Homebrew PCBs

Hi again!

I recently received a ridiculous quantity of some suspiciously 
inexpensive 0.9mm diamond burrs I won on eBay.

http://tinyurl.com/cncw6

I don't have any serious board drilling on the agenda, but I tried a 
bunch of test holes and it doesn't look too promising-

On the first couple holes the bit feels as if it's "burning" it's way 
through the PCB with some unfamiliar looking debris being tossed out 
of the cut. I actually had to remove and examine the bit with a 
magnifying glass to see if it had anything that looked like cutters. I 
tried another with the same result. They had to feed extremely slow 
due to the "not so clean" cut and I actually broke two tips by not 
giving them the time to "burn" through. They also leave a nasty raised 
lip around the entry and exit holes, which would imply that they're 
pushing rather than cutting their way through.

I had used a Dremel diamond burr for a long time, but eventually 
dulled it on something or chipped it's cutters. I got another one not 
long ago and did something stupid in a hurry (side to side pressure), 
which broke the ball off. IIRC- They cut quite nicely, however, they 
were around 2.5mm, which wasn't too good for smaller stuff, plus I 
think they were 5 or 6 bucks a pop.

Does anyone else here use dental burrs for their drill work. If so, 
how quick and clean of a cut are you usually getting?

That seller had about 650 profile hits, all positive, and states that 
the bits are all top quality, just with no names. Some of the feedback 
even praised the quality of them. (??)

Regardless of what ends up happening with these, I was sort of in a 
pinch. I don't like the idea of buying one or two non-standard micro 
small bits locally and the 5 pack of mini Dremel drill bits (in a 
glass tube) is no longer around here.

How are the rest of you guys stocking up, and from where?

                             -Thanks Again!
George

I think the best would be to actually use a drill to drill holes, like  
everyone else ;-)

Those grinders are meant for very hard material (ceramics, teeth, glass),  
not soft epoxy that smears.
Some of the diamont grinding bits don't even have conventional cutters,  
they just have a rough surface with diamonds embedded.


What you need is drills, ideally carbide. If you use carbide drills you  
need a press or something else they'll break. If you use plain HSS bits  
they won't break, but dull after like 15 holes. Carbide bits will not dull  
(nobody has ever managed to dull one that is, they will break before that  
'cause of mistakes etc.)

You can get them cheap at ebay, like 10eur for 100 is what i'd expect to  
pay if i can select the size.

ST

On Sun, 11 Dec 2005 10:21:11 +0100, soffee83 <soffee83@...> wrote:

> Hi again!
>
> I recently received a ridiculous quantity of some suspiciously
> inexpensive 0.9mm diamond burrs I won on eBay.
>
> http://tinyurl.com/cncw6
>
> I don't have any serious board drilling on the agenda, but I tried a
> bunch of test holes and it doesn't look too promising-
>
> On the first couple holes the bit feels as if it's "burning" it's way
> through the PCB with some unfamiliar looking debris being tossed out
> of the cut. I actually had to remove and examine the bit with a
> magnifying glass to see if it had anything that looked like cutters. I
> tried another with the same result. They had to feed extremely slow
> due to the "not so clean" cut and I actually broke two tips by not
> giving them the time to "burn" through. They also leave a nasty raised
> lip around the entry and exit holes, which would imply that they're
> pushing rather than cutting their way through.
>
> I had used a Dremel diamond burr for a long time, but eventually
> dulled it on something or chipped it's cutters. I got another one not
> long ago and did something stupid in a hurry (side to side pressure),
> which broke the ball off. IIRC- They cut quite nicely, however, they
> were around 2.5mm, which wasn't too good for smaller stuff, plus I
> think they were 5 or 6 bucks a pop.
>
> Does anyone else here use dental burrs for their drill work. If so,
> how quick and clean of a cut are you usually getting?
>
> That seller had about 650 profile hits, all positive, and states that
> the bits are all top quality, just with no names. Some of the feedback
> even praised the quality of them. (??)
>
> Regardless of what ends up happening with these, I was sort of in a
> pinch. I don't like the idea of buying one or two non-standard micro
> small bits locally and the 5 pack of mini Dremel drill bits (in a
> glass tube) is no longer around here.
>
> How are the rest of you guys stocking up, and from where?
>
>                              -Thanks Again!
> George
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and  
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>

Diamond burrs are for cutting Glass (window glass) not epoxy glass.  
These bits will not work well at all on anything else.  There is a 
guy on Ebay that sells boxes of drill bits for PCBs - that might be 
a better start for you - however, don't try to drill holes without a 
drill press. Carbide drill bits are very brittle and will break 
quickly if drilling by hand.

