Playing with Drill Bits

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I'm mostly sharpening challenged.  I know how to do it on a grinder, but my mind doesn't always match what my hands are doing  Results: usually a bit that's in worse shape than before it's been "sharpened"So, I broke down and bought a Drill Doctor a while back.  Ok, so I'm a wussWhile it's not perfect.  A good machinist using a good (expensive) tool grinder could do a better job, but it's not too bad.The more advanced 750X has an adjustment to change the clearance/relief angle.  IE, it can alter the chisel angle on each flute.  Less aggressive, or more aggressive, cutting action.  This all depends on the material you're cutting.  An aggressive angle works well on mild steel, while a flatter angle works better on harder steel.I went to a steeper angle, and was amazedI'm shooting quite a few holes lateley, for me anyhow, and the sharpener has done me good.The increased angle can be felt in the handle on the drill press.  Less pressure, and faster feed.  A note of caution........If you're using a low powered belt driven press like mine, initial feed should be slow to keep the belts from slipping due to the increased torque required for the increased thickness of the chip.  Once the bit takes hold, you'll be amazed at how fast, and smooth the feed is.  You can resume a steady feed.  Don't lean on it, let the bit do the work.  You'll be very happy with it.I'd say I picked up near 25% to maybe near 50% efficiency.A VERY IMPORTANT CAVEAT...............  The increased angle makes for a more fragile chisel point.  It's more prone to chipping because it's thinner.  I use a flood coolant system to keep heat down, and to provide steady lubricant.  I'm not seeing any noticeable dulling of the bit.  And I'm used to my equipment and have a feel for the correct feed.In the pics you'll notice the unusual thickness of the chips.  This means more material is being removed with each rotation of the cutting tool, the bit.Pic one....... a workpiece in the pressPic two....... a chip laying on the milling table to give a better viewSo, if you got one of these little gizmos, check out the part of the manual that deals with relief angles.  It's pretty cool stuff, well..........for me anywaysJust thought I'd pass it on Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I mostly make my Christmas Tree decorations from Brass!
Reply:..... Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Thanks Samm.I'll have to take a closer look at the instructions on my unit. I nabbed the 750x last year around Christmas as it was on sale. Buddy of mine swears by his unit and had showed me how simple it was to use his. I must have a shoe box of old bits I got picking things up at yard sales and so on. Not so much for the bits themselves, but for the other stuff that came in the boxes etc. I just CAN'T throw what could be useful tools away, so I'll have to sit and play with it extensively one day. I'll play with the reliefs also..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I don't believe it truly gets the bit back to factory, but it's serviceable.The basic instructions in the manual are a bit vague.  There doesn't seem to be many good technical writers out there these days.  The DVD that comes with the unit is much better, and unbelievably simple.The relief angle thing isn't in the video though, but it's simple once you have the overall feel for the machine"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Yeah, Samm, I have one I bought when they first came out and really like it. I have a little trouble w/ it on the 3/16" and smaller bits, Have to roll them "forward slightly in the alignent jig or they're ground too flat and won't cut. They've come down enough in price now I'm thinking on getting 750 myself .                                   MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:We bought a Drill Doctor last year, and I really like it.  We had a pile of bad drill bits, my bench grinder gave up the ghost about 5 yrs ago, and I never replaced it.  Just don't use one that much.  In fact, sharpening drill bits is about all I ever used it for.  Just use an angle grinder for everything else.  We don't drill many holes, ususally it's drilling broken bolts, so we're kinda hard on bits when we do use them...
Reply:I love mine.  Yes, I can easily grind my bits by eye/hand, but with a little practice, you can get bits better than factory with this thing.The big difference between hand sharpening, and using the drill doctor jig, is that when done in the DD, the bits show less tendency to walk, and in the drill press, the swarf comes out evenly from both sides.  Being able to split points is great for anything over 1/4" when drilling steel (especially stainless).What I find interesting, is that the DD is made by Darex, using similar designs to their Darex sharpeners (which are what's used to sharpen bits at the factory).  This is just the plastic version of the same tool.  It won't last as long, but for my purposes, I don't think I could wear it out.
Reply:i use to sharpen bits by hand, but when i found the drill dr.  oh baby!  it was so easy especially on the small ones.  i still do the larger ones like 1/2 inch and up by hand.  i just have to keep a fresh wheel that hasn't been gouged by a tungsten.  the tig welders at the shop seem to have a fetish about a fresh wheel and hate dressing it after they finish carving a groove down the center.
Reply:Hell, I'll jump on the bandwagon too!  I've got one and it works great.  One thing the doctor can't fix though... is when you have a buddy that thinks the way to drill steel, is at the highest speed possible.  I guess he figures that if he can get the bit hot enough it'll just burn/melt its way through.   Bits never seem to want to hold an edge after they've been heated to the surface temperature of the sun... wonder why that is???I make sure to hide my good bits when he's in the area.Work HARDER, not smarter! ------------------------ Miller Bobcat 250Millermatic 251Lincoln Precision TIG 185Hypertherm PM 600Hobart 135 HandlerOxweld 400 FlameMaster
Reply:I've tried the drill doctor out a couple times (not mine, belonged to a friend).   I still grind the bigger bits by hand (5/16" on up),  I find it's cheaper and better to just buy the little bits in bulk, throw them away when they get dull.
Reply:Yeah, you can't sharpen a drill bit on a wheel that's been messed up by a tungsten.Actually, if I'm hand sharpening, I use my belt grinder.  No need to re-dress, its always flat.I don't know how someone managed to kill the temper on a bit, drilling too quickly in steel.HSS needs to be heated to a dull red, before its temper is lost.  That's one reason its used as a drill bit.
Reply:Ill throw in my 2 bits too. This is a quick handy quide for somebody whos learning how to sharpen a drill by hand. Take a brand new drill bit and 2 nuts, say a 1/2 " drill and a pair of half inch nuts. lay 2 flat edges of the nuts together and put the drill in between and the angles will match up.  This is a quick way to check the angles of your bits, but not everything you need to know. Make sure the cutting edge is higher than the heel, (the back side of the bit) 8 to 12 degrees lower (that part i learned in my metalworking text). Still not everything you need to know but as Samm said in the OP you might need to change the angles a little for differnt applications. At least this way you can get you back on track.Nothing Ever Got Done By Quitting, Never Give Up.
Reply:Originally Posted by rlitmanYeah, you can't sharpen a drill bit on a wheel that's been messed up by a tungsten.Actually, if I'm hand sharpening, I use my belt grinder.  No need to re-dress, its always flat.I don't know how someone managed to kill the temper on a bit, drilling too quickly in steel.HSS needs to be heated to a dull red, before its temper is lost.  That's one reason its used as a drill bit.