Drills and Routers
Webpages concerning "Drills and Routers"
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Wikipedia-Article "Drills"
- For other uses, see Drill (disambiguation).
A drill is a tool with a rotating drill bit used for drilling holes in various materials. Drills are commonly used in woodworking and metalworking.
The drill bit is gripped by a chuck at one end of the drill, and is pressed against the target material and rotated. The tip of the drill bit does the work of cutting into the target material, slicing off thin shavings (twist drills or auger bits) or grinding off small particles (oil drilling).
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History
The earliest drills were probably bow drills. The invention of the electrical drill is credited to both Arthur James Arnot [1], in 1889, at Melbourne, Australia and Wilhelm Fein [2], in 1895, at Stuttgart, Germany. In 1917, Black & Decker patented a trigger-like switch mounted on the handle.
Types
There are many types of drill; some powered by hand and others using electricity or compressed air as the motive power. Drills with a percussive action such as (hammer drills, jackhammers or pneumatic drills) are usually used in hard materials such as masonry or rock. As well, drilling rigs are used to bore holes in the earth to obtain water or oil. An oil well, water well, or holes for geothermal heating are created with large drill rigs up to a hundred feet high. Some types of hand-held drills are also used to drive screws.
Hand tools
- bow drills.
- gimlet
- "Eggbeater" drill
- brace and bit
- pin chuck, a small hand held jewellers drill.
Electric Drill
Hand-held electric drills are ubiquitous. They usually look like a pistol, with a trigger-like switch. They are also used for driving screws and are often provided with a hammer action which makes them capable of being used as masonry drills. In fact, screw guns or electric screwdrivers are generally suitably modified drills.
These drills typically employ a universal motor with brushes. The original designs featured a single forward speed with a simple on-off action of the trigger; they could operate equally well on AC or DC power. Modern variable speed drills contain solid state phase control circuits that limit their use to AC power only. As a tradeoff, the electronics now give them variable speed, reversibility and torque control.
Hammer Drill
The hammer drill is similar to a standard electric drill, with the exception that it is provided with a hammer action for drilling masonry. The hammer action may be engaged or disengaged as required.
Rotary hammer drill
The rotary hammer drill (also known as roto hammer drill or masonry drill) is an electric drill type dedicated to drilling holes in masonry. The rotary hammer drill is a percussion drill that uses a weight to create the impact force on the masonry bit. Generally, the drill chuck of the rotary hammer drill is designed to hold SDS drill bits. Some styles of this drill are intended for masonry drilling only and the hammer action cannot be disengaged. Other styles allow the drill to be used without the hammer action for normal drilling.
Cordless drills
A cordless drill is a type of electric drill which uses rechargeable batteries. These drills are available with similar features to an AC mains-powered drill. They are available in the hammer drill configuration and most also have a clutch setting which allows them to be used for driving screws.
For continuous use, a tradesman will have one or more spare battery packs charging while working, so that he can quickly swap them, instead of having to wait several hours during recharges.
Early cordless drills started with interchangeable 7.5V battery packs, and over the years the battery voltage has been increased to 18V, and higher, allowing these tools to produce as much torque as many mains-powered drills. The drawback of most current models is the use of NiCd batteries, which develop a "memory effect" or internal short circuits due to dendrite growth, severely limiting their useful life, and posing a hazardous materials disposal problem. Drill manufacturers are now introducing lithium ion batteries, most notably Makita Electric Works and Milwaukee Electric Tool Corporation. The main advantages are lack of memory effect and very short charging time. Instead of charging a tool for an hour to get 20 minutes of use, 20 minutes of charge can run the tool for an hour. Lithium ion batteries also have a constant discharge rate. The power output remains constant until the battery is depleted.
Drill press
A drill press (also known as pedestal drill, pillar drill or bench drill) is a fixed style of drill, which may be mounted on a stand or bolted to the floor or workbench. It consists of a base, column (or pillar), table, spindle (or quill) and drill head, usually driven by an induction motor. The head has a set of handles (usually 3) radiating from a central hub which, when turned, move the drill spindle (and chuck) vertically, parallel to the axis of the column. The table can be adjusted vertically and is generally moved by a rack and pinion, however some older models rely on the operator to lift and reclamp it in position. The table may also be off-set from the spindle's axis and in some cases rotated perpendicular to the column.
