BAB TIGA ( 3 )KIKIR ( FILE )

DISEDIAKAN OLEH :

HASNUL MUNAWAR BIN GHANI

POLITEKNIK JOHOR BAHRU

JABATAN KEJURUTERAAN MEKANIKAL

FILE SHAPEFlat file* Cutting face are parallel to one another *cutting teeth on both edges *suitable for reducing to size and shape/ fit finishingMill file* Thinner and smaller than flat file *have only one row of teeth* Suitable in small slot

Hand file* Teeth on only one edge * suitable in filling of a shoulder or internal edge of a square/rectangular

Round file* Also call as ‘rats tail’ * suitable for enlarging or elongating holes/for filling the inner diameter of tightly curved surfaces

Half Round file* One face flat, other rounded* suitable in enlarging big diameter holes and same times use for filling gentle curves

Square file* Equal widths on each cutting face * suitable for enlarging square and rectangular cut-outs

Triangular file* Teeth on all surfaces (including the corners) *Suitable for restoring threads and gear teeth, also for get a round file started

TEETH

Rasp cutraised teeth used for cutting soft materials

Single cutthe file has a single row of teeth, making for smooth cuts

Double cuttwo rows of teeth arranged at an angle to each other

Selecting a file for the job1. Teeth coarseness :

- too coarse 1) make very deep scratches 2) potentially take off too much material- less coarse 1) will take longer time to do job 2) potentially safe way

2. File shape :- large flat surface, pick widest file- enlarging a hole, pick the largest round file that fit the hole

Try first before you file

FILLING TECHNIQUES

Used to removed a lot of material

One hand holds the file, other hand firmly grasps the other end.

File moved back & forth, with more pressure on push stroke than the return

Heavy filling

Light filling

Used for shallow cuts especially when approaching the marked line.

One hand holds the file, other hand holds the end with finger tips.

File moved back & forth, with light pressure.

Draw Filling

Used for removing scratches left by the other filling techniques/polish the surface.

Both hand hold on the file face.

File moved back & forth, in the form of a cross .

File Cards

Used on soft materials tend to clog, clean the teeth

Tiny metal chips caught in the file teeth may reduce efficiency of the file and may severe scratching the surface.

CARE STEP FOR A FILE

Always have handle fitted to a file. Not only is the file then much safer to use, but it will also give you better control.

Never use a file as a lever or pry bar. The hardened steel is brittle and will snap.

Files are best stored apart so that their teeth are not touching.

In hot, wet environments, files can rust. To stop this occurring, give them a wipe over with a thin coating of engine oil.

If they are cheap enough, secondhand files are always worth buying. Even worn files can be used as final-finish tools.