Etching out broken taps & drills.
I'm trying to determine which of the acids we used to use, in the old days,
to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
John wrote:
I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John If you find something which will disolve tool steel out of cast iron without eating up the cast iron too, please let me know. Think EDM... Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
For that depth I'd get a solid carbide end mill and set it up in a mill.
We took out a broken EZ Out a couple weeks ago, just melted right through it. I was quite impressed! But don't even THINK about doing it in a drill press. John wrote: I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
RoyJ wrote:
For that depth I'd get a solid carbide end mill and set it up in a mill. We took out a broken EZ Out a couple weeks ago, just melted right through it. By reading this, I just got an idea (not proofen to work, it just flashed up in my confused brain). Set the piece up in a mill, and "rubb" on the broken drill with some hardened rod. Of course, the rod is rotating and pressed down firmy onto the bit. It might start to melt and weld onto the broken drill. Maybe the mill should go in reverse. Works just like the welding process does. Comments? Should I forget that idea? You can use the trick to localy anneal leaf springs to get a hole in them. Nick -- Motormodelle / Engine Models http://www.motor-manufaktur.de todays SPAMfeed: |
"Jeff Wisnia" wrote in message ... John wrote: I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John If you find something which will disolve tool steel out of cast iron without eating up the cast iron too, please let me know. Think EDM... Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) You're right Jeff, it might eat up a small amount of the C.I., but in this particular case that's not to important. The part is too odd shaped to mount to a machine table to mill out. If we could loosen the drill slightly I think we might be able to get it out. I just remember that in the past there have been occasions where we removed broken cutting tools from a base material with an acid. I don't recall which specific acid or base material worked the best. Obviously if it eats up your part it wouldn't be too good. I wouldn't propose doing it on a precision machined part, that's why I thought this group might have a suggestion or two. I've removed many broken tools over the years with left hand drills and left hand carbide end mills, but that won't work too well in this case. 73, John (W7JDA) ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
I've heard of nitric acid for disolving taps in AL. Bet it eats cast faster
than tool steel. Karl "John" wrote in message ... I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
If I remember correctly, cast iron is more resistant than steel, to attack
by sulphuric acid. If you can fill the hole with H2SO4, you may find that it dissolves enough of the drill to remove it. You'll have to keep trying it on a regular basis though, as I have no idea as to how long it will take. I could give you the usually boring warnings about strong acids and gloves and glasses, but if you don't know enough about already, you shouldn't mess with it at all. Tom miller "John" wrote in message ... "Jeff Wisnia" wrote in message ... John wrote: I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John If you find something which will disolve tool steel out of cast iron without eating up the cast iron too, please let me know. Think EDM... Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) You're right Jeff, it might eat up a small amount of the C.I., but in this particular case that's not to important. The part is too odd shaped to mount to a machine table to mill out. If we could loosen the drill slightly I think we might be able to get it out. I just remember that in the past there have been occasions where we removed broken cutting tools from a base material with an acid. I don't recall which specific acid or base material worked the best. Obviously if it eats up your part it wouldn't be too good. I wouldn't propose doing it on a precision machined part, that's why I thought this group might have a suggestion or two. I've removed many broken tools over the years with left hand drills and left hand carbide end mills, but that won't work too well in this case. 73, John (W7JDA) ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
John wrote:
"Jeff Wisnia" wrote in message ... John wrote: I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John If you find something which will disolve tool steel out of cast iron without eating up the cast iron too, please let me know. Think EDM... Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) You're right Jeff, it might eat up a small amount of the C.I., but in this particular case that's not to important. The part is too odd shaped to mount to a machine table to mill out. If we could loosen the drill slightly I think we might be able to get it out. I just remember that in the past there have been occasions where we removed broken cutting tools from a base material with an acid. I don't recall which specific acid or base material worked the best. Obviously if it eats up your part it wouldn't be too good. I wouldn't propose doing it on a precision machined part, that's why I thought this group might have a suggestion or two. I've removed many broken tools over the years with left hand drills and left hand carbide end mills, but that won't work too well in this case. 73, John (W7JDA) Try putting a little light oil or Kroil in the hole and then try tapping against the flutes of the busted drill tip with a sharp punch and a light hammer. If it's only in 3/16" deep, I bet you can wiggle it enough to let the oil get down into the crevices and help you make it easier to back it out. Ay least that's what I'd try first, you can alway go on to more exotic methods if my suggestion fails. Jeff - Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
