Q: How to make a micro sized nut driver?

[mmagliaro]

I will be using these for the crank screws on the drivers of my 0-6-0 project
http://www.macsmodeling.com/T2m%204002.jpg

They are Tuner Model Manufactory stainless hex-head M0.7 bolts (yes, M0.7... much smaller than metric M1.0).
The distance across the flats on that hex head is only 1.1mm

I can work with them "the hard way" by wheedling them in and rotating them 1/3 of a turn at a time with tweezers,
but it's pretty miserable work.

I cannot find anybody that makes a nut driver this small, so I'm wondering if there's a way to make one.
I cannot possibly machine a hex recess that small in the end of a piece of steel, so that's out.

I considered gripping one of the bolts in a jewlers vise, and then pressing the end of a styrene or delrin rod down over the head
while I heat the bold up with a soldering iron.  I think that would melt a hex-shaped recess into the end of the plastic.
But I doubt a plastic wrench would work very well or hold up.

Thinking caps on, boys and girls.  How can I make a tool for spinning these in and out?  Any ideas?

[peteski]

How about making it out of solder?  Use a piece of thin-wall brass tube, fill it with melted solder, then put the head of the screw in the middle and let the solder harden?  Then pull the screw out and you have a wrench. With the surface tension of the liquid solder it might be tough for it to conform to the screw head, but it is worth a try.

[Chris333]

Find thin tube that will tightly fit around it. Force a nut in the end and queeze the flats with pliers.

Just a guess.

[Kentuckian]

Looks like the folks that make the bolt would make a wrench.  But how about chucking a bolt in a pin vise, heating it, and plunging it into a styrene sheet? You could then cut  the wrench out, making the handle as long as you want.  Surely you won't need much torque, but if one wears out after one or two bolts make another.

[kornellred]

Break off an appropriately sized drill bit and sink it just below the pin vise collet and use the collet to turn the hex head.

[havingfuntoo]

Have a look at the bay under jewelers tools, here is an example I found in the first page of entries:-   http://www.ebay.com/itm/16pc-Precision-Screwdriver-Set-Electronic-Micro-Hobby-Jeweler-Watch-Mini-Hex-/181889603990?hash=item2a59771996:g:Z1sAAOSw9r1WDOOx

[Missaberoad]

How much clearance do you have? Would it be possible to make a square socket that can contact two opposite faces? I'm sure that would be all you need with the torque you'd be applying..

[u18b]

Max,

Let's think "outside the box".   

A micro box end would be really hard to make.

But what about taking a small screw driver set.

The straight blade (regular) screwdrivers we need are usually the smallest 2.
That leaves the largest size we almost never use.

Why not take a micro cut-off wheel and simply cut a slot in the blade.
Or one of the smaller blades.

I'll post photos next.

[u18b]

You will remember on my EP-2 project that I needed to make micro-cuts in the frame for the step handrails.

Left and middle are two typical ceramic cut-off wheels.  Rather fat for your purpose.  But look at the one on the right.




The thin one is made by dental supply people.  A retired dentist gave me this.  They sell for about $50-$70!


Because these are so thin, they are a little floppy.  I found I could get VERY fine cuts by sandwiching the thin wheel between two smaller wheels- leaving a thin cutting edge.




This is the best I could do before.



This is what I can do now.

[Showme]

Ace Hardware makes a 1/16" precision nut driver. I got one a month ago for some small hex head screws that I am using for truck pins.  Five bucks and they got it from the local warehouse overnight. Looks like you need something a little smaller than  1/32". You might be able to take a 1/16" nut driver and shim the flats down with tiny slivers of brass flat stock  super glued in to get there.

Bob

[Showme]

Max

Let me revise my last reply. I misread the size you needed.  1/16" is 1.5mm and 3/64" is 1.19mm. still doable with a shimmed down 1/16"nut driver.

Bob

[basementcalling]

Deleted

[u18b]

Max,
Throw a screw in an envelope and I'll see what I can do.

[Lemosteam]

Max

Take a stainless tube with a 1mm ID about 1" long.  Flare the soon to be hex end slightly. Put the screw in a hole in a steel block with the hex facing up. Take the tube in pliers. Have a small bowl of cold water handy.  Use a mapp gas torch (pipe sweating or butane torch) to heat one end, put the flared heated end atop the nut and tap the opposite end with a brass hammer until the tube conforms to the hex of the nut. Reheat the formed end and quench in the water to harden the material.

Add a magnet up the hex end, add a handle.

[up1950s]

After an hour of thought and searching I came up with an idea .

Find a screw with a 0.7MM hex hole head for a 0.7mm male hex wrench .

Use the head of that screw upside down as the socket . You may want to extend the screw end to be more finger friendly , They sell 0.7mm hex wrenches , so there must be a screw too .