Materials

Question 1

what should you consider prior to selecting a given material for your project?

Answer 1

• strength: how strong does it have to be
• workability: do i have the tools and skills to make use of the material
• expense: can i afford the material

Question 2

what are two types of wood?

Answer 2

hardwood, softwood and plywood

Question 3

what are the properties of hardwood?

Answer 3

• strong
• can be difficult to work with
• more likely to split when nailing or screwing if not careful
• used for decking usually

Question 4

what are the properties of softwood?

Answer 4

-not as strong
-easier to work with, more forgiving
-can be light and soft
can be used for a range off applications

Question 5

what are the properties of plywood?

Answer 5

• sheet material, made up of layers of thin sheets of wood(piles) which alternate in sheet direction
• strong in all directions
• resistant to splitting
• good for curved components
• easy to saw but hard to shape with hand tools

Question 6

in what direciton must the grain be?

Answer 6

in the direction of load

Question 7

what are the properties of acrylic?

Answer 7

• shatter-resistant alt to glass
• transparent, half as heavy as glass
• difficult to work witih by hand, must use a lazer cutter etc

Question 8

what are some other names to acrylic?

Answer 8

perspex, plexiglass, polyglass, lucite

Question 9

what are the properties of aluminium?

Answer 9

• easy to work with
• if thin, can be cut with tin snips
• can make it stronger by folding layers upon layers, highly malleable

Question 10

how do you convert electrical energy into mechanicall energy?

Answer 10

connecting a shaft coupler to a dc motor

Question 11

what can i use to mount a motor to the chassis?

Answer 11

mounting bracket

Question 12

how do i convert rotational motion to linear motion?

Answer 12

connecting a lead screw

Question 13

what are some common types of fasteners?

Answer 13

screws
bolts
nuts 
glues
solder
pop rivets
welding
duct tape

Question 14

what are the three types of screws and what distinguishes them from one another?

Answer 14

wood to wood:
wide spaced thread with a threadless shank

sheet metal to wood:
consists of a threaded and threadless shaft combination with wings near the bottom of the nail. wings prevent the threads from engaging with wood. wings break in contact with metal allowing threads to become engaged with metal. must be drilled into wood first then metal

metal to metal:
threads are closer together and the whole shaft is threaded

Question 15

what are pop rivets good for?

Answer 15

very good for sheet metal, not very good for plastic

Question 16

what are the three types of glue and what distinguishes the three?

Answer 16

white glue: joining wood to wood, relatively tight fit

many epoxy-type adhesives: mix and apply

superglue: may not be useful