I have two pieces set of precision hand drill. One of them had the drill bit became loose and detached, which makes it no longer usable.

Precision hand drills including one to repair

Product information (copy of text in English found on the packaging, which may be subject to translation errors by the manufacturer):

2 pcs. set: 1.0 mm, 1.5 mm (approx. 0.04/0.06 in.)
Usage: For drilling of handicraft, plastic model, hand works
Materials: High speed steel, Iron

The tool body has a hole with very small clearance, which makes it almost impossible to put any adhesive inside to secure the drill bit back in place (the adhesive glue will either resist the drill bit to be inserted again in place, or will cause most of them to ooze out). I also tried using some epoxy glue at outside surface that was sandpapered, but failed to withstand the hand-drilling force.

Is there anyway to secure the drill bit to the tool body; alternatively, if repairing as such is not possible, is there other way to secure the drill bit to something else for hand use (not machine)?

P.S.: The main question is "how to secure (repair)". Although, I am open to other lifehack solutions that may be possibly better than repairing this tool.

P.P.S.: The alternative method should restore the functionality of the precision hand drill, preferably at very low cost (a lifehack is required).

Update (13 Aug): Thanks for all the suggestions; although, the repair seemed to be more difficult than expected with each new answer. Meanwhile, I have figured out a low-cost lifehack and I think I can self-answer my own question soon.

Update (15 Aug): By using the same epoxy and the glue applying method suggested by the first answer, the drill bit apparently remain secured. But I am not confident with the adhesive; I happened to found another "free" drill bit of same size (1.5 mm) from my junk parts' box, so I worked on the alternative method.

  • What are you asking: "How to repair?" or "How to reuse a drill bit?" – Weather Vane Aug 10 '19 at 17:06
  • Fixed word choice: "reuse" -> "secure to something else". That should be more clear and no more confusion. – user27887 Aug 10 '19 at 23:26
  • your tool chuck is made from aluminium, which fails when you crank it. ditch it. – user2497 Aug 13 '19 at 2:46

You say you tried placing adhesive in the hole but it is too tight a fit: there is nowhere for the excess adhesive to go.

Instead, apply the adhesive to the shank of the drill bit. Then any surplus adhesive will be pushed further up the shank and not impede entry.

Thoroughly degrease the drill bit and the hole first, with repeated application of solvent.

Looking at a zoom of the image, it seems as if the shank of the drill bit is hexagonal, and the hole too. If it weren't for that, I would say it won't be possible to make a satisfactory repair.

If you can't repair it, you can re-use the drill bit if you have a pin vice (vise) with an adjustable collet or chuck, such as this.

enter image description here

An adjustable pin vice (vise) is a good investment anyway, because drill bits go blunt and break (especially small ones), so all you need to buy is another bit, not the whole tool.

  • Please suggest only one solution, as per the meta FAQ. The main question is "how to secure the drill bit"; I wrote "is there other way to reuse" as the alternative if the former is not possible. – user27887 Aug 10 '19 at 16:47
  • Er, I reworded the answer slightly, as the horizontal line wasn't clear enough. Only you know if it is possible. You asked two questions, and I answered both of them. That's not what the meta you linked says. – Weather Vane Aug 10 '19 at 16:55
  • I would not know if such precision tool is repairable or even worth repairing or not. Therefore, I am open to the possibility of other lifehacks by not repairing. – user27887 Aug 10 '19 at 17:06
  • +1 for the glue applying method. In my case, a vice is not worth buying because I have only a single drill bit (1.5 mm) that I use most for many years. – user27887 Aug 12 '19 at 8:57
  • I tried this recently on a similar object (screwdriver). The blob of epoxy on the end of the shank created an airtight seal, so the bit would be pushed out by air pressure. I solved that by putting the screwdriver in a vise to keep the shank pushed in while the epoxy dried. I haven't tried yet how much torque the screwdriver will take. – Hobbes Aug 12 '19 at 11:16

Braze it or Silver Solder it

If glues and epoxies fail, for a more permanent solution, you can try brazing the drill into the holder. You would need a torch setup to do it. If you don’t have the equipment or care to buy it all, maybe a jeweler, welding shop, or friend who has a torch could braze it for you(but probably for more than what a new one would cost).

  • Wikipedia noted that: "Soldering performed using alloys with a melting point above 450 °C (840 °F; 720 K) is called "hard soldering", "silver soldering", or brazing." That doesn't seem to be feasible for general home users; can a soldering iron do the job (the one used in electronics)? – user27887 Aug 12 '19 at 13:56
  • @clearkimura the first soldering iron I clicked on Amazon that is <$20 said it heated to 450C, so I think that most soldering irons would probably work. – UnhandledExcepSean Aug 12 '19 at 18:58
  • Good proposal! For such a small job, a small butane / propane torch or even jet lighter should work. Or a LPG kitchen stove. First fill the shaft with liquid solder while heating further, then push in the drill bit. As with all soldering, proper cleaning, flux and adequate solder is key. There is also silver based soft solder which works at lower temps and should still be strong enough here. (Source: did it this way for a small bowden cable that had come loose from a pull knob.) – tanius Aug 12 '19 at 22:39

