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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
Not easy... ..3125" through 7" of 304SS on the lathe with a 12" extension drill with about 3" of flutes. This gave me .2" of nudging it along before unlocking the tailstock and pulling the whole thing back to clear chips before shoving it back in, locking the tailstock and nudging another ..2". Took forever and a day in my 99F shop, but somehow I got it done. |
#2
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Pete C." fired this volley in news:53d59c7f$0$12266
: Not easy... .3125" through 7" of 304SS on the lathe with a 12" extension drill with about 3" of flutes. This gave me .2" of nudging it along before unlocking the tailstock and pulling the whole thing back to clear chips before shoving it back in, locking the tailstock and nudging another .2". Took forever and a day in my 99F shop, but somehow I got it done. Yeah, it's a chore... and I'll bet it's _perfectly_axial_ to the chuck the whole way through, too! not G Lloyd |
#3
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Pete C." wrote in message
. com... Not easy... .3125" through 7" of 304SS on the lathe with a 12" extension drill with about 3" of flutes. This gave me .2" of nudging it along before unlocking the tailstock and pulling the whole thing back to clear chips before shoving it back in, locking the tailstock and nudging another .2". Took forever and a day in my 99F shop, but somehow I got it done. That's about the only job I still use my little AA/Sears lathe for instead of the South Bend, because the little guy spins so much faster. -jsw |
#4
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Gun drilling without a gun drill...
"Lloyd E. Sponenburgh" wrote: "Pete C." fired this volley in news:53d59c7f$0$12266 : Not easy... .3125" through 7" of 304SS on the lathe with a 12" extension drill with about 3" of flutes. This gave me .2" of nudging it along before unlocking the tailstock and pulling the whole thing back to clear chips before shoving it back in, locking the tailstock and nudging another .2". Took forever and a day in my 99F shop, but somehow I got it done. Yeah, it's a chore... and I'll bet it's _perfectly_axial_ to the chuck the whole way through, too! not G Lloyd It looks pretty good actually. It was a high quality drill, Guherig (sp?), so it behaved pretty well. At any rate, it is coaxial with the OD at the start point, so if I flip it around and center that end in the 4 jaw, with the tailstock in the exit hole and then re-turn the OD it should center it up. The 1.75" OD ends up at 1.25" so there is plenty left to remove. |
#5
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Pete C." fired this volley in news:53d5a550$0
: so if I flip it around and center that end in the 4 jaw, with the tailstock in the exit hole and then re-turn the OD it should center it up. The 1.75" OD ends up at 1.25" so there is plenty left to remove. Over only 7", it won't curve much, but you can be pretty certain the hole isn't merely angled, but actually arc'd. Chucking it isn't the way to get the two ends true to center. Catch the piece between centers, and dog it. Lloyd |
#6
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Gun drilling without a gun drill...
"Lloyd E. Sponenburgh" wrote: "Pete C." fired this volley in news:53d5a550$0 : so if I flip it around and center that end in the 4 jaw, with the tailstock in the exit hole and then re-turn the OD it should center it up. The 1.75" OD ends up at 1.25" so there is plenty left to remove. Over only 7", it won't curve much, but you can be pretty certain the hole isn't merely angled, but actually arc'd. Chucking it isn't the way to get the two ends true to center. Catch the piece between centers, and dog it. Yes, but it will be close enough since I turned the OD at the starting end. If I center that to a tenth the hole will be centered. I might do it between centers, depends on my ambition level and the shop temperature. I needs to be pretty accurate given the projectile passing through, but it's got a fair amount of clearance so It can tolerate a little misalignment. |
#7
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Gun drilling without a gun drill...
