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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
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Drilling 304 Stainless
I may have asked this before, but I'm slow:
I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
#2
Posted to rec.crafts.metalworking
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Drilling 304 Stainless
Tim Wescott fired this volley in
: Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. Are you center-punching the holes before drilling? If so, there IS a "skin" to break through... you've work-hardened the piece where it's punched. A better strategy is to use a really short bit, and just drill. LLoyd |
#3
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Drilling 304 Stainless
"Tim Wescott" wrote in message ... I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com Perhaps you could hone a very fine split point on the drill? That's tiny but could be done with a small diamond file and a steady stroke. It's worth a try.... pdk |
#4
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Drilling 304 Stainless
On 8/30/2012 7:59 PM, Tim Wescott wrote:
I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. 304 SS is junk stainless, but cheap. The reason it's so hard to cut is an absence of sulphur in the alloy for lubrication. You have to get the speed & feed just right to cut it, and you still get short tool life. A few more pennies spent on a better alloy will save a lot in tooling. Or have the parts cut on a LASER, we cut 304 all day long and the LASERs don't wear out! David |
#5
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Drilling 304 Stainless
Tim Wescott fired this volley in
: This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". Forgot, Tim... Even the drilling must be done apace. If you dawdle or idle in the hole, it will work-harden. You must drill smoothly through in one pass, or at least _instantly_ retract the bit if you must stop before penetrating it. Some coolant or cutting oil will help preserve your edges, too. LLoyd |
#6
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Drilling 304 Stainless
On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott
wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. Any reason not to use 6061T6 aluminum instead??? If you NEED to use stainless, you will NEED a better drill bit. With stainless you need a POSITIVE feed - never let the bit skate on the surface. I'd try a good center punch - or use a "center drill" to make the starting dimple, then follow through with the normal bit. Get one of those that they show at tradeshows etc drilling through files and leaf springs, and using them as milling cutters. |
#7
Posted to rec.crafts.metalworking
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Drilling 304 Stainless
Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. I'm thinking very short carbide drills in the CNC mill for precise and consistent feed rate and perhaps some appropriate coolant. |
#8
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Drilling 304 Stainless
304 stainless work hardens if you don't put enough pressure on the drill
bit. Also slow is much better than fast, a surface speed of about 50 ft. per minute. If you have a workhardened started hole if you continue drilling the new or sharpened drill will get dull as it cuts the workhardened metal. Once you get through the work hard metal, resharpen or replace the drill or you will wind up with another work hardened hole. You could get a carbide drill that would work much better. John Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. |
#9
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Drilling 304 Stainless
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#10
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Drilling 304 Stainless
On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott
wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. If you can live with 1/8" thick material, McMaster has 303 SS up to 2" wide. Thin 304 sheet is cold rolled, and consequently work hardened, making it much nastier to machine than hot rolled stock. 303 is a free machining (relatively speaking) grade, and would be the best bet if you can use an available size. But not recommended for welding. -- Ned Simmons |
#11
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Drilling 304 Stainless
On Thu, 30 Aug 2012 21:50:56 -0400, clare wrote:
On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. Any reason not to use 6061T6 aluminum instead??? If you NEED to use stainless, you will NEED a better drill bit. With stainless you need a POSITIVE feed - never let the bit skate on the surface. I'd try a good center punch - or use a "center drill" to make the starting dimple, then follow through with the normal bit. Get one of those that they show at tradeshows etc drilling through files and leaf springs, and using them as milling cutters. Aluminum wears too quickly. The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. But it would make the job much easier. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#13
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Drilling 304 Stainless
On Thu, 30 Aug 2012 21:58:48 -0400, Ned Simmons wrote:
On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. If you can live with 1/8" thick material, McMaster has 303 SS up to 2" wide. Thin 304 sheet is cold rolled, and consequently work hardened, making it much nastier to machine than hot rolled stock. 303 is a free machining (relatively speaking) grade, and would be the best bet if you can use an available size. But not recommended for welding. Good thought, but 1/8 is much too thick. Man, I'm really not trying to reject all advise here... -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#14
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Drilling 304 Stainless
On Thu, 30 Aug 2012 20:22:29 -0500, David R. Birch wrote:
On 8/30/2012 7:59 PM, Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. 304 SS is junk stainless, but cheap. The reason it's so hard to cut is an absence of sulphur in the alloy for lubrication. You have to get the speed & feed just right to cut it, and you still get short tool life. A few more pennies spent on a better alloy will save a lot in tooling. Or have the parts cut on a LASER, we cut 304 all day long and the LASERs don't wear out! Kinda spendy for one-offs. I know a guy who laser cuts balsa -- maybe I'll see what kind of price he'd give me for making a handful of the metal parts, assuming he wants to and can. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#15
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Drilling 304 Stainless
Aluminum wears too quickly. The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. But it would make the job much easier. Just a thought... could/would some sort of hardened bushing/fairlead/lead-out work? It would make the handle assembly lighter as well Erik PS, I also flew a lot of C/L as a kid it was the mid/late 60's... Combat, rat, and even dabbled in a little jet speed. The hot handle of those days was red plastic, with a piece of cable threaded through it. The ends of the cable had eyes swaged in with 'Nicopress' like sleeves. Not sure of the name... EZ-Just or EZ-Adjust comes to mind... |
#16
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Drilling 304 Stainless
On Thu, 30 Aug 2012 22:43:57 -0700, Erik wrote:
Aluminum wears too quickly. The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. But it would make the job much easier. Just a thought... could/would some sort of hardened bushing/fairlead/lead-out work? It would make the handle assembly lighter as well Erik PS, I also flew a lot of C/L as a kid it was the mid/late 60's... Combat, rat, and even dabbled in a little jet speed. The hot handle of those days was red plastic, with a piece of cable threaded through it. The ends of the cable had eyes swaged in with 'Nicopress' like sleeves. Not sure of the name... EZ-Just or EZ-Adjust comes to mind... EZ-Just. I have one. The hot ticket for control line stunt is a hard-point handle of some sort, with no heavy cable to soften the response by acting as a spring. The handle design I'm using uses a line of holes to adjust spacing, and different-sized clips at the handle to adjust the neutral point. It's exceptionally simple -- except for drilling those damned holes. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#17
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Drilling 304 Stainless
"David R. Birch" wrote in message ... 304 SS is junk stainless, but cheap. Blink! Blink! Junk stainless? I don't think so. The reason it's so hard to cut is an absence of sulphur in the alloy for lubrication. You have to get the speed & feed just right to cut it, and you still get short tool life. A few more pennies spent on a better alloy will save a lot in tooling. While I'd agree that a change of alloy would be helpful, to imply that this is an inferior alloy is nonsense. It's no such thing. It simply isn't free machining, as you implied, which has no relationship to its quality. A free machining grade of stainless, if anything, might be considered a somewhat inferior alloy, as the presence of sulfur (or selenium) tends to lower chemical resistance, although improving machining characteristics immeasurably. I If the article in question can be fashioned from bar stock, that would be my choice---303 S (or Se) stainless. However, that grade is not available as plate, as it does not lend itself to welding, so there is limited need in that configuration. Harold |
#18
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Drilling 304 Stainless
Tim Wescott fired this volley in
: The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. So, line the holes with SS grommets/hollow rivets. It would even "look cool", with the grommets indicating that someone had done something about the wear issue. Lloyd |
#19
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Drilling 304 Stainless
In article ,