A drill press has a number of advantages over a hand held drill:
- less effort is required to apply the drill to the workpiece. The movement of the chuck and spindle is by a lever working on a rack and pinion, this gives the operator considerable mechanical advantage.
- the table allows a vise or clamp to position and lock the work in place making the operation secure.
- the angle of the spindle is fixed in relation to the table allowing holes to be drilled accurately and repetitively.
Speed change is achieved by manually moving a belt across a stepped pulley arrangement, some types introduce a third stepped pulley to increase the speed range. This makes selecting the correct spindle speed more likely.
Geared head drill
The geared head drill is identical to the drill press in most respects, however they are generally of sturdier construction and often have power feed installed on the quill mechanism, and safety interlocks to disengage the feed on overtravel. The most important difference is the drive mechanism between motor and quill is through a gear train (there are no vee belts to tension) this makes these drills suitable for the larger sizes of drill bits (16mm or 5/8ths" upwards) which would normally stall in a drill press.
Radial arm drill
A radial arm drill is a geared head drill that can be moved away from its column along an arm that is radiates from the column. These drills are used for larger work where a geared head drill would be limited by its reach, the arm can swivel around the column so that any point on the surface of the table can be reached without moving the work piece. The size of work that these drills can handle is considerable as the arm can swivel out of the tables area allowing an overhead crane to place the workpiece on the fixed table. Vices may be used with these machines but the work is generally bolted to the table or a fixture
Mill drill
Mill drills are a lighter alternative to a milling machine, they combine a drill press (belt driven) with the x y co-ordinate abilities of the milling machines table and a locking collet that ensures that the cutting tool will not fall from the spindle when lateral forces are experienced against the bit. Although they are light in construction they have the advantage of space saving combined with versatility and are suitable for light machining which may otherwise not be affordable.
Related tools
- Milling machines, metal lathes and routers are also used for drilling.
See also
External link
 WikiProject Metalworking:
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Die head | Drill | Drill bit | Drill bit shank | Drill bit sizes | Drilling| Pin chuck| Taps and dies | Tap wrench |
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Metalworking topics: Casting | CNC | Cutting machines | Cutting tools | Drilling and threading | Fabrication | Finishing | Grinding | Jewellery | Lathes | Machining | Machine tooling | Measuring | Metalworking | Hand tools | Metallurgy | Milling | Occupations | Press tools | Smithing | Terminology | Welding |
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Wikipedia-Article "Routers"
- This article describes the computer networking device. A wood router is a kind of rotating cutting tool.
A router is a computer networking device that forwards data packets across an internetwork toward their destinations, through a process known as routing. Routing occurs at layer 3 (the Network layer) of the OSI seven-layer model.
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Function
In non-technical terms, a router acts as a junction between two networks to transfer data packets among them. A router is essentially different from a switch that connects devices to form a Local Area Network (LAN). One easy illustration for the different functions of routers and switches is to think of switches as neighborhood streets, and the router as the intersections with the street signs. Each house on the street has an address within a range on the block. In the same way, a switch connects various devices each with their own IP address(es) on a LAN. However, the switch knows nothing about IP addresses except its own management address. Routers connect networks together the way that onramps or major intersections connect streets to both highways and freeways, etc. The street signs at the intersection (routing table) show which way the packets need to flow.
So for example, a router at home connects the Internet Service Provider's (ISP) network (usually on an Internet address) together with the LAN in the home (typically using a range of private IP addresses) and a single broadcast domain. The switch connects devices together to form the LAN. Sometimes the switch and the router are combined together in one single package sold as a multiple port router.
In order to route packets, a router communicates with other routers using routing protocols and using this information creates and maintains a routing table. The routing table stores the best routes to certain network destinations, the "routing metrics" associated with those routes, and the path to the next hop router. See the routing article for a more detailed discussion of how this works.
Routing is most commonly associated with the Internet Protocol, although other less-popular routed protocols are in use.
