In reply to harold walmsley:
Sweat and chalk will increase the friction. When you brush it, do it across, rather than in and out. Also, just check with a spirit level that yours is plumb vertical, it makes a huge difference if it’s even slightly out. Shim the bottom out if it’s not vertical.
I’ve a 1000 which I’ve had for a long time, and a much more recent 2000 and the difference in friction is pronounced.