Small nuts and fat fingers

[Cheshire Steve]

I thought I was being smart making a small stop valve for my little steam engine and using flanged steam pipe couplings. But actually getting the nuts on the 12BA bolts for the flanges is proving more challenging than I thought (they are 'small-head' bolts too). I wonder if anyone has any tips for starting the nut on the thread, I think I should be OK after that. I think the main problem is that the nut and bolt head are quite close to the pipe, so I can't get my fat fingers in, though both just have sufficient clearance to rotate.

Its at times like this when I get a strong urge to do larger scale modelling .. like 1:1

Steve

 

[tel]

Two pairs of tweezers will often get you out of trouble. Or, if you can source 'em, those locking surgical forceps in the smaller sizes (I have a range of thos here)

 

[Mainer]

If you can find a short piece of plastic tubing of the correct diameter, you can push it down over a nut and use the tubing to hold the nut while you get it started on the thread.

 

[Bluechip]

I use a 'pearl picker' similar to these:

http://cpc.farnell.com/_/tw1129/spring-loaded-pick-up-tool/dp/AR71399

Except mine has 3 fingers, fits hexagon better.

Used mine on m1.6 nuts yesterday OK.

Otherwise I resort to a variation of Mainers trick with heatshrink tube :



BC

 

[DickDastardly40]

How are you tightening them up when they are on?

I've never tried quite as small as 12BA but for small stuff I use a box spanner or socket with a blob of blu-tack inside to stop the nut dropping. Another option if you only have a spanner that small is to put some masking tape across the jaws on one side leaving a sticky patch in the gap and getting the nut to stick to that for the all important first half a turn.

Good luck.

 

[Cheshire Steve]

How are you tightening them up when they are on?

Good luck.

When I get them on I will let you know ! My torque wrench is a bit big ! They are off the end of my range of BA spanners (bolt head is 2.5mm across flats, nut is 2.23mm), and it will need to be open ended as nut is v close to the pipe. I think I have a slitting saw that thin so I will be able to make a couple of spanners.

 

[rkepler]

A 3/32 box end tool should work OK to start the nuts - it would be 2.38mm across the flats and should engage the flanks of the 2.23 nut. I use a dab of grease or oil to hold in a nut, sometime back it up with another nut or 2 if the hex on the driver is too deep.

(3/32 is the size for 0-80 hex nuts here. Fun to play with when you fingers are all torn up from work.)

 

[bentprop]

What you need is an old BA ignition spanner set.They are usually hinged together on a pin.Look at garage sales or markets.
Doesn't help with that first turn though.I was going to suggest a magnetic pickup tool,but that won't work in your case.

 

[Alixan]

I have found that a filed flat end of a suitable rod with blue tack gets you started, then a flat blade screwdriver wedged against the flat of the nut to hold it still.
I also use screw heads rather than bold to overcome the small spanner problem.

 

[tel]

Still, the tweezers work well enough for me with small stuff, and carefully tighten with mini n/n pliers (you don't need much torque)

Below my finger in the second pic you can see part of a pair of forceps

 

[Cheshire Steve]

A bit of blue-tack on a flat blade to hold the nut true to the bolt, and tweezers to turn the bolt, with the combination of valve and stub pipe held in toolmakers clamp (I must make some super small clamps - I am always finding new uses for them). With hindsight I should have made the valve flange thicker and fitted studs into it, as the bolts have to come up from below.

Anyway, just the gasket to do, and the flanged couplings will be OK. Top of the valve is complete - though not present in the shot - all bar the packing and handle. Top is held down by 6 9BA bolts - which are a lot easier to handle ! The other valve connection is flanged too, so 8 of the little beggars to do up. And another 4 when I get to the exhaust stub ...

 

[tel]

You got there in the end, that's the main thing! Thm:

Fun, ain't they!

 

[Shadow]

I often work with small fasteners in odd places and use a tool like this. I've also made similar ones with smaller tubing and sewing thread. Youu can align the fastener with the hole without losing the grip. For the picture I just used what was around the bench, the nut was a #10 and the screw a 2.5mm.

 

[GailInNM]

Shadow,
I like that. I had no seen that before.
You have posted several tips in the past for working with small fasteners. Thanks.
Gail in NM

 

[metalmuncher]

Hi Small cap head screws make nice socket spanners for the small stuff and you don't have to worry that the nuts go too far in.
Regards Metalmuncher.

 

[Gedeon Spilett]

Hi,
I generally use tweezers but for the odd cases I make my own flat spanners with a piece of hacksaw blade or a flat worn needle file with my dremel and a cutoff disc.
If the fit on the nut is on the tight side, it will not fall during the crucial first turn.
I also make small nut runners by drilling a piece of carbon steel first to allow room for the screw then I drill for the corresponding nut size, i.e. that allows a nut to be inserted not too deeply, then by squeezing in the vice on each side of the flats a nut runner of the exact size is rapidly formed on the nut, which may be used without hardening for the smaller ones, M1, M1.2, M1.6, M2 and M2.5. (about 14-7 BA)
Yes holding small nuts is a problem, but holding small tools is not that easy now, arthritis is not my friend.
Cheers
Zephyrin

 

[Ken I]

I make socket spanners from cap screws which have the correct internal hexagon - face them down to hold a nut thickness and drill a pilot hole just over thread diameter to clear studs.

A bit of press stick can be used to secure nuts into the socket.

As previously mentioned "pearl pickers" in 3 and 4 jaw available from watchmaking supplies are cheap and handy.

 

[cwelkie]

Building on the use of hex (socket head)cap screws ... I've used "slices" from the socket to make combination wrenches (or spanners). The handle is from the stainless steel spine of an old windshield/screen wiper.

 

[Ken I]

Nice tip - applause.

Ken

 

[cwelkie]

In my excitement at being able to actually share something that might be of value I hit "post" without including a reference and acknowledgement to the original source of my inspiration ... apologies to Rich Carlstedt.

Mr. Carlstedt wrote a article for Model Engine Builder (#13, Oct'07) about silver brazing up small wrenches in this fashion.

Charlie