How should I go about removing a machine anomoly from a piston?

I bought a set of older out of Production NOS pistons for a future project.

Upon inspection one piston has a broken drill bit stuck in it... in the oil feed hole to the piston pin.

It is behind the oil ring area, feeding into the piston pin area. I can see the broken bit in there from the hole in the piston pin bore that intersects with the hole from the oil ring.

❓ The Question i have for you sages is how to ge the darn thing out without damaging the piston?

Thanks,

Greg

Is a photo possible?

Find a machine shop with an EDM machine?  Literally what they were first designed for.

In reply to jharry3 :

Yes I can get you one in a bit.

Greg

Mr_Asa said:

Find a machine shop with an EDM machine?  Literally what they were first designed for.

Exactly this ...

Bit is stuck in this oil feed hole behind the oil ring:

20210208_105324 by Hyperpack, on Flickr

Drill Bit is stuck inside this hole..  you cant' see it in the photo but it's there.When a wire / small screwdriver is put in the intersecting hole  You cannot see it inside the hole in this view due to the broken drill bit.

20210208_110722 by Hyperpack, on Flickr

The high tech approach is wire EDM.  The low tech approach is to find or make a punch that's a light sliding fit in the hole and drive that bad boy out from the pin bore side to the ring side.

If this is for a highly stressed race engine then EDM is the way to go.  For pretty much any other application I'd drive it out.  That hole is basically as large as it can be without intersecting any other geometry when it's drilled. 

Thanks guys,

I found 2 shops within 6 miles of the house that have edm capabilities, I will have to call / email to see if they would be willing to futz with such a mundane, small non industrial job like mine.

This is not for an all out balls to the wall race build so I think I might try futzing with the small pin / punch first to see if I can get it out.

Thank you, as I learned About EDM and 2 places near me that offer those services.

Now I have to check the other pistons in the set and be sure about those as well... to make sure there's no odd bits of stuff broken off in them.

Greg

Put the piston in the toaster oven at 400 F for 20 minutes and you might just shake the bit out. Aluminum will expand more than the bit.

AngryCorvair (Forum Supporter) said:

Put the piston in the toaster oven at 400 F for 20 minutes and you might just shake the bit out. Aluminum will expand more than the bit.

That's a great idea! 

Head over to the spice section of your grocery store and pick up some Alum. It will dissolve steel but not aluminum. 

APEowner said:

AngryCorvair (Forum Supporter) said:

Put the piston in the toaster oven at 400 F for 20 minutes and you might just shake the bit out. Aluminum will expand more than the bit.

That's a great idea! 

Thermal expansion for the win!

In reply to RichardSIA :

did the state of ' kalifornia. take it away from you?

Tap extractor?

In reply to 914Driver :

Thanks for that idea too.

Is there a tap extractor in sizes smaller than Ø1/8" ?

Greg

In reply to AngryCorvair (Forum Supporter) :

This will be easy to try, So I probably will try it first. - My oven is no stranger to having car parts on the cookie sheet