If you are considering selling used machinist tools, eBay is your best bet. While the market for these items tends to be oversaturated, the eBay marketplace can be very profitable. Although eBay charges a listing fee, new sellers can get these fees waived during certain promotions. The selling power of your tools also depends on the type of seller account you choose. Different accounts offer different selling privileges, including increased visibility, more amenities, and sales protections.
Source: https://sites.google.com/view/sell-used-machinist-tool/