[Steve Law]

With respect to all the valid thoughts earlier, I'd spend some time and make quite sure the hemp was as neat and parallel as I could - the colour is irrelevant, but I always use waxed, and finish by running the drone parts together for a good while to settle the hemp and going back again and checking.... usually find that once that's sorted a small application of cork grease to the slides helps smooth operation.

I bought a new set last year and it did take a little while to settle the hemp, but now it's sorted as above there's no problem.

Hemp is as cheap as chips and it's hard to see how anyone could inadvertently cause a huge problem - too little and the slide will rock and leak, too much and you won't be able to turn with two fingers and thumb.....take some time and work with it - lots less hassle than going back to the factory - although that remains an option if the simple stuff doesn't work