Need to buy a "sharp but broad" slotted screwdriver for a particular job

[mrodent]

Renovating 1930s house. The hinges of the windows (all original) are screwed on with a particular type of very narrow slot slotted screw. The slot is also very shallow! Scratching my head about what screwdrivers the 1930s carpenters may have used.

So I'm trying to a) understand how to specify this when I go searching for a screwdriver and b) find recommendations from here.

Diameter of screwheads is about 7 mm.

I *think* I'm looking for a screwdriver which is specified as "slotted/flathead 0.5 mm / 7 mm". I.e. this will have a pretty "sharp" bit. Unfortunately these either don't exist or are difficult to track down. I assume that the metal will have to be hardened steel or something to prevent distortions. Maybe that's why the 0.5 mm "sharpness" screwdrivers appear to be max 4 mm wide. Which really wouldn't give the ideal torque and might even damage the slots.

Searching seems to suggest screwdriver heads may be classified according to particular codes... "SL3" ??? Does this mean something?

 

[MarkAW]

Could always sharpen an old one you don't use

 

[recipio]

I needed an 18 mm wide screwdriver and had to make my own after fruitless searching. I bought an 18 mm spade/flat bit, cut off the point and ground the bit to a flat edge. It was about 1 mm thick so if you were to do this you would obviously need to grind it down. I then inserted it with some epoxy into a turned handle. It worked a treat but if that's too much hassle have a look at gunsmiths screwdrivers which should have a 7 mm wide bit.

 

[Adam W.]

@mrodent These were used, you can get them off ebay for not much money and sharpen them to fit.

 

[Jacob]

I keep all old screwdrivers just in case. Probably got 30+ now, plus Yankees and other oddities.
Good idea to sharpen the end a touch to give it a good grip, across if narrow enough already.
Useful tip - yes good fit to the slot, clean out old paint, also tighten the thing a touch to break its grip, before loosening. If you damage the slot tightening you still have a good slot left for looseneing

 

[mrodent]

These are all great ideas, thanks. I can see a consensus emerging.

@Adam W: what exactly are those? Are they some sort of chisel? To withstand the torque I'd be applying the metal would have to be solid stuff. Mostly the stuff I've bought of ebay made 50 or more years ago seems to be 10 times more robust than the most expensive stuff you find these days, so I'm less worried about the handles on those being securely attached. But did you check they were of a particular steel or anything?

Come to that I may have a suitable wood carving chisel hanging around: I bought an ancient set off ebay not long ago.

 

[Adam W.]

These are all great ideas, thanks. I can see a consensus emerging.

@Adam W: what exactly are those? Are they some sort of chisel? To withstand the torque I'd be applying the metal would have to be solid stuff. Mostly the stuff I've bought of ebay made 50 or more years ago seems to be 10 times more robust than the most expensive stuff you find these days, so I'm less worried about the handles on those being securely attached. But did you check they were of a particular steel or anything?

Come to that I may have a suitable wood chisel hanging around: I bought an ancient set off ebay not long ago.

No, they are not chisels, but screwdrivers.

 

[loftyhermes]

Adam, back in the day, would they be called turnscrews?

 

[Ollie78]

Look at gunsmiths style screwdrivers they are more the shape you need.
I agree that grinding up one to fit is probably a quick and easy way to do it but you might have luck if you look at slotted bit sets for hex drive.

Ollie

 

[niall Y]

The screwdrivers that @Adam W. shows are known as London Pattern Screwdrivers.

 

[mrodent]

The screwdrivers that @Adam W. shows are known as London Pattern Screwdrivers.

Learn something every day. Quite a few available on ebay.

 

[Bingy man]

I’ve used a medium sized masonry nail to clear the screw slot , tedious but that paint is rock hard , you need a good tight fit of the screwdriver blade into the slot , tapping it home with a medium sized pin hammer will help. Once you get it started keep plenty of pressure on the screw. Your screwdriver will probably be wrecked by the time you get done ..

 

[Bingy man]

Renovating 1930s house. The hinges of the windows (all original) are screwed on with a particular type of very narrow slot slotted screw. The slot is also very shallow! Scratching my head about what screwdrivers the 1930s carpenters may have used.

So I'm trying to a) understand how to specify this when I go searching for a screwdriver and b) find recommendations from here.

Diameter of screwheads is about 7 mm.

I *think* I'm looking for a screwdriver which is specified as "slotted/flathead 0.5 mm / 7 mm". I.e. this will have a pretty "sharp" bit. Unfortunately these either don't exist or are difficult to track down. I assume that the metal will have to be hardened steel or something to prevent distortions. Maybe that's why the 0.5 mm "sharpness" screwdrivers appear to be max 4 mm wide. Which really wouldn't give the ideal torque and might even damage the slots.

Searching seems to suggest screwdriver heads may be classified according to particular codes... "SL3" ??? Does this mean something?

Just re- read your op - are you removing these screws to replace hinges or repair/ replace the windows or another reason SL3 is a modern term applied to slotted screwdrivers-have a look at vde screwdrivers for electrical work as these will be sized in width of blade and thickness of blade and are generally sharper than regular screwdrivers. So you’ll want 7mm x the width of your screw slots ..

 

[paulrbarnard]

Learn something every day. Quite a few available on ebay.

Quite a lot of them were craftsman made from old files. I have a few from my grandfather and great grandfather.

 

[Scruples]

Sometimes, I can remove stubburn screws using a drill set to hammer setting. The secret there is to let the action loosen the screw and not force it.

 

[Dee J]

Agree on customising an old screwdriver. Hollow or step grind so the sides are parallel rather than tapered. If the screws are particular tight/painted/rusted then applying the tip of a red-hot bar to the screwhead can help - softens the paint and eases the fit in the wood.

 

[pgrbff]

I'd have a look at Wiha softfinish. They come in a number of sizes and are very high quality.

 

[stuart little]

I keep all old screwdrivers just in case. Probably got 30+ now, plus Yankees and other oddities.
Good idea to sharpen the end a touch to give it a good grip, across if narrow enough already.
Useful tip - yes good fit to the slot, clean out old paint, also tighten the thing a touch to break its grip, before loosening. If you damage the slot tightening you still have a good slot left for looseneing

The tip should be ground parallel not tapered, for a positive grip. Very rare with 'over the counter' divers.

 

[Fergie 307]

I’ve used a medium sized masonry nail to clear the screw slot , tedious but that paint is rock hard , you need a good tight fit of the screwdriver blade into the slot , tapping it home with a medium sized pin hammer will help. Once you get it started keep plenty of pressure on the screw. Your screwdriver will probably be wrecked by the time you get done ..

You can make a great tool for cleaning out the slots from an old hacksaw blade, just grind the teeth off at the end so you have a thin blade then grind the end to maybe 45 degrees. Avoids rounding the sides of the slot. Jacob's tip of tightening a touch first is a good one, works on nuts and bolts too.

 

[Jacob]

The tip should be ground parallel not tapered, for a positive grip. Very rare with 'over the counter' divers.

Yes but difficult to achieve for a non engineering woodworker.
Doesn't do to over think these things!
My solution has been to keep a box full of old screwdrivers and use the one which is the best fit, and occasionally square off an end if necessary.
Stanley ratchets and spiral yankees are good.
A few "perfect" pattern (metal right through the handle) are handy and can be tapped with a hammer for a tight fit or to clear out slots. Some yellow plastic handled have metal right through and are worth keeping for this alone.