Actions

Difference between revisions of "Twist Drills"

From DT Online

m (Added link)
m
 
(2 intermediate revisions by the same user not shown)
Line 1: Line 1:
[[File:TwistDrillSet.png|150px|right]]
+
[[File:TwistDrillSet.png|250px|right|link=http://www.amazon.co.uk/gp/product/B009K1S3ZY/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=B009K1S3ZY&linkCode=as2&tag=dton06-21]]
 +
__TOC__
 +
 
 +
 
 +
=====Description=====
 +
 
 
[https://en.wikipedia.org/wiki/Drill_bit '''Twist Drills'''] are the most commonly used drill bit and are suitable for drilling most materials including [https://en.wikipedia.org/wiki/Carbon_steel#Mild_and_low-carbon_steel '''Mild Steel''']. They are more completely known as '''Morse Twist Drills''', named after the American Engineer, [http://www.morsecuttingtools.com/cgi/CGP2CSGEN?PAHDID=000000112731547&PARDID=316332221178492&PMSIDE=Y&PMFILE=MS2ABOUT01.html '''Stephen A. Morse'''] who first developed them in 1864.
 
[https://en.wikipedia.org/wiki/Drill_bit '''Twist Drills'''] are the most commonly used drill bit and are suitable for drilling most materials including [https://en.wikipedia.org/wiki/Carbon_steel#Mild_and_low-carbon_steel '''Mild Steel''']. They are more completely known as '''Morse Twist Drills''', named after the American Engineer, [http://www.morsecuttingtools.com/cgi/CGP2CSGEN?PAHDID=000000112731547&PARDID=316332221178492&PMSIDE=Y&PMFILE=MS2ABOUT01.html '''Stephen A. Morse'''] who first developed them in 1864.
[[File:TwistDrills.png|200px|right]]
+
[[File:TwistDrills.png|250px|right]]
  
 +
 +
=====Features and Uses=====
  
 
Most '''Twist Drills''' have a [https://en.wikipedia.org/wiki/Drill_bit_shank#Straight_shank '''Parallel Shank'''] and, for everyday use, come in sets covering [https://en.wikipedia.org/wiki/Drill_bit_sizes '''Drill Sizes'''] up to 13mm diameter. Larger diameter drills may have a reduced diameter shank to fit into '''[[Portable Electric Drills]]''' or can have a [https://en.wikipedia.org/wiki/Drill_bit_shank#Morse_taper_shank '''Morse Taper Shank'''], ''(also named after Stephen A. Morse)'', which fits directly into the hollow spindle of a '''[[Drill Press|Bench Drill]]''', '''[[Drill Press|Pedestal Drill]]''' or '''[[Centre Lathe|Lathe Tailstock]]''' for example. Drill lengths too can vary but the most common are the [https://en.wikipedia.org/wiki/Drill_bit_sizes#Jobber-length_drill '''Jobber'''] length of drill.
 
Most '''Twist Drills''' have a [https://en.wikipedia.org/wiki/Drill_bit_shank#Straight_shank '''Parallel Shank'''] and, for everyday use, come in sets covering [https://en.wikipedia.org/wiki/Drill_bit_sizes '''Drill Sizes'''] up to 13mm diameter. Larger diameter drills may have a reduced diameter shank to fit into '''[[Portable Electric Drills]]''' or can have a [https://en.wikipedia.org/wiki/Drill_bit_shank#Morse_taper_shank '''Morse Taper Shank'''], ''(also named after Stephen A. Morse)'', which fits directly into the hollow spindle of a '''[[Drill Press|Bench Drill]]''', '''[[Drill Press|Pedestal Drill]]''' or '''[[Centre Lathe|Lathe Tailstock]]''' for example. Drill lengths too can vary but the most common are the [https://en.wikipedia.org/wiki/Drill_bit_sizes#Jobber-length_drill '''Jobber'''] length of drill.
Line 12: Line 19:
 
[[File:CentreDotPunching.png|100px|right]]
 
[[File:CentreDotPunching.png|100px|right]]
 
