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drill press help?

Discussion in 'The Hokey Ass Message Board' started by Bugman, Feb 2, 2006.

  1. Bugman
    Joined: Nov 17, 2001
    Posts: 3,485

    Bugman
    Member

    For some reason, the drill press and I can't seem to get along. I was drilling some 5/16th holes in 3/8" steel plate the other day(with 1/8" pilot hole), and i could not get them to drill correctly. . The first hole went great. quiet and smooth. the rest I barly got drilled. The bit screeched, and would not cut. I tried another bit with similar results...lots of noise, very little drilling. I tried cutting oil...didnt help. Ii tried speeding up and slowing down the spindle speed, and that didnt help either. Any suggestions? Thanks.
     
  2. The drill bits need to be shapened CORRECTLY,as necessary.
    Once they get dull,they don't fix themselves.

    Run around 650 rpm,add coolant as necessary.


    Most people run them too fast,and burn the edge off,
    or too slow and snap them.

    2 minutes sharpening will save 10x that in one job.Easy.






     
  3. 19Fordy
    Joined: May 17, 2003
    Posts: 4,480

    19Fordy
    Member

    Man, that should be a breeze. What kind of drill bits are you using? I always use HSS (high speed steel) drill bits at the correct RPM with oil. The HSS speed bits with the titanium (gold looking) color are great too. Make sure they are sharpened correctly with 180 degree included angle. Carbon steel drill bits dull rapidly. Work on wood, but not on steel.Not trying to be a smarty pants, but I assume you are not using left handed drill bits. It's been known to happen. Are you sure the steel you are drilling is mild steel?
     
  4. ol fueler
    Joined: Oct 6, 2005
    Posts: 935

    ol fueler
    Member

    Your 1/8 pilot hole was too big. you would have been better off with no pilot hole than one too large. a pilot hole should be no bigger than the very point of your drill bit. If it is any wider than the very tip of the drill bit , what happens is the cutting edge of the bit is only touching at the edge of the hole on a razor sharp edge , this extremly small contact surface will cause the pressure on the cutting edge to be literaly hundreds of thousands of pounds per square inch & will instantly overheat & ruin the bit.
     
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  5. Deuce Rails
    Joined: Feb 1, 2002
    Posts: 2,015

    Deuce Rails
    Member

    You might also want to try a 5/16 end cutting mill tool. They're meant for milling machines, but they do wonders in drill presses. You can find them at either www.mcmaster.com or mscdirect.com.
     
  6. 19Fordy
    Joined: May 17, 2003
    Posts: 4,480

    19Fordy
    Member

    Excellent answer. That makes good sense. The pilot hole needs to be only the size of the drill bit dead center, which doesn't cut. Wish I had thought of it.
     
  7. Jobbers bits are 118 degrees,not 180.

     
  8. Django
    Joined: Nov 15, 2002
    Posts: 10,182

    Django
    Member

    Can I poke my nose in here?

    My chuck is wobbly at the teeth, but straight at the shaft. I sprayed some WD40 up in the teeth and worked it open and closed several times, but it is still wobbly. Any suggestions?
     
  9. jerry
    Joined: Mar 2, 2001
    Posts: 3,390

    jerry
    ALLIANCE MEMBER

    If you have a dial indicator clamp it to the table and chuck a piece of round stock in the chuk. Spin the chuck by hand slowly and tap the chuck with a small hammer to realign it.


    jerry
     
  10. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,015

    HemiRambler
    Member

    I am gonna have to respectfully disagree here. I believe this process is called STEP DRILLING and I do agree IF NOT CAREFUL you can overheat the edge of your bit since the required force is so much less with the large "pilots" but it doesn't mean you cannot do it. Matter of fact when drilling holes LARGER than my machine's capacity I have often resorted to step drilling to achieve the desired hole size. There is a balance between DOC (depth of cut), FEED and SPEED. Keeping those happy will let your bit LIVE. A drill bit is nothing more than a cutting tool - not alot different than a boring bar - in some respects. Pushing for all it's worth while trying to drill a little step is gonna likely overheat just as you said, but keeping the surface speed in mind (bigger bits need LESS speed) you often get by with LESSER equipment to do BIGGER jobs.I have literally drilled hundreds if not thousands of STEPPED holes on my lathes and drill presses - if done properly the bits don't suffer at all. Matter of fact at times it is a preferred method.Granted drilling a pilot the size of the "chisel point" is good manufacturing practice for exactly the reasons you stated, but there's ALWAYS more than one way to skin a cat.That's my story and I am sticking to it.
     
