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Thread: Problem drilling mild steel flat bar

  1. #26
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    Re: Problem drilling mild steel flat bar

    On mild steel you should produce ribbons, not chips.

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  3. #27
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    Re: Problem drilling mild steel flat bar

    Using a sharp bit, try it on 900 and 570 rpm. I think you will leave it on 570 rpm when you see the difference. I doubt you saw any ribbons at 2000+ rpm.

    I know your bits will last longer.
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  5. #28
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    Re: Problem drilling mild steel flat bar

    Perhaps look at the chart as up to the drill size, so 1360 would be recommended. My drill was altered for drilling large holes and using hole saws. So, I drill everything at 100ish rpm’s. Slow for small drill bits, but beautiful to always see ribbons being produce and positive progress.

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  7. #29
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    Re: Problem drilling mild steel flat bar

    I agree that "slower is almost always better" -- for the simple reason that you're less likely to overheat the bit and/or harden the workpiece -- but I believe there is also such a thing as "too slow." I'm not a machinist, but I believe that if you go too slow, things can get "grabby," potentially breaking the drill bit, mangling the workpiece and injuring the operator...I'm always careful to fixture/clamp everything down good when using slow cut speeds. There's a LOT of torque at the chuck when you step down the "gear ratio" so much.
    Last edited by StandarDyne; 4 Days Ago at 08:27 AM.

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  9. #30
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    Re: Problem drilling mild steel flat bar

    Quote Originally Posted by Flyer58 View Post
    I did use cutting fluid, which I called oil earlier, and set the speed based on the decal on the drill press. The metal is actually 1/8 mild steel but my handy dandy thickness gauge is in decimal and gauge. I'm totally sold on the idea of getting a sharpener or at least watching a few videos about how to resharpen the bit I have. I appreciate everyone input

    Drill press recommended RPM:

    Attachment 1742226
    You should have been drilling at less than 1300, so 900 if that's the next speed down

    Sent from my fab shop using a mig welder and a grinder

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  11. #31
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    Re: Problem drilling mild steel flat bar

    This old Tony has a pretty good sharpening tutorial

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  13. #32
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    Re: Problem drilling mild steel flat bar

    When doing a lot of drilling in A36 using a 3/16" drill bit I use 1800 to 2000 rpm

    Dave

    Quote Originally Posted by MetalMan23 View Post
    You should have been drilling at less than 1300, so 900 if that's the next speed down

    Sent from my fab shop using a mig welder and a grinder

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  15. #33
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    Re: Problem drilling mild steel flat bar

    Need a battery drill for hand drilling, I realize there are other ways and lots more guys know way more than I do about it but not many beat me up when it is time to punch a few holes in a strip. I hand drill host things even in the shop, small holes with odd setups are just so much faster on the bench or in a vise vs truing to fit everything in a jig on a press. Again I understand other ways of doing this but I grew up with the same thing, my first drilling wasnt what it is now whare I get feel for speed and prtessure and regulate easily with battery drill and also much safer on larger holes as the tool is power limited.
    As I mention, I drill most all of this dry and often use a few drops of water if I wanna cool but I am finishing and painting and dont want that crap all over my shop, if it ruins a little bit, oh well, if I gotta sharpen a bigger on so be it, like a grinding wheel just part of the cost, when it becomes cheaper I toss. I buy the small bits for a dollar and they are those noresman ones USA and simply get a handfull on occasion, be different if they were 5 but at a dollar, 2 for a 1/4, bought 10 and going to get 10 more this year a size up. They get lost, spread out, ruined, sharpened on occasion. I got an index, a couple with all the sizes but got a tackle tray on a bench with pile of bits and use all those for the rough fab.
    I am so accurate hand plasma I blow a lot of holes with it, I got to be careful to make them big enough, can do it to near thread a bolt in.

