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techtalk:ref:tools030 [2021/01/27 23:38] hippysmack [Removing a Broken Tap] |
techtalk:ref:tools030 [2023/12/20 16:33] (current) hippysmack |
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====== REF: Tools & Fasteners ====== | ====== REF: Tools & Fasteners ====== | ||
====== General Drilling and Tapping ====== | ====== General Drilling and Tapping ====== | ||
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- | ===== Thread Tolerance ===== | ||
- | |||
- | 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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Back them out, clean and re-lube them periodically to minimize any loose particles getting loose in your work area. \\ | Back them out, clean and re-lube them periodically to minimize any loose particles getting loose in your work area. \\ | ||
This also helps to control heat buildup. \\ | This also helps to control heat buildup. \\ | ||
- | | Lubing bits. ((photos by sifty of the XLFORUM http://xlforum.net/forums/showthread.php?t=1592463&page=5)) ||| | + | | Lubing bits. ((photos by sifty of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/146604-first-harley-1975-xl1000-caf%C3%A9-project/page5?t=1592463&page=5)) ||| |
|{{techtalk:ref:tools:lubing_bits_1_by_sifty.jpg?direct&300|}}|{{techtalk:ref:tools:lubing_bits_2_by_sifty.jpg?direct&300|}}|{{techtalk:ref:tools:lubing_bits_3_by_sifty.jpg?direct&300|}}| | |{{techtalk:ref:tools:lubing_bits_1_by_sifty.jpg?direct&300|}}|{{techtalk:ref:tools:lubing_bits_2_by_sifty.jpg?direct&300|}}|{{techtalk:ref:tools:lubing_bits_3_by_sifty.jpg?direct&300|}}| | ||
+ | |||
===== Make a Pilot Hole Before Drilling ===== | ===== Make a Pilot Hole Before Drilling ===== | ||
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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 https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/51523-question-about-my-rocker-oil-lines?t=221093&highlight=split+rocker+box)) \\ |
+ | |||
+ | ===== Thread Tolerance ===== | ||
+ | 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)) | ||
+ | |||
+ | \\ | ||
===== Removing a Broken Tap ===== | ===== Removing a Broken Tap ===== | ||
- | * The best way to remove a broken carbon steel tap is to use a small hole punch to the center of the broken tap and smack it with a hammer while exploding the hardened tap. You don't stand a chance at drilling it out without damaging the hole/ threads and chances are since pressure was enough to break the tap, it'll take more pressure than that to remove the broken lil stubby that's left. ((hippysmack)) ((Article by Oldrump1 [[http://xlforum.net/forums/showthread.php?t=1959533]])) | + | * The best way to remove a broken carbon steel tap is to use a small hole punch to the center of the broken tap and smack it with a hammer while exploding the hardened tap. You don't stand a chance at drilling it out without damaging the hole/ threads and chances are since pressure was enough to break the tap, it'll take more pressure than that to remove the broken lil stubby that's left. ((hippysmack)) ((Article by Oldrump1 [[https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-general-discussion-and-problems/181908-assembly-prep?t=1959533]])) |
===== SAE and Metric Tap Drill Sizes ===== | ===== SAE and Metric Tap Drill Sizes ===== | ||
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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 ====== | ||
+ | |||
+ | ^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 | | ||
+ | |||
+ | ====== Slotting Holes ====== | ||
+ | |||
+ | {{:techtalk:ref:tools:enlarging_holes_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ | ||
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