  11. fatassbuick
    Joined: Jul 6, 2001
    Posts: 987

    fatassbuick
    Member

    Me:

    758 RPM (easy and dirty formula for steel spindle speed is 240/diameter of tool. Let's not play the chip load per tooth game right now...just a quick reference..)

    Pull solidly and fearlessly, ,chip should roll off like Annie's hair curls (straw colored ships are a good sign of feed and speed superiority!) Avoid purple chips.

    Coolant, as in motor oil or something a little more modern and environmentally safe is a good idea.

    Pilot drilled holes tend to make noise. Get used to it.

    If the tool chips or breaks, your feeding too fast. If the tool burns or turns black, your spindle speed is too high.
     
  12. 19Fordy
    Joined: May 17, 2003
    Posts: 4,480

    19Fordy
    Member

    Thanks. 59 x 2 don't equal 180. Don't know why I thought it did.
     
  13. Jeez, this is a guy drilling holes in a garage, not a NASA workshop. LOL.

    A 1/8 pilot hole, or no pilot hole, it won't make hardly a bit of difference to a basic hole being drilled in mild steel, as long as the drill bit is correctly sharpened and somewhere near the right speed. The usual problem with badly sharpened drill bits is they never have any clearance. It's not difficult to do, if you know how to do it, but get it wrong and you can spend all day chattering and burning away your hole.

    Deuce Rails, a slot drill (as we call them in the UK) will wander and chatter all over when you start drilling, unless you have a good and solid bench drill. A properly sharpened twist bit will do a far superior job.
     
  14. corncobcoupe
    Joined: May 26, 2001
    Posts: 3,031

    corncobcoupe
    SUPER MODERATOR
    Staff Member

    Some things to think about.
    Steel plate ? What kind ?
    If it's a junk boiler plate - I've seen sections that have high nickle crusties or ball bearing/razor blade material in them.
    First drill always runs great, except the work hardening process.

    Speeds and feeds are important to drill life.

    As stated in an earlier post, wheat colored chips are ideal, purple and you are running too fast.

    Also - get a Drill Doctor sharpener (great for garages and home shops).
    They pretty much will sharpen the drills correctley 99% of the time.

    With a step drill - the biggest problem is a lot of times when the larger diameter hits the hole, the drilling takes place more on the web of the drill cutting surface - thus the singing.

    I wouldn't even use a step drill.
    Just a standard jobbers 118.
    If your drill press is older and has spindle slop, you might want to go to
    135 degree split point drills. They start a bit quicker and drill a bit straighter.

    You can buy a drill doctor and drills at www.mscdirect.com

    Hope this helps.

    Cob
    Forum Moderator
     
  15. I totally agree, I frequently step drill to help keep the holes closer to size when needed, plus for those without any machining knowledge (ie having a feel for what the tool is doing) a pilot hole will help eliminate wandering, especially when the bits do start to dull. My 2 cents with .0199999 change back.
     
  16. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,015

    HemiRambler
    Member

    Cob, just to make certain we are on the same page - the process I was referring to was STEP DRILLING - not using a STEP DRILL. The STEP DRILL most common I think is the Unibit type- which would probably be great for sheet metal but not too good for going through 3/8" plate steel. Of course there are Stepped Drills that have their uses as well but I don't want to cloud the discussion with those. STEP DRILLING is a process where you incrementally increase the size of your drill bit sometimes using several sucessive sizes to get to your final size. The "problem" with this process is that if you are going from a 3/4" dia hole to a 1" dia and treat that 1" bit like "normal" then you're likely gonna overheat that bit and anneal the cutting edge. In tis case you are only cutting a 1/4" (total) of material and your PRESSURE ought to be closer to what you'd put on a 1/4" drill bit not a 1" one - the kicker is that you also NEED to SLOW that 1" bit down!!!!! Chatter is the first hint that you've got something wrong - usually the SPEED is TOO FAST - next might be your FEED (or pressure) is too LOW - this is where step drilling can cause problems - it is RELATIVELY easy to give it TOO MUCH FEED (PRESSURE) and cause problems - as suggested watching the chips color is key but when in doubt run SLOW and WORK UP on it.

    Ideally - you want to drill a pilot that is the size of the Chisel Point - but if you machine lacks the stones to do it in one shot then you have litle other choice than to step drill.

    The metal has no idea what is cutting it - meaning that having a "pilot" that is TOO BIG is NOT a PROBLEM - if you proceed with the appropriate SPEED and FEED. This gets to be a real challenge on SOFTER material where they have a tendancy to grab and SELF FEED - this can be a problem - snap!!

