USING A MACHINE REAMER TAPER REAMERS AND ADJUSTABLE(EXPANDABLE) REAMERS

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USING A MACHINE REAMER, TAPER REAMERS AND ADJUSTABLE(EXPANDABLE) REAMERS

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The diagram below shows a machine reamer being used, to accurately finish a drilled hole to size. The material (in this case steel) has been drilled on the centre lathe, to within 0.05mm of the final diameter. It should not be taken out of the chuck, until reaming has taken place. The reamer should be slowly introduced to the material, with coolant being applied liberally. One continuous ‘pass’ of the reamer through the drilled hole, should produce the accurate finished dimension. The lathe is left on, whilst the reamer is withdrawn from the metal. Notice that the reamer’s morse taper shank, fits into the tailstock spindle.

A point of interest - The morse taper of a lathe tailstock spindle, is produced by machine reamer. The same can be said, for the morse taper of a drilling machine.

TAPER REAMERS / TAPER PINS

Taper reamers are used to produce tapered holes, capable of receiving a taper pin. Taper pins are used to fit gears, cams, pulleys and collars to shafts. This is important when dealing with machines, which have rotating parts.
The example opposite, shows a motor with a pulley wheel attached. The pulley wheel is secured with a tapered pin. The hole goes through the collar of the pulley and the motor’s shaft. It has been drilled and then reamed to a specific angle. Taper pins are supplied ready made and have a standardised taper.

The taper pin is carefully tapped into position with a cooper / nylon hammer and can be removed, if maintenance is required.

ADJUSTABLE / EXPANDING REAMERS

Adjustable reamers have 5 or 6 blades, which can be set to ream a small number of accurate diameters.

The diameter is set by turning both the ‘adjusting’ nuts, at the same time. This causes the blades to move inwards or outwards, according the required diameter. The finished hole is checked with a ‘plug’ gauge, or the component that will eventually fit the precise hole.

Adjustable reamers can be useful, but it is advisable to have a set of these reamers, as adjustment on each one is limited.

One advantage of adjustable reamers, is that the blades can be resharpened, extending its working life.

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