Singer 45k 92 Flat bed

[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