Singer 336K Help Needed

[cgleathercraft]

I have an old Singer 336K that I picked up at an auction from a guy who did upholstery work. I got a steal on it ($50). I've had it gone over and it was sent back to me with a piece of triple layered denim that had been sewn quite a bit so I knew the had it working. However whenever I try to sew on it the darn thing races and ends up either breaking the thread or needle, which is not very fun when the shrapnel hits at high speed. I feather it the best I can but no matter how much i try it takes off on me. I put a new belt on to keep it from dragging till it catches but that didn't solve the problem. They told me I could do a couple layers of suede with it but my experiences says otherwise.

It's not a walking foot but I'm only sewing 2 layers layers together and not looking to make cases, holster, or belts with it.

Any help would be much appreciated, otherwise it'll find its way back to another auction lol.

[Wizcrafts]

First of all, as long as you keep the old clutch motor, change the motor pulley to the smallest replacement that fits the output shaft. In most cases, that is a 3/4 inch inside diameter, type 3L pulley and belt. 3L means 3/8 inch v-belt.

Note the diameter of the pulley on the motor now. When you locate the smaller replacement, subtract one inch of belt length for every inch of diameter reduction.

Example:

Existing pulley: 4 inches (~100 mm)

Existing v-belt: Type 3L x 44 inches

New Pulley: 2 inches (~50 mm)

New v-belt: Type 3L x 42 inches

This change results in a 2:1 speed reduction, across the board. It also inherits a 2:1 torque increase.

Note, you can easily replace the clutch motor with a 550 Watt servo motor if the existing setup has 3 mounting holes in the table. You would order the servo motor with a 2 inch (50 mm) pulley, and a new 3L v-belt that is 1 inch shorter per inch difference in diameter from clutch motor pulley. The above mentioned motor can be easily controlled to sew at less that 1 stitch per second, all the way up to about 30 stitches per second, by your foot position.

Edited January 15, 2014 by Wizcrafts

[cgleathercraft]

I've read that reducing the size of the pulley on the motor would help. I need to try that before I drop the money to get a servo motor. Also, thought that servo motors would be 2 or 3 times that price.

Thanks for the advice! I'll see if I can find a different pulley before I take the dive for a servo motor.

[Anne Bonnys Locker]

The 336 was built as a high speed fabric sewer and would struggle with most leather except garment weight. Theoretically it could handle 138 (if it uses 134 needles) but probably is going to work best with 69 thread through an 18g needle.

Needles breaking repeatedly suggests a problem. Are you running the right size needle for the thread and is the thread running smoothly through the machine?

[cgleathercraft]

I'll verify the size of the needle and thread as soon as I can. I don't have the machine where I can use it because of the issues I've had with it. I had always asked for the largest needle when I went to buy more but it still may not have been big enough.

The thread always broke at the needle so I would assume that the needle isn't correct. Otherwise the thread seemed to run through fine.