Remove broke screws from hardwood

[GoSeigen]

The four screws securing a door hinge to the hardwood (really hard wood!) door frame have all sheared partway down their threaded part, leaving the bottom of the screw buried in its hole. As a result I can no longer get new screws in to secure the door hinge.

I suppose I could relocate the hinge but it would be a bit of a job and leave a mess. Instead I guess the best option is to use a metal drill to drill out the remaining pieces of screw.

Any advice on doing the job? My main concern thinking ahead is that the drill will slide off the top of the damaged screws and drill down next to them, is there a cunning trick to prevent that?

And what's a good way of stopping the screws shearing in future if I ever need to remove them? I think the wood is so dense and sticky that the screws almost become glued in there.

TIA

GS

[88V8]

The four screws securing a door hinge to the hardwood (really hard wood!) door frame have all sheared partway down their threaded part, leaving the bottom of the screw buried in its hole.
Any advice on doing the job? My main concern thinking ahead is that the drill will slide off the top of the damaged screws and drill down next to them, is there a cunning trick to prevent that?
And what's a good way of stopping the screws shearing in future if I ever need to remove them? I think the wood is so dense and sticky that the screws almost become glued in there.

Oak and some other hardwoods contain tannic acid which rusts steel screws so that over time they become immovable.
Brass or bronze screws only should be used, but they need to be put in with care in precisely the right size hole or they will shear as you tighten them which would rather defeat the object.

When putting brass screws into hardwood, I start with a steel screw the same size and gently drive that in by hand not with a power driver, gradually increasing the hole size if needs be, then I go with the brass screw once I am sure it can be driven home, again using a hand driver only.

Drilling them out will certainly fail as you fear. The best way is to drill around each screw with a small core drill, then break out the wood core with the screw inside, then fill the hole with a dowel of the correct diameter and start again.
Here is some who actually made his own drills for that purpose...

When you put in the new screws dip them in vaseline, that may help with future removal, but if you use brass you should not have a problem.

V8

[csearle]

Any advice on doing the job?

You could use one of these¹ to drill out a tube around the stuck screw, then use pliers to remove the screw vestiges.

After that, either glue a dowel in place to restore the material or use longer screws to engage with the timber further into the doors.

Chris
¹ There are longer ones available that allow quite deep holes to be drilled around screws without the screw interfering with the drill bit (very useful for lifting boards where screw heads are damaged).

[servodude]

I've got screw removal bits that work pretty well - if you remember to run the drill backwards!!

They're just "own brand" from the local big shed so I image they're easy enough to find anywhere

[kempiejon]

I've got screw removal bits that work pretty well - if you remember to run the drill backwards!!

They're just "own brand" from the local big shed so I image they're easy enough to find anywhere

me too but don't you need access to a chunk of screw to get started?

leaving the bottom of the screw buried in its hole.

[kempiejon]

And what's a good way of stopping the screws shearing in future if I ever need to remove them? I think the wood is so dense and sticky that the screws almost become glued in there.

Into the screw holes tap rawlplugs?

[Arborbridge]

I wouldn't use brass or bronze screws in a case where I was worried about shearing - they are as soft as cheese.

I'd probably choose stainless, well greased.

Arb.

[GoSeigen]

Thanks, rally useful advice here.

Oak and some other hardwoods contain tannic acid which rusts steel screws so that over time they become immovable.

Thant's a new one for me but certainly rings true. I've no idea what the wood is, it's really hard dense and dark coloured. I've seen it described as blackwood but not sure that it would literally be acacia melanoxylon, it may be just a generic description. But it certainly chews up screws. A while ago I was using my battery powered drill to remove and rehang a door and the drill actually caught fire before I realised it was being overworked!

Brass or bronze screws only should be used, but they need to be put in with care in precisely the right size hole or they will shear as you tighten them which would rather defeat the object.

When putting brass screws into hardwood, I start with a steel screw the same size and gently drive that in by hand not with a power driver, gradually increasing the hole size if needs be, then I go with the brass screw once I am sure it can be driven home, again using a hand driver only.

The wood is so dense that the doors are really heavy, not sure if brass screws would support them for long. They are also in a commercial premises so likely to suffer heavy use or abuse from time to time. But I'm intrigued by the chemistry suggested here.

Drilling them out will certainly fail as you fear. The best way is to drill around each screw with a small core drill, then break out the wood core with the screw inside, then fill the hole with a dowel of the correct diameter and start again.

That's a great idea, it hadn't occurred to me that you could get small enough diameter core drill bits.

When you put in the new screws dip them in vaseline, that may help with future removal, but if you use brass you should not have a problem.

Thanks, maybe I'll try that, should provide a protective layer over the metal too. (But might an oil substance not get absorbed by the wood?)


GS

[Urbandreamer]

Brass or bronze screws only should be used, but they need to be put in with care in precisely the right size hole or they will shear as you tighten them which would rather defeat the object.

When putting brass screws into hardwood, I start with a steel screw the same size and gently drive that in by hand not with a power driver, gradually increasing the hole size if needs be, then I go with the brass screw once I am sure it can be driven home, again using a hand driver only.

The wood is so dense that the doors are really heavy, not sure if brass screws would support them for long. They are also in a commercial premises so likely to suffer heavy use or abuse from time to time. But I'm intrigued by the chemistry suggested here.

GS

Brass should be strong enough to support most doors. That is assuming that the door is not a bank vault door.

However note the advice that you can't use brass directly. In essence the advice was to prepare a tapped hole in the hardwood frame to accept the brass screw. The brass shank of the screw supports the weight of the door. The threads stop the slamming of the door pulling the shank out.

