Giant Screwdriver Restoration

[Rhyolith]

This is a 28 1/2" long turnscrew that so far remains the longest single piece screwdriver I have ever seen. There is no makers name on the blade, there are some remnants of words on the handle which I have not spent time trying to discern yet. The handle is lovely, compose of unknown dark knotted wood that is very smooth.

Giant Screwdriver (prior to restoration) by Rhyolith, on Flickr

I want to make the metal parts look better as they are all covered in muck an rust.

Have started with an angle grinder using 100p paper to carefully grind the rust off the blade and my usual drill mounted wire brush for the ferrule.

After Grinding:
Giant Screwdriver After Grinding by Rhyolith, on Flickr
Other Side:
Giant Screwdriver After Grinding (other side) by Rhyolith, on Flickr

I have not ground it down very much and am contemplating whether to leave it with some pitting and dings in it or go for a completely mirror finish by removing them entirely... thoughts?

Giant Screwdriver After Grinding (close up) by Rhyolith, on Flickr

There are lots of little scratches left by the grinder as you would expect and I know from the pumps that my 600p wet and dry leaves a worse finish than than that (though that was on brass). So I am after advice on the best way to proceed once I am happy with the level of grinding. Should I just get some finer paper or something else? Please only cheap options. I have polishing wheels for the final finish, so what I want is a way to get rid of all the little sanding scratches.

 

[ED65]

Wow that's a beast! Only ever seen one that sort of size before, I think in Tommy Walsh's hands.

I have not ground it down very much and am contemplating whether to leave it with some pitting and dings in it or go for a completely mirror finish by removing them entirely... thoughts?

Totally up to you.

Although they could be very bright I believe we can be fairly sure these were not in a true mirror polish originally so you could use that as a guide to what it 'should' look like, but you can give it the finish you prefer just like on any other tool.

I think it's very risky to use an angle grinder on something like this, not that the grit you used was too coarse it's just with the speed and power of the tool behind it there's so much potential for a mistake you can't come back from.

...I know from the pumps that my 600p wet and dry leaves a worse finish than than that (though that was on brass).

Something very wrong there! Softer metal or not the finish from P600 should be miles beyond that from 100 alox paper used dry.

 

[sunnybob]

Thats not a screwdriver, its a druid ceremonial dagger.

 

[Vann]

Thats not a screwdriver, its a druid ceremonial dagger.

I was thinking: a blunt sword :mrgreen:

There is no makers name on the blade...

When I started my apprenticeship (back in 1973), if you knew someone in the Blacksmiths Shop they'd make you a turnscrew from old spring material. So there are probably lots around with no makers name.

Cheers, Vann.

 

[yetloh]

I think I would have just removed the dirt and rust using electrolysis so as to maintain some patina reflecting the age of the tool, but too late now. Given where you are now, what you do from here must be entirely a matter of your personal taste.

Jim

 

[Biliphuster]

Does anyone know what these were used for? Are they long so as to reach into tight recesses or some other reason? The tips are not that much larger than on a large cabinet screwdriver so the extreme size has always been a bit of a mystery to me.

Nice screwdriver, I would rub it over with some scotchbright and leave it at that to get a nice dark patina back.

 

[sunnybob]

the length gives more torque to the screw. In the days before ratchets and power drivers, that thing could put a steel screw deep into the hardest wood,

 

[bugbear]

the length gives more torque to the screw. In the days before ratchets and power drivers, that thing could put a steel screw deep into the hardest wood,

I'm not sure I understand the mechanics of that. Surely radial torque would come from diameter, not length?

You don't make a socket set more powerful by putting a length extender bar in...

http://www.halfords.com/workshop-tools/ ... ion-bar-10

BugBear

 

[Rorschach]

the length gives more torque to the screw. In the days before ratchets and power drivers, that thing could put a steel screw deep into the hardest wood,

I'm not sure I understand the mechanics of that. Surely radial torque would come from diameter, not length?

