Broken Drill Removal

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

daves1459
Posts: 93
Joined: Mon Jun 07, 2010 7:58 pm

Broken Drill Removal

Post by daves1459 » Wed Sep 19, 2018 6:57 pm

Does anyone have an idea on how to remove a 3/64" diameter drill tip, about 1/8" long, from 360 brass? Or a shop that can do it? There are shops around here that offer spark erosion removal services. But, they only go down to 1/8" diameter or a #5 screw.

Dave

squandt
Posts: 41
Joined: Wed Jul 16, 2014 1:15 pm
Location: cleveland ohio

Re: Broken Drill Removal

Post by squandt » Wed Sep 19, 2018 7:05 pm

if I recall ,there are several other post's on how to do this, I removed a broken tap using acid (battery) from a brass casting. Worked very well, took 2 days, acid was cut with water, casting is now finished pump( water).
stay on the shine side of the rail

User avatar
Builder01
Posts: 470
Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: Broken Drill Removal

Post by Builder01 » Wed Sep 19, 2018 8:08 pm

Here's the thread you want to read:

http://www.chaski.org/homemachinist/vie ... al#p203721

I used this method to remove a broken 3-48 tap in a piece of stainless. It takes a while, but, it worked and I saved the part!

David

User avatar
ChuckHackett-844
Posts: 91
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Broken Drill Removal

Post by ChuckHackett-844 » Wed Sep 19, 2018 8:30 pm

I believe that you can use alum (hydrated double sulfate of aluminum and potassium) available at the grocery store. It will attack steel but not brass. I believe I have used it in the past to remove a broken tap. Google "using alum to remove a broken tap".
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

daves1459
Posts: 93
Joined: Mon Jun 07, 2010 7:58 pm

Re: Broken Drill Removal

Post by daves1459 » Wed Sep 19, 2018 8:41 pm

Thanks for the tips. I knew that it there was anybody who knew about removing broken taps or drills it would be the Chaski bunch. Ha! Ha! Anyway I'll try the alum technique. I wonder if layout dye would be a viable barrier to the alum solution to prevent discoloration.

Dave

User avatar
ChuckHackett-844
Posts: 91
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Broken Drill Removal

Post by ChuckHackett-844 » Wed Sep 19, 2018 10:26 pm

daves1459 wrote:
Wed Sep 19, 2018 8:41 pm
.... I wonder if layout dye would be a viable barrier to the alum solution to prevent discoloration.

Dave
perhaps something sturdier ... Lacquer, nail polish [don't tell the wife :-) ] ?
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

User avatar
John_S
Posts: 696
Joined: Wed Apr 06, 2011 8:21 pm
Location: Cumming, GA

Re: Broken Drill Removal

Post by John_S » Fri Sep 21, 2018 10:14 am

I've used alum to dissolve a broken tap in a brass part for a pump I was building. I put the part in a small crock pot with water and alum and left it on low for a couple days. The tap turned to mush and washed right out of the hole.

I found alum at WalMart (but not at Publix or Kroger).

Brian Hilgert
Posts: 235
Joined: Mon Jan 21, 2013 8:35 am
Location: Pittsburgh, PA

Re: Broken Drill Removal

Post by Brian Hilgert » Mon Sep 24, 2018 12:54 pm

I have used the Alum trick also, the trick is to keep it heated, It is also helpful to keep picking at the tap with an old scribe. it seemed to work better for me.

User avatar
Bill Shields
Posts: 5143
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: Broken Drill Removal

Post by Bill Shields » Thu Sep 27, 2018 9:42 am

FWIW: I use white vinegar with a 'pinch' of salt tossed in.

if all else fails and it is an important ($$$) part -> find someone with an EDM DRILL.

rkcarguy
Posts: 871
Joined: Tue Aug 22, 2017 10:33 am

Re: Broken Drill Removal

Post by rkcarguy » Thu Sep 27, 2018 1:17 pm

You've got lots of options, as there are many things out there that will eat away at the steel but not the brass.
We used to hang onto broken carbide drills and end mills at our machine shop, as we found that a single relief could be ground into the end and at high speed in the mill it could be plunged into the hole and it would cut through the HSS broken off in a part.
With a #3 thread through, chemical disolving would be the best bet.

daves1459
Posts: 93
Joined: Mon Jun 07, 2010 7:58 pm

Re: Broken Drill Removal

Post by daves1459 » Tue Oct 09, 2018 8:39 pm

It works! The alum in hot water did an excellent job of removing two broken 3/64" drills stuck in the brass cab door of my NYC&HR 999 project. The door is 1/4" thick x aprox. 2" wide x aprox 7" long. I broke two 0-80 tap drills for one of the doll house hinges I using to attach the door. I put about an inch of water in glass bread loaf baking dish and dissolved about one pound of alum. I painted the door with everyday Krylon rattle can paint masking the hinge seat with the two broken drills. When dry rested the door on two 1/4" scrap brass bars in the alum rich solution, covered the dish with aluminum foil, rested a piece of flat steel on the foil and put the whole lot on a counter top toaster oven. A chemist friend told me the rich alum solution raised the water boiling temperature by 10 to 20 degrees so I set the thermostat at 220F. I'm not sure how long it took to dissolve the drilsl. I cycled the mixture at 220F for 30 hours over a three day period turning the oven off over night. Upon inspection after the 30 hours I found the drills to be gone. The process is amazing and didn't dimensionally affect the door including the other four 0-80 tapped holes for the other hinges. I found a few things interesting:
1. I could dissolve one pound of alum in an inch of water in the load dish.
2. When hot the solution looks like aeriated tap water. When cooled to room temperature the solution solidifies to soft solid mass that resembles the paraffin wax my Mom used to seal her preserves when I was a youngster.
3. When clean steel is in the solution it fizzes like an AlkaSeltzer. The least little oxide or other coating and the chemical reaction stops.
4. The painting of the door was a waste of time. The Krylon may be porous as the door still discolored. But, the discoloration was minimal and easily removed with 320 grit emery cloth.
5. I wonder if the solidified solution can be stored and reused at a later date? Or will it corrode or foam or grow mushrooms or something.

Dave
Attachments
DSC01897.JPG
DSC01903.JPG
DSC01906.JPG
DSC01910.JPG

John Hasler
Posts: 966
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: Broken Drill Removal

Post by John Hasler » Tue Oct 09, 2018 8:54 pm

The solution will keep pretty much forever.

Post Reply