removal of spring clips 35 and then locking pins 34 by a light tap removal of studs 31 from sockets 32 is not quite so simple because it is necessary to move both fastenings together along parallel paths or each one alternately with the other for a short distance particularly if the extension should become bent and not restored exactly to its original condition it is accordingly preferred to weld hammer pads 37 to each extension close to each mounting 31 a few taps of a hammer or other solid object against pads 37 will remove extension 30 very quickly without battering or otherwise damaging the mounting studs 31 convenient use of extensions requires provision of a place for carrying them when they are not in use accordingly an extra socket 28 is welded to the back of blade 20 in a location such that extension 30 can be supported by socket 38 on the back of blade 20 without projecting beyond its lateral edge this socket 38 is provided with a locking pin 34 and spring clip 35 to prevent loss of the extension 30 during activities not requiring the extension to be in its operating position this carrying socket 38 must of course have its axis spaced somewhat farther from the surface of blade 20 than socket 32 to allow for the thickness of the extension 30 a lower socket is not required in this inactive position of extension 30 although the preferred form of the invention described above is quite simple in construction and reliable and convenient in use many other arrangements for quick and firm mounting and removal of a blade extension are possible fig4 shows.