You don't make a socket set more powerful by putting a length extender bar in...

http://www.halfords.com/workshop-tools/ ... ion-bar-10

BugBear

I have heard lots of people say that before too and it doesn't make sense at all.

 

[bugbear]

I have heard lots of people say that before too and it doesn't make sense at all.

Perhaps it's "common sense", not theory :wink:

BugBear

 

[Phil Pascoe]

Try taking out a seized screw with a short driver (even one with decent handle) - it's more difficult than using a longer one. No idea why, but it is. I once had a pair over two feet long that were invaluable for only one use I found - getting seized screws out from the undersides of wash basins. They were put in with a short driver or a longer one out of line, but by the time they had rusted there was no way would they come out with one. Invariably the shape of the bottom of the basin would prevent the use of one six to twelve inches or so long because it couldn't be kept square to the screw. Sounds daft but they saved hours of faffing about.

 

[sunnybob]

A long vertical bar will give more torque.
A long radial handle will give more foot lbs for the effort expended.
dont confuse the two.

 

[Jacob]

Try taking out a seized screw with a short driver (even one with decent handle) - it's more difficult than using a longer one. No idea why, but it is. ..

Agree.
I think it's because the length makes it more stable and secure; a little wobble at the handle end is less likely to translate into camming out at the other end, and also it makes it easier to aim and hold accurately square-on to the screw head

 

[Rorschach]

Try taking out a seized screw with a short driver (even one with decent handle) - it's more difficult than using a longer one. No idea why, but it is. ..

Agree.
I think it's because the length makes it more stable and secure; a little wobble at the handle end is less likely to translate into camming out at the other end, and also it makes it easier to aim and hold accurately square-on to the screw head

I agree, I think this makes it seem like you are getting more torque, in reality what you have is more control, a better position and a better grip on the screwdriver.
This means that the theory is still somewhat true, a longer screwdriver is better, but not for the reasons proposed.

 

[Rhyolith]

I have been told these short of screwdrivers were used on steam engines and the like, as the long glad helped get into all the gaps you would have on such machines. Later versions seem to have been used for tank maintenance during the wars, mainly WW2. It is difficult to get concrete evidence for either of those theories of course.

I think I will keep the remaining patina (as I like it) so now Just need to get rid of the fine scratches left by the grinder. Should I just get some 1000p paper or something?

 

[bugbear]

This means that the theory is still somewhat true, a longer screwdriver is better, but not for the reasons proposed.

You do get a fair bit of that...

BugBear

 

[ED65]

I think I will keep the remaining patina (as I like it) so now Just need to get rid of the fine scratches left by the grinder. Should I just get some 1000p paper or something?

Need to bridge the gap first I would have thought, at least some P240 and P400? I think the scratches from P600 are very pleasantly fine and I'd be quite happy with that on many things but ideally the scratches should be neat and parallel which can be tough to do well.

Since you're keeping some of the old patina would you have any interest in restoring some patina on the blade? Some people frown upon this sort of thing but I have no problem with it personally. Although the surface will naturally settle down a bit over time I think a really high polish on the blade and the rest looking more vintage might look decidedly odd,

 

[Rhyolith]

You mean let it oxidise a bit? Probably not since it would take a while and I don't like thr idea of corroding it.

The handle is actaully quite shiny, so I think I will go with that kind of look all over.

What I am leaving on is the remains of some pitting and scratches (from use not sanding).

 

[RobSmart]

This is what I always thought. The longer the handle the more off centre you can go, and therefore more torque can be applied.

https://blog.lostartpress.com/2013/05/3 ... w-drivers/

 

[bugbear]

This is what I always thought. The longer the handle the more off centre you can go, and therefore more torque can be applied.

https://blog.lostartpress.com/2013/05/3 ... w-drivers/

That analysis is only true if the axis of rotation is that of the screw (as the guy asserts in his drawing), not that of the screwdriver.

I don't think this is the case.

BugBear