These tools are almost never made well these days, as you have found; drill bits pushed into a metal handle of mediocre grade alloy and relying on friction alone to grip. The drill bit's surface is smooth and grip is poor

I've generally had a rule with tools that I buy cheap ones and replace those that fail with ones of better quality. Additionally, the handle of this tool is not much fatter than the bit that it holds, so it doesn't offer appreciable extra torque over just using the bit in your fingers. Look for a replacement tool that has a handle with a slim part (for faster rotation) and a fatter oart( if you need greater torque). If you break a good quality version of this tool, leverage the manufacturer warranty to replace it and consider that you're probably drilling something that requires use of an actual chucked drill

It would however be possible to repair this tool thus:

  • Use a grinder to grind a flat spot into the side of the drill bit shaft, at the end that is inserted into the tool handle. The size of the flat spot depends on the torque you anticipate applying; bigger flat spot allows more torque

Crude sketch of a cylinder with a flat spot on one side

  • Apply epoxy to the flat spot. Because there is now space for the epoxy, sufficient quantity will remain on the drill bit when is is inserted into the handle. The epoxy's job is not to resist the turning force but simply to retain the bit in the handle

  • Insert the drill bit to the handle, put the handle in a vise and gently crush the handle into the flat spot. Leave the epoxy to set

If you're concerned about misalignment of the drill bit (I wouldn't be) consider alternatively drilling a small hole in the side of the handle so that the hole aligns with the center of the flat spot. Load the epoxy into the handle down the large hole where the drill bit goes - it will succeed now that the air can escape out the small hole. Push the bit into the hole so epoxy squeezes out the small hole. Clean up and wait for set. The epoxy will form a key between the small hole and the flat spot preventing slip, but it won't be able to resist as much torque as the crush method

enter image description here

Apologies for the crudeness of the images; they were drawn with a fat finger on a cellphone that has a thick glass screen protector and it was hard to be precise, but hopefully they convey the meaning

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    +1 for good explanation with illustration. The repair method looks solid, but not really doable or worth doing for a small and cheap precision tool that I have. – user27887 Aug 13 '19 at 7:58
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    Indeed, hence my starting out with the "buy cheap, replace when your skills/requirements outpace it" point :) – Caius Jard Aug 13 '19 at 8:15

When faced with this problem, I've pressed the drill bit into the holder. Put a drop (ONLY) of Cyanoacrylate adhesive at the point where the drill bit enters the holder. Wait (according to directions). A tight fit is best for this "repair" as liquid glue is drawn into the space between the materials by capillary action.

Put the bit against something soft such as a block of wood and push the handle rather than the bit to mate the two pieces prior to applying the glue.

These glues are sometimes known generically as instant glues, power glues or superglues.

If the fit is too tight, use an abrasive on the shaft until you achieve a press fit of the two pieces.

Good luck

  • I can't try this now, since I am waiting for the epoxy to cure using the method advised by the other answer. I may try this if epoxy did not work. – user27887 Aug 12 '19 at 9:02
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    Even with the epoxy, I doubt if any consumer grade adhesive will ever work. Does superglues actually work for steel-iron bonding (materials noted on packaging)? – user27887 Aug 12 '19 at 9:06
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    @clearkimura After you've gotten epoxy into the handle, you can forget about using this suggested answer. Sorry. – Stan Aug 12 '19 at 13:07

This is how I did: Secure the drill bit to something else.

That something else will use the following items:

  1. One paired screw terminal (this kind that will secure the drill bit)
  2. One empty ink barrel of ball pen (that will offset/centre the drill bit)
  3. One empty marker pen or highlighter (that will be the tool body itself)

These items are available at relatively zero cost. One may recover these items from some old and broken electrical appliances or junk parts from old electronics projects, and use any ball pen, marker pen, or highlighter that can no longer write or has run out of ink.

Important: The item selection should follow the order of numbered list. The diameter of ink barrel to use will depend on the hole diameter of screw terminal; and the diameter of tip holder of marker pen to use will depend on the size of screw terminal itself. Hence item 1 must be found first, then only 2 and 3.

To build that something else, use these tools:

  • One slot-head or cross-head screwdriver
  • One blade knife
  • One flat file (160 x 7 mm, similar to this tool)

This is how that something is being built:

The substitute tool body - howto

Important: The selection of items 1-2-3 will affect the build quality, and one's own skill will affect the build precision. Hence the result may vary from person to person.

This is the alternative method that I prefer most: Low cost (I had all used items), no adhesive build (ready to use), less time consuming (zero cure time without adhesive), and modular parts (each part can be replaced or improved).

A picture is worth a thousand words: I will skip the details and let other people understand from the combined photos as above. I may update this answer later if needed.

  • Even for all my hair-brained crazy ideas, this looks a bit over complicated and unbalanced. I definitely appreciate the engineering and thinking outside the box-itiveness, though. – computercarguy Aug 15 '19 at 17:50

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