How to set / replace the looper in the Juki DDL-900A-S lockstitch machine

I will show you how to position the hook and how it can be done quickly. The manual also matches other models and brands.

We start by tilting the machine slightly backwards and move the plate to the left.

Raise the presser foot and remove the 2 screws from the needle plate.

We remove all accumulated dirt and unscrew the transport teeth.

Unscrew the plate from the knives and remove it.

Now everything will be clearly visible.

In my case, there was a notch on the needle bar indicating the service setting, but on most machines it is and it looks like this. The notches are to align with the guide line on the machine.

At this point, the hook should be there

The hook should be at a distance of 0.1-0.05 mm from the needle. In fact, this is not realistic to set and sets itself almost zero. When sewing thick and dense material, even offset from the needle helps. Approximately it looks like this:

It was the distance from the needle and now what the time of the hook looks like.

It looks something like this

To make the adjustment, tilt the machine to the back and lightly loosen the 3 screws from the hook so that it does not spin too loosely. We can then set the distance and its time in relation to the needle.

And now I will show you how to do it quickly.

With this method, you don’t even need to unscrew the needle plate.

After tilting the machine, unscrew the grip of the raceway treadmill.

We loosen 3 screws

It can now be removed and possibly polished gently the tip of the blade. Setting it is not difficult but it is possible and it looks like this from below.

But for this you need to have some experience and practice.