Month: April 2023

After you set the machine on its side and remove the bottom cover of the free arm, you can push the needle plate pins out from the underside.

The pin on the right may be obstructed by the feed bar. Adjusting the stitch length to maximum will help you see the hole below the pin.

After loosening the set screws, I used a small drill to push the broken portion of the pin from the hole.

The needle plate pins for these machines were made from spring steel and were commonly broken. Only a few of the German 400 series machines used these pins and replacements are not available.

The following picture shows a with only 3 of the 4 sides of each pin intact.

Magnetic Pin Set – Game Changer

700 series Singer sewing machines use the same diameter pins as the 421G and 431G. On those machines, the needle plate is held on with a magnet that is embedded into the machine case.

I drilled an offset hole in 2mm thick by 10mm diameter neodymium magnets and created replacement stainless steel pins on a metal lathe.

The stainless pins are corrosion resistant, durable and non-magnetic so they will not stick to dressmaker pins.

The solution is simple and it holds extremely well.

Drilling the Magnets

Drilling the magnets is very difficult. I used a carbide glass bit and a lot of coolant to drill mine.

If there is sufficient demand, I would consider making pins for others and having magnets custom made with an offset hole to fit these older machines.

NOTE

When you put a needle plate pin in the hole on the right (closest to the stop motion wheel), you need to be careful not to place it too deeply or it will interfere with the feed dog bar.

Replacement pins need to be two different lengths and the short pin needs to go in the hole on the stop motion wheel side.

Always turn the machine by hand after making modifications to make sure nothing jams.

My original push nut broke when I removed the stitch plate cover from the lid.

I ordered 100 4mm push nuts from McMaster Carr for about $15. These fit the cover and I now have 99 to spare.

I found the easiest way to install these is with a 1/4-inch or 6mm nut driver. It fits over the outside of the push nut and makes it easy to push it down evenly.

I tried a few different solutions for fitting spool pins to my 431G.

The best solution I found was to use double chainring bolts that were designed for bicycle sprockets.

These chainring bolts are 10mm in diameter and have a small 3 or 4 mm hexagonal hole in the top. They fit well in the 431G top.

The attached photo shows similar items on Amazon.

You may have to try a few spool pins to get the correct fit. I just made my own out of HDPE cutting board material on my hobby lathe.

You may have to cut or sand some of the finish off of the inside of the spool pin holes to get the chainring bolts to slide in.

You will need a small spacer to hold the top of the chainring bolts flush with the top of the machine. I bought a nylon bushing at the hardware store and cut slices to fit.

I purchased a 120V Singer 626 on Facebook Marketplace for $40.

All the gears in the machine were melted but the motor, wiring, and foot pedal were in good shape.

The motor fit perfectly in the 431G and the gear pitch was the same so I did not swap the motor gears.

I had to wire the foot pedal into the 431G cord.

I eventually purchased an electronic foot pedal to replace the mechanical one and it worked perfectly.

The stop motion wheel on the 431G is made of plastic and will crack over time.

I tested a stop motion wheel and washer clutch from a Singer 401a and they fit and worked perfectly. If the wheel ever breaks, I can replace it with the metal parts from a Singer 401a.

I was looking for a very rare Singer 431G but the only ones I found were on Etsy and they were priced between $600 and $900 U.S.

I took a chance and went to the German version of eBay (eBay.de).

I found German language listings that did not appear on eBay.com.

I found the following listing and paid around $60 USD and about $150.00 USD for shipping. So my total cost was a little over $200 USD.

The machine included the chain stitch accessories and was in good shape but it had a few common problems:

• There was no user manual.
• The spool pins were broken or missing.
• The machine needed cleaning and de-greasing.
• The needle plate pins were missing and the zigzag plate had been drilled to accommodate a machine screw to hold it in place.
• The rubber feet needed to be replaced (there are 5).
• The foot pedal wasn’t working.
• The motor was 220V which isn’t convenient in the U.S.

The restoration is described in other posts on this site.