00:00Grazie a tutti.
00:44Grazie a tutti.
01:08Grazie a tutti.
01:41Grazie a tutti.
04:44the sheets again we start by drilling our number 30 hole the sheets are then disassembled and
04:51machine dimples separately on the squeezer note the angle of the dimpling tools the dimpling punch
04:59for the top sheet has an angle of 100 degrees the same as the rivet head the dimpling die has
05:06an
05:06angle of 110 degrees the dimpling punch for the bottom sheet is also 110 degrees to correspond
05:14with the top sheet and the dimpling die is 120 degrees this difference is necessary in order to
05:22get a good nesting of parts upon completion of the dimpling operation the parts are reassembled
05:34sheet metal riveting clamps are used to hold the parts together until riveting is completed
05:40the rivet is inserted and from here on the work proceeds using a regular flush riveting set
05:47and the ordinary bucking bar driving this type of rivet requires the same skill on the part of
05:54the operator as in the former dimpled method it is very important that the rivet be driven
06:01straight we have just illustrated the pre-dimple method of riveting the sheets were taken apart
06:08and machine dimples separately on the squeezer this is a method used when the sheets are too heavy
06:14for the double dimple process
06:19for sheet gauges where the top sheet is too thin to countersink and the bottom sheet too thick to dimple
06:25we must use a combination of pre-dimpling and countersinking the top sheet being under 40
06:33thousandths must be dimpled the bottom sheet being over 40 thousandths will be countersunk
06:39again we start by drilling a number 30 hole sheets are disassembled and the upper sheet is machine dimpled
06:47using special dimpling tools on a squeezer type machine the bottom sheet is countersunk using the special
06:55countersinking tool the angles of the dimple and countersink are very important the angle of the
07:03dimple next to the rivet must be 100 degrees because the rivet head is 100 degrees the angle on the
07:10opposite
07:10side of the sheet is 110 degrees the angle of the countersink is also 110 degrees parts are reassembled
07:20using sheet metal clamps rivet is inserted this is followed by driving the rivet using a standard flush
07:27driving set and bucking bar this riveting technique is fairly simple because there is no lip on the under
07:35sheet to cause cracking or failure from clincher rivets we have just demonstrated the combined
07:43countersink and dimple method of flush riveting this combination is used in cases where the sheet next
07:49to the rivets manufactured head is too thin to be countersunk and the bottom sheet is too thick to be
07:58now let's review the four methods of flush riveting just demonstrated countersinking used when the top
08:06sheet is 40 thousandths thickness or greater the flushness of the rivet is obtained by setting it into a hole
08:14countersunk by a special tool double dimpling used when the total thickness of the sheets being riveted is
08:2240 thousandths or less in this method the flushness of the rivet is obtained by using the rivet itself
08:29as the punch to form the dimple pre-dimpling used when the top sheet is 40 thousandths or less and
08:38the total
08:39thickness of both sheets is over 40 thousandths and under 90 thousandths the flushness of the rivet is
08:46obtained by setting it into a dimple formed mechanically on a squeezer combination
08:53countersinking and dimpling used when the top sheet is too thin to countersink and the bottom sheet is
09:00too thick to dimple the top sheet is dimpled and the bottom sheet is countersunk
09:08the result obtained by each of these different methods is the same
09:12the head of the rivet is flush with the surface so that the turbulence or drag is held to a
09:19minimum
09:22a little bit faster so that the thickness of the lower part the bottom sheet of the
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