Slotted screwdriver blade thickness

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75RR
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Slotted screwdriver blade thickness

#1 Post by 75RR » Thu Jan 03, 2019 2:45 pm

Slotted screwdriver blade thickness

One of the quaint peculiarities of Zeiss microscopes is the thinness of the screw slots. As everyone knows a good slot fit is fundamental if damage is to be avoided.

To this end I purchased a set of 8 Wiha Slotted Precision screwdrivers a while back.

Now they are very nice and I am happy with them but the fit is not ideal.

By this I mean that to match the slot I have to use a narrower blade than the screw merits, losing torque and potentially damaging both screw and screwdriver, although fortunately that has not happened yet.

I have therefore been looking for a make of screwdriver that specifies the thickness of the blade, which would allow not only a correct slot fit but also the full use of the width of the screw.

So far no luck, although I am sure there is one, probably made for clockmakers but they do not appear to be sold on either amazon nor ebay.

Was anyone fortunate enough to find one?
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Re: Slotted screwdriver blade thickness

#2 Post by MicroBob » Thu Jan 03, 2019 3:48 pm

These thin blades are damaged easily so you need a bench grinder anyway.
Grinding screw driver tips is a nice beginner training task by the way.

Bob

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Re: Slotted screwdriver blade thickness

#3 Post by Hobbyst46 » Thu Jan 03, 2019 4:14 pm

Hi Bob,
I suppose the tips of these quality screwdrivers such as the Wiha (I have some too) or Wera are made of hardened steel. Will they withstand grinding?

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Re: Slotted screwdriver blade thickness

#4 Post by 75RR » Thu Jan 03, 2019 4:18 pm

Looking at watch maker sites it would seem standard to provide extra blades with their screwdrivers (blades are held on to the handle with a screw)
The expensive part is the handle apparently.
With changeable blades grinding makes sense.

Still I think I would prefer a more normal arrangement with standard screwdrivers with slightly thinner blades.

https://www.eternaltools.com/blog/compl ... rewdrivers
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Re: Slotted screwdriver blade thickness

#5 Post by Peter » Thu Jan 03, 2019 4:45 pm

Hi 75RR,
Many years ago I was told, by a Zeiss agent who had visited the Zeiss factory, that the Zeiss workers make their own screwdrivers using sword steel for the blades. That being the case I doubt you will find a commercial equivalent. Best find some tough steel and start making your own.
Hope this helps.
Peter.

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Re: Slotted screwdriver blade thickness

#6 Post by 75RR » Thu Jan 03, 2019 5:07 pm

Peter wrote:Hi 75RR,
Many years ago I was told, by a Zeiss agent who had visited the Zeiss factory, that the Zeiss workers make their own screwdrivers using sword steel for the blades. That being the case I doubt you will find a commercial equivalent. Best find some tough steel and start making your own.
Hope this helps.
Peter.
Thanks Peter. Interesting story - Wonder if that holds true for the Zeiss repair facilities abroad. Zeiss had sales offices that would also service their microscopes in dozens of countries.
One would think that Zeiss would have got around to providing them with all the right tools, but then if made in-house, they would not be available to the public.

Does that mean that Zeiss made their own screws?
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Re: Slotted screwdriver blade thickness

#7 Post by desertrat » Thu Jan 03, 2019 5:27 pm

If you have some time on your hands, you can put some medium grit sandpaper on a flat surface and rub the blades across it, switching sides frequently. Then switch to fine grit paper to get a better finish. This takes a while, but to me is a bit more controllable than a bench grinder, which works pretty fast with small screwdriver blades.
Rick

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Re: Slotted screwdriver blade thickness

#8 Post by Peter » Thu Jan 03, 2019 5:34 pm

75RR wrote:
Does that mean that Zeiss made their own screws?
I have no idea but I would say probably.
Peter.

