How to drill ejection pin hole in point forming die ?

J

J. Valentine

Guest
How do I approach the drilling of the small ejection pin hole in a point forming die ogive cavity. The style of Die is Corbin M type . Ejection pin .079,
Depth .5 , steel D2 grade Bohler K110 . Normal twist drills?
 
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I think it is aking quite a bit to expect them to divulge their trade secrets. Dave is a nice guy so is Richard but I don't like putting him on the spot over things like this .
 
If the die is hardened, nothing short of an EDM.

If not, a premium cobalt drill. D2 work hardenes easily when drilled if the proper speed/feed isn't observed. I can make a certerdrill glow red... :eek:
 
like AJ said it all depends on if it's been hardened yet. if it is you should be able to drill it with a carbide drill in your milling machine. don't ever try using a carbide drill in a drill press.


Jake
 
Thanks for the help so far .
It would not be hardened at that stage.
The theory is to drill the ejection pin hole from inside the ogive cavity after step drilling or during step drilling in the lathe ?
Is this a good or bad idea?
The depth left to be drilled after the ogive cavity is step drilled would be . 5 inch . Which is 6.25 times drill diameter deep.

Ok so a high quality cobalt drill is better.
Keep it very cool .

Should I just drill it all the way from inside the die cavity or drill from both ends ?
 
Drill it from both ends, with an undersize drill, then finish drill thru
from cavity end. Depending on what your making, consider something
smaller than .079. Where the pin hole emerges in the cavity, some
flaring may occur as you finish the die, and this raises hell with the point.
The ej pin hole can be lapped later. Drill the back end in a lathe and
the cavity end vertical in a mill to eliminate droop in a long bit.
 
Thanks Bob .
The .79 size ejection pin is for hunting bullets not target bullets.
The larger size pin makes the dies more reliable and less chance of penertrating the meplat and damaging it or failing to eject properly.
The slightly larger meplat is superior for a game bullet than a needle nose is.
Also I have plenty of spare pin wire in this size and some other dies I have also have this pin size that work very well.
My plan was to drill the internal part of the hole using the center provided by the step drilling before any ogive reaming and lapping is done that way any burrs or flaring from drilling would be removed from the cavity.
Does this sound ok?
Swapping to the mill is something I had not considered.
I will have to think about that.
 
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