Tools Flashcards
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
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
3
3 - AXIS OF DRILL
Center of drill bit
4
4 - BODY
Portion of drill between the shank and the point
5
5 - LAND
Body surface between the flutes
6
6 - FLUTE
Spiral grooves that wind around the body, used for chip removal
7
7 - MARGIN
Narrow portion formed by griding away some of the land to give the drill body clearance
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
9
9 - CHISEL EDGE
Chisel edge is at the very point of the drill bit
How to sharpen drill bit
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.
Sprial Point
Has a sharp point on the end to prevent walking, reducing hol oversize by 50%, more accurate
Chisel Point
Has a chisel edge at the point, less accurate, needs a center punch or bushing to prevent walking,
Inspecting Chisels
1 - No dings or broken tips
2 - No mushroomed head, check not bent
3 - Proper cutting angle and sharpness
Grinding Chisels
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
Inspecting Grinder
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
Hacksaws
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)
Files
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
Types of bearings
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
Plain bearings
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
Rolling element bearings
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
