Principal Parts of Shaper | Machine Tools | Industries | Engineering

The following points highlight the principal parts of a shaper used in the industries. The parts are: 1. Power Transmission 2. Ram 3. Shaper Head (Tool Head Assembly) 4. Shaper Gibs 5. Clearance Angles 6. Rake Angle.

Part # 1. Power Transmission:

The power is transmitted to the shaper from an electric motor through the V-belt drive. A gear train is used to provide the different speeds, or strokes per minute, of the ram. The gears may be shifted by the speed change levers. The last gear in the train of gears is large gear and is called the bull gear or crank gear.

Part # 2. Ram:

It is the reciprocating member and carries the shaper head in its front, on which the cutting tool is mounted. It slides on the accurately machined guideways made on the top of the column. It is designed to be as rigid as possible, consistent with reasonable lightness to allow rapid reversals of direction.

A mechanism is provided inside the ram to change its position relative to the job. It gets its drive from the quick return mechanism which makes it run faster while returning and slower while cutting.

Part # 3. Shaper Head (Tool Head Assembly):

It is clamped firmly to the front of the ram and consists of a tool slide, tool post and clapper box. The head can be swivelled to any angle to enable the tool to take angular cuts. Vertical feed to the tool is given by the vertical tool feed screw and the slide movement can be measured by means of a micrometer dial near to the handle.

The clamp, provided to fix the slide to the head, should always be tightened when taking a cut using the table feed. It should be tightened very lightly, or to a snug fit, when the tool is fed by the shaper head slide. The tool holder rests in a clapper block which is fitted on the clapper box which in turn is fastened to the front of the shaper head slide.

The fit between the clapper box and the clapper block is very close, although the clapper block is free to pivot forward and up on a taper pin which holds it in place. This provision is made in order to allow the tool to swing up on the return stroke, otherwise the work surface is likely to be badly gouged and the tool quickly damaged by wear.

The clapper box is also provided with a slotted arc in order to permit it to be swivelled away from the work surface which is particularly important when vertical and angular cuts are made.

i. Column:

It is a hollow structure consisting of two vertical walls and cast from cast iron. Column is a rigid structure giving support to the ram on its top ways and is supported by the base. The cross-rail carrying the table and the drives to move the table up or down or cross-wise is also supported on column, and slides by the front side of column. In one of the two vertical walls, a hole is made to inspect the driving mechanism of the ram located in it.

ii. Base:

It supports the whole of the machine and is bolted to the floor with the help of foundation bolts.

iii. Cross-Rail:

It is a box like structure over which the saddle slides horizontally. The cross rail is maintained accurately square to the column. The table cross feed screw and the cross rail vertical feed screw are housed inside it. For supporting it and guiding its movement, the front vertical ways of the column are machined properly.

iv. Saddle and Table:

The table is bolted on the saddle and is capable of moving in horizontal and vertical directions. It can be fitted in inclined position also. The job is supported on the table with the help of vise or some simple fixtures.

The table is provided with T-slots for clamping vise, fixtures and other tooling on it. The shaper table may be either plain type with vertical and cross feed motions, or universal type to permit machining of complex angles.

Part # 4. Shaper Gibs:

In a shaper, gibs are provided.

(a) To adjust the saddle on the cross rail.

(b) To adjust the ram on the column.

(c) To adjust the tool head slide on the swivel head plate.

These gibs need to be adjusted properly and the bearings should be oiled regularly.

Part # 5. Clearance Angles:

Usually shaper tool is given a front clearance angle of 4 degrees and side clearance angle of 2 or 3 degrees. If front clearance is high, then the cutting edge will not be strong because of lack of supporting metal and tool may dull quickly or crumble. On the other hand if on front clearance is provided, the cutting edge can’t under the chip and will merely rub, spoiling the appearance of the work by leaving grooves and tool marks.

Part # 6. Rake Angle:

The shape of tool is usually provided a side rake of 10 degrees or more, depending on the kind of tool and on the hardness of the metal to be machined. For roughing tool no front rake is provided and some value is given for finishing tool.