Capstan and Turret Lathe:
- A Capstan and Turret lathe is fundamentally production lathe. It is used to manufacture any number of identical pieces in the minimum time.
- It was modified of engine lathes.
- They were first developed in United State of America by PRATT and WHITNEY IN 1860.
- Capstan and turret lathes are Semi-automatic lathes that help in making the Auxiliary motion quick and accurate.
- The Tail stock is replaced by an index able multi station tool head.
- Turret head has a Hexagonal block having six faces with a bore for mounting six or more than six tools at a time. The threaded hole on these faces are used to hold the tools.
- The work piece is held in collect or chucks that is actuated hydraulically or pneumatically. On the turret head, all the needed tools are held in the respective holes.
- The tool is moved with the help of turret head, according to the sequence of operation.
- Drilling, boring, turning, reaming, threading tools are mounted on the turret head.
- Forming, Chamfering, Knurling tools are mounted on the front end of the turret.
- The Parting tool is mounted in an inverted position on the rear end of the turret.
- The turret head is moved back to its initial position after completing each operation where indexes the tools automatically.
- The production rate is high.
- Different ranges of speeds are obtained.
- A number of tools can be accommodated.
- Less skill operators are required hence lowers the labor cost.
- higher rigidity so can withstand heavy loads.
Difference Between Capstan and Turret lathe:
|S. No.||Capstan lathe||Turret lathe|
|1.||The turret head is mounted on the ram and the ram is mounted on the saddle.||The turret head is directly mounted on the saddle and the saddle slides over the bed ways.|
|2||The saddle is fixed during machining.||The saddle is moved along with the turret head during machining.|
|3||The turret head can’t be moved crosswise.||The turret head can be moved crosswise.|
|4||The lengthwise movement of turret is less.||The lengthwise movement of turret is more.|
|5||Maximum bar size is up to 60 mm||Maximum bar size is up to 200 mm|
|6||Collect is used to hold the work piece.||Jaw chuck is used to hold the work piece.|
|7||Rate of tool feeding relatively faster||Rate of tool feeding relatively slower|
|8||It is a light weight machine||It is a heavier machine|
|9||It has a simple tool head.||It has hexagonal tool head.|
|10||Automatic indexing.||Manual indexing.|
Capstan and Turret Lathe Tools:
- Turning tool
- Facing tool
- Parting tool
- Forming tool
- Chamfering tool
- Boring tool
- Counter bore
- External thread cutting tool
- Internal thread cutting tool
1. Turning tool:
- Turning tool is mounted on the cross-slide or knee holder.
- Hollow mill is a special turning tool used in capstan and turret lathe.
2. Facing tool:
- Facing tool may be mounted on the cross-slide or on the knee tool holder.
3. Parting tool:
- The tool is mounted on the rear tool post.
- All round clearance is given on tool to clear the work while cutting.
4. Forming tool:
- The forming tools may be straight or circular type.
- The twist drill is mounted on the turret face holders are the standard tools used for drilling holes.
6. Boring tool:
- The boring tools mounted on boring bars are used for enlarging a hole in a capstan or turret lathe.
7. Counter bore:
- The counter bores are used for enlarging the drilled hole from one end.
- The reamer are used for sizing and finishing a hole.
- Reamers may have two or more straight or helical flutes in the body.
9. External thread cutting tool:
- External thread are cut on a job in a capstan or turret lathe by using any one of the following tools:
a. Solid button dies:
- Radial chaser
c. Single point tools:
10. Internal thread cutting tool:
- The internal thread may be cut in a capstan or turret lathe by using any one of the following tool:
a. Solid tap
b. Collapsible tap
c. Single cutting tool or chaser
11. Chamfering tool:
- The chamfering tool is mounted on the four station turret on cross-slide.
- The extreme longitudinal position of the saddle is adjusted by a stop.
- It is mounted on the turret face for maintaining correct length of bar for machining .
- After it has been pushed through the collet chuck.
Work Holding Devices & Tool Holding Devices:
|S.NO.||Work Holding Devices||Di gram||S.NO.||Tool Holding Devices||Di gram|
|1.||jaw Chucks||1.||Straight cutter holder|
|a.||Self centering chuck||2.||Multiple cutter holder|
|b.||Independent chuck||3.||Offset cutter holder|
|c.||Combination chuck||4.||Combination tool holder|
|d||Air operated chuck||5.||Knee tool holder|
|2.||Col let chucks||6.||Slide tool holder|
|a.||Push out type||7.||Knurling tool holder|
|b.||Draw in type||8.||Boring bar holder|
|c.||Dead length type||9.||Recessing tool holder|
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