The Singer 431G is a stellar machine. Seriously, it’s one of my favorites but it and its sibling, the 421G do have flaws. The 421G suffers from the first one and the 431G suffers from both. Luckily, both issues are easily solved.
Flaw #1: I feel that the throat plate pins were a poorly thought out design.
In the photo above, you can see that both pins are broken. Originally, it looked a lot like a Philips (cross) screw from the top and I think this might be how they get broken.
Some people may have thought that a screwdriver was needed to remove the throat plates – and “conveniently”, there’s probably one that fits right in the accessories box just inches away.
These plates lift off, no driver required.
All of the 431Gs that have been on my bench have had at least one of these pins broken or missing. One machine had some ground down screws as replacements that scored and gouged the aluminum horribly. That machine came with a service invoice that showed that some “helpful” serviceman had even charged for the privilege of having the machine so damaged.
So, once the pins are broken, how does one fix this? After all, the parts are long since discontinued.
First, the method. Replacement is very easy.
- Remove the throat plate.
- Take the bottom of the machine off and remove the bottom of the free-arm.
- For the left pin, loosen but don’t remove the set screw circled in red. After the set screw is loose, the throat plate pin can be pulled free from the machine.
- For the right pin, there’s a tiny bit more work.
- Loosen the set screw that my screwdriver is pointing to in the photo below, and remove the pin.
- This pin is a little shorter than the left pin. When you remove the old pin, measure it and cut your donor pin to the same length. You can do this with a hacksaw or a pair of nippers or anything that will get the job done. Smooth the ends with a file or sandpaper before inserting it.
- Set the new pins at the same height as the old – or flush with the throat plate and tighten the set screws.
- Reassemble the free arm cover and the base of the machine.
But, I can hear you asking – where do the donor pins come from?
The throat plate retaining pins from several of Singer’s later machines are an almost direct replacement. They’re a direct replacement for the left pin and the right just needs to be altered as mentioned above.
Better still, they don’t have the slot in the top and so no one will be tempted to use a screwdriver on them. The part number is 174256.
This is a non-exhaustive donor machine list that I’ve been able to gather so far. There are bound to be others.:
417, 717, 719, 714, 717, 719
734, 724, 774, 776, 737, 750
755, 756, 758, 770,775, 778
900 (Futura)
920, 925 (Futura 2)
1060 (Athena)
2000 (Athena)
2001
A lot of people parting these machines out may not know that part number because it’s not stamped onto the pin but if you tell them what it is and what machine it’s from, they should be able to help.
Edit Mar 14, 2023: Lots of people seem to be finding this post lately. Instead of commenting below for me to put you on a waiting list for pins, please hit contact at the top of the page and let me know that way. It’s just too cumbersome to try to go back through the comments. If there’s an email I’ve flagged, it’s easy to find.
Flaw #2: The other flaw with the 431G is the same that all of those G series machines have – the spool pins.
I posted about how to replace them with stock pins here (with video), and an upgrade method that I didn’t blog about but made a video demonstration of is here: https://www.youtube.com/watch?v=7AdDLL0XuQo. This method was developed by John F and he blogged about it here. I strongly recommend the upgrade. You’ll never have to pay for the expensive 507077 pins again. Apparently it takes less time to upgrade them too based on the length of both videos. 🙂
If you want the double chainring bolts and spool pins, I hope to have some in the shop in the next few weeks The pins can now be found in the shop here, or you can contact me by hitting that contact link up in the upper right corner. Otherwise, your local bicycle shop will have them or various online sources. John says not to spring for the expensive Campagnolo chainring bolts – you don’t need those for this project. Get the ones that have a hex head though. They’re easiest to deal with and fit the pins really nicely.
Today’s post title brought to you by Ryan! He suggested this post title. 🙂 Stevie Nicks and Tom Petty covering Needles and Pins.
My mother bought a 431G in the early 60’s and used it for 60 years to make a living. The machine passed to me quite a while ago. There were some some maintenance issues, like the motor was weak, the bottom rubber feet gone along with the very custom screws to hold them in, and the throat plate pins were of course broken. I have rebuilt the motor (effort worthy of a small book), tooling is on the way to re-tap the feet for new cushion screws (small book #2), and I have just finished with the throat plate pins. Here is my saga on pins.
I have slowly collect information on the machine. I now have a copy of the parts and list for the 431G. And Singer P/N for the pins. It should be easy. Plan A is to order some pins! Ah, the optimism of the ignorantly innocent. After a few months searching I know that there are no pins to be bought on the planet.
Time for plan B. I have run lathes and such for a couple of years. I can make pins. An hour with broken pin remains and a dial caliper and I had a drawing of the part. Some guessing about the kind of steel, All I need is access to a metal lathe. Years ago I could pop into the machine shop and use a lathe over lunch. I am retired and have no access anymore. Take a class and use the machine? Today schools want to turn out machinists with a 2 year degree, I would have to take several classes (months and $$$) to get to the lathe class. Nope.
