Q: How to make a micro sized nut driver?

[mark.hinds]

Now the trick is to try and find a screw THAT USES that size torx feature...  Been searching all day for ya Max!  Nada so far.

But could we tell solely from the printed specs that a particular torx screw would or would not work for a specific bolt head?  Since they aren't intended to mate with each other, I would think that a definitive determination would require actual trial-and-error, as Max implies with his "T3 or T4". 

On a parallel track, I have numerous phones with different sizes of these things in them (from my old job), and others may have a similar collection.  But even if I couldn't find just the right size, and even though the one in my image is probably too large to fit the bolts in the OP image, I wonder if it would fit tightly enough if a thin sheet of metal foil were formed over the bolt, and inserted into torx screw-head depression.  You could then glue the metal foil in the depression as a sort of filler.  Note the extra space in the "corners" of the depression. 

MH

[wazzou]

Can you make a confined mold of the bolt head using something you have on hand like Loctite? 
If you use a mold release of some sort, so that the head will come out, you can put the Loctite in a small cylinder so that the resulting mold/wrench isn't to large.

[Sokramiketes]

Why does it have to be a nut driver, and not just a notched piece of brass stock used as a wrench?

[peteski]

Why does it have to be a nut driver, and not just a notched piece of brass stock used as a wrench?

To me, because it is easier to start threading a tiny short screw with a socket wrench than open-end wrench. Plus it is also easier and faster to turn a socket wrench.

[peteski]

Narrowminded... I get what you are trying to have me make - a hex-shaped ram to press into a tube to cut/shape/form the
hexagonal inner faces, the trick being that the ram is from hardened tool steel and the tube is softer (brass or something similar).

I've seen some "normal" size socket wrenches made that way.  Probably inexpensive ones. I've seen the curled up pieces of metal inside them.

[mmagliaro]

I considered cutting a slot in the end of a steel strip to make an "open end wrench".
Yes, that would work and certainly be better than tweezers, but still a pain.   Remember just how painfully tiny these bolts actually are.
It's tedious screwing them in and out of anything with a wrench. 

However....  a simple plastic nut driver (just heat the bolt and press the end of a styrene rod over it)
would probably make a good enough driver to spin the bolt in most of the way, and then a wrench could be used to tighten it.
That would be at least a help.

 But not as easy as a nut driver.

[narrowminded]

I've seen some "normal" size socket wrenches made that way.  Probably inexpensive ones. I've seen the curled up pieces of metal inside them.

Snap-On used to have at least some sockets like that.  I think it was deep well but may have been all of them.  Maybe some special tools.  I don't remember for sure because it was not remarkable, pretty common to see in sockets.  I was a Snap-On dealer in the seventies.

[Sokramiketes]

However....  a simple plastic nut driver (just heat the bolt and press the end of a styrene rod over it)
would probably make a good enough driver to spin the bolt in most of the way, and then a wrench could be used to tighten it.
That would be at least a help.

That sounds like the best overall plan to date.  They styrene rod should be plenty strong to run it home, then a quick bump with the wrench to secure it.  And then more time on the loco and less on tools and fixtures!

[up1950s]

What about a piece of neoprene tubing Max .

[narrowminded]

If epoxy was felt to be adequate you could drill a hole in the end of a piece of round that fit the corners, fill it with epoxy and then insert a vaseline treated bolt in it, casting it in place.  One of the metal filled epoxies might be better in compression than plain epoxy.  After normal cure a bake in the oven at about 200 degrees for a couple of hours can assure a through cure, as good as it gets.  More is available online about post heating epoxies but improvements in the range of 20% sticks in my mind as normal.  Even though many or even most don't require that in the instructions, most or if my memory serves me right, even all, will benefit from that.  And I guess there's nothing to stop you from mixing some metal filings of your own in otherwise standard epoxy.  Make sure it's clean material that you file up.

[wazzou]

If epoxy was felt to be adequate you could drill a hole in the end of a piece of round that fit the corners, fill it with epoxy and then insert a vaseline treated bolt in it, casting it in place.  One of the metal filled epoxies might be better in compression than plain epoxy.  After normal cure a bake in the oven at about 200 degrees for a couple of hours can assure a through cure, as good as it gets.  More is available online about post heating epoxies but improvements in the range of 20% sticks in my mind as normal.  Even though many or even most don't require that in the instructions, most or if my memory serves me right, even all, will benefit from that.  And I guess there's nothing to stop you from mixing some metal filings of your own in otherwise standard epoxy.  Make sure it's clean material that you file up.

I wish I'd thought of that...

[peteski]

If epoxy was felt to be adequate you could drill a hole in the end of a piece of round that fit the corners, fill it with epoxy and then insert a vaseline treated bolt in it, casting it in place.  O

How about the idea I posted really early in the thread about using some brass tubing and melted solder to form a socket around the screw head?  That should be plenty strong.  Just plunge the screw head into the melted solder and let it harden around it. Then remove the screw and you have a socket wrench.

[narrowminded]

You know what I'd be doing but some of these other things really might be adequate, including solder.  But boy, solder's some pretty soft stuff structurally.  But then again, I really doubt the applied torque will even be measurable in foot pounds.   Most of these things are easy enough to try and at no loss if it's not great.

[mmagliaro]

Keep 'em coming boys....

Yes, I considered filling a tube with JB weld and putting the head into it to make the impression.
I don't think I'd get a very crisp-edged socket that way, though.
I have that same concern about Peteski's solder idea (which he already considered when he posted it...)
It would be soft, and the corners and sides would probably be roundy.

I did have a new idea... The open end wrench thing got me thinking.

Take a brass strip.  carefully cut a 1.1mm slot in it.  (I have some .009" dremel disks and I could use those, or a
wider one, and just gently work it.  But let's assume I can make an accurate slot).

Now... do that three times.   Make three strips.
Now, place the bolt into a block, head sticking up.
Lay the three slotted ends over each other on the bolt, each one aligned over a different opposing pair of faces.
(like 3 open-end wrenches staggered around the bolt head).

There will indeed be a hex-shaped hole through the 3 strips if you were to look down through them from the top.
Tape em down so they don't wiggle around, and solder them together.

Now cut off the little soldered-together part, and solder it to the end of a brass tube or stem as the tool handle.

Yes, the 6 faces of my socket head are staggered vertically, but I don't think that will hurt.
The brass strips need to be thin, probably .010", so that they all stack up without going over the head of the bolt.

The thing I like about this one especially is that it HAS to fit.. because... well... because... it just HAS to.
the three piece will be locked around an actual bolt head while I solder them.  The only gotcha is to make the slots
neat, but that isn't hard.   

Picture:

[wcfn100]

After reading all this, I like the idea Chris had except I'd try a styrene tube with a ID about the diameter of the flat parts of the nut. then either heat the nut and press, or just shape the inside with an exacto.

Jason