I bought 10 of those,first one was great.Went together easily with removal of centre pin then solder on the 14AWG cable & rebuild.The second one though,same method (remove centre pin,solder on 14AWG) split the insulator,and then split a few more insulators so I finally lost the plot(swearing like a Navvy)and forced the silicon insulation up the 14AWG and over the soldered joint,before placing the top shoulder from a split insulator under the shoulder on the centre pin.Result was a safe 510 that doesn't short out when I change over atty.