Plan C. I have a part drawing. I’ll get a machinist to make a couple of dozen pins! Well, today the machine shops are very automated. They target business with a large number of parts, not a few dozen. Lots of machine programming time, then the cost per part is low, it you buy a bunch. Nope.
Plan D. I can buy a lathe. Cheapy “mini-lathes” are $750 or so. This makes a pin about $50 each! Nope. Time to sell the Singer as parts??? No, I am on a quest now.
Plan E. I found the (slightly wrong) used pins listed in this article as “174256” from eBay. 2 came in the mail for ~$15. Cheapest solution by far. the pin head was a bit smaller that the original, but in practice they work fine. I think the new pin shafts are a tiny bit smaller too, and when they get tightened in the machine they locate a tiny bit off center, just enough to take up the slack in the plate hole. It’s all a luck accident, and it works!
So many thanks to this site for help and inspiration. Now on to the rubber feet remount!
Ha! Welcome to the issues I’m having with getting the pins made! I don’t do metal lathe work and could possibly turn out some pins on the wood lathe in brass but I doubt they’d hold up. Ryan keeps telling me I’d likely love a metal lathe – I keep telling him I don’t need another hobby!
I suspect you’re right about the pins being a touch offset. The couple of pairs I had here seemed really close but it’s possible they varied some from model to model or in the replacements. I may also not have noticed back in the day but I don’t recall a machinist friend mentioning they were off either – it’s possible we got lucky with that batch.
Good luck with your rubber feet! There’s always something to tinker with on these machines. They’re rarely broken seriously but there are a myriad of little tweaks they all love.
As to pins off, in this case, that’s a good thing. The pins heads are a tiny bit small, and if they were perfectly centered the plate would be loose. Because the pins are a bit small, they get pushed off center by the set screws. This means the heads make contact with the plate in a way that hols the head from moving. A lucky accident!
Very interesting thread this one is: ) I love the Slants, all of the 400 series anyway, but the 431Gs are just the best. (I admit to 4 currently…)
The original spool pins are still available, but expensive IMO. Buying old plastic NOS or used does not appeal to me. The fix with chain-ring bolts is an elegant solution I do believe. You can always return to original if that’s your thing, as well: )
The throat-plate pins are a different matter. Originals unavailable at any cost, you need a spares machine to get originals. But the pins from the 600 series do work well. No lateral movement, & the vertical movement is controlled/restricted by the foot pressure in use. They work really well. The 600s had weakish inbuilt magnets for the vertical fixing, but you don’t really need magnets on the 431s in use, I know now. I’ve got one machine that has a pair of Tammis remanufactured pins. Has worked perfectly over 2+ years: ) Prior to this it worked OK with only one segment of both pins remaining. Full speed twin needle zig zags/pattern stitches, etc. Seemed a bit risky at the time (& not really recommended) but I never broke a needle & never had any problem. Except, that in my head, initially, I was thinking, ‘I don’t want to damage the machine’… Went for it & didn’t do any harm at all: ) & if I can add a link here, you will see the machine: https://www.slant.zone/singer-431-goto-machine/ Not pretty, but very cool & usable. It just purrs. They are super machines of Singers last, best productions IMO. Engineered, as opposed to injection moulded. Treasure yours & look after it I say.
I’ve never had a problem with replacing the bed cushions. Yet.
But I got one to do shortly.
Best of luck with yours anyway.
I’m long retired here in UK BTW: )
Hey John! Good to “see” you again! One thing I really like about the chain ring bolt mod is that it doesn’t require any permanent modifications to the machine.
You’re right, the original pins are still available but they’re super expensive and the part that goes into the machine is a little too short to easily grip with the push nuts – unless you use a thinner spacer which means the pins sit low. They’re also so fragile that a bump will ruin one and then you have to take that stitch plate off again which wears out the pin that the push nut goes on to hold it on as happened with my 411G that I did all of my videos with. It’s somewhat possible to install a new pin without removing that stitch plate but you risk bending the plate. All in all, it makes more sense to mod once and use less expensive pins and not have to remove the plate again.
As to the throat plate pins, I do think the originals were slightly over-engineered and not intuitive enough for users. Simpler seems to be working just fine. 🙂
Hi, I have a 431g with broken pins. would like to be put on your list when some become available
Has someone here had success replacing a completely broken throat plate pin? My machine’s right one is still in there, just sadly without any of the original cross parts. So I have the replacement pins, just no way of getting the old right one out yet.
Hi Monika, if you refer to the last and second last pictures in this post, it should show how to replace the right pin. There’s no need to have any part of the pin intact unless to grab it after you loosen that set screw at the back. If you don’t have enough to grab, try something sticky – like double-sided tape stuck to something or even a sticker of some sort. I’ve changed many of these pins using the directions above.
