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techtalk:ref:tools030 [2021/01/27 23:39] hippysmack [Thread Tolerance] |
techtalk:ref:tools030 [2021/06/06 08:08] hippysmack [Slotting Holes] |
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====== Tapping ====== | ====== Tapping ====== | ||
Make sure to use sharp tap and dies. ((Shadowdog500 of the XLFORUM http://xlforum.net/forums/showthread.php?t=221093&highlight=split+rocker+box)) \\ | Make sure to use sharp tap and dies. ((Shadowdog500 of the XLFORUM http://xlforum.net/forums/showthread.php?t=221093&highlight=split+rocker+box)) \\ | ||
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+ | ===== Thread Tolerance ===== | ||
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+ | Threads can be cut to a tighter or looser fit depending on the needs or sometimes availability of drill bit sizes. For instance, drill bits are available in a wide variety of sets or kits. The most common sizes are usually the ones that are provided. However, many suppliers carry a drill index kit which comes with a huge amount of drill bits in step sizes. Some are in 1/32 steps and some are in one thousandths increments. So, if you want a close tolerance fit on a 3/8"x16 threaded connection, you could use a 0.2969" pre-drill or for a looser fit you could use a 0.3230" pre-drill. Even with a standard 0.3125" drill bit, a hand drill is not going to produce a straight hole every time. If you have to over compensate with it and wallow out the hole just a bit to get it straight, you may be producing a looser threaded connection without realizing it. Care should be taken on tighter pre-drilled holes since it creates more friction and heat when tapping than a standard or slightly larger hole and it can lead to breaking taps off in the hole or cracking the piece you're working on. ((hippysmack from the XLFORUM)) | ||
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===== Removing a Broken Tap ===== | ===== Removing a Broken Tap ===== | ||
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|1"x12 | 59/64" |0.9219" ^ | | |1"x12 | 59/64" |0.9219" ^ | | ||
|1"x14 | 15/16 |0.9375" ^ | | |1"x14 | 15/16 |0.9375" ^ | | ||
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+ | ====== NPSC Tap Drill Sizes ====== | ||
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+ | ^Tap / Thread Size ^Drill Size ((Starrett tap drill sizes chart)) | | ||
+ | |1/8-27 |11/32 | | ||
+ | |1/4-18 |7/16 | | ||
+ | |3/8-18 |37/64 | | ||
+ | |1/2-14 |23/32 | | ||
+ | |3/4-14 |59/64 | | ||
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+ | ====== Slotting Holes ====== | ||
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+ | {{:techtalk:ref:tools:enlarging_holes_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ | ||
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[[:techtalk:menu|{{:techtalk:gototechnicalmenu.jpg|}}]] | [[:techtalk:menu|{{:techtalk:gototechnicalmenu.jpg|}}]] |