I really like this idea! I wonder if the heat would cause the part you
wish to remove to expand and be more difficult to get out. Perhaps if you did is fast. I goes without saying that you plan to run the milling machine counter clockwise. Good Luck! Rick |
Harbor Freight sells a very small air turbine that will take dental
drills. I have had good luck using one of those to get broken taps out. Not real fast, but it does work on tool steel. Dan John wrote: I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John |
"John" wrote in message ... I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John =---- One trick I have used in the past with quite good results is an arc welder. Put a sleeve down the hole to protect the sides, use a piece of mild steel with the welder set on fairly low current. Stick the "electrode" down the sleeve until it "sticks" to the whatever you are trying to get out. Turn the welder off - you now have an extension on the whatever it is stuck in the hole. Actually works fairly well many times. mikey |
"Jeff Wisnia" wrote in message ... John wrote: "Jeff Wisnia" wrote in message ... John wrote: I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John If you find something which will disolve tool steel out of cast iron without eating up the cast iron too, please let me know. Think EDM... Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) You're right Jeff, it might eat up a small amount of the C.I., but in this particular case that's not to important. The part is too odd shaped to mount to a machine table to mill out. If we could loosen the drill slightly I think we might be able to get it out. I just remember that in the past there have been occasions where we removed broken cutting tools from a base material with an acid. I don't recall which specific acid or base material worked the best. Obviously if it eats up your part it wouldn't be too good. I wouldn't propose doing it on a precision machined part, that's why I thought this group might have a suggestion or two. I've removed many broken tools over the years with left hand drills and left hand carbide end mills, but that won't work too well in this case. 73, John (W7JDA) Try putting a little light oil or Kroil in the hole and then try tapping against the flutes of the busted drill tip with a sharp punch and a light hammer. If it's only in 3/16" deep, I bet you can wiggle it enough to let the oil get down into the crevices and help you make it easier to back it out. Ay least that's what I'd try first, you can alway go on to more exotic methods if my suggestion fails. Jeff - Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." Expanding on that idea, if you heat it up first (propane torch should be adequate, if you use OA, be conservative with it...) and then squirt some WD-40 into it, it should loosen. A part of the problem is that the broken drill is tight against the sides and it makes it difficult for the oil to penetrate. But, if you heat the whole mess up a little, then squirt it, the oil will cool the drill and it will contract enough that the oil can penetrate the gap. Then proceed as Jeff suggested. Jerry |
Look in the Machinery's Handbook under Removing a broken tap. One part
nitric acid and 5 parts water. Jim "John" wrote in message ... I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
" Jim Sehr" wrote in message ... Look in the Machinery's Handbook under Removing a broken tap. One part nitric acid and 5 parts water. Jim "John" wrote in message ... I'm trying to determine which of the acids we used to use, in the old days, to disintegrate broken taps or drills. I remember when that was done occasionally, but don't remember which acid was used. I have a friend who has a broken drill in cast iron and I thought this might be a possibility before we start chopping at it with carbide tools and make matters worse. It might at least loosen it up enough to remove by hand. It's a 1/8" dia. drill and not in too deep, about 3/16", but it's bound pretty tight. Thanks John Thanks to everyone for the suggestions. Some of which I've not tried in the past. It's amazing how many good ideas there are out there! Thanks Jim, for the reference to the Machinery's Handbook. Duh, I guess I should have thought to look there first. That's the specific info that I was looking for. Thanks again to all. John ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
"Tom Miller" wrote in message ... If I remember correctly, cast iron is more resistant than steel, to attack by sulphuric acid. If you can fill the hole with H2SO4, you may find that it dissolves enough of the drill to remove it. You'll have to keep trying it on a regular basis though, as I have no idea as to how long it will take. I could give you the usually boring warnings about strong acids and gloves and glasses, but if you don't know enough about already, you shouldn't mess with it at all. Tom miller Truth is, iron won't dissolve in *concentrated* sulfuric acid, but if there's any water present, all bets are off. Cast iron kettles used to be used in processing sludge from silver cells, to separate residual silver particles from the sludge, from which the rest of the precious metals were extracted (gold and the platinum group metals). The silver particles were dissolved by boiling the sludge in concentrated sulfuric acid. Harold |
Karl Townsend wrote: I've heard of nitric acid for disolving taps in AL. Bet it eats cast faster than tool steel. Karl Nitric acid or a concentrated alum solution will eat the tap without harming the aluminum. Don't know of anything that will help in cast iron, though. John Martin |
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