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  17. #34
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    Re: Problem drilling mild steel flat bar

    I need to get another can of Rapid Tap, good thing to have on hand but use it a few drops at a time and can use it right up at the end of a cut without running all over. A lot of my dripping really does end up in chips,,, but,,, its relatively fast and there is a hole when I am done, I dont care about a curled chip at the finish,, I want the hole and it really doesnt know if its the proper way or not.
    I dont always go so fast but I timed a "what could" time with actual drilling, already had the pilot and 3/8 thick with 3 drops per 1/8 and could cut this 1 1/8 in 40 seconds. Now,,,, there are other ways, better bits I am sure, some more perfect scheme involving lots morre tools and a whole puddle of fluid but aint no way, no how to do this in place this fast and accurate with as few tools and economical as this.
    Attached Images Attached Images  
    Last edited by Sberry; 4 Days Ago at 10:05 AM.

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  19. #35
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    Re: Problem drilling mild steel flat bar

    In the case of the op,,, overheated the bit, too fast, too long mayube, not enough pressure at the right time, etc but most likely a combination of that and burning the end of the bit in to a hard admix left in the hole, drilling from other side with new was easy,,, not a real huge mystery.

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  21. #36
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    Re: Problem drilling mild steel flat bar

    I try avoiding any type oil for drilling steel it is one thing that needs cleaning before welding and or painting.

    When do use cutting that need cutting I just use pipe threading

    Dave

    Quote Originally Posted by Sberry View Post
    I need to get another can of Rapid Tap, good thing to have on hand but use it a few drops at a time and can use it right up at the end of a cut without running all over. A lot of my dripping really does end up in chips,,, but,,, its relatively fast and there is a hole when I am done, I dont care about a curled chip at the finish,, I want the hole and it really doesnt know if its the proper way or not.

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  23. #37
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    Re: Problem drilling mild steel flat bar

    I generally wipe off the oil after I'm done drilling. Paint sticks better that way.

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  25. #38
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    Re: Problem drilling mild steel flat bar

    I am hesitant to use cutting fluid when i punch or drill, since it will need to be cleaned off. I used soapy water on my lathe once for aluminum machining, the resulting red/ orange finish has lasted about 15 years.

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  27. #39
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    Re: Problem drilling mild steel flat bar

    I tried soapy water and its cheap and works well but the resultant rust on iron worker, drill press and vises wasn’t worth it.

    I now prefer petroleum based coolants followed by a wipe down with stoddard solvent.


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  29. #40
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    Re: Problem drilling mild steel flat bar

    Sounds great
    But try that with 20 to 100 tons a month in steel. Even brushing oil take time.
    If doing a little projects I will use cutting oil.

    Dave

    Quote Originally Posted by tapwelder View Post
    I am hesitant to use cutting fluid when i punch or drill, since it will need to be cleaned off. I used soapy water on my lathe once for aluminum machining, the resulting red/ orange finish has lasted about 15 years.

  30. #41
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    Re: Problem drilling mild steel flat bar

    Well this was my first attempt at sharpening a 3/8 drill on the bench grinder. In some ways it was easier than expected but I also determined I needed to be a bit more exact when getting proper alignment, angles and straight edges so it will take more practice and a lot more time if i try making a split point using my Dremel. I also need a better magnifying glass and some accurate measuring tools. Small diameter bit aren't gonna happen at this point without a dedicated sharpening tool. Maybe with better reading glasses.

    Here's the cutting results, dry and the press set at 900 RPM. I think there were two ribbons but I stopped when something flew off and I could never find it so it's possible only one edge was cutting.

    Name:  10.jpg
Views: 94
Size:  658.3 KB
    Last edited by Flyer58; 3 Days Ago at 05:58 PM.

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  32. #42
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    Re: Problem drilling mild steel flat bar

    The titanium coated bits are very brittle and chip often. I prefer to sharpen them lightly more often than to wait for them to go dead.
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  33. #43
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    Re: Problem drilling mild steel flat bar

    Quote Originally Posted by StandarDyne View Post
    I agree that "slower is almost always better" -- for the simple reason that you're less likely to overheat the bit and/or harden the workpiece -- but I believe there is also such a thing as "too slow." I'm not a machinist, but I believe that if you go too slow, things can get "grabby," potentially breaking the drill bit, mangling the workpiece and injuring the operator...I'm always careful to fixture/clamp everything down good when using slow cut speeds. There's a LOT of torque at the chuck when you step down the "gear ratio" so much.
    The only problem I have at 80 rpm is that it will slip the belt when it "grabs". I do use cross slide vises to hold the victim steady but I haven't experienced a lot of damage or injury. Sometimes with thin sheet you need to hold it down flat with high clearance vice grips or C clamps. A reverse on the drill would come in handy for when it jambs and "some day" it's going to get wired for a reversing switch.
    The harder you fall, the higher you bounce...