"Pete C." fired this volley in news:53d5b563$0
: Yes, but it will be close enough since I turned the OD at the starting end If you didn't need accurate drilling, why'd you call it "gun drilling"? A 7" deep hole 5/16" in diameter ain't really much of a challenge, anyway. A conventional "aircraft drill" would have turned the trick. If you really needed it true, you'd have drilled it undersized and reamed it to diameter, then turned it between centers to true up the o.d.. Lloyd |
#8
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Lloyd E. Sponenburgh" wrote in message . 3.70... "Pete C." fired this volley in news:53d5b563$0 : Yes, but it will be close enough since I turned the OD at the starting end If you didn't need accurate drilling, why'd you call it "gun drilling"? A 7" deep hole 5/16" in diameter ain't really much of a challenge, anyway. A conventional "aircraft drill" would have turned the trick. If you really needed it true, you'd have drilled it undersized and reamed it to diameter, then turned it between centers to true up the o.d.. Lloyd ================================================= A 5/16 hole 7-in. long, drilled undersize, isn't going to provide enough side force to make a reamer run true. The reamer would just follow the drilled hole. There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. -- Ed Huntress |
#9
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Lloyd E. Sponenburgh" wrote: "Pete C." fired this volley in news:53d5b563$0 : Yes, but it will be close enough since I turned the OD at the starting end If you didn't need accurate drilling, why'd you call it "gun drilling"? A 7" deep hole 5/16" in diameter ain't really much of a challenge, anyway. A conventional "aircraft drill" would have turned the trick. If you really needed it true, you'd have drilled it undersized and reamed it to diameter, then turned it between centers to true up the o.d.. Lloyd You work with what you've got. |
#10
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Ed Huntress" fired this volley in
: A 5/16 hole 7-in. long, drilled undersize, isn't going to provide enough side force to make a reamer run true. The reamer would just follow the drilled hole. There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. Ed, they make reamers that small with flutes 6" long. That would provide plently of 'guide' surface. The reamer could bend some, but wouldn't if you took it slowly. But anyway... unless you have a coolant-ported drill and a high-pressure coolant pump, you're going to have to peck anyway, past about six drill diamters deep. I didn't even consider a d-bit to be in his options; especially considering he's talking about just re-chucking to true the piece up. Pecking IS a pain. Some day, I'm going to make that lever drilling attachment I've always envied, or put together a right proper carriage drill holder. LLoyd |
#11
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Ed Huntress" wrote in message
... ... There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. -- Ed Huntress In my limited experience D bits are tricky to sharpen without a surface grinder and fixturing, to keep them cutting at the center and not binding at the full-sized OD behind the cutting edge as it wears smaller. They don't cut at all if the center point is high and can't tolerate it being too low because the thin wire left in the middle becomes an obstruction. I use D bits to ream tapered holes in fluid nozzles for my experiments, not for deep hole drilling since grease passages in axles don't need to be straight. They can cut brass and aluminum if simply ground half-round from unhardened drill rod without normal edge relief clearances and forced into the pilot hole with the tailstock handwheel. -jsw |
#12
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Jim Wilkins" wrote in message ... "Ed Huntress" wrote in message ... ... There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. -- Ed Huntress In my limited experience D bits are tricky to sharpen without a surface grinder and fixturing, to keep them cutting at the center and not binding at the full-sized OD behind the cutting edge as it wears smaller. They don't cut at all if the center point is high and can't tolerate it being too low because the thin wire left in the middle becomes an obstruction. I use D bits to ream tapered holes in fluid nozzles for my experiments, not for deep hole drilling since grease passages in axles don't need to be straight. They can cut brass and aluminum if simply ground half-round from unhardened drill rod without normal edge relief clearances and forced into the pilot hole with the tailstock handwheel. -jsw ================================================== ======= [Ed] There are several configurations of drill bits and reamers that are called "D-bits." It sounds like you're making the kind with a center point. They're a b**ch to make, as you suggest. I've had much better luck with the simpler kind that's flat on the end. I learned to make these from the old English MAP hobbyist books, which describe several types. This article from a 1967 issue of Popular Science describes D-bits pretty well: http://tinyurl.com/qdcnuoa -- Ed Huntress |
#13
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Gun drilling without a gun drill...
"Ed Huntress" wrote in message
news "Jim Wilkins" wrote in message ... In my limited experience D bits are tricky to sharpen ... -jsw ================================================== ======= [Ed] There are several configurations of drill bits and reamers that are called "D-bits." It sounds like you're making the kind with a center point. They're a b**ch to make, as you suggest. I've had much better luck with the simpler kind that's flat on the end. I learned to make these from the old English MAP hobbyist books, which describe several types. This article from a 1967 issue of Popular Science describes D-bits pretty well: http://tinyurl.com/qdcnuoa -- Ed Huntress That version is easier to make than the ones in Lindsay's "Deep Hole Drilling". I stop at the step where the lathe tailstock needs to be aligned, since trade school apes misused the original spindle on my lathe as an anvil horn. The dealer swapped it but the replacement is loose, drill bits visibly jump up to the center of rotation when they bite into the work. Centering with one of these center drill collets instead of a drill chuck helps a lot: http://www.collistoolholder.com/cgi-..._9_TYP_Q_GRP_1 -jsw |
#14
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Gun drilling without a gun drill...
