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Encyclopedia > Reamer

A reamer or ream is a tool used in machining to make existing holes dimensionally more accurate and to improve surface finish. Reamers are used mostly in the metalworking areas of machining. They may be used as hand tools or in the spindles of machine tools such as milling machines or drill presses. This article is about the kitchen utensil. ... A lathe is a common tool used in machining. ... Turned chess pieces Metalworking is the craft and practice of working with metals to create structures or machine parts. ... A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by machining, which is the selective removal of metal. ... Endmills for a milling machine. ... Hand held A bit and brace, a hand-powered drill. ...

Contents

Overview of design and function

Reamer body

A typical reamer consists of a set of parallel straight or helical cutting edges along the length of a cylindrical body. Each cutting edge is ground at a slight angle and with a slight undercut below the cutting edge. Reamers must combine both hardness in the cutting edges, for long life, and toughness, so that the tool does not fail under the normal forces of use. They should only be used to remove small amounts of material. This ensures a long life for the reamer and a superior finish to the hole.


The spiral may be clockwise or counter-clockwise depending on usage. For example, a tapered hand reamer with a clockwise spiral will tend to self feed as it is used, possibly leading to a wedging action and consequent breakage. A counter-clockwise spiral is therefore preferred even though the reamer is still turned in the clockwise direction. A clockwise motion is one that proceeds like the clocks hands: from the top to the right, then down and then to the left, and back to the top. ... The word feed has a number of uses: Feeding is supplying food. ...


Shank types (drive types)

For production machine tools, the shank type is usually one of the following: a standard taper (such as Morse or Brown & Sharpe), a straight round shank to be held by a collet, or a straight round shank with a flat for a set screw, to be held by a solid toolholder. For hand tools, the shank end is usually a square drive, intended for use with the same type of wrench used to turn a tap for the cutting of screw threads. Machine tool operators must be able to install or remove cutting bits or other accessories quickly and easily from the machine tools powered rotating spindle. ... Machine tool operators must be able to install or remove cutting bits or other accessories quickly and easily from the machine tools powered rotating spindle. ... A collet is a holding device that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened. ... A set screw, also called a grub screw in British English, is a type of screw generally used to secure an object within another object. ... Two Bar tap wrenches and a T style tap wrench A tap wrench is a hand tool used to operate any small tool that has a square driving head as part of its body. ... Taps and dies are generally metalworking tools for the creation (cutting) of screw threads in metal parts. ... Screw thread, used to convert torque into the linear force in the flood gate. ...


Why ream? Why not just drill to size?

The geometry of a hole drilled in metal by a twist drill may not be accurate enough (close enough to a theoretically true cylinder of a certain precise diameter) and may not have the requisitely smooth surface finish for certain engineering applications. Although modern twist drills can perform excellently in many cases—usually producing sufficiently accurate holes for most applications—sometimes the stringency of the requirements for the hole's geometry and finish necessitate two operations: a drilling to slightly undersize, followed by reaming with a reamer. The planned difference between the drill diameter and the reamer diameter is called an allowance. (It allows for the removal of a certain small amount of material.) The allowance should be <.2 mm (.008 in) for soft materials and <.13 mm (.005 in) for hard materials. Smaller allowances can damage the reamer. The drilled hole should not be enlarged by more than 5% of the drilled diameter. Drilling followed by reaming generally produces hole geometry and finish that is as close to theoretical perfection as possible. (The other methods of hole creation that approach nearest to perfection under certain conditions are boring [especially single-point boring] and internal cylindrical grinding.) Drill bits are cutting tools used to create cylindrical holes. ... A right circular cylinder An elliptic cylinder In mathematics, a cylinder is a quadric surface, with the following equation in Cartesian coordinates: This equation is for an elliptic cylinder, a generalization of the ordinary, circular cylinder (a = b). ... Roughness or rugosity is a measurement (see surface metrology) of the small-scale variations in the height of a physical surface. ... The examples and perspective in this article or section may not represent a worldwide view. ... Boring, in this sense, is the process of drilling a hole into the solid Earth. ... Cylindrical grinders are a class of grinding machines used on the work pieces that are symmetrical about an axis of rotation (e. ...


