Centre Lathe Accessories - Catch plate and dog carriers
 
Catch plates are either screwed or bolted to the nose of the threaded, stock spindle. A projecting pin from the dog fits into the slot provided in catch plate. This imparts a positive drive between the lathe spindle and work piece.
   

Advantages turning between centres

Disadvantages turning between centres

  • Work can be removed for checking and re-set with no loss of centricity
  • Work can be transferred among machines with no loss in centricity
  • Can turn work around with no loss in centricity
  • Long shafts can be machined, using the full length of the bed
  • Easy to setup

 

 

  • Cutting speed effected id revolving centre is not used in tailstock
  • Centre holes must be drilled before work can be set
  • Boring, drilling, reaming processes can not be performed
  • Vibration due to dog carrier
  • Long shafts can bend without lathe steadies
  • Only relative small cuts can be performed due to limited clamping power of the dog carrier
  • Need considerable pressure to keep centres in position
   

Steps to follow when turning between centres:

 
  • Drill each end of the shaft with centre holes
  • Mount catch plate (driving plate) in headstock spindle
  • Place soft dead centre in headstock spindle
  • Place revolving centre in tailstock (can use dead centre but need to be lubricated regularly)
  • Select correct size dog carrier and place on workpiece
  • Use shim stock between dog carrier bolt and workpiece.  This is not to damage work.
  • Make sure the leg of dog carrier is making proper contact with catch plate
  • Stet spindle speed correct
  • Select correct feed for the operation

Note:  This accessories are only used when machining between centres. Videos Additional website

 
Pin catch plate Bend dog carrier Slotted catch plate Bend dog carrier
   
A three jaw chuck can also be used as a catch plate.  Normally a dead centre will be turned in the three jaw chuck and a bend dog carrier will then be used.