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Re: Slotted screwdriver blade thickness

#9 Post by 75RR » Thu Jan 03, 2019 6:48 pm

I have no idea but I would say probably.
Thanks Peter, would be nice if someone were able to confirm that.
desertrat wrote:If you have some time on your hands, you can put some medium grit sandpaper on a flat surface and rub the blades across it, switching sides frequently. Then switch to fine grit paper to get a better finish. This takes a while, but to me is a bit more controllable than a bench grinder, which works pretty fast with small screwdriver blades.
Agree that a bench grinder would be overkill on such small screwdrivers.

I do however have a sharpening stone, with which I have just about perfected the art of dulling my kitchen knives.

Perhaps I should purchase some cheapo ones to practice with first ...
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Re: Slotted screwdriver blade thickness

#10 Post by MichaelG. » Thu Jan 03, 2019 7:17 pm

Eze-Lap hones make screwdriver sharpening/thinning relatively simple.
https://www.ezelap.co.uk/tools/Diamond- ... Stone.html
https://www.ezelap.co.uk/tools/Credit-C ... Stone.html

Cheaper brands are available, but caveat emptor

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Re: Slotted screwdriver blade thickness

#11 Post by 75RR » Thu Jan 03, 2019 7:27 pm

Thanks for the tips MichaelG.
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Re: Slotted screwdriver blade thickness

#12 Post by PeteM » Thu Jan 03, 2019 8:11 pm

I'm not into gunsmithing, but do own a full set of gunsmith's screwdrivers; with a wide variety of widths and thick to thin blades. These can be bought individually if you're not comfortable modifying one yourself. There's almost surely one that will be a close fit.

I find it helps to use some sort of clamp/sliding fixture when resharpening screwdrivers; so when you flip to the other side you maintain an exact 180 degree grind. In addition, a 6" wheel -- either freshly dressed soft white or hard CBN -- is a good diameter to allow the tip to be parallel rather than wedge-shaped where it meets the slot. If you use a diamond hone, you'll want to finish up cross-wise at the end, to avoid a wedge shape. Lots of old microscope screws require the best fit possible to avoid stripping.

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Re: Slotted screwdriver blade thickness

#13 Post by Hobbyst46 » Thu Jan 03, 2019 9:09 pm

From the gunsmith web boards I found the majic sesame "hollow ground bits". I think these might be the clue. There are Amazon kits of such bits and a common handle. One maker claims that the bit breaks before is screw is damaged, signalling to the gunsmith to stop using brute force and seek some other solution.

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Re: Slotted screwdriver blade thickness

#14 Post by MichaelG. » Thu Jan 03, 2019 9:21 pm

For 'hollow ground' tips on small screwdrivers, this is possibly the best solution:
https://www.eternaltools.com/horotec-wa ... -sharpener
... excellent in principle, but a bit pricey for me.

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Re: Slotted screwdriver blade thickness

#15 Post by apochronaut » Fri Jan 04, 2019 12:49 am

I bought a cheap 10.00 multi bit set about 10 years ago and fashioned the slot bits with sandpaper blocks and a whet stone . They are excellent quality, don't burr or bend or deform in any way. I broke one but it reworked with some careful grinding.
Here is a similar set that is claiming 56 HRC. Hard to think you are going to lose at 20.00. There are lots of slot bits to form to your taste. https://www.ebay.com/itm/Multi-Bit-Scre ... :rk:3:pf:0
For odd small screws or really thin ones I use sections of hack saw blade formed to fit. Sometimes they break but they are disposible .

Moody makes excellent hobby or jewellers tools. http://www.moodytools.com/ I bought a bunch from a former Wild dealer a few years ago and I can vouch for them.
One set on ebay that seems underpriced; https://www.ebay.com/itm/Precision-Scre ... rk:26:pf:0

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Re: Slotted screwdriver blade thickness

#16 Post by 75RR » Fri Jan 04, 2019 6:41 am

PeteM wrote:I'm not into gunsmithing, but do own a full set of gunsmith's screwdrivers; with a wide variety of widths and thick to thin blades. These can be bought individually if you're not comfortable modifying one yourself. There's almost surely one that will be a close fit.