Types of routers
In the original era of routing (from the mid-1970s through the 1980s), general-purpose mini-computers served as routers. Although general-purpose computers can perform routing, modern high-speed routers are highly specialised computers, generally with extra hardware added to accelerate both common routing functions such as packet forwarding and specialised functions such as IPsec encryption.
Other changes also improve reliability, such as using DC power rather than line power (which can be provided from batteries in data centers), and using solid-state rather than magnetic storage for program loading. Large modern routers have thus come to resemble telephone switches, with whose technology they are currently converging and may eventually replace, whilst small routers have become a common household item.
A router that connects clients to the Internet is called an edge router. A router that serves solely to transmit data between other routers, e.g. inside the network of an Internet service provider, is called a core router.
A router is normally used to connect at least two networks, but a special variety of router is the one-armed router, used to route packets in a virtual LAN environment. In the case of a one-armed router the multiple attachments to different networks are all over the same physical link.
In mobile ad-hoc networks every host performs routing and forwarding by itself, while in wired networks there is usually just one router for a whole broadcast domain.
In recent times many routing functions have been added to LAN switches (a marketing term for high-speed bridges), creating "Layer 2/3 Switches" which route traffic at near wire speed.
Routers are also now being implemented as Internet gateways, primarily for small networks like those used in homes and small offices. This application is mainly where the Internet connection is an always-on broadband connection like cable modem or DSL. These are routers in the true sense because they join two networks together - the WAN and the LAN – and have a routing table. Often these small routers support the RIP protocol, although in a home application the routing function does not serve much purpose since there are only two ways to go - the WAN and the LAN. In addition, these routers typically provide DHCP, NAT, DMZ and Firewall services. Sometimes these routers can provide content filtering and VPN. Typically they are used in conjunction with either a cable modem or DSL modem, but that function can also be built-in.
Manufacturers of routers
There are a number manufacturers of routers including:
- 3Com (www.3com.com)
- Alcatel (www.alcatel.com)
- Belkin (www.belkin.com)
- Cisco Systems, Inc. (www.cisco.com)
- D-Link Systems (www.dlink.com)
- Enterasys Networks (www.enterasys.com)
- Hewlett-Packard (www.hp.com)
- Huawei Technologies (www.huawei.com)
- Juniper Networks (www.juniper.net)
- Linksys (www.linksys.com)
- Mikrotik (www.mikrotik.com)
- Motorola (www.motorola.com)
- NETGEAR (www.netgear.com)
- Nortel (www.nortelnetworks.com)
- Pivotal Networking (www.pivnet.com)
- Siemens AG (www.siemens.com)
- SMC Networks (www.smc.com)
- Tellabs (www.tellabs.com)
- MRV Communications (www.mrv.com)
- Zoom Telephonics (www.zoom.com)
- Trendware (www.trendware.com)
- ZyXEL (www.zyxel.com)
"Software" routers
With the proper software, ordinary PCs can be made into routers.
Most Unix-like operating systems include all necessary software to perform routing:
- LEAF Project (leaf.sourceforge.net)
- Coyote Linux (www.coyotelinux.com)
- FREESCO (www.freesco.org/)
- GNU Zebra (www.zebra.org)
- SmoothWall (smoothwall.org)
- m0n0wall (m0n0.ch/wall)
- FreeBSD (www.freebsd.org)
- NetBSD (www.netbsd.org)
- OpenBSD (www.openbsd.org)
- IPCop (www.ipcop.org)
- The Linux Router Project (www.linuxrouter.org)
- fdgw (www.fml.org/software/fdgw/)
- Basic Internet Routing Daemon (bird.network.cz)
The list includes only some examples that specialise in routing. See List of Linux distributions, BSD, Unix-like for more.
Other solutions include:
- Microsoft Internet Connection Sharing (only some routing capabilities)
- WOOWEB-PRO (Windows software)
- Mac OS X Internet Sharing
See also
External links
- www.bsdrouter.org - website that covers router software based on BSD operating systems
- HowStuffWorks: How Routers Work by Curt Franklin
- Linux Advanced Routing & Traffic Control HOWTO