<span style="color: green">'''Note:'''
 
<span style="color: green">'''Note:'''
For accurate drilling through harder and smoother surfaced materials such as steel, hole centres should be marked with a '''[[Punches|Centre Punch]]''' and when extreme precision is required, the hole diameter should be scribed with '''[[Dividers and Compasses|Dividers]]''' and its intersections with the two axes marked with a '''[[Punches|Dot Punch]]''' - an accurately drilled or bored hole would cut each of the dot punched marks in two!       
+
For accurate drilling through harder and smoother surfaced materials such as steel, hole centres should be marked with a '''[[:Category:Punches|Centre Punch]]''' and when extreme precision is required, the hole diameter should be scribed with '''[[Dividers and Compasses|Dividers]]''' and its intersections with the two axes marked with a '''[[:Category:Punches|Dot Punch]]''' - an accurately drilled or bored hole would cut each of the dot punched marks in two!       
 
</span>
 
</span>
 
----
 
----
  
__TOC__
+
=====Maintenance and Manufacture=====
  
 
=====Maintenance and Manufacture=====
 
 
[[File:TwistDrill.png|400px|right]]
 
[[File:TwistDrill.png|400px|right]]
 
Twist Drills can be sharpened using a '''[[Tool Grinder|Bench Grinder]]''' and are usually ground to a '''Cutting Angle''' of 59° to its axis for general work ''(to create a '''Point Angle''' of 118°)'' but this can vary for hard or soft materials ''(e.g. 45° is more suitable for [https://en.wikipedia.org/wiki/Cast_iron '''Cast Iron'''] and [https://en.wikipedia.org/wiki/Brass '''Brass'''])''.
 
Twist Drills can be sharpened using a '''[[Tool Grinder|Bench Grinder]]''' and are usually ground to a '''Cutting Angle''' of 59° to its axis for general work ''(to create a '''Point Angle''' of 118°)'' but this can vary for hard or soft materials ''(e.g. 45° is more suitable for [https://en.wikipedia.org/wiki/Cast_iron '''Cast Iron'''] and [https://en.wikipedia.org/wiki/Brass '''Brass'''])''.
Line 27: Line 32:
  
  
=====[https://en.wikipedia.org/wiki/Drill_bit#Lip_and_spur_drill_bits Dowel Bits]=====
+
=====Dowel Bits=====
[[File:DowelBits.png|200px|right]]
+
 
 +
[[File:DowelBits.png|250px|right|link=http://www.amazon.co.uk/gp/product/B0001P19BI/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=B0001P19BI&linkCode=as2&tag=dton06-21]]
  
Ordinary HSS Twist Drills can be used to drill wood but, because of its fibrous nature, this can result in the [https://en.wikipedia.org/wiki/Wood_grain '''Grain'''] tearing and leaving a rough edge to the hole. '''Dowel Bits''' ''(aka Brad Point or Spur Point drills)'' are not ground to the usual Point Angle but are sharpened to have a small point at the tip of the bit and '''''spurs''''' on either side which first cut across the [https://en.wikipedia.org/wiki/Wood_grain '''Grain'''] to ensure clean, straight holes.
+
Ordinary HSS Twist Drills can be used to drill wood but, because of its fibrous nature, this can result in the [https://en.wikipedia.org/wiki/Wood_grain '''Grain'''] tearing and leaving a rough edge to the hole. [https://en.wikipedia.org/wiki/Drill_bit#Lip_and_spur_drill_bits '''Dowel Bits'''] ''(aka Brad Point or Spur Point drills)'' are not ground to the usual Point Angle but are sharpened to have a small point at the tip of the bit and '''''spurs''''' on either side which first cut across the [https://en.wikipedia.org/wiki/Wood_grain '''Grain'''] to ensure clean, straight holes.
  
