Clarke CL430 Spécifications télécharger pdf (Page 20)

Fig.19

The taper, or bevel, is cut by setting the cross

slide appropriately then using the compound

slide feed handle to advance the cutting tool

in the direction of the arrow as shown in Fig.18.

D. SCREW CUTTING

This operation requires a degree of skill and

accuracy, and should not be attempted

unless you are completely familiar with all

aspects of the lathe.

Essentially, the saddle will move towards the

headstock under power, the same as

cutting using auto feed, except the rate of

feed is greater, as determined by the gear

configuration. The cutting tool therefore, is

moving ever closer to the rotating chuck.

Great care and concentration must be exercised therefore, to ensure that the two

do not meet when the machine is operating, as this could be disastrous.

Imperial Threads in a range from 11 to 40 threads per inch, and Metric threads with

a pitch of 0.5 to 3mm may be cut. It is important to remember that the type of

thread you need to cut, i.e. Metric, UNF, BA, BSP, BSW etc., will be totally dependant

upon the cutting tool profile, as profiles differ from thread to thread. .

For detailed information regarding screw cutting techniques, cutting tools etc.,

you should consult a suitable handbook or obtain advice from a qualified person.

The general procedure for screw cutting is as follows:

1. Try to get as much distance from the chuck to the end of the proposed screw

thread as possible, and if your design allows, cut a ‘run-off’ into the work which

is of a smaller diameter than the root diameter of the proposed screw thread.

NOTE: that for long threads it may be necessary to use steadies.

2. Install the appropriate gears for the thread required, and correctly mount the

cutting tool. Set your required depth of cut, in the same manner as that for

normal turning, and position the tool well to the right of the workpiece.

NOTE: Depth of cut is vitally important and may be calculated or obtained from an

appropriate reference manual. Bear in mind that more than one pass may be necessary

3. Taking all necessary precautions previously stated, and ensuring the FORWARD/

REVERSE switch is in the FORWARD position, start the machine with the power

feed lever in its’ disengaged (3 o’clock) position.

4. When ready, engage the power feed and prepare to switch OFF the machine

as the cutting tool approaches the end of the intended screw thread.

When the machine has stopped, continue to wind the tool forward by turning

the chuck by hand to complete the thread.

5. Switch the FORWARD/REVERSE switch to REVERSE and switch ON the lathe. The

cutting tool will move back towards the start point. DO NOT TOUCH THE

CROSS-SLIDE HANDLE. Switch OFF again at the end of the thread.

6. Switch back to FORWARD, increase the depth of cut, as required, then switch

ON again to take another cut.

1 2 ... 15 16 17 18 19 20 21 22 23 24 25 26 27

Commentaires sur ces manuels

Pas de commentaire

Clarke CL430 Spécifications Page 20

Commentaires sur ces manuels