What is reamers
A reamers is a rotary cutting tool (of cylindrical or conical shape) used for enlarging or finishing a previously formed hole to precise dimensions. These can have solid or inserted blades, be adjustable or non-adjustable, and be designed for manual use (hand reamers) or machine use (Chucking reamers).
A reamer is machining tool which is used to enlarge or finish a hole which is previously drilled, bored or cored for giving a finish and an accurate dimensions.
What is reaming ?
Reaming is the operation of finishing and sizing a hole which has been previously drilled or bored .The tool used is called the reamer, which has multiple cutting edges. The reamer is held on the tailstock spindle either directly or through a drill chuck and is held stationary while the work involved at a very slow speed the feed vary from 0.5 to 2 mm per revolution.
The nomenclatures of reamers shown in figures (A), (B), (C), and (D) are as follows (D).
The elements of the reamer are described below :-
1. Axis :- It is the longitudinal center line of reamer.
2. Backer taper :- The diameter reduction per 100 mm length of reamer from the entering end to the shank.
3. Bevel lead :- The angular cutting portion at the inlet’s end that facilitates the reamer’s entry into the hole. This part is not provided with circular land.
4. Body :- The section of the reamer extending from the reamer’s entering end to the beginning of its shank.
5. Circular land :-On the leading edge of the land, the cylindrically ground surface adjacent to the cutting edge.
- Primary :- That portion of the land removed for providing clearance immediately behind the cutting edge.
- Secondary :-That portion of the land removed to provide clearance behind the primary clearance or circular land.
7. Cutting edge :- The cutting edge formed by the face’s intersection with the circular land or surface left by provision of the primary clearance.
8. Face :- The area of the flute surface next to the cutting edge where the chip impinges as it is cut from the work.
9. Flutes :- The grooves in the reamer’s body to produce cutting edges, for permitting the chips to be removed, and allowoing fluid to reach the cutting edges.
10. Heel :- The edges produced by intersection of surface left by provision of the secondary clearance and the flute.
11. Land :-That part of the fluted body that is left between the flutes, the surface, or the surfaces included between the cutting edge and the heel.
12. pilot :-A cylindrically ground portion of the body at the reamer’s entering end to keep the reamer in alignment.
13. Recess :- It is that portion of the body which is reduced in diameter below cutting edges, pilot, or the guided diameter.
14. Shank :- The reamer’s shank is the portion of the reamer by which it is held and driven.
15. Diameter :- It is The maximum cutting diameter of the reamer at the inlet end.
Types of reamers
There are various classification of reamers depending upon the operation, purpose and shape.The commonly used as detailed in this specification are following :-
- Hand reamer
- Machine Bridge reamer
- Machine Jig reamer
- Parallel hand reamer with parallel shank
- Parallel or taper shank socket head reamer
- Taper pin hand or machine reamer
- Shell reamer
- Expansion reamer
- Chucking reamer with parallel or taper shank a.) Fluted reamer , b.)Rose reamer
- Combinations reamer
1. Hand Reamer
A hand reamer has a longer front taper or lead in than a machine reamer. This is done to compensate for the difficulty of starting a hole with only hand power. It also allows the reamer to begin straight, reducing the risk of breakage. The flutes can be either straight or spiral.
2. Machine Bridge Reamer
Machine bridge reamer is a type of reamer which has a parallel cutting edges ,with a lead integral with a taper shank which is used to hold and drive the reamer.
A machine bridge reamer is shown in the figure.
Machine bridge reamers are used in portable electric or pneumatic tools for reaming in shipbuilding, structural, and the plate work.
The flute of machine bridge reamer may be straight or helical.
The diameters of this reamer vary from 6.4 mm to 37 mm.
3. Machine Jig Reamer
Machine jig reamer is a types of reamers which have shot, virtually parallel cutting edge with bevel lead and guide between the shank and cutting-edges integral with a taper shank which is used for hold and drive. The flutes if this reamers are helical.
The plain part of the body is designed to fit into a bushing in the jig and precisely locate the reamer. The reamer’s diameter ranges from 7 to 50 mm. The river is depicted in the figure.
4. Parallel Hand Reamer with Parallel Shank
This reamers consist of virtually parallel cutting edges with taper and the bevel lead integral with a shank of the nominal diameter of the cutting edge and, with a square on the end side
The flutes of this reamer may be straight or helical.
The hand reamer has a square tang and is designed to be driven by hand to accurately size the holes.
The reamers are designed to remove the least amount of metal between 0.05 and 0.125 mm. For easy starting, it is slightly tapered towards the end for a distance equal to its diameter.
The figure depicts this type of reamer.
5. Parallel Taper Shank Socket Head Reamer
This reamer could have a straight or taper shank and be driven by hand or machine. The reamers have taper cutting edges that are integral with a parallel or taper shank to suit Morse taper. The flutes of this reamer may be Straight or helical.