    If your material is WORK HARDENING (alloy steel) then you are drilling with a DULL drill that will definitely not get better as you proceed. Low carbon isn't gonna be much of a problem here - just sharpen your bit - make sure it has some CLEARANCE and drill away.

    Stainless is a GREAT material for illustrating the effects of Work Hardening - if you "dilly dally" you can get it to work harden even with a moderately sharp bit - it needs a certain amount of aggressiveness from the user to ensure you are cutting - sulfur based oil can be a useful lube when drilling - some materials, but it stinks when you get it too hot (clue that you are too fast) and unless it's a difficult material or I am cutting very SLOWLY- normally I just use plain old motor oil - not ideal but adequate for many jobs. It starts to sizzle when things are getting too hot!!


    Bugman - how FAST was your 5/16" drill bit going?????? Try slowing it down and see how that goes. Use lube if you can - but that wouldn't be near as critical IF your speed was lower.

    There was also a good point made about drilling to size. Just a few things I have noticed - just because you grab a 1/4" bit does NOT ensure you drill a 1/4" hole - noramlly the hole size can go BIGGER than you want because of various factors. If your bit isn't sharpened properly (flank lengths the same - for instance) if one cutting edge is longer than the other - the bit WILL have a tendancy to cut oversize. If you use a bunch of feed again it will tend to cut oversize. When drilling holes that I need to be more accurate and I don't have a reamer I will often grab a bit a '64th under drill with that and then go back and drill with the final size - there are times where the final size never even cuts - cheap bits are also a common offender of drilling LARGER than marked. At least the CHEAPIES I have used are!

    Another excellent point made was the type of drill bit used - Carbon Steel is definietly JUNK for steel drilling - they are strictly wod grade stuff. Stick with HSS (High Speed Steel) bits - you'll be a lot happier. Coated ones are good too, but not necessary for home use - IMHO.

    Drilling who'd of thought there was so much BS involved!!!
     
  17. Fossil
    Joined: Jan 9, 2006
    Posts: 357

    Fossil
    Member

    I drill a lot of holes using a "center cutting" type mill. They'll put a nice clean hole in your work. Instead of a drill press I'm using a Bridgeport, but I don't see why it wouldn't work in a drill press. The only problem might be locating the hole precisely on a drill press-but you could locate by chucking an indicator into your press, or using a drill bit to locate into the pilot hole, and then switching to the end mill after you've locked everything into place. Just like with a bit...use a cutting lubricant, watch your speed and feed, etc.

    -Scott
     
  18. That pretty much settles it and End mills in a drill press are sketchy at best
     
  19. 23 bucket-t
    Joined: Aug 27, 2005
    Posts: 1,368

    23 bucket-t
    Member

    a step drill { pilot drill } is when you want to to keep two holes concentric with each other . lets say you want to drill a hole .500 2 in. dp, and a .375 thru. you will want to drill the .500 drill to depth, then you will need to use a .4995 / .3755 step drill, then you will drill about 1/4 inch deep, that depending on the length of the pilot { just keep it back about .050 } then you can drill the .375 thru ****** but what this guy is refusing I believe to is a center drill. it is so you can center the hole where you need to put it. why -- because if you do not center drill first the twist drill tends to wobble and it will be off location by a few R.C.H.s also you can get bell mouth., which you my not want. When using a center drill you use the correct size drill, down to about the same size of the twist drill. which should be no more than about 1/4 inch dp. then you will be able to drill your hole. But if you have a dull drill or an incorrect drill point you will not be able to drill it, then again if you have cheep steel, which my have hard and soft spot in it and it can dull the drill very quickly . so what you will want to do is center drill first, then twist drill about 750 rpm. use a light grade oil, and light presser, using the waight of your hand push down. take it slow.
     
  20. Bugman
    Joined: Nov 17, 2001
    Posts: 3,485

    Bugman
    Member

    Thanks for all the info. It did help. I think I setteld on my problem being shoddily sharpened bits. I used to be able to hand sharpen a mean bit, but I've lost my touch. Drill Doctor here I come :)
     
