My Drill Bit Broke. Am I stuck?

[AzShooter]

I tried to install a new fiber optic front sight on my S&W 617. I was using a #54 drill bit and it broke without even going 1/2 way through the sight but it will not come out.

What are my optioned? Should I just put Blue Loctite on the bit and let it alone? Should I try to drill from the other side?

How about using a 1/16 bit from the opposite side?

 

[BMCM]

Assuming you are working on a mill or drill press.

I will also assume you have the barrel rigidly fixtured.

You cannot do this with a hand drill.

This is how I would tackle the problem...

You're going to need a couple more of those tiny drill bits.
Flip the workpiece over and drill from the other side. Go very slowly and use cutting fluid ie. Do-drill or Vipervenon cutting oil. This drill bit used here is sacrificial as it will get wrecked when it reaches the broken stub of the first drill, that's why you need more than one.

Once you have reached the broken bit from the other side, back out and clean out the hole best you can then take the broken shank from the first drill that broke and insert the shank in the hole and use that as a punch to try and gently tap out the broken stub.

Once you have the stub out, chase out the hole with another new drill bit. Again. go slow and use cutting oil.

Since you used a #54 drill instead of the chucking reamer, the hole will likely be slightly over size for the factory pin, so...

You should pull the new sight out of the barrel mortise and clean all the oil off with acetone. Install the clean & dry sight into the mortise then bump the pin in place. (note you need a "cup tip" punch to install the pin). Once it's all back together, apply some Loctite 290 and allow it to cure. 290 is wicking grade and will seep into all the voids around the sight and secure it even if the pin is slightly loose.

Without seeing or examining what you have there, that is my best advise. Good Luck.

Cheers
Bill

 

[AzShooter]

BMCM

Thank you very much.

 

[mmaher94087]

If, the big IF, there is part of the bit protruding or a way to grasp the broken piece then you might be able to 'unscrew' the bit from the work. If this is a possibility, then heat the sight base with a heat gun as this expands the drilled hole and makes the extraction easier. A #54 drill is small, and one may not be able to grasp it.

Drilling from the other side is an option but eventually the new bit will hit the hardened steel of the broken bit. The broken bit will need to be punched out before the hole can be completely drilled through. Heating the broken drill to red hot and allowing it to air cool will anneal or soften the broken bit which might help. Good luck.

 

[colt_saa]

As Bill has already covered . . . . . . .

Those #54s break easily if any movement of the bit/part alignment occurs while drilling

Go slow while drilling, I meant to say GO SLOW

I think my vendor sells those bits in 5 or 10 packs

I use the Do-Drill and green locktite . . . can't recall the number on the locktite. It is the sleeve retainer and I put some on as the pin is being tapped into place wiping off any excess

 

[BMCM]

There are a bunch of "green" Loctite compounds, the green ones I have on hand here are...

620 retaining compound... for when you need to fill large gaps, apply prior to assembly. Usefull for bedding poor fitting AR barrels to loose upper receivers, among other things.

680 retaining compound... same thing for the most part.

The stuff I was describing above in my previous post is this...

290 threadlocker, medium strength, wicking grade... Apply after assembly, wicks into the smallest voids like penetrating fluid. Same strength as the common 242 Blue. Also useful for sealing up sight dovetails after installation to prevent moisture/sweat wicking in there and corrosion welding the parts together.

Cheers
Bill

 

[AzShooter]

Here's my jig for my drill press. I'll try to drill it out tomorrow. Wish me luck.

I've done it before with no troubles but for some reason I had my trepidations on doing it this time. I should have waited until I felt more confident.

 

[BMCM]

Honestly, I would clamp that barrel right up close up to the frame with the flat barrel top strap against the fixed jaw of your vise.

Let the muzzle end overhang off to the side of the vise. That way you take advantage of the flat top strap to make sure your sight rib where you're drilling is perfectly perpendicular to the drill.

Looks like you have a piece of leather in there cushioning the barrel. You'll want something rigid for the top of the barrel to rest against so it indexes perfectly instead of the soft leather? A little piece of aluminum bar or you can take a little piece of copper tubing beaten flat and use that. So something rigid but non marring against the top and use the leather or whatever that is to cushion the underlug.

And...if the speed is adjustable on your drill press, set your spindle speed to the slowest rpm setting.

Cheers
Bill

 

[AzShooter]

I ordered a sheet of brass to replace the leather. I've reduced the power to my drill press, I ordered 290 thread locker.

Now I need the confidence to try again or sent it out for repair.

 

[jfd]

Wow, what a beautiful 617! Good luck, let us know how it works out.

 

[BC38]

I'd try the "drill from the other side" suggestions - but I'd use a left-hand drill bit, if I could get one. That way when the new drill makes contact with the broken one it will be turning in a direction that will encourage the broken piece to back out...

 

[ms]

Nope

I'd try the "drill from the other side" suggestions - but I'd use a left-hand drill bit, if I could get one. That way when the new drill makes contact with the broken one it will be turning in a direction that will encourage the broken piece to back out...

Not if you're drilling from the other side.

 

[BC38]

Not if you're drilling from the other side.

Now that I think more about it, you are correct. From the opposite side a standard right-hand drill would turn in the right direction to cause the broken bit to "back out"...

 

[BMCM]

Ya know, tiny drill bits such as we have here will often bind up just as they start to poke through the other side of what your drilling through. It might be worth the effort to take what's left of that broken bit and stick the shank end in the hole opposite the broken off piece and giv'er a couple taps just to see if that might dislodge the broken off piece.

Cheers
Bill

 

[chief38]

As a last resort when tiny drill bits break, I use a Foredom Electric tool (like a Dremel on steroids) with a tiny little diamond dental burr. The diamond burr eats up the drill bit and has always worked for me. On the Foredom tool I have the option to spin it in the opposite direction also, so some times by spinning the tool counter clockwise it actually "unscrews" the drill bit before it has to eat it all up. A Dremel only spins in one direction so you would have to actually erode all the metal of the drill bit.

Before doing that I'd give drilling it from the opposite side first. Then you may be able to use a punch to push it out.

HINT:

I always have on hand a box of drill rod. Drill rod is what they make drill bits from but it does not have the flutes on it - just a solid rod. They are precision made and uniform, as hard as a drill, and by having all the sizes available I can make up any sized pins I need. So for instance if after removing the drill bit I needed a slightly larger pin (due to hitting the sides a little) I could use the next size drill bit to clean up the hole, then use a piece of drill rod to make a new pin. BTW, you can also do the same thing with the bottom of a drill bit (sacrifice it). The different size pin is so negligible, no one would see it.