Small screw threads.

[ukracer]

I am looking for the size of a bolt that fits a Japanese sewing machine to hold the needle bar thread guide.
2 mm is to small. 3mm is to big.
(Well I say Japanese but it was made in the UK)

I had some 2.5mm coming today but as I suspected it's an imperial size ..

So i tried to rethread a 2.5 bolt into the original hole in the needle bar. But it gets very tight very quickly so I need to either tap the thread in the sewing machine (needle bar) or run a die down the bolt i am using.
Problem is I don't know what that thread is going to be. Google seems to indicate 3/32 but I am wondering if it might be BA size.
I don't suppose we have any small thread experts on the forum??

 

[Pete.]

Coul dbe 6ba, 7ba or 8ba

 

[Dapph2]

Try a sewing machine repair shop or see if you can get a machine or two off freecycle ?

 

[Agroshield]

Being Japanese, BA is most unlikely.

I read that some Japanese machines used the same (imperial) threads as US Singer machines, so finding the corresponding Singer item might be worth five minutes of your time.

There is an M2.3 x 0.4 and M2.2 x 0.45 thread.

Screw a piece of wood into it and at least that will get you the pitch.

 

[ukracer]

Try a sewing machine repair shop or see if you can get a machine or two off freecycle ?

I have been trying sewing machine repair shops. Non of them are really interested unless I want a full service.
Not sure how they can do that without spares, but still. Not one of them knows what thread it is.
Just goes to show how useful Ai really is.
Some of the responses are worse than sewing machine repair shops. Lol

 

[ukracer]

Being Japanese, BA is most unlikely.

I read that some Japanese machines used the same (imperial) threads as US Singer machines, so finding the corresponding Singer item might be worth five minutes of your time.

There is an M2.3 x 0.4 and M2.2 x 0.45 thread.

Screw a piece of wood into it and at least that will get you the pitch.

The M2.5 actually screws into it so I don't think it's smaller. But the strange thing is I would expect that same screw to screw out and then be fairy easy to screw back in but it's actually harder.

 

[MattF]

But the strange thing is I would expect that same screw to screw out and then be fairy easy to screw back in but it's actually harder.

That's because you're damaging the threads.

 

[Memmeddu]

M3 tap .....
You can fit M3 screws after using it

 

[bourbon]

whereabouts in the world are you? Try Nutts of Bloxwich. What make of machine is it? and Have you tried the OEM?

 

[ukracer]

whereabouts in the world are you? Try Nutts of Bloxwich. What make of machine is it? and Have you tried the OEM?

OEM has long gone. Its a Reads Sailmaker.

But not tried Nutts will check them out tomorrow.

I am close..I am in kidderminster.

 

[ukracer]

M3 tap .....
You can fit M3 screws after using it

Well i was thinking of tapping to 2.5 and it all else fails drilling it out and fitting a m2.5 threaded bush.

 

[Memmeddu]

Well i was thinking of tapping to 2.5 and it all else fails drilling it out and fitting a m2.5 threaded bush.

If there's space go straight to M3 you're more like to make a decent threaded hole cause you have all the thread contact.
Going 2.5 is likely to have not enough meat to make a solid thread and potentially strip it straight away.
Other option is Helicoil but I'm pretty sure they'd be a pain to install correctly due to the tiny size.
They do actually exist that small but kinda hackward to use

 

[Erie Fred]

Could it be 4-40 ?

ANSI Internal Screw Threads Size and Tolerances Table Chart

Unified Screw Threads per. ANSI/ASME B1.1-1989 Reference Table Nomenclature, are used. Acceptability criteria

www.engineersedge.com

 

[TEO]

Might be worth asking on the Practical Boat Owner site? Plenty of people using & servicing similar machines on there.

 

[bricol]

There is an M2.4 too - as I discovered as a kid with Japanese radio control racing cars.

 

[6ply]

Could you "screw" something soft into the threaded hole, unscrew and then measure the thread pitch? I have a box containing hundreds of small oddball sizes. BA and others.

 

[dave h 2]

Could it be 4-40 ?

ANSI Internal Screw Threads Size and Tolerances Table Chart

Unified Screw Threads per. ANSI/ASME B1.1-1989 Reference Table Nomenclature, are used. Acceptability criteria

www.engineersedge.com

4-40 is a squeaky tight fit for M3 (on D-type plugs at least) so sounds about right.

 

[bourbon]

01922 497603 That's the phone number for Nutts

 

[ukracer]

Could it be 4-40 ?

ANSI Internal Screw Threads Size and Tolerances Table Chart

Unified Screw Threads per. ANSI/ASME B1.1-1989 Reference Table Nomenclature, are used. Acceptability criteria

www.engineersedge.com

Yes it's possible as others have mentioned that in American machines.
But can't find any 4-40 bolts .

 

[ukracer]

4-40 is a squeaky tight fit for M3 (on D-type plugs at least) so sounds about right.

3mm does not fit at all though.