The reamers come in three sizes: roughing, pre-finishing, and finishing. For finishing, reamers of various diameters are available. Morse taper holes numbered 1 through 6. The illustration depicts a socket reamer.
6.Taper Pin Reamer
Taper pin reamers are types of reamers which are used for finishing, shaping, or increasing the size of holes for a near perfect fit when inserting the taper pins into your work piece.
This reamer may be hand or machine driven.This reamer has taper cutting edges for holes to suit pins with a taper of I in 50, having-a parallel or taper shank to hold and drive the reamer.
The flutes of this reamer may be straight or helical.
7. Shell reamer
Shell Reamers are multi-fluted end-cutting tools that are used to enlarge previously formed holes to a precise diameter with a smoother finish.
The figure of shell reamer shown in the below:
A shell reamer has an axial hole which is used on an arbor. A shell reamer has virtual parallel cutting edges with a sharpened bevel lead. These reamers are used for finishing large holes in order to save the tool cost .
Shells of various sizes can be interchanged on a single arbor. This saves the cost of the solid shank in each case. The shell reamer can be of the rose chucking type for truing the hole or the fluted type for finishing.
The flutes of this reamer may be straight or helical .The reamer diameter ranges from 24 to 100 mm.
8. Expansion reamer
Expansion Reamers are multi-fluted end cutting tools with adjustable flutes that are used to slightly enlarge previously formed holes to a precise diameter with a smoother finish.
An expansion reamer is constructed in such a way that it can be adjusted by a very small amount to compensate for wear or to accommodate some variation in hole size. To effect expansion, loosen the clamping nut and push the plug 1 inward, as shown in the figure. The blades expand slightly as a result of this.
9. Chucking Reamer with Parallel or Taper Shank
Chucking reamers, are general-purpose cutting tools which provides the superior wear and tear resistance at high temperatures.
Note :- Chucking reamers are also known as machine reamer
Chucking reamers, are the most common type of reamer . It used in lathes, drill presses, and screw machines which provides a smooth finish to the hole.
These reamers have short virtually parallel cutting edges with bevel lead and long body recess between shank. Cutting edges integral with a parallel or taper shank for holding the reamer.
The flutes of this reamer are all straight but the shank may be straight or taper.
It is driven at slow speed and the entire cutting is done along the flutes. The fluids are spaced irregularly around the circumference of the body of the reamer. It helps in reducing the tendency of chattering.
The fluted reamer is used for reaming more accurate reaming. The diameter of a straight shank chucking reamer ranges from 1-5 to 32 mm, and that of a taper shank chucking reamer ranges from 5 to 32 mm.
Chucking Reamer ( rose )
Rose reamers are different from the fluted type . In fluted type, the cutting edge all the beveled edge at the end.
The chamfered cutting edges form a 45° angle. The fluted body is designed to fit into the reamed hole.
To prevent bending in the hole, the body is slightly tapered, becoming smaller towards the shank. This type of reamer can remove more metal than a fluted reamer. The figure depicts a chucking rose reamer.
10. Combinations Reamer
A reamer with two or more cutting surfaces is known as a combination reamer. The combination reamer is precision ground into a pattern that resembles the multiple internal diameters of the part. The advantage of using a combination reamer is that it reduces the number of turret operations while holding depths, internal diameters, and concentricity more precisely. Combination reamers are typically used in screw machines or second-operation lathes rather than CNC machines because G-code can easily be generated to profile internal diameters.
Applications of reamers
Some of the application of reamers are following :-
- A reamer is a rotary cutting tool that is commonly used in metalworking.
- A reamer is a tool used to expand or finish pre-drilled holes, bore holes, or cored holes to achieve a good finish and precise dimension.
- The reamer is designed for use in a drill press or turret lathe.
- The screw-cutting machine also employs the use of a reamer.
Rotations of Cutting of Reamer
Reamer is named according to the direction of rotation as follow
Left hand cutting reamer :
A reamer which cuts while rotating in a clockwise direction when viewed on the entering end of it.
Right hand cutting reamer :-
It is a reamer which cuts while rotating in a anticlockwise directions when viewed on the entering end of it.
The angle of rivers are given below
Bevel lead angle :- the angle formed by the cutting edges of the weevil lead and the reamer axis.
Clearance angles :- the angles formed by the primary or secondary clearances and the tangent to the periphery of the reamer at the cutting edge edges.
Helix angle :- The angle between the cutting edge and the reamer axis.
Rake angle :- The angles in a diametral plane formed by the face and a radial line on the cutting edge.
- If the face and the radial line coincide, the angle is zero degree and the face is called radial.
- If the angle formed by the face and the radial line falls behind the radial line in relation to the direction of current in the rake angle is positive and defence in an undercut
- If the angle formed by the face and the radial line falls in front of the radial line in relation to the direction of the cut, the rake angle is negative and the face is known as over cut
Taper lead angle :- The angle formed by the cutting edge of the taper lead and the axis of the reamer.
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