European screwdriver sizes

[Stinky_Pete]

So I have been looking to replace some old screwdrivers and decided to look at Wera and PB Swiss because of all the good things I hear about them on this forum. The problem is, all my life I've been using slotted screwdrivers in sizes like 3/16 and 1/4, and I see the European screwdrivers and their sizes say 4.0, 4.5, 5.0, etc. I assume they mean the tip width in millimeters, but how does that compare to the fractional sizes I'm used to, if they are comparable? Also, do the European drivers have thicker ends as they go up in size like the fractional USA ones?

 

[techieman33]

So I have been looking to replace some old screwdrivers and decided to look at Wera and PB Swiss because of all the good things I hear about them on this forum. The problem is, all my life I've been using slotted screwdrivers in sizes like 3/16 and 1/4, and I see the European screwdrivers and their sizes say 4.0, 4.5, 5.0, etc. I assume they mean the tip width in millimeters, but how does that compare to the fractional sizes I'm used to, if they are comparable? Also, do the European drivers have thicker ends as they go up in size like the fractional USA ones?

They just use metric measurements instead of SAE. If you need to know their SAE equivalent just look at at conversion table. And yes the tips typically get thicker as they get wider. I know Wera typically lists all the dimensions for their drivers.

 

[4xdog]

1 inch = 25.4 mm

So, for example, 1/4 in = 0.250 in = 6.35 mm


PS: For those *seriously* OTT about this, the relevant standard is ISO 2351-1:2007
Assembly tools for screws and nuts — Machine-operated screwdriver bits — Part 1: Screwdriver bits for slotted head screws.
https://www.iso.org/standard/41054.html

Note that's behind a paywall -- ISO doesn't share their standards for free, alas.

 

[Stinky_Pete]

Thank you gentlemen. 1 hour after I post my question is answered. Another reason this site is the best for tool knowledge.

 

[Dave455]

If you usually use 3/16, 1/4 and 5/16 then pick the metric equivalents. Probably 5, 6.5 and 8mm.

However, although we tend to pick the nearest size when grabbing a slotted screwdriver, it’s worth bearing in mind that screw slots, like drivers, come in inch and metric sizes. You get the best fit if you use the right driver for the screw!

PB Swiss, especially, are sized to be a perfect fit in the relevant VSM (Swiss Standard) screw slot. I find they work well on most metric screws, but on some inch sized screw heads, I’m definitely better off with an inch sized screwdriver!

I find PB Swiss to be about the highest quality drivers out there. I don’t use them on crappy screw heads though. Wera produce very tough screwdriver blades. I particularly like their stainless steel ones. I do use these if I have to work with crappy screw heads, as there’s no plating to damage!

 

[measuredtwice]

German slotted screwdrivers run a big thick compared to American screwdrivers. For example, a German 6.5 mm wide screwdriver is often 1.2 mm thick whereas an American 1/4" wide screwdriver is often around 1.0 mm thick. A lot of folks use an undersized German slotted driver. So you might need a 5.5 mm (1mm thick). It's not ideal to use an undersized driver but you rarely hear it talked about when they talk about German screwdrivers. In general, most folks seem to think all screwdrivers are the same except the colorful handles.

I prefer American or Swiss drivers for slotted. The PB Swiss 6.5 wide slotted driver is 1.0mm thick like most American drivers. The "parallel tip" that is part of the Swiss VSM standard fits very well but it's not suitable for prying. Get a cheapo screwdriver for prying paint lids... or get a pry bar. I like German DIN, and Japan standards for Phillips.

 

[rlitman]

...PB Swiss, especially, are sized to be a perfect fit in the relevant VSM (Swiss Standard) screw slot. I find they work well on most metric screws, but on some inch sized screw heads, I’m definitely better off with an inch sized screwdriver!...

I have not used a slotted screwdriver on just about anything made in the past 30 years, with the exceptions being terminal strip screws and certain circuit breakers. Just about everything made post WWII in the US dropped slotted screws for Phillips. Because of that, unless I'm working on a Swiss watch (which uses metric screws) every slotted screw I encounter is either SAE, or simply predates any national standard.

However, I find myself using slotted screwdrivers quite a bit. On older things. Just the other day, I was working on a Singer sewing machine with all slotted screws (it dated to 1948, but since it was Canadian, it didn't use Phillips screws). I pulled out my Brownells slotted super set and had something that perfectly fit everything.

https://www.brownells.com/gunsmith-...a-tip-sets/magna-tip-super-sets--prod417.aspx

Slotted screws are something really easy to screw up, and since I'm only encountering them on antiques, it made sense to me to get a top notch gunsmithing slotted screwdriver set to minimize the odds of messing up an antique.