Some of the idler pulley bearings that came with the Robodigg metal corners are quite noisy after just 6 hours of use.
I found some good Japanese bearings here
ezo f623zz but you need to buy 20 or more for the price to go down to 2.33£ +vat.
I only need 6 and I was thinking, if you live in UK and want some I could buy in bulk and then post them to you for the same price plus a 1st class stamp.
PM me if interested. We only need a order of 20 or so.