Types of reamers

Adjustable hand reamer

Adjustable hand reamer
Adjustable hand reamer

An adjustable hand reamer can cover a small range of sizes. They are generally referenced by a letter which equates to a size range. The disposable blades slide along a tapered groove. The act of respectively tightening and loosening the restraining nuts at each end varies the size that may be cut. The absence of any spiral in the flutes restricts them to light usage (minimal material removal per setting) as they have a tendency to chatter. They are also restricted to usage in unbroken holes. If a hole has an axial split along it, such as a split bush or a clamping hole, each straight tooth will in turn drop into the gap causing the other teeth to retract from their cutting position. This also gives rise to chatter marks and defeats the purpose of using the reamer to size a hole. Image File history File links Download high resolution version (1875x609, 215 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... Image File history File links Download high resolution version (1875x609, 215 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... Axial has different meanings: In geometry it means: along the same line as an axis (coaxial) or centerline: parallel (geometry), contrary to radial or perpendicular In anatomy it relates to an anatomical direction of animals and humans. ...


Straight reamer (precision)

A straight reamer is used to make only a minor enlargement to a hole. The entry end of the reamer will have a slight taper, the length of which will depend on its type. This produces a self centering action as it enters the raw hole. The larger proportion of the length will be of a constant diameter.


Reamed holes are used to create holes of precise circularity and size, for example with tolerances of -0/+0.02mm(0.0008") This will allow the force fitting of locating dowel pins, which need not be otherwise retained in the body holding them. Other holes, reamed slightly larger in other parts, will fit these pins accurately, but not so tightly as to make disassembly difficult. This type of alignment is common in the joining of split crankcase halves such as are used in motorcycle motors and boxer type engines. After joining the halves, the assembled case may then be line bored (using what is in effect a large diameter reamer), and then disassembled for placement of bearings and other parts. The use of reamed dowel holes is typical in any machine design, where any two locating parts have to be located and mated accurately to one another - typically as indicated above, to within 0.02mm or less than 0.001". For other uses, see Motorcycle (disambiguation). ... The Boxer engine, first patented by German engineer Karl Benz A flat engine is an internal combustion engine with pistons that are all relatively horizontal. ...


Another use of reamed holes is to receive a specialized bolt that has an unthreaded shoulder - also called a shoulder bolt. This type of bolt is commonly used to replace hot peened rivets during the seismic retrofit of structures. Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. ...


Hand reamer

A hand reamer has a longer taper or lead in at the front than a machine reamer. This is to compensate for the difficulty of starting a hole by hand power alone. It also allows the reamer to start straight and reduce the risk of breakage. The flutes may be straight or spiral.


Machine reamer

Spiral fluted machine reamer
Spiral fluted machine reamer

A machine reamer only has a very slight lead in. Because the reamer and work piece are pre-aligned by the machine there is no risk of it wandering off course. In addition the constant cutting force that can be applied by the machine ensures that it starts cutting immediately. Spiral flutes are essential on a machine reamer to clear the swarf automatically. Image File history File links Download high resolution version (1953x564, 208 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... Image File history File links Download high resolution version (1953x564, 208 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ...


Rose reamer

A rose reamer has no relief on the periphery and is offset by a back taper to prevent binding. They are primarily used as roughing reamers.


Shell reamer

Shell reamers are designed for reaming bearing and other similar items. They are fluted almost their whole length.


Tapered reamer (precision)

Four small tapered pin reamers
Four small tapered pin reamers

A precision tapered reamer is used to make a tapered hole to later receive a tapered pin. A taper pin is a self tightening device due to the slow angle of the taper. They may be driven into the tapered hole such that removal can only be done with a hammer and punch. They are sized by a number sequence (for example, a No.4 reamer would use No.4 taper pins). Such precision joins are used in aircraft assembly and are frequently used to join the two or more wing sections used in a sailplane. These may be re-reamed one or more times during the aircraft's useful life, with an appropriately oversized pin replacing the previous pin. Image File history File links Download high resolution version (1818x906, 323 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... Image File history File links Download high resolution version (1818x906, 323 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... Taper pins are tools used for enlarging holes usually for mechanical, Machine Tapers or body modification purposes. ... A 380 mm (15 in) ball-peen hammer. ... A variety of punches are used in engineering. ... Gliders are un-powered heavier-than-air aircraft. ...


