rusted screw threads, head is stripped

[mighty_fine_sawdust]

Have an outside table that I needed to move and decided to take the table top off the base for moving. The screws that attach directly to the underside of the table were rusted and two of them would not come out and allen wrench bit eventually stripped the head of the screw trying to remove them. I'm looking for tips on how to get these screws out now so that I can get the table top off my to-do list. thanks.

(the screw you see in the second image is a 'lucky' screw as it did come out successfully. the screw you see in the 3rd image was not so lucky)

 

[Dee2]

You might drilling out the screw with a left-hand twist drill bit.

 

[Henry W]

I'd be inclined to cut that screw at the leg/top interface using a fine blade metal saw or more likely an oscilatting multitool. You don't necessarily even have to remove the reamining bit in the table top assuming this is a flush cut.
The leg should come away and the top of screw 'should' drop drop out of leg hole. Then 'all you do' is re-locate the holes for the leg screws by X amount and drill new mounting holes for NEW screws.

 

[Jack A.]

Maybe try hammering a slightly larger torx bit into the socket.

 

[Mark Johnson]

That is certainly not a wood screw, so you have a nut hidden in there somewhere. I would see if I could get a penetrating oil down the threads first. Then drill the head and buy a screw extractor to back out slowly.

 

[tghsmith]

I would drill off the head.. leaving the shaft after the leg is pulled off,, then it's P-oil and vise-grips time..

 

[Jack A.]

I would drill off the head.. leaving the shaft after the leg is pulled off,, then it's P-oil and vise-grips time..

This is probably the best idea, though it requires care with the drill to avoid gouging the wood. It's helpful to combine this with left-hand drill bit to avoid tightening the screw further. I actually have a set you can borrow if you'd like. I bought them for just this sort of thing and haven't used them since.

 

[bob vaughan]

A Dremel tool with a cut-off blade. Cut a slot and use a slotted screwdriver. Cut with the grain so the slot doesn't readily show.

 

[mighty_fine_sawdust]

Maybe try hammering a slightly larger torx bit into the socket.

I sort of tried this, I didn't have a hammer or anything substantial to "hit" it with but I put the torx bit in my screwdriver, set the bit onto the screw head, then pounded the other end of the screwdriver with my hand. all I got was a sore hand. ;-) I'll give that another go with a hammer.

 

[mighty_fine_sawdust]

That is certainly not a wood screw, so you have a nut hidden in there somewhere. I would see if I could get a penetrating oil down the threads first. Then drill the head and buy a screw extractor to back out slowly.

thought about this too. Was a little concerned about an oil stain but considering this is the bottom of the table top we're talking about, it's low risk and could be a simple fix. But, I've just never been successful with screw extractors.

 

[HMH]

What the others have said - that’s a bolt, not a screw. Likely threading into either a recessed nut, or threaded insert of some kind. I’d soak it in some sort of penetrating oil, and then grind a slot in the bolt head w/ a dremel, to allow a coarse bladed flat-head screwdriver. And then back it out from there. It wasn’t installed w/ much torque, so it’s really just a matter of breaking that initial “bond” of rust/ cured finish/ etc. it should come out easily once you get beyond the first few threads from there.

 

[tghsmith]

one has to remember the mechanics aditch, "one stuck bolt can turn a 15 minute repair into a three day ordeal"
I add to that is " anti-sieze is your friend"

 

[smallboat]

one has to remember the mechanics aditch, "one stuck bolt can turn a 15 minute repair into a three day ordeal"
I add to that is " anti-sieze is your friend"

and “never use your hand for a hammer”

 

[Brantnative]

Doesn't that bolt connect the leg to the underlying strip? If the head is broken then the leg is just held by friction or rust inside the screw hole. Try unscrewing the leg itself. That leaves the headless bolt you can get out with a pair of Vise Grips and penetrating oil..

 

[mighty_fine_sawdust]

Doesn't that bolt connect the leg to the underlying strip? If the head is broken then the leg is just held by friction or rust inside the screw hole. Try unscrewing the leg itself. That leaves the headless bolt you can get out with a pair of Vise Grips and penetrating oil..

the head is inside a countersink. I can't get enough of the head exposed to get a grip with anything.

 

[Martin Roper]

Speedout was recommended to me some years back, but I had no luck with them. I stripped a Phillips screw, drilled it out a bit, then tried the Speedout bit but it just wouldn't "grab." I ended up drilling out the screw head entirely, making a plug, then driving a new screw nearby.

 

[Gofor]

You know the diameter of the shaft from the other screw. Using that diameter or smaller, drill into the head until the head pops off. (Probably only about 1/8" deep) The rounded out head will keep the bit centered. If you do go too far, it will be into the bolt shaft, not the counter sink face. Remove leg and extract bolt with vice grips. If you drill past the head thickness and the head hasn't come off, re-drill with the next larger bit.

Tips:
Keep the drill bit in line with the bolt shaft.
Drill bit should be sharp and harder than the bolt/screw. Cheap drill bits rarely work well for this. If that's all you have, use the "step up" method mentioned below.
You do not need high rpms or a lot of pressure. Let the bit do the cutting.
For multiple fasteners, use drill lubricant to save your bit. With wood, just dip the tip of the bit into the lube so as not to have so much it stains the wood. Vaseline will work in a pinch.
When removing the remainder of the head from the drill bit, DO NOT grab it with your bare hands. It will be hot and possibly have very sharp edges.

Sometimes, especially for larger bolts, it is easier to start with a bit small enough to fit into the rounded out depression in the head to keep the hole centered. Drill deep enough to get into the shaft, and then go to a larger bit, stepping up until you get to the shaft diameter, which is when the head pops off.

I have done this numerous times removing "stripped" fasteners from aircraft panels.

 

[tvrgeek]

The problem with drilling it out is it may be a hardened screw.

 

[mighty_fine_sawdust]

I drilled the heads til they popped off. All was good until one of the threaded inserts came out during extraction with vise grips.

 

[mdbuntyn]

I drilled the heads til they popped off. All was good until one of the threaded inserts came out during extraction with vise grips.

That's a simple enough fix: Plug the hole with a dowel and install a new insert