Plastic or nylon washers, if you have a bunch of left over flat faucet washers they could be drilled out. bolts a consideration too. Threaded part through tubing not as nice as round shank for a bearing surface. Check for any metal to metal pivot points on tubes/framing too. a washer can fit between some if they rub. Carpet can deaden alot of grating or mesh vibration,
Olive oil on stand joints as last resort. Good luck and great hunting.