Tools

Question 1

1

Answer 1

1 - TANG

Provided on the end of tapered shanks to prevent the drill from slipping while cutting and ease of removal from spindle withing the shank being damaged

Question 2

2

Answer 2

2 - SHANK

Part of the drill that goes into the drill chuck

Bits up to 1/2” or 13mm have straight shanks with those over have tapered shanks

Question 3

3

Answer 3

3 - AXIS OF DRILL

Center of drill bit

Question 4

4

Answer 4

4 - BODY

Portion of drill between the shank and the point

Question 5

5

Answer 5

5 - LAND

Body surface between the flutes

Question 6

6

Answer 6

6 - FLUTE

Spiral grooves that wind around the body, used for chip removal

Question 7

7

Answer 7

7 - MARGIN

Narrow portion formed by griding away some of the land to give the drill body clearance

Question 8

8

Answer 8

8 - CUTTING EDGE

Formed by the intersection of the flutes, must be equal length and have the same angle so the drill will run true and not cut a larger hole

Question 9

9

Answer 9

9 - CHISEL EDGE

Chisel edge is at the very point of the drill bit

Question 10

How to sharpen drill bit

Answer 10

3 Factors

Correct lip clearance - 8-12* for most steels, this allows the cutting edge to engage the work

Correct lip angle - 118* for general purpose - faster and less exertion of power, 60-90* for softer materials, 135-150 for harder materials. - USe drill point gauge

Correct point location - if the point isn’t centered, via unequal angles or lengths on the cutting lips, you can cause torsion strain, bellmouth holes, rapid dulling, poor tool life, or oversized holes.

Question 11

Sprial Point

Answer 11

Has a sharp point on the end to prevent walking, reducing hol oversize by 50%, more accurate

Question 12

Chisel Point

Answer 12

Has a chisel edge at the point, less accurate, needs a center punch or bushing to prevent walking,

Question 13

Inspecting Chisels

Answer 13

1 - No dings or broken tips

2 - No mushroomed head, check not bent

3 - Proper cutting angle and sharpness

Question 14

Grinding Chisels

Answer 14

Debur or round the hitting end, grind mushroom flat, round over edge, flatten top

Grind cutting edge to 70* on both sides

Always keep cool by dipping in water to preven loss of temper

Question 15

Inspecting Grinder

Answer 15

Should inspect grinder for missing/defective parts (electrical connections/plugs, switches, guards, grinding wheel, bearings, loose/missing hardware)

Check the grinding wheel by tapping lighting with small hammer, it should ring if good, thud if not

Keep the wheel dressed to keep it true

Keep the work piece rest no more than 1/8” from the wheel to prevent wedging/damage to to the wheel & flying debris or springing the grinder spindle

Keep top guard (Spark arrestor) withing 1/8” of the wheel

Question 16

Hacksaws

Answer 16

Using a hacksaw - Cut slowly, no more than one stroke per second, use oil to reduce friction and keep temperature down

Choose the right blade for the material, keep the blade rigid and from properly aligned, use entire length of blade in each stroke, clamp thin, flat pieces and pipe.

Tooth couth from 14-32 tpi, thin stock can use more teeth, thick stock, less teeth

Three different “sets” - regular - softer metals with no iron, teeth touch and alternate left and right, raker - for thick metals, teeth are in sets of three, wavy - for hard thin metals, teeth are in a wave pattern from left to right for a smooth cut

Frames - fixed (only one size) or adjustable (multiple sizes)

Question 17

Files

Answer 17

Face - main cutting edge, multiple cutting edges

Edge - narrowest surface, usually coarser teeth, used for notches, corners, special shapes or tight areas, some have safe edges so you can file close to another surface without damage

Tang - narrow, tapered section for attaching a handle too, do not use without handle, tang edges are sharp and can cut

Single cut (mill files) - single series of teeth for smooth finishes; Double cut - two series of diagonal rows of teeth, rougher finish and require more pressure; Rasps - used for wood/soft materials, removes large amounts quickly; Curved tooth - soft metals, wood and plastic, self cleaning

Flat, Pillar, Sqare, 3 Square (triangle), knife, half-round, warding, round

Question 18

Types of bearings

Answer 18

plain/journal bearning - sliding/rotating shaft - cylindrical sleeve with inner lining usually softer than shaft

rolling element bearing - rolling friction, cylinder containing moving inner ring of steel balls/rollers

Question 19

Plain bearings

Answer 19

any bearing using a sliding action

may or may not be lubricated

sometimes referred to as journal or sleeve bearing

Class I - lubricated from outside source - babbitt, solid bronze, carbon

Class II - internal lubricant (impregnated with oil, etc) - sintered bronze, carbon

Class III - have graphite, Teflon or made of plastic, requires no lubrication - cast iron (has graphite in it), plastic

hydrodynamic lubrication - coating action and rotation of shaft to keep metal separated; boundary lubrication - extremely thin film present; mixed-film lubrication - part is supported by boundary and part is supported by a full film; full film lubrication - continuous thick film separates metal; when a plain bearing starts up, it goes through all three

hydrostatic lubrication - outside pressure source to keep a continuous stream of lubricant to separate metal; has full film lubrication at all speeds; advantage of more efficient and longer life; disadvantage of more expense and problems with external pumping system

Question 20

Rolling element bearings

Answer 20

produces less friction than plain bearings

radial loads 90* to shaft; axial thrust loads parallel to shaft; combination loads both radial and axial

ball bearings (all three loads); roller bearings (all three loads); needle bearings (only radial and axial)

inner and outer rings (races) seperated by balls or rollers equally spaced by a separator or cage

dynamic load rating - basic rating life of 1 million revolutions

static load rating - life expectance with stationary or slow-moving loads