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Super long super small hole

cc22288

Aluminum
Joined
Dec 27, 2019
Hey all,

I have a challenge at work im trying to solve. I need to drill and ream a 2.1mm hole into copper 34mm deep. I've looked around for tooling and I cant seem to find anything that will work to those depths. I'm also nervous to spend money on tooling when this strikes me as near impossible without breaking drill bits left and right or walking off center. To add, i need to make the hole flat bottomed, and then go back with a 60degree tip drill and put an additional feature down the bottom of that hole. Would a custom tool do the job? am i dreaming here?

csJ5n1r.jpg

thanks in advance
 
Good morning cc22288:
Two questions:
1) Do you get to choose the grade of copper?
If so, then I recommend C145 tellurium copper because it is super machinable especially for drilling.
Get it from McMaster Carr.

2) Can you make it out of two pieces silver brazed together?
If so, I recommend drilling a start hole from each end, then wire EDM cutting the finished bore, then brazing on a cap with the countersinked stepped hole.
It'll come out dead nuts accurate if that's what you need.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Micro Carbide Drills - GUHRING

It's not going to be easy. That link is a Drill that has the physical characteristics you need, from Guhring.

I would probably Drill as deep as needed from one side, flip the part around Drill the smaller end, and do some fancy ID Grooving from that side.

E
 
As previously mentioned, go with a gun drill. I would then talk to Harvey Tool about a custom counterbore tool to bore the 2.1Ø to size and make your flat bottom.
 
Hey all,

I have a challenge at work im trying to solve. I need to drill and ream a 2.1mm hole into copper 34mm deep. I've looked around for tooling and I cant seem to find anything that will work to those depths. I'm also nervous to spend money on tooling when this strikes me as near impossible without breaking drill bits left and right or walking off center. To add, i need to make the hole flat bottomed, and then go back with a 60degree tip drill and put an additional feature down the bottom of that hole. Would a custom tool do the job? am i dreaming here?

View attachment 274638

thanks in advance


If you have thru spindle coolant nothing is impossible.

I have a job every once in a while that I drill a 2.2 hole deeper than your requirement here in CU101. I'm using Walter-Titex drills and pecking which seems to do the trick. No noticable lead off or premature tool failure. I wouldn't want to be making hundreds or thousands of them but it works for the dozen or so I need to make every few months.

That is a difficult hole to put in so spend the money for the right tools and pass that on to the customer who needs you to know magic to make their parts.

I'm no help on the flat bottom part but the hole itself isn't bad.
 
FYI I disagree with Gundrilling. This is a 15:1 Ratio. It isn't crazy deep or small. 25:1 is when I start thinking Guns.

R
 
Its a bit ghetto but since I don't have high pressure coolant I have in the past rigged up an el cheapo pressure washer to a gundrill in the lathe. Just remember to disconnect the hose before indexing the turret :willy_nilly:. Same should apply to any through coolant drill.

Not going to go into mass production with a pressure washer but it beats sending the work out on short runs.
 
Its a bit ghetto but since I don't have high pressure coolant I have in the past rigged up an el cheapo pressure washer to a gundrill in the lathe. Just remember to disconnect the hose before indexing the turret :willy_nilly:. Same should apply to any through coolant drill.

Not going to go into mass production with a pressure washer but it beats sending the work out on short runs.

Thats awesome! Got to keep that one in mind for sure. You just plumb the regular coolant supply to the pressure washer input I guess? I can see this working great for me at times. Now onto Kijiji to look for a cheap pressure washer.... lol
 
Back in the old days and maybe even today we would have a tool grinder cut is a formed carbide reamer for this type of job. it would be perfect every time.
 
Thats awesome! Got to keep that one in mind for sure. You just plumb the regular coolant supply to the pressure washer input I guess? I can see this working great for me at times. Now onto Kijiji to look for a cheap pressure washer.... lol

Correct, depending on how long you want the pump to last you may opt to install a minimalist filtration system.

I got the idea from someone I saw doing it on a manual machine. That was a bit insane if you ask me, he had to regear the feeds so they would go slow enough for a gun drill, and build a coolant shroud. But when I saw it I thought hell, a turning center already has all that good stuff going on, all I would have to add to mine is the high pressure go go juice.
 
For a one of a kind, drill it,then make an electrode the shape you need and sinker EDM the shape into the bottom of the hole. If you need lots of parts, buy or make a form tool.
 
Good morning RJT:
I am curious; have you had good success sinker EDM cutting copper?
I have not, although I tried everything I could think of to make it go.

I know it must be possible because I've successfully wire EDM cut boatloads of it, but successfully sinker cutting it has always eluded me.

So if you have a strategy that works, I'd love to hear it!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Thanks for the advice everyone. Im going to try one the guhring drill and the helios drill by sgs and see if i have any luck.
 
For a one of a kind, drill it,then make an electrode the shape you need and sinker EDM the shape into the bottom of the hole. If you need lots of parts, buy or make a form tool.

Was logging in to say exactly this.

Arc Drilling in Valley View Ohio will most likely knock this out for you.
 








 
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