I just bought a new Juki serger MO-644D and I can't figure out the knives and how to release them

Here is your Manual:

JUKI MO 644D Instruction Manual

Good luck. I found a replacement part for one of mine on Ebay. Just search for Used Juki Serger for parts. Maybe you'll find a 644D for cheap enough that you can scavenge parts for a few more years.

I suggest taking the machine in to be serviced

take back the machine to the store you bought it from and get another machine.that is if you have warranty.you will have more problem later on.that needle like metal is from under the machine and it broke off the tension feeder. good luck.

Oil, Oil and regular oiling Girl [email protected]

How to Thread Juki MO-134 Serger from watching lady at Lyles. Turn upper blade up. Push in first then turn up.It makes threading easier. Blue Thread upper looper first. Pull thread through tension knob. Don'tjust lay it there. (She thought that is what I must have done) Orange Thread lower looper next. Pull thread through tension knob as inthreading upper looper. Adjust lower looper so it is right nextto upper looper so that their points are almost together and directly belowsewing needles. Lower looper will be in front of upper looper (I believe). With tread from upper looper pulledback, slightly lift lower looper above upper looper and thread. I think this isright. Pull thread back with other thread. Tension is the key. Remember that. Yellow: Thread left needle first.Remember tension. Pull thread through curled wire on left side of needle arm. Green: Thread right needle. Rememberabout tension. Pull thread through curled wire on right side of needle arm. b> Note: Before sewing turn the wheel tomake sure the stitches are going together correctly.

Email me at [email protected] should be able to help.

try at www.ifixmachines.com

Herre is a link to the threading diagram: http://www.sewusa.com/Threading_Diagrams/Threading_Pages/Juki_Sewing_machine_threading/Juki_MO_634_Threading_Diagram.htm

Put new needles in it.

Following the colors, thread the upper looper first, then the lower looper. Next thread the needles. Always thread in this order.