Chriss



--- In Homebrew_PCBs@yahoogroups.com, "soffee83" <soffee83@y...> 
wrote:
>
> Hi again!
> 
> I recently received a ridiculous quantity of some suspiciously 
> inexpensive 0.9mm diamond burrs I won on eBay.
> 
> http://tinyurl.com/cncw6
> 
> I don't have any serious board drilling on the agenda, but I tried 
a 
> bunch of test holes and it doesn't look too promising-
> 
> On the first couple holes the bit feels as if it's "burning" it's 
way 
> through the PCB with some unfamiliar looking debris being tossed 
out 
> of the cut. I actually had to remove and examine the bit with a 
> magnifying glass to see if it had anything that looked like 
cutters. I 
> tried another with the same result. They had to feed extremely 
slow 
> due to the "not so clean" cut and I actually broke two tips by not 
> giving them the time to "burn" through. They also leave a nasty 
raised 
> lip around the entry and exit holes, which would imply that 
they're 
> pushing rather than cutting their way through.
> 
> I had used a Dremel diamond burr for a long time, but eventually 
> dulled it on something or chipped it's cutters. I got another one 
not 
> long ago and did something stupid in a hurry (side to side 
pressure), 
> which broke the ball off. IIRC- They cut quite nicely, however, 
they 
> were around 2.5mm, which wasn't too good for smaller stuff, plus I 
> think they were 5 or 6 bucks a pop.
> 
> Does anyone else here use dental burrs for their drill work. If 
so, 
> how quick and clean of a cut are you usually getting?
> 
> That seller had about 650 profile hits, all positive, and states 
that 
> the bits are all top quality, just with no names. Some of the 
feedback 
> even praised the quality of them. (??)
> 
> Regardless of what ends up happening with these, I was sort of in 
a 
> pinch. I don't like the idea of buying one or two non-standard 
micro 

> small bits locally and the 5 pack of mini Dremel drill bits (in a 
> glass tube) is no longer around here.
> 
> How are the rest of you guys stocking up, and from where?
> 
>                              -Thanks Again!
> George
>

soffee83 wrote:
> Hi again!
> 
> I recently received a ridiculous quantity of some suspiciously 
> inexpensive 0.9mm diamond burrs I won on eBay.
> 
> http://tinyurl.com/cncw6
> 
> I don't have any serious board drilling on the agenda, but I tried a 
> bunch of test holes and it doesn't look too promising-
> 

Drills drill, grinders grind, and burrs burr...........

I have invested maybe $40-50 and have close to 100 carbide drill bits, and
not just junk sizes either... most of my bits are of the size for small
(most discretes) component legs (#71), or larger (headers, IC's, larger
transistors, etc) component legs (1mm), with the rest being an assortment of
sizes from small to large, 2-4 bits per size, and so far I've always had the
bit for any given hole.  And all of my bits are from ebay.

for drilling with carbide bits, if you don't have a drill press already, I
suggest this rotary tool drill press attachment:
http://www.minicrafttools.com/PZ541.html
it's FAR more solid than the sloppy dremel drill presses I've used, and I
have yet to break a drill bit as long as I hold the board down well with my
hand while drilling.  With the dremel on its highest speed, the bits go
through PCB like a hot knife through butter.


[Non-text portions of this message have been removed]

Thanks for all the replies!

Yes, I am actually using a drill press (a smaller Delta). I can't 
imagine doing some of these boards by hand. I usually have a solid 
backer board to keep the exit side clean too. I'm also thinking of 
sticking a pulley and cord on the ceiling and hooking it to a bass 
drum pedal or something to lower the quill, so I can use both hands. 
The drive belt usually stays on the lowest speed.

