Precision Hand Reamer Guide: Techniques, Tips, and Tool Selection

hand reamer tapered reamer

What does a metal reamer do?

A metal reamer is a precision cutting tool designed to enlarge and shape holes in metal workpieces. It removes material gradually as it rotates inside the hole, ensuring precision and smoothness in the final hole diameter. There are two main types of reamers: hand reamer and machine reamer.

Hand Reamer Definition

A type of reamer tool used to ream holes by hand. Hand reamer is a commonly used metal machining process for finishing and semi-finishing the holes, to improve the hole machining accuracy and reduce the roughness of its surface.  

Are hand reamers accurate?

Yes, hand reamers can achieve high accuracy, typically following standard tolerance grades like H7, H8, or H9

What is the rule of thumb for hand reamer?

Material Selection:
Choose appropriate reaming materials based on hardness and cutting properties to ensure smooth cutting.

Process Parameters:
Select the right reamer type, size, speed, and feed to enhance reaming quality and efficiency.

Safe Operation:
Use stable equipment and work surfaces to prevent workpiece movement during reaming.

Preparation:
Measure and prepare the hole, removing burrs to ensure optimal reaming conditions.

Cutting Lubrication:
Apply cutting oil or fluid to reduce friction and improve tool longevity and reaming quality.

Cutting Direction and Force Control:
Control cutting direction and force to maintain stability and prevent damage during reaming.

Tool Maintenance:
Grind and dress the reamer regularly to maintain hole quality and tool condition.

Conclusion

Successful manual reaming demands expertise and attention to detail in material selection, process parameters, safe operation, lubrication, cutting direction, and force control.

Processing Allowance for Common Hole Drilling, Enlarging, and Reaming
Accordance with the base hole system, grade 7 tolerance (H7) (mm)
Diameter
Diameter of machined holeFirst DrillSecond DrillEnlargingReaming
32.93H7
43.94H7
54.85H7
65.86H7
87.88H7
109.810H7
121111.8512H7
131212.8513H7
141313.8514H7
151414.8515H7
161515.8516H7
181717.8518H7
201819.820H7
222021.822H7
242223.824H7
252324.825H7
262425.826H7
282627.828H7
30152829.7530H7
32153031.7532H7
35203334.7535H7
38203637.7538H7
40253839.7540H7
42254041.7542H7
45254344.7545H7
48254647.7548H7
50254849.7550H7
60305559.560H7
70306569.570H7
80307579.580H7
903080Boring90H7
1003080100H7
Note: 1. When machining holes with a diameter up to 15mm on cast iron, reaming drilling is not necessary;
2、When machining holes with diameters up to 30 and 32 mm on cast iron, drill only once with a drill with diameters of 28 and 30;
Machining of holes according to tolerance class (H9)(mm)
32.93H9
43.94H9
54.85H9
65.86H9
87.88H9
109.810H9
1211.812H9
1312.813H9
1413.814H9
1514.815H9
161515.8516H9
181717.8518H9
201819.820H9
222021.822H9
242223.824H9
252324.825H9
2622425.826H9
282627.828H9
30152829.830H9
32153031.7532H9
35203334.7535H9
38203637.7538H9
40253839.7540H9
42254041.7542H9
45254344.7545H9
48254647.7548H9
50254849.7550H9
603055Boring60H9
70306570H9
80307580H9
90308090H9
1003080100H9
For holes with diameters of 30 and 32 mm in cast iron, drill only once with drills with diameters of 28 and 30.

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