  21. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,015

    HemiRambler
    Member

    Bugman, good to hear that you are zooming in on your problem. I have often been accused of overthinking things - just my nature - I can't help it. My philosophy is that the more we comprehend the better equipped that we are to solve problems that arise. So what does this babble have to do with sharpening drills???? Just this - let's say you get your drill doctor and you put a perfect cutting edge on your previously smoked HSS drill bit and wha-lah!!! It works exactly the same as before!!!!!! Like crap!!!! My guess is that you probably ANNEALED the tip of your drill bit. HSS Drill bits are made of tool steel and as a result perform well at elevated temperatues, BUT you can overheat and anneal them. Once you do that - putting a "keen edge" back on really isn't gonna do anything. You HAVE to grind back through until you get to "GOOD" (hard) metal. The problem here is that IF you're careless on the grinder you can ANNEAL (soften) the bit during THAT process as well. This is why you should have a small container of water next to your grinding wheel - before you build a ton of heat in your cutting tool - go ahead and dunk it in the water to keep the heat down. Grind , dunk, grind, dunk, grind, dunk - repeat until you are ok. The damaged bit will often appear straw or blue in color - this is definitely a sign of overheating. If all you need to do is barely touch the cutting tool on the grinder then granted - you won't need to worry about keeping it cool. This is also the reason why you SHOULDN'T keep forcing a dull bit though the material - all you do is "melt" the bit through and anneal the crap out of it. Sharpening drill bits is relatively easy - the biggest stumbling block is the curvature of the wheel confuses us sometimes - holding your bit facing the center of your wheel and then tilting it down establishes the clearance angle - tilting it sideways establishes the point angle - couple degrees down 30 degrees over -plunge straight in and then roll the bit down (tip contacting wheel in the same place - but you move the far end down in a rotating/pivoting motion) and you ought to be close enough to make chips. Knowing the basics will serve you far longer than your drill doctor will. IMHO.




     
  22. Some excellent info here.

    I hope this piece makes it into the tech archive.



    I'd like to add a little hint, saves some $$ as well.

    We've all broken the tip off a center drill.
    Even so, you can still use it by turning it into a spotter drill - i think that's the right name.

    Easily done, just clean up the broken tip - which is almost always completely gone since it breaks at the base of the tip.

    Retain the original secondary angles and you'll have a spotter drill with a true center.

    Spotter drills stay on center very well and you don't have to risk using a small center drill on a job that doesn't really require it.

    Nice part is, the spotter drills are quite strong as far as side forces go - compared to the center drill tip anyway.


    Another small tip to keep the drill, regardless of style, in the center punched hole is to draw file the center punch depression so the turned up metal around the center punched hole doesn't lead the drill astray.
    You want the metal adjacent to the depression the same height as the surrounding metal

    This technique works well with small twist drills and just takes a few seconds to do.


    And a few words about center punching.

    The basics are to use a small prick punch - that's it's name and it doesn't allude to some of your acquaintances - to strike the initial depression.

    Next comes the center punch that is larger in diameter and most times has a shallower angle ground into the tip.

    The center punch spreads the depression so the drill will stay within.

    Automatic center punches - the spring loaded gizmo's are handy when starting a hole that needs to be located accurately, but a careful guy with a prick punch for the initial strike can do as well.
    These neat little gizmo's are adjustable for striking force and at times make a suitable depression for the spotter drill, but most times they need a little help from a hammer driven punch.


    So, you've attempted to punch the initial depression and your punch mark is off the marks.

    Just tilt the punch about 20 degrees pointing in the direction you want to go and restrike.
    It may take a couple of tries, but most times the depression will move to the place you want to be.

    Pilot holes are good and I use them a lot, but as noted above don't make em too large.
    Let the final drill size do most of the cutting.


    Unibits are great for drilling sheet metal in my experience.
    I know a lot of guys like to use them for general drilling if the metal's not too thick, but why destroy an expensive drill by trying to save a few minutes?

    DeWalt makes a drill set with a small drill on the tip that acts like a pilot drill.
    These drills are great for drilling sheet metal.
    They work well if you're doing the match drill bit and drilling say a piece of 1/8" steel and on into a piece of sheet metal.

    I have a set of these and save them for sheet metal and other semi-critical stuff where the built-in pilot drill would be handy.
    I keep that to a minimum cuz the DeWalt drills look to be difficult to sharpen on the main body size.
     
  23. Bugman
    Joined: Nov 17, 2001
    Posts: 3,485

    Bugman
    Member

    So much great info here. Good tip about the annealed bits HemiRambler. I used to see students do that all the time. They'd burn the end of the bit blue, then just touch up the edge an wonder why it still wouldn't cut worth a darn.

    This is kind of a "Duh" thing, but it's also good to make sure the bit is spinning the right direction. I once watched a student bore a 3/4" hole through 1" cast aluminum on a Bridgeport with the bit spinning backwards.
     

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