I find it helps to use some sort of clamp/sliding fixture when resharpening screwdrivers; so when you flip to the other side you maintain an exact 180 degree grind. In addition, a 6" wheel -- either freshly dressed soft white or hard CBN -- is a good diameter to allow the tip to be parallel rather than wedge-shaped where it meets the slot. If you use a diamond hone, you'll want to finish up cross-wise at the end, to avoid a wedge shape. Lots of old microscope screws require the best fit possible to avoid stripping.
All good tips PeteM thanks
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Re: Slotted screwdriver blade thickness

#17 Post by 75RR » Fri Jan 04, 2019 6:50 am

From the gunsmith web boards I found the majic sesame "hollow ground bits".
Yes, I think Hollow ground is the way to.
... excellent in principle, but a bit pricey for me.
me too sadly ...
Moody makes excellent hobby or jewellers tools. http://www.moodytools.com/ I bought a bunch from a former Wild dealer a few years ago and I can vouch for them.
Thanks for the tip apochronaut, they just might be the solution.

https://www.ebay.com/itm/Moody-Tools-55 ... rk:30:pf:0
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Re: Slotted screwdriver blade thickness

#18 Post by MicroBob » Fri Jan 04, 2019 10:09 am

For screw drivers a small bench grinder is just right, 125 to 150mm wheel diameter. This cost just 15€ and doesn't take up much space. This wheel diameter gives the right amount of hollow grind.
A proper screw driver is made from hardened steel and shouldn't be warmed to much more than 200 °C.
This can be done this way: Hold the screw driver in a way that allows to bring it repeadedly into the same position with ease. For example by holding the grip between thumb and index finger and putting this against the grinding rest.
Then slightly hold the blade against the turning wheel and grind a little bit. Then look at the ground surface: Did you manage to set back the whole surface or did you just grind on edge? =>Adjust position and side ways angle of screw driver and repeat.
Between the little grinds the screw driver tip is dipped into water, close to the grinder. Hissing sound means that you are at least close to overheating the blade. Ground parts are always hottest where they are thinnest, at the business end, so beware.

When you have managed to grind your screw drivers you can move on to wood chisels and drill bits. Bigger tools are easier to grind because ti takes longer and they don't overheat so fast.

When you have a screw driver that deforms easily at the tip it can be hardened if the grip can be kept cool enough. Heating until no longer magnetic, then dipping into oil. Afterwards annealing: Properly clean the surface with emery paper, then slowly heat to a light brown colour, just a hint.

Zeiss for sure made their own screws: When they started out in the 1840s there won't have been much of a supplier market in Jena.
But in the time of the Zeiss Standard they will have bought these parts from outside suppliers.

Bob

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Re: Slotted screwdriver blade thickness

#19 Post by MichaelG. » Fri Jan 04, 2019 10:36 am

MicroBob wrote:For screw drivers a small bench grinder is just right, 125 to 150mm wheel diameter. This cost just 15€ and doesn't take up much space. This wheel diameter gives the right amount of hollow grind.
With the greatest repect, Bob ... I must mention that 125 to 150mm wheel diameter is much too big for small screwdrivers; the curvature needs to be reasonably 'in proportion' with the size of the tip.

Aside from that: Your advice is excellent.

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Re: Slotted screwdriver blade thickness

#20 Post by 75RR » Fri Jan 04, 2019 10:39 am

MicroBob wrote:For screw drivers a small bench grinder is just right, 125 to 150mm wheel diameter. This cost just 15€ and doesn't take up much space. This wheel diameter gives the right amount of hollow grind.
A proper screw driver is made from hardened steel and shouldn't be warmed to much more than 200 °C.
This can be done this way: Hold the screw driver in a way that allows to bring it repeadedly into the same position with ease. For example by holding the grip between thumb and index finger and putting this against the grinding rest.
Then slightly hold the blade against the turning wheel and grind a little bit. Then look at the ground surface: Did you manage to set back the whole surface or did you just grind on edge? =>Adjust position and side ways angle of screw driver and repeat.
Between the little grinds the screw driver tip is dipped into water, close to the grinder. Hissing sound means that you are at least close to overheating the blade. Ground parts are always hottest where they are thinnest, at the business end, so beware.