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  34. #44
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    Re: Problem drilling mild steel flat bar

    You got chips 🍟.
    I have been sharpening drill bits since the 1960's.

    Great job 👏 👍 👌

    Dave

    Quote Originally Posted by Flyer58 View Post
    Well this was my first attempt at sharpening a 3/8 drill on the bench grinder. In some ways it was easier than expected but I also determined I needed to be a bit more exact when getting proper alignment, angles and straight edges so it will take more practice and a lot more time if i try making a split point using my Dremel. I also need a better magnifying glass and some accurate measuring tools. Small diameter bit aren't gonna happen at this point without a dedicated sharpening tool. Maybe with better reading glasses.

    Here's the cutting results, dry and the press set at 900 RPM. I think there were two ribbons but I stopped when something flew off and I could never find it so it's possible only one edge was cutting.

    Name:  10.jpg
Views: 94
Size:  658.3 KB

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  36. #45
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    Re: Problem drilling mild steel flat bar

    Quote Originally Posted by smithdoor View Post
    You got chips ��.
    I have been sharpening drill bits since the 1960's.

    Great job �� �� ��

    Dave
    Thanks! LOL. Not the first time I've ended up with chips. My avatar is a potato chip like the first time, 25 years ago, when I welded a square tube door frame and didn't know about distortion and how to minimize it.
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  38. #46
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    Re: Problem drilling mild steel flat bar

    I was buying a gross of drill bits and reshaping. So paid big time to reshaping .

    Try contact tips.
    I would throw a boat load till one I ran out. The welder need one as got to close to work with tip and weld the wire to tip.
    I remove the cup took grinder and ground back the bad spot and he keep welding.
    The only other option was stick and I only that could weld stick and 1,000 of pieces to weld. Hard to keep employees working when your under the hood. They will stop and watch you welded.

    Dave

    Quote Originally Posted by Flyer58 View Post
    Thanks! LOL. Not the first time I've ended up with chips. My avatar is a potato chip like the first time, 25 years ago, when I welded a square tube door frame and didn't know about distortion and how to minimize it.

  39. #47
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    Re: Problem drilling mild steel flat bar

    We used to dril a ton of contact tips, being copper a dull drill would snap almost immediately, we drilled them in a lathe with a collet setup, usually .045 tips that we'd punch to 1/16.

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  40. #48
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    Re: Problem drilling mild steel flat bar

    I remember Bernard had some wrongly labeled Centerfire tips. Customers couldn't understand why the wire wouldn't go through their new contact tips. Things like that can make some customers pretty irate... and for good reason.

  41. #49
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    Re: Problem drilling mild steel flat bar

    Quote Originally Posted by Sberry View Post
    I need to get another can of Rapid Tap, good thing to have on hand but use it a few drops at a time and can use it right up at the end of a cut without running all over. A lot of my dripping really does end up in chips,,, but,,, its relatively fast and there is a hole when I am done, I dont care about a curled chip at the finish,, I want the hole and it really doesnt know if its the proper way or not.
    I dont always go so fast but I timed a "what could" time with actual drilling, already had the pilot and 3/8 thick with 3 drops per 1/8 and could cut this 1 1/8 in 40 seconds. Now,,,, there are other ways, better bits I am sure, some more perfect scheme involving lots morre tools and a whole puddle of fluid but aint no way, no how to do this in place this fast and accurate with as few tools and economical as this.
    Rapid Tap is good stuff. I used it with the boring head in the drill press. It definitely helped.

  42. #50
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    Re: Problem drilling mild steel flat bar

    You can use rapid a couple drops at a time, different than the regular cutting fluid used to flood it.

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