Tim Wescott wrote: I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. How thick is the stuff you are drilling? Stainless work-hardens in a flash - you can't be dainty with it. Use screw machine bits. Minimize stick-out. You want rigidity - if you could stick a 1/16th collet in the mill and use it as an overbuilt drill press, with the absolute minimum stickout to drill your sheet, that would be lovely. But you should be able to do it in a drill press if it's not terribly sloppy, and you do what you can to minimize stickout, such as buying screw-machine bits. Heat-Resistant Cobalt Steel Short-Length Drill Bits $1.48 - $1.26 for 12+ (McMaster) Carbide can be good and bad - it's hard which helps with cutting, but it's brittle so it's prone to break if there is any flex. Plus it costs more than steel. You might also want to dab a bit of lube on there. If you have fairly thin sheet, McMaster does seem to have ONE "combined drill and countersink" with a 1/16th drill-point part - that gives you something extra-rigid right down to the top of a very short drill. 2915A72 - kinda spendy at $6.54, but you do get two ends. Then you have things like... Straight-Flute Carbide Short-Length Drill Bits for Hard Steel ($11.13) Carbide Small-Diameter Drill Bits with 1/8" Shank ($4.51) -- Cats, coffee, chocolate...vices to live by Please don't feed the trolls. Killfile and ignore them so they will go away. |
#20
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Drilling 304 Stainless
On Aug 31, 12:06*am, Tim Wescott wrote:
Man, I'm really not trying to reject all advise here... -- Tim Wescott Control system and signal processing consultingwww.wescottdesign.com Carpenter Tech has some excellent literature on machining stainless. I think you have to register to download it, but well worth the effort. I would also look for cutting lube made for stainless. There are some unusual lubes for stainless including ones with iodine in them. Not sure if any of them are especially good for machining stainless, but Carpenter Tech should have the information. Dan |
#21
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Drilling 304 Stainless
I would use carbide on my CNC mill, personally. CNC also helps with
consistently using the same feedrate. i On 2012-08-31, Ecnerwal wrote: In article , Tim Wescott wrote: I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. How thick is the stuff you are drilling? Stainless work-hardens in a flash - you can't be dainty with it. Use screw machine bits. Minimize stick-out. You want rigidity - if you could stick a 1/16th collet in the mill and use it as an overbuilt drill press, with the absolute minimum stickout to drill your sheet, that would be lovely. But you should be able to do it in a drill press if it's not terribly sloppy, and you do what you can to minimize stickout, such as buying screw-machine bits. Heat-Resistant Cobalt Steel Short-Length Drill Bits $1.48 - $1.26 for 12+ (McMaster) Carbide can be good and bad - it's hard which helps with cutting, but it's brittle so it's prone to break if there is any flex. Plus it costs more than steel. You might also want to dab a bit of lube on there. If you have fairly thin sheet, McMaster does seem to have ONE "combined drill and countersink" with a 1/16th drill-point part - that gives you something extra-rigid right down to the top of a very short drill. 2915A72 - kinda spendy at $6.54, but you do get two ends. Then you have things like... Straight-Flute Carbide Short-Length Drill Bits for Hard Steel ($11.13) Carbide Small-Diameter Drill Bits with 1/8" Shank ($4.51) |
#22
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Drilling 304 Stainless
On Fri, 31 Aug 2012 07:49:40 -0400, Ecnerwal
wrote: In article , Tim Wescott wrote: I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. How thick is the stuff you are drilling? Stainless work-hardens in a flash - you can't be dainty with it. Use screw machine bits. Minimize stick-out. You want rigidity - if you could stick a 1/16th collet in the mill and use it as an overbuilt drill press, with the absolute minimum stickout to drill your sheet, that would be lovely. But you should be able to do it in a drill press if it's not terribly sloppy, and you do what you can to minimize stickout, such as buying screw-machine bits. Heat-Resistant Cobalt Steel Short-Length Drill Bits $1.48 - $1.26 for 12+ (McMaster) As above use screw machine length drills, cobalt, not just plain HSS. Run at 2773 RPM this should be 45 SFM. I would use original Cool Tool if I had it, you know the stuff that really worked and was banned by the Feds. Find some cutting juice recommended for stainless. Remove 333 to reply. Randy |
#23
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Drilling 304 Stainless
In article ,
Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. I've drilled lots of 304 sheet using cobalt HSS drill bits (gotta be new and SHARP) in a drill press, or better a mill used to drill, lubricated with black sulfur oil. The trick is to set the drill press or mill to turn slow and powerful, be very heavy handed while drilling, and be liberal with the black sulfur oil. Some drill presses cannot turn slow enough for the larger drill bits, like Unibits to cut a 1/2" hole. Joe Gwinn |
#24
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Drilling 304 Stainless
On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott
wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. Greetings Tim, In your situation I would use stub length cobalt split point drills. The split point is important. Use a high sulfur cutting oil. Your local hardware store probably sells some type of cutting oil made for threading. The dark stuff is usually a high sulfur cutting oil. You need to make sure there is constant pressure on the drill and that it is always cutting. If you start the drill gingerly there is a good chance that the 304 will work harden and then the pressure it takes to get the drill to cut goes way up. So start drilling like you mean it. Also, back up the sheet with another piece of metal. Aluminum is fine, mild steel too. Even hard maple might be OK. You don't want the sheet flexing away from the drill. This lowers the cutting pressure which leads to work hardening. Drilling into mild steel might be the best because it is close to 304 in hardness(but not nearly as tough!) and this will help prevent a burr being pushed out of the 304 and into the back up material. So you end up with cleaner holes and the dril is not as likely to break as it exits the 304. Ideally the drill should be spinning at about 2400 rpm. But this means you would need to feed the drill fast through the part to make sure it is cutting the whole time. Less than a second to go through 1/16 material. So maybe slower speed with constant pressure right from the start will be best for your situation with the drill press. Eric |
#25
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Drilling 304 Stainless
wrote in message news On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. Greetings Tim, In your situation I would use stub length cobalt split point drills. The split point is important. Use a high sulfur cutting oil. Your local hardware store probably sells some type of cutting oil made for threading. The dark stuff is usually a high sulfur cutting oil. You need to make sure there is constant pressure on the drill and that it is always cutting. If you start the drill gingerly there is a good chance that the 304 will work harden and then the pressure it takes to get the drill to cut goes way up. So start drilling like you mean it. Also, back up the sheet with another piece of metal. Aluminum is fine, mild steel too. Even hard maple might be OK. You don't want the sheet flexing away from the drill. This lowers the cutting pressure which leads to work hardening. Drilling into mild steel might be the best because it is close to 304 in hardness(but not nearly as tough!) and this will help prevent a burr being pushed out of the 304 and into the back up material. So you end up with cleaner holes and the dril is not as likely to break as it exits the 304. Ideally the drill should be spinning at about 2400 rpm. But this means you would need to feed the drill fast through the part to make sure it is cutting the whole time. Less than a second to go through 1/16 material. So maybe slower speed with constant pressure right from the start will be best for your situation with the drill press. Eric Suggest maybe a carbide spade drill--although he''ll get a tubular exit burr, the sheet won't lift up due to flute helix causing slippage etc as it breaks through. http://www.travers.com/images/Items/...20-805-024.jpg |
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Drilling 304 Stainless
On Fri, 31 Aug 2012 06:09:17 -0500, Lloyd E. Sponenburgh wrote:
Tim Wescott fired this volley in : The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. So, line the holes with SS grommets/hollow rivets. It would even "look cool", with the grommets indicating that someone had done something about the wear issue. The holes need to be spaced 100 mils apart, and the hole in the grommet couldn't be less than 50 mil, and 1/16 is better. So it'd need to be a pretty teeny grommet. Any suggestions where to find such? -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
#27
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Drilling 304 Stainless
Tim Wescott wrote:
On Fri, 31 Aug 2012 06:09:17 -0500, Lloyd E. Sponenburgh wrote: Tim Wescott fired this volley in : The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. So, line the holes with SS grommets/hollow rivets. It would even "look cool", with the grommets indicating that someone had done something about the wear issue. The holes need to be spaced 100 mils apart, and the hole in the grommet couldn't be less than 50 mil, and 1/16 is better. So it'd need to be a pretty teeny grommet. Any suggestions where to find such? Stainless POP rivets? Install rivet, pop, hit the back side with a grinder to smooth them off. If you want the back to look pretty use a cupped grinding point to dress them. Or use the rivet heads and a press to form the back. Could even spin the back side down. -- Steve W. |
#28
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Drilling 304 Stainless
On Fri, 31 Aug 2012 13:17:45 -0400, Steve W. wrote:
Tim Wescott wrote: On Fri, 31 Aug 2012 06:09:17 -0500, Lloyd E. Sponenburgh wrote: Tim Wescott fired this volley in : The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. So, line the holes with SS grommets/hollow rivets. It would even "look cool", with the grommets indicating that someone had done something about the wear issue. The holes need to be spaced 100 mils apart, and the hole in the grommet couldn't be less than 50 mil, and 1/16 is better. So it'd need to be a pretty teeny grommet. Any suggestions where to find such? Stainless POP rivets? Install rivet, pop, hit the back side with a grinder to smooth them off. If you want the back to look pretty use a cupped grinding point to dress them. Or use the rivet heads and a press to form the back. Could even spin the back side down. With a 1/16" shank, and a head (and hole size) smaller than 1/10"? -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