When you have managed to grind your screw drivers you can move on to wood chisels and drill bits. Bigger tools are easier to grind because ti takes longer and they don't overheat so fast.

When you have a screw driver that deforms easily at the tip it can be hardened if the grip can be kept cool enough. Heating until no longer magnetic, then dipping into oil. Afterwards annealing: Properly clean the surface with emery paper, then slowly heat to a light brown colour, just a hint.

Zeiss for sure made their own screws: When they started out in the 1840s there won't have been much of a supplier market in Jena.
But in the time of the Zeiss Standard they will have bought these parts from outside suppliers.

Bob
Thanks Bob. Do like the idea of sharpening drill bits. Will look into a grinder as a future project.
But in the time of the Zeiss Standard they will have bought these parts from outside suppliers.
That is what I thought. Makes sense at the beginning due to a lack of suppliers but not later on.
Someone then must make screwdrivers that fit those thin slotted supplied screws.
Unless of course they were made specifically for Zeiss (who specified thin slots - much the way Apple tried with the Pentalobe screw) to avoid what they considered to be customer tampering.
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Re: Slotted screwdriver blade thickness

#21 Post by MicroBob » Fri Jan 04, 2019 12:48 pm

75RR wrote:Unless of course they were made specifically for Zeiss
This sounds so much like Zeiss, it has to be true. Lagrely they had the attitude to do things as good as ever they could, forget the cost. They also used whatever thread or screw head they tought best without much regard towards standards. This will be true to some extent for most instrument makers, but I have the impression that Zeiss acted very much this way.

Drill sharpening is a very rewarding thing to do: Whatever you do, the drill won't cut worse than a thoroughly dulled drill! :lol:
I once had the opportunity to work in a workshop for a short while where they built heavy asphalt milling machines in a very shoddy way and where they had lots of dull drills and few sharp ones. So I started to improve on my free hand grinding skills on drills of 40mm or so. This helped a lot.

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Re: Slotted screwdriver blade thickness

#22 Post by 75RR » Sat Jan 05, 2019 12:47 pm

Drill sharpening is a very rewarding thing to do: Whatever you do, the drill won't cut worse than a thoroughly dulled drill!
Very true and an encouraging thought!
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Re: Slotted screwdriver blade thickness

#23 Post by billbillt » Sun Jan 06, 2019 4:59 pm

75RR wrote:
I have no idea but I would say probably.
Thanks Peter, would be nice if someone were able to confirm that.
desertrat wrote:If you have some time on your hands, you can put some medium grit sandpaper on a flat surface and rub the blades across it, switching sides frequently. Then switch to fine grit paper to get a better finish. This takes a while, but to me is a bit more controllable than a bench grinder, which works pretty fast with small screwdriver blades.
Agree that a bench grinder would be overkill on such small screwdrivers.

I do however have a sharpening stone, with which I have just about perfected the art of dulling my kitchen knives.

Perhaps I should purchase some cheapo ones to practice with first ...
Hello,

Sharpening knives on stones is an art that requires a lot of practice.. Just keep trying and one day it will work...
Last edited by billbillt on Mon Jan 07, 2019 5:23 am, edited 1 time in total.

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Re: Slotted screwdriver blade thickness

#24 Post by KurtM » Mon Jan 07, 2019 1:36 am

Anyone wanting to learn to sharpen knives (or any other blade) would do well to use a stereo microscope to monitor results... :idea:
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Re: Slotted screwdriver blade thickness

#25 Post by MichaelG. » Mon Jan 07, 2019 5:32 pm

Here is an awkward little nut:
SmithsClock_Nut.jpg
SmithsClock_Nut.jpg (148.04 KiB) Viewed 14479 times
... and a slotted driver, made yesterday from a standard 4mm straight blade; using Needle files and an Eze-Lap
SlottedDriver_a.jpg
SlottedDriver_a.jpg (187.13 KiB) Viewed 14479 times
SlottedDriver_b.jpg
SlottedDriver_b.jpg (157.08 KiB) Viewed 14479 times
SlottedDriver_c.jpg
SlottedDriver_c.jpg (157.15 KiB) Viewed 14479 times
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