The dental burr recommendation originally came from some usenet or 
website discussions about longer lasting bits for PCB work. The Dremel 
burr made decent cuts while it lasted, but from what you guys have 
said, I probably just got lucky on the style of cutting edge they used 
or something.

If anyone knows an eBay dealer,etc. who normally sells the large 
quantity of one size (like Stefan mentioned), I'll probably be 
shopping. I've looked before, but I didn't really know the standard 
size (for resistor type holes) and most of the deals were for 
assortments. I've got two decent sized cases of the "#" valued bits in 
just about every size under 1/4", but I've eaten up the first few 
small ones in both sets. I should be fine for all the regulator type 
sizes up.

BTW- Some other info also recommended HSS against carbide stating that 
the carbide was brittle enough to snap frequently on PCB's. They said 
to go with a quantity of regulars and just replace them every so 
often. Going by info here, I guess carbide is a decent choice 
afterall. I'll still probably want a lot either way.

         Let me know if there's any shopping pointers.

-Thanks!

On Mon, 12 Dec 2005 01:27:49 +0100, soffee83 <soffee83@...> wrote:

> The drive belt usually stays on the lowest speed.


You should run carbide drills quite fast. 30000 RPM is not too fast for  
them.
A regular drill press is on the slow side in any setting, and might even  
have too much runout.

I bought them bits via ebay germany, don't remember the seller. Asked  
off-auction for what i needed and got a reasonable price so bought direct.  
Just search ebay, you want used bits that have been replaced in cnc  
machines routinely way before they were properly dull they are dirt cheap.  
Also, avoid assortments with sizes smaller than 0.6 you don't want to use  
them and they are plentiful 'cause of vias. Better get a seller where you  
can select sizes. I must have paid something like 0.2eur per bit.


ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
> You should run carbide drills quite fast. 30000 RPM is not too fast 
>for them. A regular drill press is on the slow side

I had wondered about that too. I had always related PCB stuff as 
similar to metals, where you wanted more cutting and waste removal and 
less heat/friction.

I may look into a Dremel press. My Delta is supposed to serve 
woodworking duties and it's never around for that lately.

The runout and precision could be an issue too, but I've been lucky to 
usually have a clean etched pad/hole to keep the bit centered. That 
was one of the things that scared me away from a Dremel-press rig. I 
had always assumed that the parts would have even more play in them.

Take Care

-George

The dremel brand drill presses tend to have a lot of slop. Their most recent
one was 90% plastic and was even worse than past ones, but has since been
recalled thanks to complaints (including mine).  Once again, I recommend the
minicraft press attachment I linked earlier, it's pretty much entirely made
of metal so it doesn't have nearly as much play.  Your ability to hold the
board securely while drilling is the real factor in whether you break bits
with that press.

-Evan

On 12/11/05, soffee83 <soffee83@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@g...> wrote:
> > You should run carbide drills quite fast. 30000 RPM is not too fast
> >for them. A regular drill press is on the slow side
>
> I had wondered about that too. I had always related PCB stuff as
> similar to metals, where you wanted more cutting and waste removal and
> less heat/friction.
>
> I may look into a Dremel press. My Delta is supposed to serve
> woodworking duties and it's never around for that lately.
>
> The runout and precision could be an issue too, but I've been lucky to
> usually have a clean etched pad/hole to keep the bit centered. That
> was one of the things that scared me away from a Dremel-press rig. I
> had always assumed that the parts would have even more play in them.
>
> Take Care
>
> -George
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>
>
>


[Non-text portions of this message have been removed]

soffee83 wrote:

>--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
><stefan_trethan@g...> wrote:
>  
>
>>You should run carbide drills quite fast. 30000 RPM is not too fast 
>>for them. A regular drill press is on the slow side
>>    
>>
>
>I had wondered about that too. I had always related PCB stuff as 
>similar to metals, where you wanted more cutting and waste removal and 
>less heat/friction.
>
>  
>

  Yes, but the bits are generally so small that 30K RPM is not too bad, 
slower than that and with much feed rate you will dig in and the bit 
will snap before it cuts the chips..

toolsandtunes  Has good deals that end on Monday mornings, if you miss 
this Monday's look again next Thursday or Friday.  Limited sizes and the 
deals vary, so check many of them before buying.  Great guy to order 
from too.

drill-bits 
<http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback&userid=drill-bits&iid=7567718209&frm=284>   
I haven't ordered any from this one yet, but seems to have some ok deals 
too..