#29
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Drilling 304 Stainless
Tim Wescott wrote:
I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". Try some split-point cobalt drill bits. They are literally only a few cents more when you buy them from MSC, KBC, etc. than the plain HSS bits. They are much more capable of handling harder materials. Jon |
#30
Posted to rec.crafts.metalworking
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Drilling 304 Stainless
Tim Wescott fired this volley in
: The holes need to be spaced 100 mils apart, and the hole in the grommet couldn't be less than 50 mil, and 1/16 is better. So it'd need to be a pretty teeny grommet. You can purchase all variety of gauges of stainless hypodermic tubing (McMaster-Carr), and spin-rivet it. LLoyd |
#31
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Drilling 304 Stainless
On Fri, 31 Aug 2012 16:28:33 -0500, Lloyd E. Sponenburgh wrote:
Tim Wescott fired this volley in : The holes need to be spaced 100 mils apart, and the hole in the grommet couldn't be less than 50 mil, and 1/16 is better. So it'd need to be a pretty teeny grommet. You can purchase all variety of gauges of stainless hypodermic tubing (McMaster-Carr), and spin-rivet it. What's a spin rivet? -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
#32
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Drilling 304 Stainless
Tim Wescott fired this volley in
news What's a spin rivet? It's a technique. Using a former with a conical nose and an annular groove around the nose, the nose is inserted in the bore, and the former is spun, forming the tubing into a flanged head. LLoyd |
#33
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Drilling 304 Stainless
This would increase the number of operations per hole, but anyway you might
consider getting a small-diameter, say 1/8", spotting drill or countersink with a 120-degree point. Set you depth stop carefully and spot it, then switch to a 1/16" screw machine drill (shorter fluting and longer solid shank) to complete the hole. Tom "Tim Wescott" wrote in message ... I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
#34
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Drilling 304 Stainless
Tim Wescott wrote:
On Fri, 31 Aug 2012 13:17:45 -0400, Steve W. wrote: Tim Wescott wrote: On Fri, 31 Aug 2012 06:09:17 -0500, Lloyd E. Sponenburgh wrote: Tim Wescott fired this volley in : The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. So, line the holes with SS grommets/hollow rivets. It would even "look cool", with the grommets indicating that someone had done something about the wear issue. The holes need to be spaced 100 mils apart, and the hole in the grommet couldn't be less than 50 mil, and 1/16 is better. So it'd need to be a pretty teeny grommet. Any suggestions where to find such? Stainless POP rivets? Install rivet, pop, hit the back side with a grinder to smooth them off. If you want the back to look pretty use a cupped grinding point to dress them. Or use the rivet heads and a press to form the back. Could even spin the back side down. With a 1/16" shank, and a head (and hole size) smaller than 1/10"? I've seen them used on R/C stuff before. Not sure where they get them though. I don't use them since I have a press and just make my own from tubing like Lloyd mentions. Actually real easy to do. -- Steve W. |
#35
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Drilling 304 Stainless
On Thu, 30 Aug 2012 23:03:50 -0500, Tim Wescott
wrote: On Thu, 30 Aug 2012 21:50:56 -0400, clare wrote: On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. Any reason not to use 6061T6 aluminum instead??? If you NEED to use stainless, you will NEED a better drill bit. With stainless you need a POSITIVE feed - never let the bit skate on the surface. I'd try a good center punch - or use a "center drill" to make the starting dimple, then follow through with the normal bit. Get one of those that they show at tradeshows etc drilling through files and leaf springs, and using them as milling cutters. Aluminum wears too quickly. The holes are for steel line clips, which must bear the centrifugal force of the airplane at the same time that the handle is being worked. But it would make the job much easier. Make 6 in less time than it takes to make 1 in stainless, and throw them away when they wear. 6061T6 is pretty darn tough stuff too. |
#36
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Drilling 304 Stainless
On Thu, 30 Aug 2012 23:06:07 -0500, Tim Wescott
wrote: On Thu, 30 Aug 2012 21:58:48 -0400, Ned Simmons wrote: On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott wrote: I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. If you can live with 1/8" thick material, McMaster has 303 SS up to 2" wide. Thin 304 sheet is cold rolled, and consequently work hardened, making it much nastier to machine than hot rolled stock. 303 is a free machining (relatively speaking) grade, and would be the best bet if you can use an available size. But not recommended for welding. Good thought, but 1/8 is much too thick. Man, I'm really not trying to reject all advise here... Can you get the use of a turret punch??? |
