用pressfiting,从前面的洞也够了

http://www.google.de/search?biw=1024&bih=140&tbm=isch&sa=1&ei=zCyzUvv9BMnSsgaXt4DIAg&q=pressfitting&oq=pressfitting&gs_l=img.1.0.0l2j0i10j0j0i10j0l3j0i24l2.7756.26295.0.28585.9.6.3.0.0.0.393.1398.0j3j1j2.6.0....0...1c.1.32.img..5.4.566.JB1Mz27cpr8