carbide tutorial please

alinwa said:
I
re the "brass tube smaller than the hole"...... can't imagine this. Some sort of brass capillary tubing?

I
al
Click to expand...

You use a brass/copper tube smaller than the hole you drilled for the tap. A tube that is smaller than its hole is invisible!!
 
In 1968, Popular Mechanics or a similar magazine, had the plans and photos of a homemade EDM machine. It was set up in a drill press, used 200w and a smaller light bulb plus some caps and maybe other components in the circuit.
I made one and had some fun with it, the dielectric was distilled water. The different wattage of the bulbs controlled the burn rate. The closer both bulbs were to each other, the lower the burn rate. The biggest negative was that the whole thing had 110v to zap you when it was turned on, you had to be careful. Electrode wear was quite high.
Can't imagine something like that being in a magazine, today.

Jay
 
I use carbide endmills with 2 flutes. I have lost an endmill or 2, but was always able to remove the drill or tap. I lower the quill and haven't tried raising the knee.
BUTCH
 
Not really applicable here, but I've seen taps washed out of turbine casings with torches. You heat the tap up red with a small cutting tip and shut the gas off, and only use oxygen to burn the tap. Was quite interesting..
 
alinwa said:
Today I snapped off the tip of an 1/8" centerdrill leaving it in the hole. I was able to flip the piece and drill back into it and proceed but I'd like to know HOW to drill one out for future.



Anyone got the time to 'splain it to me? I've got some pieces coming up that I can't flip and drill back to.... I'll only get the one shot to start the little 1/8" centerdrill into a center-punched divot....... I expect to be doing some carbide drilling. :)


thanks


al
Click to expand...

For a broken center drill tip I've used a diamond coated dental burr, round end. Chucked it up in the mill, used plenty of fluid and proceeded slow. It was a well used burr from my lab so I wasted the burr, but got the center drill tip out. These burrs can be had from dental lab supply houses. Get one with a straight handpiece 3/32" shaft not the friction grip shaft. They come in various head sizes. A new one should last a little longer.

I'm not a pro but I have found this worked for me.
 
It's starting to come together..... first thing seems to be to get some sort of coolant system going on my little mill ;)

probably one of those vortex air thingies...

al
 
Drill bit Warehouse, Choosing the right drill bit for the job.

alinwa said:
I've always heard of using carbide drill bits to drill out broken taps and such but I've never done it.

Today I snapped off the tip of an 1/8" centerdrill leaving it in the hole. I was able to flip the piece and drill back into it and proceed but I'd like to know HOW to drill one out for future.

-where do I buy 1/8"carbide bits and how do I use them?
-speed/feed? Do I want the carbide to try to "bite" like a HSS drill or just chip it's way along?
-What about heat? Do I crank the speed up like a Dremel tool or low and slow like HSS?
-How much down pressure?

I need real-world details. What works and what will just scrap my bit..... I've got no plan here.... no understanding of the characteristics of teeeny carbide spinners. Are they tough or brittle? Do they burn up? Shatter? How do they handle interrupted cuts like drilling a tap?

Anyone got the time to 'splain it to me? I've got some pieces coming up that I can't flip and drill back to.... I'll only get the one shot to start the little 1/8" centerdrill into a center-punched divot....... I expect to be doing some carbide drilling. :)


thanks


al
Click to expand...

I found that a solid carbide 140 degree notched drill point works great as well as a solid carbide ball nose endmill for drilling out broken taps and broken easyouts. You can find everything you need at http://drillbitwarehouse.com
 
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