#37
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Drilling 304 Stainless
On 2012-08-31, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Tim Wescott fired this volley in : Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. Are you center-punching the holes before drilling? If so, there IS a "skin" to break through... you've work-hardened the piece where it's punched. A better strategy is to use a really short bit, and just drill. And, to prevent it walking, best is to get split-point drill bits. (I might get by preference cobalt steel split point bits in screw machine length, since you don't need the longer flute length of jobber's length bits. An alternative to the split points (or perhaps just something to use in *addition* to the above) would be to put down a layer of masking tape, which makes it easier to keep a bit from walking when it starts. Good luck, DoN. -- Remove oil spill source from e-mail Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
#38
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Drilling 304 Stainless
wrote in message ... snip--- But it would make the job much easier. Make 6 in less time than it takes to make 1 in stainless, and throw them away when they wear. 6061T6 is pretty darn tough stuff too. Make them from 6061-T6 aluminum, then have them *hard anodized*. Much better at wear resistance than stainless. Harold |
#39
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Drilling 304 Stainless
The web of the point of typical twist drills doesn't cut.. instead, it rubs
under pressure to displace the metal (all the way through the workpiece or to the bottom of a blind hole). That's exactly what needs to be avoided with work-hardening materials. Split-point drills begin cutting as soon as contact is made, and continue cutting until the drill is stopped/withdrawn. Aside from carbide drills, I believe the best approach would be to use quality split-point drills, as Phil recommended trying, with a good cutting lubricant.. while following the "uninterrupted feed" method which is critical when cutting work-hardening materials, IME. If the holes need deburred after drilling, a small mounted stone in a Dremel/rotary tool will be quick, although a larger drill or countersink will also do the trick (even if just turned with fingers), just so the turning stops when the pressure is released. -- WB .......... "Tim Wescott" wrote in message ... I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
#40
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Drilling 304 Stainless
Let's all give Wild Bill a round of applause, eih?
;)} My filters left me 56 posts to look at and only TWO were on topic metalworking! Thanks Bill ! Good advice too..... I wonder how Tim worked it out? I've been playing around making a couple of eulers disks for the heck of it with various radius'. Got one at 14.5 " 16" and 20" radius so far. Made disks with various edges too to play with. Fun..... philk "Wild_Bill" wrote in message ... The web of the point of typical twist drills doesn't cut.. instead, it rubs under pressure to displace the metal (all the way through the workpiece or to the bottom of a blind hole). That's exactly what needs to be avoided with work-hardening materials. Split-point drills begin cutting as soon as contact is made, and continue cutting until the drill is stopped/withdrawn. Aside from carbide drills, I believe the best approach would be to use quality split-point drills, as Phil recommended trying, with a good cutting lubricant.. while following the "uninterrupted feed" method which is critical when cutting work-hardening materials, IME. If the holes need deburred after drilling, a small mounted stone in a Dremel/rotary tool will be quick, although a larger drill or countersink will also do the trick (even if just turned with fingers), just so the turning stops when the pressure is released. -- WB ......... "Tim Wescott" wrote in message ... I may have asked this before, but I'm slow: I have some 304 sheet. I use it to make control-line model airplane handles. Each handle needs to have about 20 1/16" or .050" holes drilled in it, in a pair of tidy lines. This stuff breaks my regular old HSS drill bits, and my drill hand- sharpening mojo is pretty spotty at 1/16". I'm using them in a drill press. The whole process feels weird -- it feels like there's a skin on the metal which prevents the drill from starting to cut unless I feed it fairly hard, but once broken through doesn't cause much problem. Most of the time that I break a drill bit it's because I'm feeding it "just a bit harder", then SPING -- I've broken another bit. Is there a better drill bit to use, or have I just doomed myself to trouble? Is there a better flavor of _stainless_ to use? I understand that 304 is difficult to work with, but it's what McMaster had in the thickness I wanted; having experienced its joys, however, I'm ready to consider something else. I think my next step is to get a dozen 1/16" drill bits, but if there's some magic material that'll help here, I'm listening. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com |
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