CARBIDE SUCKS

just tried drilling boards with carbide bits. Broke all of them. I don't have a press. Anyone know where I can get steel bits in wire sizes in the US besides digikey? Or a press for my dremel??

your doing something wrong if your breaking carbide bits.

you could be under rpm'ing them. they are made to cut best at extremely high rpm, as in 30,000-50,000 IIRC.


what part of Ga are you in? im in savannah.

I'm pretty sure home depot has a press for the dremel.
Caine

I am in Macon. I think they break if you do any sideways motions with them.

Small carbide bits are extremely brittle and will snap right away if youre not using a press.

But once you get a press and compare carbide to HSS you'll see a huge difference.

Michael

A good compromise is Cobalt steel bits. They don't last as long as carbide, but outlast high speed steel by many times over.

I dill PC boards using a dremel and press, with carbide bits. But you have to be super-careful or the bits will break. I always press down hard on the board so there's enough friction to keep it stable. Also, the highest speed the dremel will go. The dremel press is not very stable, so the other thing is you need to develop a method to hold the dremel stable (I always push it to the right).

I've been drilling mic capsule backplates on a big mill with carbide bits (#52 through #73), and I have yet to break one. I've drilled about 8 backplates, with between 150 and 200 holes each. The key here is the mill is super-stiff so there's no side loads on the bit. The mill only goes up to 4500 RPM which is too low, but the stiffness makes that work. Before switching to the mill for doing my backplates, I broke several bits, and never got even one good backplate.

yup, def need a drill press for them insy carbide bits...

I used one of these for me dremel:

http://www.elexp.com/tol_rdps.htm

spin it fast and use a press... they are great for PCB

:sam:

Go to Sears and buy one of those $59 or $69 dollar drill press. You can load up to 1/2" drill bit or use those step drill bits for up to 1" hole.

FYI - i had a crappy 3-jaw chuck on my dremel. even with the drill press attachment there was enough runout to break my carbide resharps on every other hole. switched back to the cheapo collet and everything was fine...

-mike

One tip is to chuck the bit way up the shank so you only have about 1/4 inch showing.

I'm gonna try cobalt.

anything harder than HSS(carbide, cobalt, and any of their alloys) is going to break when loaded sidways or when it encounters drag. they are designed to cut HARD metals like heat treated steel(taps, files, locks, tool steel) and for longevity when machining. As dale116dot7 pointed out, they are really designed for use by milling machines. you are better off buying a coated HSS bit, coated with one of the Ti compounds.

I use a small dremel cutter, the smallest round cutter they make i think.. and I've drilled maybe 50 boards without it losing it's sharpness. i would try that first. i've also used a HSS drill for a lot of holes with no loss in sharpness. I'm not sure what you are doing to dull the bits out but maybe you are running them much too fast, i run mine around 1kRPM and let them cut at their own speed without forcing them.

:thumb:

[quote author="CJ"]One tip is to chuck the bit way up the shank so you only have about 1/4 inch showing.[/quote]
CJ... :shock:

WTF are you talking about???

-We're talking about drill bits here, not hookers!

Keefus Interruptus

And I was just gonna add lubricant to that post! :razz:

The collet, though cheaper looking than the standard chuck, is a lot more precise. In fact, in a mill (where the goal is stable, centered operation), a collet is the standard way of attaching whatever tool you're using.

In all the time I have been using Cobalt steel, I have never broken a bit; except when doing something really stupid. Cobalt isn't as brittle as carbide, but still considerably harder than High speed steel. If you have a good eye and a fine stone for your dremel, you can even re-sharpen cobalt bits.

... whenever i break a bit on the dremel, it's because of lateral (sideways) force. The bit breaks up near the collet., but is still sharp. Hate that... so second vote for cheap Sears drill press, more stable than that little dremel thingy, and you can use HD bits with sturdier shafts. (no jokes CJ).

yo.
i gots yo shaft hangin! :razz:

shaft. did terry manning track that?