Sharpening Small Bits


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    Question Sharpening Small Bits

    I have a Drill Doctor and it is great for 3/16 (or so) and up bits. Most of my bits are smaller! How do you folks deal with the little guys? And how small is practical? I don't think anyone really wants to mess with a #80 bit, but is it possible?

    Yeah, yeah, - why bother? OK, I'm cheap! And I think it would be a good thing to know to save a trip to the store in the middle of a job. The easy way is to have a spare on hand, but that defeats the purpose of being cheap

    robotic regards,

    Tom

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    The very small bits can be sharpened on a setup that includes a pin chuck with a Tee shaped body that includes a couple of small rollers at 180 degrees. Included in the set is a loup to see the bit tip for setting, a setting gage for tip angle (exposure), a fine six inch long stone (approx.280 or finer) and the chuck/roller with additional collets. These sets are probably still available commercially with a bit of searching. Being miserly, I enjoy not having to throw away dull micro bits, they sharpen surprisingly well, sometimes better than new.

    This pin chuck device could well be fabricated and if anyone is interested, I will gladly include a photo or two...

    Bill C.



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    Bill:

    I, for one, would be interested in seeing at least photos. And if available, drawings. I'd like very much to take a cut at building such a fixture .

    robotic regards,

    Tom



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    I will measure and give dimensions as well if needed... as you can probably see, the pin chucking device has the basic 118 degree Tee shape for grinding the bit to that angle - more- let the bit expose a little more. Operation is done by rolling the wheel, dragging the bit on the stone and relieving the tip by rolling to the right as you pull it to you across the stone. Most simple to use and very good results can be seen quickly with the loupe. Keeping the lands equal is still the necessary portion, especially with very small bits.

    Bill C.

    Attached Thumbnails Attached Thumbnails Sharpening Small Bits-resized0060-jpg  


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    Registered HuFlungDung's Avatar
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    If you practise sharpening a larger drill, you'll get more of a feel for how to do the little ones. Unfortunately, you're not getting any practise on the bigger ones because of the Drill Doctor: It's a vicious circle

    First you get good, then you get fast. Then grouchiness sets in.

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Bill:

    I don't think dimensions are needed - the only critical measure seems to be the angle.

    Feeling a bit thick here. I see the loupe, the 118 degree Tee, the small wheel on either wing(?), and the stone. But I don't see how all that goes together to sharpen a bit. Perhaps a few words of clarification for an apprentice chip sweeper (ha! you didn't know CSs had apprentices did you ).

    Hu:
    I could always give the good doctor a well-earned rest
    Hmmm, I may do that just for the practice.

    robotic regards,

    Tom



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    ^

    Attached Thumbnails Attached Thumbnails Sharpening Small Bits-may-27-jpg  


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    Aaaaah Ha !!!
    That picture is worth MANY words.
    I might even be able to make one of those

    Thank you very much Bill, appreciate it a lot.


    robotic regards,

    Tom



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    This info and pics are grest. I have been wondering about what to do with all teh little stuff my father-in-law breaks or dulls.
    Thanks,
    mc_n_g



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    Hi all, I know this is coming late in the day for this subject but the drill sharpener mentioned and shown was/is known as "the Wishbone drill sharpener".
    I first came across this item in the late 60"s and always wanted one so at last I designed one up from memory and made it.
    So far I have sharpened 1/2mm drills quite easily, and up to 6mm.
    If anyone wants a photo or design, mine differs from the bought item, I'll post some photos.
    Ian.



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    Member widgitmaster's Avatar
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    Cool

    It's easy to see the ease of use a little fixture like that has to offer, but I for one have always had access to a 25x toolmakers microscope for checking and honing the edge on micro drills! Especially usefull when checking the edge of carbide for fractures!

    It took me many years to learn how to stone an edge of a micro bit while looking through a 25x microscope, especially in an extreemly noisy and active shop!

    If you are doing lots of micro drills, I would suggest you look for a microscope and a set of miniature diamond files and fine stones!

    Eric

    Last edited by widgitmaster; 12-13-2006 at 10:08 AM. Reason: typo's


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    wow old thread, good topic though. in trying to figure out how to sharpen very small drills, for those not familiar with it, remember that the traditional or at least common geometry on the end of the drill, where the clearance is sort of 'rolled' on is not the only way to sharpen a drill. Faceted sharpening is as good or better imo this where a primary and second clearances are ground on as flats - here's a pic of some i did http://i20.photobucket.com/albums/b2...eneddrills.jpg.

    for small drills a hand held jig dragged across some fine emery cloth can be used to put a faceted point on - no grinding involved. Guy Lautard in one of his bedside readers describes how to make one.



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    Hi Mac, how anybody using small drills expects to sharpen them without a fixture of some sort escapes me.
    The other day I dropped in on a mate of mine that I used to work partime for some years back when I got retrenchedfor the last time.
    He was trying to sharpen some 1.7mm drills by jamming a jewellers loupe, 10X, In his eye, and getting too close to the grinder. Put a nice chamfer on the side of his nose.
    So I dug out a design I'd made some years back of a hand drill lapping jig, and made up two of them.
    It's always amazing how someone else's needs becomes your immediate concern.
    For years I'd hand ground tiny drills with very mixed results, and now at last I've got the solution to the problem.
    I redesigned the original concept I'd seen in the 60's.
    The new design now has the two wheels at right angles to the plate so that you can drag the drill across the honing stone instead of pushing it onto the stone.
    Same action but better control of the lapping action, and you don't run onto the sharpening stone at the end of the travel.
    I used a diamond tool honing plate that I bought on Ebay, and cut it in half to make two lapping plates.
    It started out as a 6" x 2" double sided, fine and medium diamond hone, and by carefull cutting gave two plates at 3" x 2".
    I made up a box from MDF, to hold the jig and a set of 4 collet chucks that go from 6mm down to zero, and mounted the honing plate inside.
    I know it works a treat as I had to sharpen a 1.2mm drill several times while drilling the stainless for some tiny rivets,(1.2mm welding wire) while doing the redesign.
    I reckon the principle could be expanded on to make a simple but effective drill grinding jig for drills up to 1/2" using a horizontal grinding wheel and a stop.
    Ian.



