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Drilling out a carbide bit??? S#@t F@*K

R

Racer-X

Plastic
Joined
May 31, 2017
Drilling a 0.046" 2-flute carbide bit into an unobtanium component. Broke off as it just started to exit 1/4" material.
Hard to explain, but there is a hood over the exit hole, so I cant punch it back out in reverse.
Is there some kind of 'super' drill-bit that I can drill through the carbide bit/plug? Largest bit I can use, largest ID I can go to, is 0.050"

I have scoured the interweb, and came up empty handed. EDM wont work because of the overhang/hood.

:crazy:
 
EDM should be able to sink an electrode anywhere you got a drill in. Personally, I just take a punch (core pin or ejector pin smaller than .046 should work)and try to bust up the brittle carbide. Just keep tapping away with a small hammer and punch, and blowing the chips out of the hole with air. Try not to booger up the sides of the hole too much with your punch.
 
Barry Weeks said:
EDM should be able to sink an electrode anywhere you got a drill in. Personally, I just take a punch (core pin or ejector pin smaller than .046 should work)and try to bust up the brittle carbide. Just keep tapping away with a small hammer and punch, and blowing the chips out of the hole with air. Try not to booger up the sides of the hole too much with your punch.
Click to expand...

Ejector Pins on order....Thank you!!!!!!!!!!! :cheers:
 
They can be drilled with a diamond plated pin, a high speed spindle attachment and lots of coolant but I try to break them first as above unless I'm really worried about screwing up the hole a tad.
Bob
 
CarbideBob said:
They can be drilled with a diamond plated pin, a high speed spindle attachment and lots of coolant but I try to break them first as above unless I'm really worried about screwing up the hole a tad.
Bob
Click to expand...

Yup, I've done that using the regular mill spindle, but granted that was a ~14mm drill, so easier to accommodate the low rpm. Slow feed, helixed in at about .0007"/turn, used two pins for ~.75" of broken drill.

If the "hood" is too thick to punch through you can try using a 1mm diamond pin with a tiny helix from that side, you should only have to go a little before you break through to the full hole. Diamond doesn't like cutting steel, but keep the bit cool and well flushed and it'll last for a little while.

If it shows signs of burning, stop and replace, then keep going. Don't let bits of broken diamond embed into the part, that's bad (you'll need a laser as a truly last resort).
 
If the bit was coming though as it broke I would have it upside down blowing air in the exit side and tapping it on the side with a small hammer. Might shake it loose and blow it out.

Ed.
 
How much access do you have inside the "hood" if any and what tolerances/ finish do you have to hold?

JR

Edit
I know you said unobtainiun but can you say the material or at least it's properties?
 
Milland said:
If it shows signs of burning, stop and replace, then keep going. Don't let bits of broken diamond embed into the part, that's bad (you'll need a laser as a truly last resort).
Click to expand...

THIS is good information, so you cannot burn out diamond? Sorry not an EDM guy.

R
 
litlerob1 said:
THIS is good information, so you cannot burn out diamond? Sorry not an EDM guy.

R
Click to expand...

I think compacted diamond (PDC) can be EDM'd when the binder is eroded, but diamond pins use particles of natural or synthetic diamond, which I think can't be burned as they're high-temp insulators. If someone knows different please correct me.
 
Racer-X said:
Drilling a 0.046" 2-flute carbide bit into an unobtanium component. Broke off as it just started to exit 1/4" material.
Hard to explain, but there is a hood over the exit hole, so I cant punch it back out in reverse.
Is there some kind of 'super' drill-bit that I can drill through the carbide bit/plug? Largest bit I can use, largest ID I can go to, is 0.050"

I have scoured the interweb, and came up empty handed. EDM wont work because of the overhang/hood.

:crazy:
Click to expand...

i'll bet a RAM EDM can get that out...if theres room for a drill then theres room for an electrode...use tungsten/carbide rod...or tungsten copper if you have it also....and I have done this before too....put in a heated jewelry cleaner that buzzes and put drill upside down with room for it to come out so raise job up...let cleaner vibrate pieces out and or whole drill...the heat of the cleaner will enlarge the hole sometimes and the vibration will shake it out

PS...I have RAM EDM'ed crystal before also...but its very exacting and you must determine which way the crystal grains run...it took 3 days to go about .05 deep and it was a tungsten electrode with steel settings....example ON 003 OFF 025 MA 01 I.P 1.5 SV 04 and so on
 
here is an old school way that is similar to jewelry cleaner method

 
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