How to Extract Broken Left-Hand Screw?

Chips O'Toole

Chips O'Toole

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Two days ago, I sheared the screw that attaches the chuck to my Makita lithium drill. It's broken off almost flush inside the part it screws into. I ordered a new screw, but I am wondering about the best way to get the old one out.

I have extractors for right-hand screws. This is a left-hand screw. What tools have people here used successfully? I see there are straight-fluted screw extractors. Do they actually work?

There is not enough meat to grab with Vise Grips. TIGing something to the screw for purchase is risky because I might weld the screw to the drill.
 
Those straight flute extractors work well as if the hole is the right size they don't cause a wedge action and the shock of knocking them in helps loosen things up. One thing to be aware of when working on anything Asian is that for some reason known only to the Oriental mind they ,(very),often put Superglue on the threads before assembly. This means that no matter how careful you are the fastener will either munt the head or snap when you try to remove it. Where things can't be heated with a small torch I have found a decent sized soldering iron works well. If you have a iron with interchangeable tips making a few new ones with flat and concave faces makes heating the fastener possible and once softened removal becomes easier.
 
This has the potential to be a piece of cake. I have every extractor known to man but the absolute favorite for regular broken bolts is left hand drill bits. center punch the broken bolt, get the right drill smaller than the minor diameter and try to drill straight through. If my luck held that spot at the end of drilling where it always catches, would catch and the bolt would just magically back right out.

with yours you don’t even need a special drill as a typical right hand drill bit it what you need.
 
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To add to what C-bag said making a drill guide would help and the chuck itself helps here, just make sure that you lift they guide a little once the bit has started.
 
This thing is in there pretty good, because torque is what sheared it. Not sure it will ever come out.
 
I used a Dumore to smooth out the broken end of the screw, and I used a 1/8" mill to make a shallow cavity pretty much in the center. Think I should jam a right-hand drill in there and hope it catches, or should I try to find a decent US-made straight-flute extractor?
 
I tried a right-hand drill, and it was no good.

Maybe I should drill a hole into the screw, tap it, put a right-hand screw in it, and see if turning the small screw will get the big one out.
 
The straight flute extractors are also designed for right hand threads, though they may be worth a try. They have a groove to the left of each corner making an edge to cut into the metal when turning to the left.
The torque on the screw was likely against a shoulder and may not have effect on threads, hopefully. Good luck.
Chuck
 
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