Do you have a chorus of singing PTB’s during your Tower classes? All you need is a little dab of oil and an old rag to lube them up.
Take the T-pins out one at a time, wiping the surface and dabbing a little bit of 3-in-1 oil along the axis and re-inserting them. Swing the PTB a few times to work the oil in.
If your PTB is still sticking or doesn’t hang parallel between the vertical uprights, that is a sign of another problem. Contact me to help you diagnose it.