Singer 45k 92 Flat bed

[Tingo]

Greetings everyone, I am try to get the dimensions of the screw that locks the stitch size for a Singer 45K92. Attached is a picture of the screw and nut in question. Any help will be appreciated. Thanks much

[Constabulary]

That screw is a stop screw and the nut locks the screw. The screw has a ball tip. I´ll post measures later...

[Tingo]

Is this one for sale by chance?

[Constabulary]

Unfortunately no - it is from the machine in your picture

The screw is 34mm long from underside of the knurled head to the rounded tip. The threaded part is 25mm-26mm long.

EDIT:

Outer diameter is 8.5mm

Edited December 14, 2022 by Constabulary

[billybopp]

6 minutes ago, Constabulary said:

Unfortunately no - it is from the machine in your picture

The screw is 34mm long from underside of the knurled head to the rounded tip. The threaded part is 25mm-26mm long

Correct me if I'm wrong, but didn't Singer generally use proprietary screw sizes and thread pitches?

- Bill

[Quade]

Quote

Correct me if I'm wrong, but didn't Singer generally use proprietary screw sizes and thread pitches?

I actually hate Singer for this.   I had a lathe that used oddball threads like this. It was a nightmare.  I think it was like "mechanical copy protection" back in the day to try to prevent copying. 

I wish my machines had simple metric threads. Even standard SAE threading would be fine.  I loath flat tip screws too.  Was wondering of anyone sold Singer threaded screws and bolts with torx heads. 

It should be possible to use a thread pitch gauge to determine the thread pitch.  Then someone with a lathe could reproduce that bolt. 

[kgg]

4 hours ago, billybopp said:

Correct me if I'm wrong, but didn't Singer generally use proprietary screw sizes and thread pitches?

Yes, this type of thing can drive you nuts just like the screws which go into the top of the cylinder arm of the Juki's LS-1341 and clones like Techsew 2750 or Kobe Ls-1341. It is a "Juki" thread and right now were costing as high as $4.50 CAD ($3.30 USD) each. It took me forever to track down a Chinese copy at what I would consider a reasonable cost.

4 hours ago, Quade said:

Then someone with a lathe could reproduce that bolt. 

The cost of odd ball dies would probably be prohibitive for small runs.

kgg

[shoepatcher]

Get me a screw part number and i can get the specs and pitch of the screw.

glenn

[Tingo]

Can find that screw in the manual at all. Would appreciate the info

[Quade]

Quote

The cost of odd ball dies would probably be prohibitive for small runs.

With a lathe you don't need to use a tap or die.  You set the machine to cut the proper thread spacing by either changing the gears or setting the gear box to a specific speed or both.  It's one of the more difficult things to do on a lathe. 

OP if you measure the diameter of the screw,  I can try to look up the size based on a chart someone posted here. It's got singer thread sizes by diameter.  A thread gauge is pretty cheap too.  You could measure the pitch directly. 

https://www.amazon.com/ChgImposs-Imperial-Whitworth-Industrial-Measurement/dp/B07J9V9JTK

 

 

 

Edited December 15, 2022 by Quade

[Tingo]

On 12/14/2022 at 8:10 AM, Constabulary said:

Unfortunately no - it is from the machine in your picture

The screw is 34mm long from underside of the knurled head to the rounded tip. The threaded part is 25mm-26mm long.

EDIT:

Outer diameter is 8.5mm

Is the above info enough for you  to find the pitch of the screw?

[Quade]

The closest is 5/16 which according to the chart would be 5/16-24   24 threads per inch.   You can verify the thread pitch by using an inch ruler over the bolt threads and count the number of threads that happen in a 1" space. 

8.5mm = .33"

5/16 = .31"

Singer also used 5/16x18. Your bolt looks like a finer pitch than 18. 

 

Edit - 5/16-24 is a relatively common die size meaning it's possible to make a matching bolt. 

Edited December 15, 2022 by Quade

[Tingo]

A quick progress report 5/16 bolt is a shade too small. Frustrating.

[Quade]

https://www.singersewinginfo.co.uk/screw_threads

This is one of the charts I was looking at.  

[Tingo]

Soooo 3/8 is a tad too big. I am now left with the idea of tapping the hole with a 3/8 tap. Any thoughts?

[SARK9]

"Soooo 3/8 is a tad too big. I am now left with the idea of tapping the hole with a 3/8 tap. Any thoughts?"

The size of the "tap drill" hole is the part to look at. If the 5/16 bolt is too small, but the 3/8 is "a tad too big", check out this size for a possible match.

3/8-24 NF  Drill size Ltr.Q    (21/64")   (.3320)   

Remember the hole size recommendations are targeted for an average 75% thread engagement and there is a bit of leeway on this fit for practical work that doesn't need to go through 3 levels of inspection and certifications to get paid.

 

-DC

[Quade]

I have a singer 211 here. I've had to cut come bolts loose for things like the need position adjustment. I plan on re-tapping so I can use an Allen head or torx.  I figure if I have enough meat, I can re-tap to something more common. 

I ran into this with a 120 year old lathe. I converted it the metric where I could. 

[shoepatcher]

OK  the screw part is SS#431  singer special screw.  I happen to have book on the special singer screws   specs over all length is 33.6MM.    threads are 11/32" x 28tpi.   threads 20mm long  bulb end on the screw.   Hope that helps.

glenn

Edited December 17, 2022 by shoepatcher

[Tingo]

Quick question what are the chances that this machine will sew properly without this bolt to lock the stitch length? Thank you

[Constabulary]

The screw is a stop screw for the stitch length lever. It basically has 2 functions 1. limiting the forward stitch length (longer or shorter) and 2. limiting the reverse stitch length (longer or shorter) the way that you have a reverse stitch length equal to the forward stitch length for locking the seam start and end. The machine will sew but you will not be able to adjust an equal forward and reverse stitch length. You can try to put stitch length marks on the machine body but that IMO does not make sense on the long view and is not very precise.

You can try to tap a new larger thread and insert a screw BUT you only have 1 try. When the threading is a little offset you will not be able to adjust a matching forward and reverse stitch length anymore and the forward and reverse function then IMO is useless. If it was me I would NOT do it.

Edited December 20, 2022 by Constabulary

[Quade]

Quote

You can try to tap a new larger thread and insert a screw BUT you only have 1 try. When the threading is a little offset you will not be able to adjust a matching forward and reverse stitch length anymore and the forward and reverse function then IMO is useless. If it was me I would NOT do it.

I agree it's a bit risky.

Quote

  threads are 11/32" x 28tpi.   threads 20mm long  bulb end on the screw.  

Someone more skilled than me on a lathe could cut you a bolt with this thread pitch. 

Choices seem to be:

1 - Find the bolt

2 - Make the bolt

3 - Rig something up (tap or timesert). 

Or else not use this machine. 

 

[shoepatcher]

You could take a 3/8 bolt and turn it down on a lathe and put the threads in it.  A machinist can do it if you cannot.  You need it to run the machine.    Have a nut made as well.

glenn

[Tingo]

Quick progress report. So I decided to bite the bullet and tapped the hole to 3/8  similar thread pitch. Once I timed the machine properly, fingers crossed. I believe I am good

[Tingo]

A quick progress report, I bit the bullet and tapped the hole out and install a screw size that's is readily available. Included are some pictures. I might get a little handle welded on to the nut at a later date.

[Quade]

Looks good.     If I could I'd replace every screw in my machine with a decent metric screw.