted by Chris142
Don't the bigger drill kits come with a bunch of sizes? I'm sure there is a metric equivelant in there.

I figure I'll just buy an assortment of bits. Yeah some of the SAE's are probably close enough, but then I'd have to memorize those sizes and/or mark the bits. Why not just spend a couple of bucks and get the right sizes?

Over the holidays I bought a few metric tape measures, and was then asking myself, why am I still doing everything in inches/feet/miles?

 

[Kira]

I'm the "wrench turner" in the family. My brother does wood working. LOTS of fancy, well designed IN DEMAND stuff like drawer pulls and hidden hinges is metric.

I got bro a set of metric drills years ago during a trip to Europe....so long ago they were specialty items in US catalogs.

The hardware stores over there had sets in stock (of course) and I was so far off the beaten track the shop keepers would lower the prices because I was always someone's friend.

A 4,6,8,10,12 set is the way to start. You'll find 'em here now-a-days easily.

 

[supton]

Originally Posted by Kira
A 4,6,8,10,12 set is the way to start. You'll find 'em here now-a-days easily.

There's a bunch on Amazon, and I'm sure I could find some on Ebay if I wanted to look. Just want a suggestion as to sizes to get, that's all.

 

[MasterSolenoid]

Normally, if you want a drill bit in-between a fractional size, you would get 'Letter' and 'Number' Sets.

 

[Hall]

I'm a huge fan of the metric system but for drill bits, when just drilling holes, I don't think it's necessary to use a metric bit over an SAE bit. You're not tapping (threaded) holes after all. Need a 3mm hole, use an 1/8" bit. Need 6mm, use 1/4".

 

[Skippy722]

Originally Posted by hallstevenson
I'm a huge fan of the metric system but for drill bits, when just drilling holes, I don't think it's necessary to use a metric bit over an SAE bit. You're not tapping (threaded) holes after all. Need a 3mm hole, use an 1/8" bit. Need 6mm, use 1/4".


This. Last machine shop I worked at we did this if it was just bolt holes.

 

[bunnspecial]

Originally Posted by Skippy722
Originally Posted by hallstevenson
I'm a huge fan of the metric system but for drill bits, when just drilling holes, I don't think it's necessary to use a metric bit over an SAE bit. You're not tapping (threaded) holes after all. Need a 3mm hole, use an 1/8" bit. Need 6mm, use 1/4".


This. Last machine shop I worked at we did this if it was just bolt holes.


The only metric drill bits I've ever used/handled are in the metric tap and die set we have in the machine shop at work. Those are locked in a cabinet in the shop for which there are only a couple of keys in circulation(I have one, and my co-worker who maintains the shop has the other). The reason for that is that we have piles of imperial sized bits in multiple sets that are plenty close enough for most of the things people do in the shop, and we want to keep the metric ones nice for the times when someone actually does need to use a metric tap.

BTW, that locked cabinet doesn't necessarily contain stuff that's valuable, per se, it's more just the "this has a special purpose and if someone needs something that's in here, we want to make sure they're using it as its supposed to be" cabinet. It also has things like a lot of the special jigs that we've built for specific tasks and things of that sort, as well as the thread chasing taps and dies and other odds and ends.

 

[JHZR2]

Originally Posted by hallstevenson
I'm a huge fan of the metric system but for drill bits, when just drilling holes, I don't think it's necessary to use a metric bit over an SAE bit. You're not tapping (threaded) holes after all. Need a 3mm hole, use an 1/8" bit. Need 6mm, use 1/4".


Totally agree. Unless tapping for a metric thread bolt, I don't see the use.