Category Archives: THY101

Exams: MATT & MATP STUDENTS

SUBJECT

DATE

TIME

ROOM

EAC149

Dec. 11th (Fri)

8:00 a.m. to 10:00 a.m.

205

EAC150

Dec. 14th (Mon)

12:30 p.m. to 2:30 p.m.

203 & 101

MTH148

Dec. 15th (Tue)

10:30 a.m. to 12:30 a.m.

205

MTH101

Dec. 15th (Tue)

1:00 p.m. to 3:00 p.m.

205

BPR101AB

Dec. 16th (Wed)

10:00 a.m. to 12:00 noon

205

BPR101C

Dec. 16th (Wed)

10:00 a.m. to 12:00 noon

206

IED104A

Dec. 16th (Wed)

12:30 p.m. to 2:30 p.m.

205

CNC101AB

Dec. 17th (Thu)

9:30 a.m. to 11:30 a.m.

205

CNC101AC

Dec. 17th (Thu)

12:00 noon to 2:00 p.m.

205

THY101AB

Dec. 17th (Thu)

12:30 p.m. to 2:30 p.m.

206 & 203

THY101AC

Dec. 17th (Thu)

2:30 p.m. to 4:30 p.m.

205

THY101A.STJN.20093: EAC 149

Here is a message from Mr. Cipriani: ……………….

Please note, if you have not taken the English Assessment test and are unsuccessful in completing EAC149, you may be blocked from registering for EAC 149 in the future. You must take the time now to complete the Assessment Test. Book an appointment at one of Seneca’s test centres.

Romel Cipriani

Lathe: Backgear

Beginners are sometimes confused about how to engage backgear – especially if the lathe lacks a handbook – but with a little care anyone can work out how it should be done, at least on a conventional machine. On the main spindle of the lathe, the one carrying the drive pulley, will be found a large gear, generally referred to as the “Bull Wheel”. The Bull Wheel is attached to the pulley by a nut and bolt, a spring-loaded pin, a pawl that presses into a gear on the pulley (or some other means) and, if this fastening is undone – by slackening the nut and pushing it towards the pulley, or by pulling the pin out – it should be found that the pulley will spin freely on the shaft. By moving the “backgears” into position – they generally slide sideways, or are mounted on an eccentric pin – the mechanism will come into operation. If the pulley will not spin on the shaft, or there seems to be no obvious way of disconnecting the Bull Wheel from the pulley, it may be that you are dealing with an “over-engineered” machine where some clever device has been introduced to make life “easy” for the operator. Sometimes there will be a screw, flush with the surface of the drive pulley and beneath this a spring-loaded pin that pushes into the back face of the Bull Wheel. Quick-action “Sliding-cam” mechanisms are occasionally used (as on the Drummond and Myford M Series lathes) where a knob on the face of the Bull Wheel has to be pushed sideways, and so ride up a ramp, which action disengages the connecting pin automatically. Some lathes, with enclosed headstocks (like later Boxford models) have a “single-lever” backgear; in this system moving the first part of the lever’s movement disengages the connection whilst the next brings the backgear into mesh.

Lathe: Lead Screw

The lead screw provides automatic feed and makes thread cutting possible. It is a precision-threaded shaft, driven by gears as the headstock turns. It passes through the front of the carriage apron and is supported at the tailstock end by a bearing bracket.  Controls in the apron engage a lead nut to drive the carriage as the lead screw turns. Continue reading

Lathe: Tailstock

  1. The tailstock supports long work that would otherwise sag or flex too much to allow for accurate machining. Without a tailstock, long pieces cannot be turned straight and will invariably have a taper. Some tailstocks can be intentionally misaligned to accurately cut a taper if needed. The tailstock has a centering device pressed into a shallow, specially ed hole in the end of the work piece.
  2. The center can be either “live” or “dead.” Live centers have a bearing, allowing the center to rotate along with the work piece. Dead centers do not rotate and must be lubricated to prevent overheating due to with the work piece. Instead of a center, a drill can be mounted in the tailstock.
  1. Continue reading