Grinding

Question 1

When using letters to identify hardness, A is the what? softest or hardest?

Answer 1

A is the softest and Z is the hardest

Question 1

What way should you feed the work piece into a horizontal spindle grinding wheel?

Answer 1

Always feed the work piece at the same direction as the rotation

Question 2

What is an advantage of vertical spindle and rotary table?

Answer 2

Both tooth and material rotating even outs the high points because they average out between both

Question 3

What can a surface grinder be accurate too?

Answer 3

+/- .0001 (around 10 thousandth of an inch)

Question 4

How far should a pedestal grinder rest be away? (max and minimum)

Answer 4

1/16 is the closest and 1/8 is the furthest. This allows parts to not be sucked in or to ensure the rest does not come in contact with the wheel

Question 5

What are some purposes for the wheel/ spark guard?

Answer 5

It is there to stop sparks from rotating around the wheel and being thrown towards you from the direction of inertia. The same goes for if the wheel breaks, no parts will be thrown towards your body

Question 6

What sides to the course and fine wheels go on the pedestal grinder?

Answer 6

Course wheel goes on the left and fine wheel goes on the right?

Question 7

During the tap test what sound do you want to hear?

Answer 7

A ringing sound indicates a wheel with no cracks and is good to use

Question 8

What direction do you want the nut to tighten, with or against the direction of rotation?

Answer 8

you want it to tighten against the direction of rotation

Question 9

What is the most common abrasive material on grinding wheels?

Answer 9

Aluminum oxide

Question 10

What kind of grinding abrasive would you use on non ferrous metals?

Answer 10

Silicone carbide as the non ferrous metals will clog an aluminum oxide wheel

Question 11

What are the main parts of the grinding wheel and grinding machine you have to keep in mind and check while inspecting?

Answer 11

Grinding wheel, bushing, inner and outer flange, blotter, wheel guard

Question 12

Is the lower number courser grit or the higher number?

Answer 12

lower number has a courser grit

Question 13

What is friability?

Answer 13

The ability to fracture under stress which allows the dull parts to fall off and new sharp particles to become the new grinding surface

Question 14

What is heat resistance when talking about grinders?

Answer 14

Heat resistance is the ability to withstand heat and not dull

Question 15

What is hardness?

Answer 15

The ability to scratch or penetrate another material

Question 16

What kind of bond do you use on soft materials?

Answer 16

You use a strong bond on softer materials because you can hold onto the grain for longer.

Question 17

What colours do aluminum oxide come in?

Answer 17

grey, light grey and white

Question 18

What colours do Silicone carbide disks come in?

Answer 18

Green and black

Question 19

What is a vitrified bond?

Answer 19

It is designated by the letter V and is the most common type of bond. It is a clay like substance and is what holds the wheel together

Question 20

What are the four common manufactured abrasives?

Answer 20

Aluminum oxide, Silicone carbide, Cubic Boron Nitride (CBN), and Synthetic Diamonds

Question 21

What does the term glazing refer to?

Answer 21

It is when the abrasives on the wheel becomes dull and give a shinny look

Question 22

What does the term loaded refer to?

Answer 22

It is when the spaces between the abrasives become clogged and the wheel takes on the same colour as the material

Question 23

What is the difference between cold and hot grinding?

Answer 23

Hot grinding is done at high speed where heat and spark is generated. Cold grinding is done at low speeds where it is kept cool and no sparks. Cold grinding examples are: honing, lapping