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About carbide drill bits

P

Pimpom

Jan 1, 1970
0
Carbide drill bits of 0.7-1.2mm size are priced at ~US$10 each at
Digikey and Farnell while they are offered for a fraction of that
at ebay.com, typically ~$1-1.50 per piece in a set. Does anyone
know what these cheaper offerings from eBay are like for drilling
FR4 boards?
 
C

Chieftain of the Carpet Crawlers

Jan 1, 1970
0
Carbide drill bits of 0.7-1.2mm size are priced at ~US$10 each at
Digikey and Farnell while they are offered for a fraction of that
at ebay.com, typically ~$1-1.50 per piece in a set. Does anyone
know what these cheaper offerings from eBay are like for drilling
FR4 boards?

Are you sure the digikey stuff isn't for a ten pack?

That is the way we bought drills years ago. Files too.
 
S

Spehro Pefhany

Jan 1, 1970
0
Carbide drill bits of 0.7-1.2mm size are priced at ~US$10 each at
Digikey and Farnell while they are offered for a fraction of that
at ebay.com, typically ~$1-1.50 per piece in a set. Does anyone
know what these cheaper offerings from eBay are like for drilling
FR4 boards?

Don't know, but I've had spotty results (used to be uniformly dismal)
with Chinese cutting tools.

Digikey isn't really the best place to buy that sort of thing- KBC has
M.A. Ford (made in USA) carbide 1/8" shank drills for $4.10 ea., which
is not bad for a few pieces. McMaster wants about $4.50 each, but I
don't think they ship to India.

This guy claims to have Kyocera bits at a very reasonable price
(havn't tried him)

http://www.routerburr.com/servlet/the-DRILLS/Categories


Best regards,
Spehro Pefhany
 
N

Nico Coesel

Jan 1, 1970
0
John Larkin said:
Without a serious Excelon type drill (zillion RPM air bearings, feed
rate control, entry media) carbides tend to break. For home-drilled
boards, use cheap steel drills and toss them when they get dull.

Bad idea. An HSS drill is dull after about 10 holes of FR4. Even for
hobby purposes you need carbide drill for FR4. I never had problems
with carbide drills breaking unless I drilled in the aluminum base of
my drill-press.
 
S

Spehro Pefhany

Jan 1, 1970
0
The secret for carbide is a drill setup with minimum run-out, no give,
and no wobble.

I have an old-style Dremel drill stand that holds the tool steady, and
lifts the
table up and down, like a "knee mill." That works well.

The later Dremel drill stands move the tool up and down to drill
holes. The Dremel shifts slightly
as you lower it into the workpiece, snapping the bit.

Dremels aren't perfect, but if the bearings are reasonably tight
they'll get the job done.

I've had few to no problems*. You want to run them as fast spindle
speed as possible. They cut FR4 like butta. I don't often drill much
less than 0.8mm (0.031"), which is pretty sturdy- if you're trying to
drill 0.015" holes, things might be dicier.

* A few weeks ago I reached into one of the ubiquitous little boxes of
resharpened carbide bits by mistake and about 8mm of tiny via-size bit
punctured my finger and broke off in the finger. Ouch. This was after
breaking a 1/4-20 tap off in a part, so I was grumpy to start with
(took a couple hours to salvage the part). I thought a cheap "set of
taps" would be okay at that huge size- I was wrong- bought some good
quality ones (Chinese, but top-notch stuff) and no more problems. The
cheap-a** 4-40 die wouldn't even thread onto a proper sized brass
turning. Criminally bad "tool shaped" garbage- ultra brittle, dull,
and not the right dimensions.

Moral.. don't go cheap on cutting tools!
 
P

Pimpom

Jan 1, 1970
0
Spehro Pefhany said:
Don't know, but I've had spotty results (used to be uniformly
dismal)
with Chinese cutting tools.

Hmm... I suspect that some or most of those cheap bits at ebay
are Chinese products.
Digikey isn't really the best place to buy that sort of thing-
KBC has
M.A. Ford (made in USA) carbide 1/8" shank drills for $4.10
ea., which
is not bad for a few pieces. McMaster wants about $4.50 each,
but I
don't think they ship to India.