  
Line 36: Line 42:
  
  
=====Masonry Bits=====
+
{{Twist Drill Buyers Guide}}
[[File:MasonryBits.png|200px|right]]
 
 
 
These are used mainly with '''[[Portable Electric Drills]]''' with a [https://en.wikipedia.org/wiki/Hammer_drill '''Hammer Action'''] and have a [https://en.wikipedia.org/wiki/Tungsten_carbide '''Tungsten Carbide Tip'''] to penetrate masonry such as brick, concrete and stone. Drills intended for heavier work may be designed for use with an  '''[[Portable Electric Drills|SDS Drill]]''' and have tips able to withstand the constant hammering action.
 
 
 
 
 
They are normally replaced rather than sharpened but, if sharpening is required, this must be done using a '''Green Grit''' ''(i.e. [https://en.wikipedia.org/wiki/Silicon_carbide#Abrasive_and_cutting_tools '''Silicon Carbde''']) grinding wheel.
 
  
  
 
[[Category:Drilling and Boring]]
 
[[Category:Drilling and Boring]]

Latest revision as of 19:10, 20 August 2016

TwistDrillSet.png


Description

Twist Drills are the most commonly used drill bit and are suitable for drilling most materials including Mild Steel. They are more completely known as Morse Twist Drills, named after the American Engineer, Stephen A. Morse who first developed them in 1864.

TwistDrills.png


Features and Uses

Most Twist Drills have a Parallel Shank and, for everyday use, come in sets covering Drill Sizes up to 13mm diameter. Larger diameter drills may have a reduced diameter shank to fit into Portable Electric Drills or can have a Morse Taper Shank, (also named after Stephen A. Morse), which fits directly into the hollow spindle of a Bench Drill, Pedestal Drill or Lathe Tailstock for example. Drill lengths too can vary but the most common are the Jobber length of drill.


Whenever a large hole has to be drilled, it is good practice to first drill a smaller pilot hole to act as a guide.


CentreDotPunching.png

Note: For accurate drilling through harder and smoother surfaced materials such as steel, hole centres should be marked with a Centre Punch and when extreme precision is required, the hole diameter should be scribed with Dividers and its intersections with the two axes marked with a Dot Punch - an accurately drilled or bored hole would cut each of the dot punched marks in two!


Maintenance and Manufacture
TwistDrill.png

Twist Drills can be sharpened using a Bench Grinder and are usually ground to a Cutting Angle of 59° to its axis for general work (to create a Point Angle of 118°) but this can vary for hard or soft materials (e.g. 45° is more suitable for Cast Iron and Brass).


Most modern Twist Drills are manufactured from High Speed Steel (HSS) and sometimes coated with Titanium Nitride for example, to harden the surface and give it a gold-coloured look. This is suitable for most materials but for drilling holes in masonry, a Tungsten Carbide Tip is Brazed on.


Dowel Bits
DowelBits.png

Ordinary HSS Twist Drills can be used to drill wood but, because of its fibrous nature, this can result in the Grain tearing and leaving a rough edge to the hole. Dowel Bits (aka Brad Point or Spur Point drills) are not ground to the usual Point Angle but are sharpened to have a small point at the tip of the bit and spurs on either side which first cut across the Grain to ensure clean, straight holes.


They can often be made of Carbon Steel instead of HSS and, if so, are not suitable for use on harder metals but similar drills can be used for drilling plastics and some softer metals such as Copper. Sharpening is best achieved using a file or the edge of a grinding wheel.


DT Online Buyers' Guide
  • Traditional Number Drill sizes and Imperial Drill sets are included but these can be replaced for most purposes by choosing a Metric Drill size to the nearest 0.1mm. This is true also of Letter Drill sizes. See drill size Equivalent Charts.
Drills for Wood HSS Metric Twist Drill Set for Metal ormer Jobber Drill Set Number Drill Set Letter Drill Set Taper Shank Drills Morse Taper Drill Sleeves SDS Drill Set Blacksmiths Drills Masonry Drills Set Glass/Ceramic Dill Set
Drills for Wood HSS Metric Twist Drill Set for Metal Dormer Jobber Drill Set Number Drill Set Letter Drill Set Taper Shank Drills Morse Taper Drill Sleeves SDS Drill Set Blacksmiths Drills Masonry Drills Set Glass/Ceramic Dill Set