111G156 Motor Size

[David49]

Hello from England. Thanks for having me. This is my first post.

I've had an old (possibly wartime) 111G156 for about the last 30 years. I bought it because it was available and was a good price. Unfortunately some things changed and it has sat in my workshop ever since.

However, now retired and building a 3 wheeled kit car I decided to unearth the machine and try my hand at some basic leather upholstery and maybe a soft top for the car. Having cleaned and oiled the machine it all seems to work ok except for the motor and drive arrangement which consists of a 1/3 HP Singer clutch motor and a round section leather belt.

The belt sometimes slips, the clutch may need attention and the motor wiring looks a little suspect.

I have been reading on this forum that old motors can sometimes be dangerous, and together with the drive problems makes me think that a new servo motor may be in order.

My problem is that I'm not sure what size of servo motor I would need.

Could anyone offer any advice on whether the existing motor is likely to be original size, or whether a larger one would have been installed when new.

My aim is to install a servo motor of the right size to enable the machine to perform as originally intended.

[Quade]

745.8 & 1/3hp =  250 watts (or so).   

I use a  3/8" rubber belt on my Juki. It's a cogged car belt.  I believe the cogs just make it more flexible, there are no teeth that engage them. 

I'd say 550 watts on up would work fine.  550 is the smallest servo watts I remember seeing. 

https://www.amazon.com/gp/product/B079P8RQRQ/

I have this one and don't particularly like it.  There's a large dead space on the pedal before it actually starts moving the machine. It's also hard to control it stitch by stitch. I have the small pulley on it so, it's relatively slow.   Knowing what I know know, I''d probably pick one of the DC servos. 

https://www.amazon.com/Consew-CSM3000-Sewing-Machine-Electric/dp/B01N1L1P7G/

Maybe this one. 

Edited January 3, 2023 by Quade
Added amazon links.

[dikman]

I had a similar motor on a machine I bought, and as an antique it was interesting but as a working motor - no. At that age the wiring would have to be considered highly suspect. As Quade said a 550 watt (3/4 HP) servo motor will be more than adequate. I would seriously consider adding a speed reducer too (you can build your own if you're mechanically inclined) or another option is to remove the handwheel and replace it with a large pulley, this will give much better low speed control.

[kgg]

10 hours ago, David49 said:

My aim is to install a servo motor of the right size to enable the machine to perform as originally intended.

As Quade said a 550 watt is the smallest size but should be quite capable of doing the work. The first one noted is of a 550 watt brush type servo motors. The second one referenced is a brushless servo motor with electronic controls.

Like dikman suggested to get more stitch by stitch control adding a speed reducer or increasing the size of the handwheel is the way to go. 

I don't use the brushless electronic controlled servo motors as I like to keep my machines a little more basic, hit the go pedal and the machine runs. Motor will not run change the brush's. The electronics for the motor just adds another layer of complexity of trouble shooting when things go south. Depending on what country your in the brush type servo motors may or may not be as expensive or readily available as the brushless electronic controlled servo motors. 

kgg

[David49]

Thank you for all the helpful advice. I have now replaced the clutch motor with an R9-750E Redsun 750W servo motor. I have also made and fitted a speed reducer with a 3:1 reduction.

I now have great control of the machine speed, but I'm still having some problems with thread tension. I have been using a 135x17 180/24 needle with some 3 cord nylon thread, but the needle is not a specific leather needle.

The bottom thread will not pull up into the leather despite max top tension and very loose bottom tension.

Stupid question - should I be using a leather needle and is 135x16 180/24 the right spec?

David

[CowboyBob]

1 hour ago, David49 said:

Thank you for all the helpful advice. I have now replaced the clutch motor with an R9-750E Redsun 750W servo motor. I have also made and fitted a speed reducer with a 3:1 reduction.

I now have great control of the machine speed, but I'm still having some problems with thread tension. I have been using a 135x17 180/24 needle with some 3 cord nylon thread, but the needle is not a specific leather needle.

The bottom thread will not pull up into the leather despite max top tension and very loose bottom tension.

Stupid question - should I be using a leather needle and is 135x16 180/24 the right spec?

David

The 3 cord too large & stiff to pull up,polyester is alittle softer & might pull up better or try the next size smaller thread in the bobbin FF or 138 will make a better stitch with 3 cord in the needle,if your sewing leather a leather point might help too.

[kgg]

1 hour ago, David49 said:

Stupid question - should I be using a leather needle and is 135x16 180/24 the right spec?

When selecting the right needle for the thread I would suggest sizing the needle to the thread. On CowboyBob's website there is a good guide ( https://www.tolindsewmach.com/thread-chart.html ). Depending on how thick / tough the leather is you may find that you may have to move up a needle size or two so the loop is formed properly so the hook can catch the top thread. The 135 x 17 can work in softer thin leather but the 135 x 16 is better as the tip cuts through the leather rather then punching through. The 135 x 17 is meant for fabric where you want to separate the fibers rather then cut them.

kgg