It wouldn't make much difference for me even if they did ship to
India because import hassles are a real PITA and well nigh
insurmountable for those of us in remote parts of the country.
But things have started looking up a bit recently in that
respect. There are now at least a couple of Indian companies who
offer to import just about anything from the US for a client.
Their minimum shipping charge is for 1lb.
This guy claims to have Kyocera bits at a very reasonable price
(havn't tried him)

http://www.routerburr.com/servlet/the-DRILLS/Categories

The prices are comparable to those at ebay and are certainly
better than at those other sources. At least the manufacturer's
name is known. Do you know anything about the other brand
mentioned there - Precision Carbide? Unless someone comes along
with a more attractive suggestion - not necessarily a lower
price - I think I'll make a trial order for a ten-pack each of 2
or 3 different sizes.

Another thing I'll have to deal with is the drill. The 10k rpm
drill I now use came only with 0.8mm, 1mm and 2.3mm collets.
Thanks for the helpful input.
 
B

Baron

Jan 1, 1970
0
Pimpom Inscribed thus:
Carbide drill bits of 0.7-1.2mm size are priced at ~US$10 each at
Digikey and Farnell while they are offered for a fraction of that
at ebay.com, typically ~$1-1.50 per piece in a set. Does anyone
know what these cheaper offerings from eBay are like for drilling
FR4 boards?

All the cheap ones I've bought have been sharpened off centre.
 
S

Spehro Pefhany

Jan 1, 1970
0
It wouldn't make much difference for me even if they did ship to
India because import hassles are a real PITA and well nigh
insurmountable for those of us in remote parts of the country.
But things have started looking up a bit recently in that
respect. There are now at least a couple of Indian companies who
offer to import just about anything from the US for a client.
Their minimum shipping charge is for 1lb.

McMaster will permanently cut them off if they know it's being
exported. They really want to add to the US trade deficit- only
existing large export customers are being supported.
Another thing I'll have to deal with is the drill. The 10k rpm
drill I now use came only with 0.8mm, 1mm and 2.3mm collets.
Thanks for the helpful input.

AFAIK, everyone uses 1/8" (3.175mm) shank drills (same as a Dremel
tool), so if you get one of those you'll be okay for just about
anything. It helps to be able to change the bits quickly when all the
shanks are identical. With collars you can get the length spot on too.
 
N

Nico Coesel

Jan 1, 1970
0
Spehro Pefhany said:
I've had few to no problems*. You want to run them as fast spindle
speed as possible. They cut FR4 like butta. I don't often drill much
less than 0.8mm (0.031"), which is pretty sturdy- if you're trying to
drill 0.015" holes, things might be dicier.

The thinnest drill I have 0.6mm. No problems using it. I use the
ancestor of this drill-press:
http://www.nutmegwoodworking.ca/products/proxxon/28606-web.jpg

I've drilled thousands of holes with it using carbide drills.
 
E

ehsjr

Jan 1, 1970
0
Pimpom said:
Carbide drill bits of 0.7-1.2mm size are priced at ~US$10 each at
Digikey and Farnell while they are offered for a fraction of that
at ebay.com, typically ~$1-1.50 per piece in a set. Does anyone
know what these cheaper offerings from eBay are like for drilling
FR4 boards?

Get used dental burs from your dentist, or buy them new if
you can find them for a reasonable price. They work well
in my (newer style) Dremel drill press - haven't broken one
yet.

Ed
 
T

TheQuickBrownFox

Jan 1, 1970
0
Get used dental burs from your dentist, or buy them new if
you can find them for a reasonable price. They work well
in my (newer style) Dremel drill press - haven't broken one
yet.

Ed

Filch the dumpster at the urgent care too! Get that stainless!

They used to autoclave everything and that was enough... before AIDS.
 
R

Rick

Jan 1, 1970
0
whit3rd said:
At a guess, they were just fine, when they were new.
Carbide drills for circuit board manufacture are mainly not
resharpened, but are discarded (sold as surplus) after
a certain number of holes have been drilled. If you aren't doing
plated-through holes, they're certainly good enough at
end-of-life for another few thousand holes.

I usually buy two or three to get a rather good assortment.
http://www.harborfreight.com/20-piece-solid-carbide-micro-bit-grab-bag-44924.html
 
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