PCB Micro drills and micro end mills"

eBay is full of those:

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or similar tiny carbide end mills.

My question is how usable are they on a hobby sized CNC machine like my Bridgeport Interact, with slow top speed. Is using them totally out of question, or just frustrating, or perhaps they are handly for small work?

i
Reply to
Ignoramus10035
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You need to adjust your feed rate so as not to exceed a reasonable chip load at lower RPMs but they work great particularly on nasty stuff like fiberglass. I milled out a couple double-sided PCBs using the tiny end mills and the quality was far superior to any of my previous attempts using other methods.

Try it, you'll like it.

--Winston

Reply to
Winston

Ive got about 500 of those.

send me an shipping address and Ill send you some

Gunner

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

Reply to
Gunner Asch

I've used them with a pin vise to make a hand-powered bow drill when the Dremel at work was broken. I couldn't quite locate the PC board well enough on the CNC board engraving machine to redrill the holes larger without breaking bits.

Their main limitations are spindle play and chuck centering. They worked fine at spin-with-the-fingers speed and a fairly coarse feed pressure.

There's something odd about making a stone-age tool to solve a CNC problem in a semiconductor factory. I had some spare round boards for the flywheel weight and didn't have to grind a hole in a flat pebble.

jsw

Reply to
Jim Wilkins

I got a bunch of Gunner's drills a while back. they have served me well. I know i should install the spindle speeder, but I normally don't and just use a very low feed. They are easy to break, but very cheap so not much bother.

Karl

Reply to
Karl Townsend

Well, they are used on machines not much different from hobby machines in both size, but speed is way higher. However, there are both drills and "burrs" in the machines. Obviously the drills do holes, only! The burrs are used to mill the outline of the circuit board so as to completely cut it from a panel of boards, or sometimes just leave small tabs between boards in a panel. In other cases, a special "V" shaped burr is used to mill a scoring line between boards so they can be cut apart after populating them with components.

I have several assorted sets from both Grizzly and from Ebay. All are

1/8" shank. When we have to drill or mill a board, we use a variable speed drill press, 0-20,000 or 0-39,000 rpm.

Paul

Reply to
co_farmer

Sure you can use these on your mill. Feed will have to be appropriate for the spindle RPM, something like .0001" per revolution, for the smallest ones. That makes for pretty slow going, but if you are only doing a few special holes in something, it will work fine. These are really designed for drilling composites, but you can drill copper, brass and aluminum just fine. Steel will require even more care. If the point of the drill enters even a hair off center, the drill will break.

Jon

Reply to
Jon Elson

Thanks Jon. I can live with that, this would be for one off things.

i
Reply to
Ignoramus10035

I've milled pcb's with the mills - and drills. The motor with chuck ran 12k RPM's - and side loads are death to the drill/mill.

They are carbide - and likely sharp. Often pcb drillers/plating shops send them to be sharpened, but fail to come for them as the price for new is close to grind cost.

So if you need tiny holes and are willing to live with short lifetimes - do it.

I also used them in various materials - being carbide they are capable.

Mart> eBay is full of those:

Reply to
Martin H. Eastburn

PCB drills are generaly C2 carbide, not recomended for drilling steel.

If your gonna buy some on ebay only purchase new ones, used ones will usually need to be resharpened.

Best Regards Tom.

Reply to
azotic

snip

the broken drills are almost free, and they provide a great source of carbide for engravers, etc

Reply to
Bill Noble

[ ... ]

Though I have used one for drilling out a broken HSS tap. I was rather amazed at how well it worked. This was in a sensitive drill press, with the workpiece firmly clamped and lots of speed.

Actually -- I suspect that a lot of the really cheap ones are from a resharpening facility which after resharpening discovered that they were just a little shorter than the minimum length for normal use. This could explain the batches of them which show up dirt cheap at hamfests and the like.

Enjoy, DoN.

Reply to
DoN. Nichols

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