As for tannic acid, it's well known. A mix of hardwood shavings and excrement was used to tan leather and the tannic acid in barrels plays a very important part in Whiskey production. The point about screws is not that the screws rust through, but that the surface in contact with the wood rusts. Preventing the screw from being removed.

[jfgw]

Either get inventive and make a hollow drill or buy a cheap diamond tile drill, this sort of thing, https://www.amazon.co.uk/Tykovon-Diamond-Porcelain-Granite-Materials/dp/B0B17J6ZRM/ref=sr_1_5?crid=156PY8UK8O1XZ&keywords=diamond+tile+drill+bits&qid=1691777894&sprefix=diamond+tile+drill%2Caps%2C108&sr=8-5. These are sold for drilling tiles but I would only buy good quality ones for that. Cheap ones should be ok for drilling around screws, however.

Dowels are not ideal for plugging the holes as the grain runs the wrong way. Screws do not hold as well in end grain. You could use a plug cutter to cut some plugs and glue these into the holes. You would need several plugs per hole to go the full depth, and knock them in with a punch one at a time as you go. Make sure you drill out the hole to the exact size of the plug. You may need to cut a notch along the side of each plug to allow the glue to escape (carefully run it along the blade of a fine saw such as a hacksaw. Alternatively, use a coarser saw and have a supply of sticking plasters ready). csearle has already linked to some plug cutters, or you could get this type, https://www.screwfix.com/p/erbauer-plug-cutter-9-5mm-x-56mm/86045. Try to find a suitable hardwood such as a chair leg for the plugs.

I would use stainless steel rather than brass or bronze. Bronze screws are available from chandlers' if you prefer the colour (and can afford them!). Brass screws are relatively weak, and none of these are as strong as a good ordinary steel screw.

When screwing into a hard wood (a wood that is hard, not necessarily a hardwood!), drill a pilot hole for the threaded part and drill a snug clearance hole for the shank of the screw. Lubricate the screw by rubbing it on a candle.

An alternative, if looks don't matter, is to drill and countersink new holes in the hinges.


Julian F. G. W.

[Mike4]

Either get inventive and make a hollow drill or buy a cheap diamond tile drill, this sort of thing, https://www.amazon.co.uk/Tykovon-Diamond-Porcelain-Granite-Materials/dp/B0B17J6ZRM/ref=sr_1_5?crid=156PY8UK8O1XZ&keywords=diamond+tile+drill+bits&qid=1691777894&sprefix=diamond+tile+drill%2Caps%2C108&sr=8-5. These are sold for drilling tiles but I would only buy good quality ones for that. Cheap ones should be ok for drilling around screws, however.

In my own experience of using pilotless core drills/hole saws, getting the cut started freehand is the Devil's own job. The bit runs all over the workpiece uncontrollably and my advice to the OP is not to try these unless first you devise a way to prevent this happening. I used to the diamond-covered ones regularly to drill holes in tiles when I was a bathroom fitter and I used to put them in a cheap pillar drill from the likes of Wickes, but that can't be done in a door frame fixed into a building.

Dowels are not ideal for plugging the holes as the grain runs the wrong way. Screws do not hold as well in end grain. You could use a plug cutter to cut some plugs and glue these into the holes. You would need several plugs per hole to go the full depth, and knock them in with a punch one at a time as you go. Make sure you drill out the hole to the exact size of the plug. You may need to cut a notch along the side of each plug to allow the glue to escape (carefully run it along the blade of a fine saw such as a hacksaw. Alternatively, use a coarser saw and have a supply of sticking plasters ready). Csearle has already linked to some plug cutters, or you could get this type, https://www.screwfix.com/p/erbauer-plug-cutter-9-5mm-x-56mm/86045. Try to find a suitable hardwood such as a chair leg for the plugs.
Julian F. G. W.

Never mind all that. The quick and dirty solution has already been mentioned previously. Use the wall plugs one normally uses for putting screws into masonry!

[Stompa]

In my own experience of using pilotless core drills/hole saws, getting the cut started freehand is the Devil's own job. The bit runs all over the workpiece uncontrollably...

https://www.youtube.com/watch?v=EKra3nCw8Nc

[jfgw]

When drilling into tiles with one of these, I start at about 45 degrees and gradually straighten up.

If the screws are broken part way down, you can use a twist drill first. It's quicker and provides a guide for the tile drill.

I would be wary of relying on wall plugs in a heavy wooden door. Plugs and longer screws would probably work.

Ordinary dowels are ok if you drill across the screw hole from the side so that the screw goes into the side of the dowel.


Julian F. G. W.

[88V8]

Ordinary dowels are ok if you drill across the screw hole from the side so that the screw goes into the side of the dowel.

Dowels are also OK if one drills a smaller pilot hole than one would in crossgrain.

V8

[Mike4]

In my own experience of using pilotless core drills/hole saws, getting the cut started freehand is the Devil's own job. The bit runs all over the workpiece uncontrollably...

https://www.youtube.com/watch?v=EKra3nCw8Nc

Thanks!

Good method on the bench but I'd like to see that done on a painted door frame with architraves on each side. I guess one could temporarily fix the jig in place with more screws.

I liked the way he was burning through the wood, too!

[kempiejon]

I liked the way he was burning through the wood, too!

Yeah I noted that too. Reminds me, many years ago I was working in a theatre helping with the get in. The set for a touring production of I think High Society was a giant wedding cake that opened up to reveal the inside of a room. The cake was hinged and attached to wires and winches and back to two hidden motors to be bolted to the floor with great big fixings. The young lad charged with securing the motors had been making a bit of a meal of his job, drilling away for about 20 minutes and had changed bits a couple of times. When we noticed the smell of burning and whisps of smoke coming from his drill bit it clicked that he'd been running it in reverse and slowly charring a hole in the wooden floor.