The HD15 looks like a newer incarnation of my old ha3200 dust extractor - a truly brilliant machine. It comes with a 140mm hose and this fits the outlet on my big planer. My other machines have 100mm outlets and for this I got the Scheppach reducer designed for exactly this.
My machine was a scrapper when I got it and had to get a few replacement parts at the time including:
- a 140mm hose that fits the extractor inlet;
- a 140mm spigot for the end of the hose (part no 7520 0001);
- the 140/100mm reducer (part no 7520 6001).
You should be able to get these from the ever-helpful NMA. They won’t be very cheap, but they are very robustly made and are really good to use (eg the reducer is tapered so it is a snug easy fit).
Incidentally, I don’t know if your machine has the rigid filter, but that is certainly worth having.
Cheers