What's new
What's new

Removing broken screws from insertable tooling

Gackman

Aluminum
Joined
Apr 17, 2007
Location
Minnesota
I had a small screw break off in one of my smaller insertable drills and was wondering how to remove it? Is is worth it to send out to have it repaired and what are the chances that they will have any luck? Who would be someone in the Minneapolis area good at this? The screw is small......about .08 in dia. I use lots of anti-seize lube. The screw broke off below the torx head
 
you might be able to back it out with a pick, i've done that a couple of times. basically just take a sharp point and press on the top in an unscrewing motion untill it comes out enough you can get some pliers or tweezers on it. If that doesn't work take it to the mill and get a drill thats just under the hole diameter and drill it out from the bottom side. most of the time the drill will catch and screw it out for you.
 
+1 if you have a through-hole for the screw on the toolholder, it is the most efficient way. Otherwise, drilling it out entirely from above is the only other option I've come up with... ruined a few this way, though, by the drill wandering on the broken surface of the screw and fouling the toolholder threads. I suppose a d-bit / single flute miniature drill would be better here than my standard, number size, twist drills.
 
Someone used to fine work with a TIG can put a small ball of weld on the end of the scew, then you can back it out with pliers. That's how I do it.
 
Set the holder up in a 2 axis vise so that the floor is close to flat in a B-port.
... (if we don't know the vise settings we put an insert in the pocket and place a small circular bubble level on it to adjust the vise angles)
Take an old 1/8 ballnose end mill or better yet grind a left hand spade drill from an old 1/8 end mill shank.
.....(we use leftover carbide, snap off the end in a vise and grind a point and flats to make a crude left hand spade).
Put the B-port in low gear, center the bit over the broken screw
At about 100-150 rpm turn on spindle so that it is running in the direction to unscrew the screw.
Bring the quill down and jab it into the screw.
It will bite in, keep pressure on the quill but let it rise as the screw comes out.
This works 99% of the time.

If you have to drill it out most likely you will have to drill it oversize and weld in a soft steel plug , drill and tap this plug.
It's hard not to ruin the tiny threads drilling it out.
You will need to indicate the floor within a thou when doing this and the hole is offset from center-line .003/.004 towards the pocket walls.
Bob
 
I HATE it when those little bastards break off.I have been lucky enough that after soaking over night in WD-40 I was able to pick them out with a sharp probe.
Going at something that small with the tooling most of us have which isn't desighned for micro screws ends up ruining a tool that is best left for the pro's who deal with this every day.

Speaking of getting out broken screws..how many have had customers bring in jobs were a bolt broke off and then the customer breaks off an easy-out in it partly into the threads?
And how many times has a customer brought in a broken bolt that with a squirt of WD and a little picking backs it right out in 5 minutes but still gets charged 1 hour minimum labor? :)
 








 
Back
Top