Guide to Materials.
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Aluminum:
General: Lightweight(1/3 the density of steel) and easy to machine.
Excellent thermal and electrical conductivity. Great for heat sinks. Melts around. 650° C.
When filing; use Varasol or WD-40 as a lubricant, or use chalk/soapstone on your file to prevent clogging.
When gluing; use epoxy and put the epoxy on both sides to glue and then rough the surfaces with sand paper, then add more fresh epoxy. This will remove the ‘skin’ of the aluminum and the epoxy will shield the air from reacting with the metal.
2024 - Fa - Fair workability and corrosion resistance. Limited forming ability. Cannot be brazed. Poor to anodize
6061 - Good formability, weld ability, and corrosion resistance. Can be brazed. Excellent to anodize.
7075 - One of the strongest alloys. Similar to 2024. Used when higher mechanical properties are required. Forming operations limited.
Cannot be brazed.
Poor to anodize.
Cast tool plating - Very stable.
Excellent to anodize.
Steel:
General: To harden heat until dark cherry red, or better still – heat until it is no longer magnetic. Hold temp a little longer then quench quickly.
A1: Die steel. Air hardens.
D2: Die steel. Used in making knifes.
W1: Die steel. water hardens.
O1: Tool steel. Oil hardening. Easy to find.
Drill Rod (Silver Steel): Normally O1 in rod form.
S.A.E. 4140 a very tough tool steel - good for gun barrels, gears, reamer bodies, spindles. Must use cutting oil. Hard to machine.
Superior shafting - see
4140 slightly easier to machine. Very stable
S.A.E. 1144 - Stress proof - Can be hardened to 48-52 RC. Oil Harding - do not have to temper. Great for collets, crankshafts and cams. Excellent for parts that you do not want to wear.
12L14 Leaded steel - can be brazed -not welded - high strength. Very easy to machine.
303 stainless. Non magnetic.
Good for anything that you don't want to rust i.e. valve motion work, connecting rods, crank shafts.
mediummagnetic easier to machine than 303 but can gall like aluminum. Harder to get than
303 stainless.
Tips: Stay away from 304 to 321 stainless steels, they are very hard to machine.
Cast Iron:
Tips: Be cautious when using scrap cast iron such as sash weights etc…
There can be chills (hard spots) that will dull a HSS cutter instantly – you can tell by the squealing sound! Best to use carbide cutters.
If machining large amounts of cast iron it is useful to set up a vacuum to collect all the dust.
Meehanite: A continuously cast & fine grain, no hard spots.
Machined dry only. Never user any coolant!
Great for cylinders, pistons, flywheels, sleeves, piston rings, columns, foot plates etc…
Naturally hard, can be heat-treated.
Can be silver soldered.
Copper:
General: Used for boilers, boiler tubes in steel boilers, cladding, heat exchangers.
Excellent heat transfer. Can be brazed and welded.
Work hardens when cold forming and must be annealed
Bronze:
An alloy of copper and tin. Much easier to cast than brass.
Gunmetal is another alloy of bronze.
660: bronze used for bearings.
Oillite rod - porous bronze oil filled. - Bearings.
Do not braze/weld! Watch tolerances. For press fittings.
Brass:
An alloy of copper and zinc. Very easy to machine.
Easy to get. Available in a large range of sizes and shapes.
Titanium: Half the weight of steel.
Melts at 1168°C. Resistant to corrosion. Special setups required for welding.
Lead: Very soft. Used for ballast, hammers, electrodes. Melts at 327°C. Poisonous – wash hands after touching and cast in a well vented area.
Keep water (perspiration!) away when casting. A drop of water will explode and splatter molten lead - on you.
Magnesium: A very light metal. Do not take light cuts or use a dull tool – it will catch on fire.
Only sand can be used to extinguish the high temperature, extremely bright -blinding- fire.
Non Metals:
Acetal: A Polyoxymethylene (POM) is an engineering thermoplastic noted for strength, stiffness, resistance to hydrocarbons, and excellent sliding properties. It comes in two forms: homopolymer (POM-H) and copolymer (POM-C). Colloquially known as Delrin, this tradename refers only to POM-H. Semi-finished shapes (rod, sheet), unless specifically indicated, are often POM-C as this has better thermal stability for extrusion. Tradenames for POM-C granules (used for moulding) include Celcon, Hostaform, Ultraform. Manufacturers of profiles suitable for machining use tradenames such as Techaform, Acetron.A Dupont product known as Delrin. Available in black and white.
It is non-conducting and can be used for bearings. Easy to machine, good surface finish when using a sharp tool.
Good for dials.
Teflon: Used for sliding bearings
Corian: Made by Dupont. Easy to machine.
Excellent for spark plug insulators.
Nylons - try not to use. Very hard to deburr and it absorbs water.
Artificial Ivories: Use Corian, white Delrin, horn or Tugua nuts. Mammoth tusk is the only legal ivory.
Check with the authorities before ordering any 'antique' elephant or any Narwhale ivories.
Graphite: A pure form of carbon. Used for pistons in sterling and vacuum engines. Machine dry. Use a vacuum to pick up dust as it machined.