Grounding Vintage Sewing Machines
 

I took my Kenmore's foot control apart and nearly fainted.
This thing has a metal casing, and inside there are coiled resistance wires. If one of those let go, it could easily touch the case and make it live!

The metal body of the machine with single-insulated wires makes me a little uneasy too, though I have carefully inspected them for damage.

Has anyone rewired their vintage machine to bring it up to modern safety standards?

I have an idea of how I could go about it, but there's no point reinventing the wheel if it's been done before.

So far, no, but I have on some of my vintage wood working machines. Finding or making places to attach the ground wire is the hardest part on those. I usually end up drilling and tapping at least a couple screw holes to attach the grounds on them. I don't like wires to show more than necessary so keeping the extra ground lugs out of sight is important to me.
I think the biggest challenge for you given the sizes of the wire (large compared to 2 conductor wire) and parts involved (small, so not much room for extra anything) will be doing a neat job of it.
Rodney

I've read about people replacing the old foot controllers with modern, electronic ones, but I have never read about anyone grounding a machine.

If you wanted to replace the foot control with another vintage one, buy a carbon pile type....no wire coil inside. Or if you wanted a new one, you could buy a carbon pile or electronic control.

Actually I just bought a "new, old stock" Kenmore carbon pile control on ebay for $9.99...part # 6802. It's the same one that came with the Kenmore I got new in 1971....Bakelite housing, metal bottom. I was really happy to get it...It's the best, most responsive control I've ever used & I've been sewing for over 50 years! I've bought several of this same foot control on ebay before (used but VG condition) & rewired for some of my other machines. But I was thrilled to find a brand new one!

And I also have never heard of grounding a sewing machine.

If the wiring is in good shape and there are no bare spots (which as far as I'm concerned negates the "in good shape") and the connectors and connections are properly terminated I really wouldn't go to the effort. Technically, a 2 prong plug is still "legal" or I wouldn't have so many modern appliances with them including laptops.

My cousin is an electrician AND she's a quilter and vintage machine collector and has also never mentioned needing, being so inclined or concerned that they needed to be brought up to modern standards. Only that the wiring be properly done with no exposed wire.

I have over 60 vintage sewing machines. Many of them have resistance wire foot controllers. I have had two of them break a resistance wire and no short circuit resulted. Only a great reduction in speed, or a dead spot. I've also never seen a vintage machine with a grounded cord. Only two wire plugs. As far as I can see, as long as the wires are in good condition there is no need to "update" anything to so called modern standards. Joe

Two-prong is only 'legal' if the device is double-insulated. Nowadays, this usually means that the casing of the device is plastic, like your laptop charger.

Devices in metal casings should be grounded so that if there is a fault in the insulation and the external metal surfaces become live, it will be diverted to ground.

Machines like ours, wired in the way they are, do not meet the safety standards of today.

It's true that they are probably safe enough provided you inspect them frequently for signs of damaged insulation, I'm certainly not trying to scare anyone.

J Miller, it is reassuring to know that the mode of failure on your foot pedal didn't create a dangerous situation, but that could have turned out different if the coil had broken somewhere else along its length.

I caught my 3 year old daughter copying me by pressing the foot pedal (with bare feet!) the other day. Naturally, I never leave the machine plugged in unattended, so there was never any danger, but it gave me pause for thought.


I think I've thought of a way around this, and I'll take photos along the way in case others want to do the same.

I worded that badly. If the 2 prong, assuming it's in good condition was considered completely unsafe in today's world, especially the sue happy environment we all live in, no shop in the world would repair one of these sewing machines, they would be "condemned", not grandfathered.

Absolutely agree.
I'm actually from England (moved to the States about five years ago) and the rules are a lot more stringent there, probably because mains voltage is 230-240v.
I believe that thrift stores in the UK have to have electrical devices tested before they can be sold, and they tend not to bother. I don't think a metal-cased sewing machine would pass.

It's all about condition of the insulation, and I'm not for a moment trying to start people panicking.
Your machine is safe as long as you know to regularly check the insulation.

I feel that I will sleep better at night if I ground my machine, so I'm going to do it. I live in an apartment, and my machines are in their cabinets in the living room. I can't secure my machines from my daughter. I remove the needle after every use, and fold the machine into its cabinet when I'm not using it.
As an added level of safety, I'm going to ground it too.

I'll post pictures of my modification so that people can copy it if they are so inclined.

It's actually safer to have high voltage. To achieve the same power usage you need half the current that the US 110V devices need, and current is what will stop your heart. 240VAC will certainly give a good jolt (I was shocked just yesterday - stupidly forgot to unplug a motor before removing a brush). Gave me a kick but that's all.

Electrical devices never used to be tested, and these rules are relatively recent. The reason for it is the ridiculous amount of law suits and responsibility shifting that goes on today. We've had compulsory electrical testing since about 2001.