On Monday, July 28, 2014 8:53:50 AM UTC-4, Ed Huntress wrote:
"Jim Wilkins" wrote in message ... "Ed Huntress" wrote in message ... ... There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. -- Ed Huntress In my limited experience D bits are tricky to sharpen without a surface grinder and fixturing, to keep them cutting at the center and not binding at the full-sized OD behind the cutting edge as it wears smaller. They don't cut at all if the center point is high and can't tolerate it being too low because the thin wire left in the middle becomes an obstruction. I use D bits to ream tapered holes in fluid nozzles for my experiments, not for deep hole drilling since grease passages in axles don't need to be straight. They can cut brass and aluminum if simply ground half-round from unhardened drill rod without normal edge relief clearances and forced into the pilot hole with the tailstock handwheel. -jsw ================================================== ======= [Ed] There are several configurations of drill bits and reamers that are called "D-bits." It sounds like you're making the kind with a center point. They're a b**ch to make, as you suggest. I've had much better luck with the simpler kind that's flat on the end. I learned to make these from the old English MAP hobbyist books, which describe several types. This article from a 1967 issue of Popular Science describes D-bits pretty well: http://tinyurl.com/qdcnuoa -- Ed Huntress Gotta love that Popular Science archive. |
#15
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Jim Wilkins" wrote in message ... "Ed Huntress" wrote in message news "Jim Wilkins" wrote in message ... In my limited experience D bits are tricky to sharpen ... -jsw ================================================== ======= [Ed] There are several configurations of drill bits and reamers that are called "D-bits." It sounds like you're making the kind with a center point. They're a b**ch to make, as you suggest. I've had much better luck with the simpler kind that's flat on the end. I learned to make these from the old English MAP hobbyist books, which describe several types. This article from a 1967 issue of Popular Science describes D-bits pretty well: http://tinyurl.com/qdcnuoa -- Ed Huntress That version is easier to make than the ones in Lindsay's "Deep Hole Drilling". I stop at the step where the lathe tailstock needs to be aligned, since trade school apes misused the original spindle on my lathe as an anvil horn. The dealer swapped it but the replacement is loose, drill bits visibly jump up to the center of rotation when they bite into the work. Centering with one of these center drill collets instead of a drill chuck helps a lot: http://www.collistoolholder.com/cgi-..._9_TYP_Q_GRP_1 -jsw ================================================== ==== [Ed] Yeah, that looks good. I have some similar tailstock collets that I inherited in the pile of tooling junk that my uncle passed along. I've never used them, though. -- Ed Huntress |
#16
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Gun drilling without a gun drill...
"Lloyd E. Sponenburgh" wrote: "Ed Huntress" fired this volley in : A 5/16 hole 7-in. long, drilled undersize, isn't going to provide enough side force to make a reamer run true. The reamer would just follow the drilled hole. There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. Ed, they make reamers that small with flutes 6" long. That would provide plently of 'guide' surface. The reamer could bend some, but wouldn't if you took it slowly. But anyway... unless you have a coolant-ported drill and a high-pressure coolant pump, you're going to have to peck anyway, past about six drill diamters deep. I didn't even consider a d-bit to be in his options; especially considering he's talking about just re-chucking to true the piece up. Pecking IS a pain. Some day, I'm going to make that lever drilling attachment I've always envied, or put together a right proper carriage drill holder. LLoyd I've thought about improvising a gun drilling setup on the lathe, an adapter to hold the drill in the boring bar toolpost holder, a cheap HF electric pressure washer adapted for a coolant pump, and I guess I might have to make some more gears to get the power feed on the lathe slow enough. Something to consider if I do more of these. |
#17
Posted to rec.crafts.metalworking
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Gun drilling without a gun drill...
"Ed Huntress" wrote in message
... "Jim Wilkins" wrote in message ... ... Centering with one of these center drill collets instead of a drill chuck helps a lot: http://www.collistoolholder.com/cgi-..._9_TYP_Q_GRP_1 -jsw ================================================== ==== [Ed] Yeah, that looks good. I have some similar tailstock collets that I inherited in the pile of tooling junk that my uncle passed along. I've never used them, though. -- Ed Huntress Using it requires moving the tailstock since its overhang is much less than a chuck's. It's fine for single parts but not so good if I need to drill several to the same depth. -jsw |
#18
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Gun drilling without a gun drill...
On Mon, 28 Jul 2014 09:14:58 -0500, "Pete C."
wrote: "Lloyd E. Sponenburgh" wrote: "Ed Huntress" fired this volley in : A 5/16 hole 7-in. long, drilled undersize, isn't going to provide enough side force to make a reamer run true. The reamer would just follow the drilled hole. There is a way to drill a hole like this straight, without a real gun drill. Start the hole with a regular drill bit, drill it maybe 1" deep, and follow up with a home-made single-lip drill (a D-bit). Unlike a real gun drill, you'll have to peck it to get the chips out, and it's God-awful slow. But it works. Ed, they make reamers that small with flutes 6" long. That would provide plently of 'guide' surface. The reamer could bend some, but wouldn't if you took it slowly. But anyway... unless you have a coolant-ported drill and a high-pressure coolant pump, you're going to have to peck anyway, past about six drill diamters deep. I didn't even consider a d-bit to be in his options; especially considering he's talking about just re-chucking to true the piece up. Pecking IS a pain. Some day, I'm going to make that lever drilling attachment I've always envied, or put together a right proper carriage drill holder. LLoyd I've thought about improvising a gun drilling setup on the lathe, an adapter to hold the drill in the boring bar toolpost holder, a cheap HF electric pressure washer adapted for a coolant pump, and I guess I might have to make some more gears to get the power feed on the lathe slow enough. Something to consider if I do more of these. I did a bunch of OmniTurn CNC lathes with 350lb high pressure coolant pumps a few years ago at Gertler Industries. We were drilling up to 6" deep with 3/8" and bigger coolant ported drill bits at a dead run in all manner of alloy steels. .003-..008 per rev feed rates They liked the first one so well they had me do another 17 machines Gunner -- "Living in the United States now is like being a Tampon. We're in a great place, just at a bad time." |
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