Hey, Thanks for posting the fixes for my 431G. Mine suffers from the broken needle plate locator pins. Unfortunately, I can not locate any of the alternate pins, 174256. Any suggestions for a good source? I see this part number show up on many different machines parts list, so I’m guessing it’s still a good part number. Would really like to get my machine working nice as it is a very clean and nice example.
Thanks again
You would need to find a seller who’s parting out one of the machines I listed in the post or find one of those machines as a private sale or in a thrift shop maybe. As I mentioned in the post, you may have to describe the part because it’s not stamped on the pins but those pins are not destroyed like these ones are, so they should be available if the seller knows what to look for.
I was able to order some from Helen Howes a few days ago. She doesn’t show them on the website but has them if you ask via email. They are remanufactured but should be the right part number. I’ll update once I’ve received them and put them in.
Thanks Monika! As it turns out, I now have a couple of pairs here from the same source that Helen got hers from. It was a limited run but I suspect if there’s enough demand, we should be able to get some more made. I’ll try to get a post done on it in the next week or two, after I clear my bench of another couple of projects.
Hi Tammi, so does this mean there is a supply of these pins now? I have one pin completely missing and 1 broken. The throat plate is taped in position and the tape is replaced as required. I’m no seamstress but when I need a sewing machine, this 431G just does everything I need. It would be great to get the throat plate more readily changeable.
Hey Jon,
I’ve run out of the stock I had of the throat plate pins. You could find a donor machine with the list I posted above or there has been some talk about making another run of the pins but nothing firm yet. Alternatively, I may be able to check with a machinist I know who could make some. Hit that contact button at the top of the page and I can email you when I get a line on some more.
Thanks Tammi. If I had the pins or a drawing I could re-make them myself. So I’d happily pay for the drawing instead if there is one. Or please send me the contact info for the machinist who can make them
Hi Jon, I don’t have drawings. The aftermarket pins were supplied to me and a few other vendors but were a one time run as far as I know.
I can ask the other machinist if he’s interested in making them or getting in contact though.
Hi Tammi, yes, that would be very helpful thank you
Hi Tammi,
I’m new to the Singer 431G, I just received mine from Ebay yesterday. It too has a broken throat plate pin.
If you find a place to purchase some, please let me know as well.
Thank you
Dot M
It sounds like I do need to try to get another run of these done. I will add you to the list.
Thank you. It’s seems I found a couple on Ebay last night. I’ll see how they work out, but might still be in need.
Thanks for getting back to me.
That’s great news! There are some out there if you know what to look for. I do need to look into getting another batch made regardless.
Hi Tammi,
Were you able to get another run of the throat plate pins #174256? Please add me to the list needing a set.
Let me know if you still need them. I see you managed to order some of the replacement style I mentioned in the post. If they’re the wrong ones, drop me a line and I’ll put you on the list.
I’m so grateful for the Singer 431G throat plate pin fix. I truly appreciate all the knowledge and useful fixes you are willing to teach to people like me. I own a Singer 431G and a Singer 631G, and they are awesome machines. My Singer 431G throat plate pin was missing a 1/4 of the pin. I could still sew on the machine, but I always wanted to fix it. You have helped me so much. Thank you, again.
You’re so very welcome! I’m glad that it will come in handy!
I’ve been meaning to do this post for a while and didn’t have access to a 431G to take the photos until recently.
Hi Tammy.
I note what you say above, with much interest, about the crossed throat plate pins.
What puzzled me before was how the later pins could ‘click in’ without the cross on the top? So I did not pursue it then…
But we live & learn!
I suspected it would be something like that. I get the question often enough that it made sense to make the post when I had access to the 431 one day.
Those replacement pins are ever so slightly larger in diameter at the tops and the plate slips snugly over top of them and doesn’t move. It’s not the exact same as the springiness that comes from the split top but the plate stays on and looks a lot better. 🙂
Yes! I’m ‘getting’ that now: )
I’ll find a suitable donor machine & report back. It really is an annoying fault with this otherwise lovely, amazing, vintage machine.
Having happily fixed the ‘Spool-pin problem’…
I know you are spending much time on this & I’m sure you’ll get proper appreciation for the time you spend, when the word gets out there.
You are much appreciated hereabouts: )
I will be interested to know what you think of the fix once you find a donor machine. I agree, this and the spool pin issue – which you solved – are the two small problems with an otherwise spectacular machine.
I’m really happy to be able to help keep these machines in service. 🙂
Oh thank you very much! Yes my Singer 421g has a broken pin but I thought it would be impossible to find a pin for her. Then I would need to know how to open her up! Thank you!
You’re very welcome! I’m so glad this was helpful to you! 🙂