Morse taper reamer

No. 3 morse taper reamer
No. 3 morse taper reamer

A morse taper reamer is used manually to finish morse taper sleeves. These sleeves are a tool used to hold machine cutting tools or holders in the spindles of machines such as a drill or milling machine. The reamer shown is a finishing reamer. A roughing reamer would have serrations along the flutes to break up the thicker chips produced by the heavier cutting action used for it. Image File history File links Download high resolution version (1887x921, 332 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... Image File history File links Download high resolution version (1887x921, 332 KB) Photograph taken by Glenn McKechnie on the 26th March 2005. ... For other uses, see Drill (disambiguation). ... Endmills for a milling machine. ...


Combination Reamer

This combination reamer was made for a long run, tight tolerance electronic parts.
This combination reamer was made for a long run, tight tolerance electronic parts.

A combination reamer has two or more cutting surfaces. The combination reamer is precision ground into a pattern that resembles the part’s multiple internal diameters. The advantage of using a combination reamer is to reduce the number of turret operations, while more precisely holding depths, internal diameters and concentricity. Combination reamers are mostly used in screw machines or second-operation lathes and not with Computer Numerical Control ( CNC ) machines because G-Code can be easily generated to profile internal diameters. Image File history File links Comb-reamer. ... Image File history File links Comb-reamer. ... General Brown & Sharpe Single Spindle Screw Machine. ... This article is about a lathe as a tool. ... For other uses, see CNC (disambiguation). ... G Code is a scheme to assist in the recording of television programs on video recorders. ...


Combination reamers can be made out of cobalt, carbide, or high-speed steel tooling. When using combination reamers to ream large internal diameters made out of material with lower SFM , carbide tips can be brazed onto a configured drill blank to build the reamer. Carbide requires additional care because it is very brittle and will chip if chatter occurs. It is common to use a drill or combination drill to remove the bulk of material to reduce wear, or the risk of the part pulling off on the combination reamer. SFM is Surface Feet per Minute and is a formula used in machining, identifiing the material machinability ratings. ... Brazing is a joining process whereby a non-ferrous filler metal or alloy is heated to melting temperature (above 450°C; 800°F) and distributed between two or more close-fitting parts by capillary action. ... Drill bits are cutting tools used to create cylindrical holes. ...


Tapered reamer (non-precision)

A tapered reamer may be used cleaning burrs from a drilled hole, or to enlarge a hole. The body of the tool tapers to a point. This type of reamer consists of a body which, typically, is up to 1/2 inch in diameter, with a rod cross piece at the large end acting to form a handle. It is especially useful for working softer metals such as aluminum, copper, and mild steel. A similar tool can be seen on select Swiss Army knives, such as the Electrician model, to be used on conduit.


Materials

Reamers are normally made of high-speed steel, cobalt steel, solid carbide, or are carbide tipped with an alloy steel body. The cutting edge usually has a hardness between Rc 63 and Rc 67 for steel and from to Rc 76 to Rc 82 for carbide.


Additional uses and types

Often, hobby grade radio control cars need reamers to have the holes drilled for the mounting of the bodies. Although similar to metal reamers, radio control body reamers are small, and the tip is usually conic, with flue areas on each side to help create the holes.


Additional Information

These websites contain more specific information about the reaming process. [1] [2]


See also

Look up Reamer in
Wiktionary, the free dictionary.

  Results from FactBites:
 
Reamer Manufacturers & Suppliers (220 words)
The roller stabilizer (drilling reamer) is used for all kinds of reaming stabilization in drilling operation...
The accuracy grades of the reamers are H7 H8 H9...
A reamer is a rotary cutting tool, generally of cylindrical or conical shape, intended for enlarging and finishing holes to accurate dimensions....
Conduit reamer - Patent 4076446 (1910 words)
A reamer for use with conduits comprising positioning means including engaging inclined surfaces for maintaining the reamer in relatively fixed relationship with the front or outer edge of the conduit being reamed, with the positioning means being capable of engaging conduits of various diameters and rotatable relative to the conduit being reamed.
Reamer elements are provided including a front end for positionment adjacent the aperture in the conduit being reamed and a pair of inclined sections extending outwardly from said front end in opposing inclination to the engaging inclined surfaces, and being capable of engaging the inner edge of the conduit being reamed and rotated relative thereto.
An object of the present invention is to provide a reamer that is easily utilized on conduits of various diameters to debur the inner and outer edges of the conduit opening and may be carried in the pocket of the person using same.
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