Several others on there too, most are probably good.  T&T has some small 
routers, for cutting out inner sections or boards without too much 
margin or waste, just ordered $30 of them myself. 

Alan

--- In Homebrew_PCBs@yahoogroups.com, Alan King <alan@n...> wrote:
 > toolsandtunes  Has good deals that end on Monday mornings

Indeed, and thanks for the tip Alan! I just grabbed a batch of 50 .
033" (#66) carbides from them (direct from the site). Should hold me 
quite a while. :)

I should be good to go with those two other assortment kits here. They 
still have everything from around that size up.

Thanks everyone for the help!

                               -George

I suppose there's a FAQ I could add this to...

http://www.store.yahoo.com/drillcity/pcbkit.html
http://www.store.yahoo.com/drillcity/5pacresdrilb.html
http://www.store.yahoo.com/drillcity/5pcnewwirsiz.html

Default hole sizes in Eagle are 24mil (#73), 32 mil (#67), and 40 mil (#60). 
62 mil and 1/8" are handy for hold downs and mount holes.

The small bits really like higher speed; I run them at 30k rpm. I think your 
burrs will work just as well at that speed.

----- Original Message ----- 

From: "soffee83" <soffee83@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, December 11, 2005 6:27 PM
Subject: [Homebrew_PCBs] Re: Do these diamond burrs suck?


> Thanks for all the replies!
>
> Yes, I am actually using a drill press (a smaller Delta). I can't
> imagine doing some of these boards by hand. I usually have a solid
> backer board to keep the exit side clean too. I'm also thinking of
> sticking a pulley and cord on the ceiling and hooking it to a bass
> drum pedal or something to lower the quill, so I can use both hands.
> The drive belt usually stays on the lowest speed.
>
> The dental burr recommendation originally came from some usenet or
> website discussions about longer lasting bits for PCB work. The Dremel
> burr made decent cuts while it lasted, but from what you guys have
> said, I probably just got lucky on the style of cutting edge they used
> or something.
>
> If anyone knows an eBay dealer,etc. who normally sells the large
> quantity of one size (like Stefan mentioned), I'll probably be
> shopping. I've looked before, but I didn't really know the standard
> size (for resistor type holes) and most of the deals were for
> assortments. I've got two decent sized cases of the "#" valued bits in
> just about every size under 1/4", but I've eaten up the first few
> small ones in both sets. I should be fine for all the regulator type
> sizes up.
>
> BTW- Some other info also recommended HSS against carbide stating that
> the carbide was brittle enough to snap frequently on PCB's. They said
> to go with a quantity of regulars and just replace them every so
> often. Going by info here, I guess carbide is a decent choice
> afterall. I'll still probably want a lot either way.
>
>         Let me know if there's any shopping pointers.
>
> -Thanks!
>
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>
>

> drill-bits 
>
<http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback&userid=drill-bits&iid=7567718209&frm=284>
  
> I haven't ordered any from this one yet, but seems to have some ok
deals 
> too..

> Alan


I just placed an order with this vendor (Paul at
http://www.drillbitcity.com).  

~$20 for

#81 (.0130) 5 #76 (.0200) 5 
#80 (.0135) 5 #75 (.0210) 5 
#79 (.0145) 5 #74 (.0225) 5 
#78 (.0160) 5 #73 (.0240) 5 
#77 (.0180) 5 #72 (.0250) 5 

Professional transaction, shipped when promised, and the bits look
good.  I'm not a professional drill bit evaluator, but they look
sharp, clean, and straight. Now to get the minicraft drill press....