low friction wear surface or bearing insert a low friction wear surface or bearing insert of hard carbide such as tungsten carbide titanium carbide silicon carbide diamond silicon carbide composites polycrystalline cubic boron nitride or polycrystalline diamond will provide a spring cap bearing surface 210 having both wear resistance and lo v friction to facilitate easy rotation around outer mandrel section 103 without low friction composites blade carrier 300 is shown in fig5 blade carrier 300 is comprised of symmetrical first and second tubular sections 300 a and 300 b having a curved inner bearing surface 305 the blade carriers 300 are formed by attaching sections 300 a and 300 b together at joint line 304 around the mandrel 103 not shown a plurality of socket head cap screws 308 or other suitable threaded connectors fit into corresponding threaded screw holes 309 to attach tubular sections 300 a and 300 b the blade carrier 300 has in outside diameter 301 sized for maximum blade 200 support and sufficiently small for adequate fluid flow around blade 200 when sections 300 a and 300 b are joined each section 300 a and 300 b of blade carrier 300 has an opening or blade socket 310 to receive a scraper blade 200 each blade socket 310 has a travel stop 311 that corresponds with collar 206 on blade 200 a blade 200 is fitted from within the carrier 300 to slide through blade socket 310 so collar 206 of the blade 200 comes to rest against blade travel stop 311 blade 200 fits into blade socket 310 with sufficient clearance to prevent sticking or binding of the blade 200 with carrier 300 if blade 200 is tilted within socket 310.