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    Here's a photo of the one I made.
    Ian.

    Attached Thumbnails Attached Thumbnails Sharpening Small Bits-dscn1678-jpg  


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    Ian, I'm intrigued, but slow on the uptake - the ball is not dropping on how your rig is used? any chance of pic showing how its used?

    if you have more content it would be great to see, bet you'll get a few guys making them

    thanks

    edit, ahh ok like BillC's pic above. the angle is it just hand control or do you run it along a guide of some sort?



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    Hi Mac, bill C in post #7 showed how the original "wishbone" type was used with an in line action.
    Problem is you run out of "runway" in a forward and back motion.
    If you want to get an idea of how it works, take an ordinary drill, about 1/4", and hold it in your hand with the point laid on a sharpening stone at the 58 deg angle, and the cutting edges pointing away from you.
    Now move the drill left to right while canting the drill to the right as you go.
    A sort of wiping motion.
    This does one side, turn over to do the second side.
    I decided to make the action parallel to the sharpening stone and so the wheels are moved 90 deg, and now you run back and forth along the stone while holding the jig at right angles to it.
    So if you have a stone 12" long, (unlikely) you get 12" of travel.
    The stone I use is a double sided, fine and medium diamond lap, about 3" long, and it cuts really fast.
    As soon as I can take a photo of the action I'll post it, as it works really well and to date has not had a problem.
    In the photo the long rod in the middle is one of the collet chucks that hold the drills, and the drill is held a fixed distance out,(set with a gauge), to get the point angle of 59 deg per edge, or 118deg included angle.
    I have since redesigned the set-up again to use one wheel and the drill and collet is rotated, to sharpen each cutting edge in turn, like a simple dividing head action, but this will be made some other time.
    If anyone is interested I could attach a few sketches I've made, and as it's self explanetory, it's just a matter of putting a few dimensions on paper to give it a starting point.
    Ian.



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    Quote Originally Posted by Bill C View Post
    ^
    I have what appears to be a partial set for this tool.....what are the dimensions for the little setting jig? (That I seem to be missing)

    Michael (New member Seotember 2008, with an ooooooooooold Wishbone kit I want to learn the proper use of)



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    Sharpening Small Bits-img_2732-jpg


    The setting tool merely sets the bit tip by being parallel with the frame plus the exposure dimension of the rollers, so the frame angle is your key ingredient for drill bit tip angle. Setting less bit exposure will reduce the bit angle for, such as for harder material, likewise - greater distance is a more acute angled bit tip. The setting tool will allow uniform bit angles depending on the tip angle desired and the set height. The ideal setting would have an adjustable bit tip height setting adjustment...

    This tool has worked well, but a broken bit will require resetting of the finished spiral lead - the land must be set slightly in advance of the finished 'grind' by the amount of the ground off bit material. A broken bit will, consequently take a small amount of experience with the 'setting of the bit' in the pin collet. Also, you may (by all means), purchase a longer and more precision stone for use with this great and simple to use (and make) tool.

    The bit is ground or honed in its stiffest axis and with very short exposure. Slight bending of carbide will destroy it since carbide has no yeald what-so-ever. Collet type pin vice chucks (four or six fingered) will prevent breakage of these tiny bits. We recently sharpened a .004" carbide bit quite successfully with this simple tool.

    Make one? Yes, but keep the axis of the rollers perpendicular to the drill bit so that the bit is 'ground' in its most robust plane and with ease and simplicity of sharpening technique. Something about dragging a small drill bit crossways across a stone.... doesn't appeal - but then we didn't try that 'other' technique. This 'wishbone' has been around too long and has been too successful to toss aside.

    Bill C

    Last edited by Bill C; 09-14-2008 at 08:03 PM.


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    Member neilw20's Avatar
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    Cool Here's a small copy of Ian's

    http://www.cnczone.com/forums/showpo...&postcount=181

    and here is a drawing with the G-code I used to make it.
    http://www.cnczone.com/forums/showpo...&postcount=183

    and this makes it easier to access the whole thread
    http://www.cnczone.com/forums/showth...=22760&page=19

    Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. THREE ways to fix things: The RIGHT way, the OTHER way, and maybe YOUR way, which is possibly a FASTER WRONG WAY!


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    Smile

    Thanks Bill.....have you got a pic with the ruler showing the length of the cutout? (The one at 60 deg to the length-which is not critical to operation, as far as aI can see) but the cutout depth is.

    Which also makes me think that a setting gauge with two or three stepped cutouts would allow for quick setting to two or three tip angles. Not so? But I want to get rolling (!!) with 118 tips first off, and resuscitate a whole heap of 1/16 and 5/64 and 3/32 drills I have blunted - maybe even some broken off ones!

    Last edited by mbelfer; 09-14-2008 at 08:48 PM. Reason: clarification and typos


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