The aluminum Rod:
1A) Deburring: Grab aluminum rod and deburr it by hand on both ends. deburr so that the file moves inwards into the center of the part and at the same time away from you.
>>deburring: The use of a file to remove sharp edges of an object. In this case a fine file called bastard, for metal, rather than a coarse file used for wood.
*Concentricity Tip: In a Lathe, deburring is required so that the part does not go out of concentricity when spinning. The logic goes as followed: When cutting a part, at least one portion of the edge will tend to bend outwards. This unnoticeable bending will cause the part to get tilt at a small angle when the arms of the lathe grab on to part. Eventually this translates to a part that is not concentric, getting worse if the part is longer, and which could cause severe damage if the part is used in high speed applications because the part will not come concentric
1B) Facing
We start by making one end perfectly flat, so we could use that as both, a reference datum right after, and as support for later when "center drilling" the part.
1B-1> Start by facing one end of the aluminum rod, which should have been deburr already.
**Facing: Smoothing a surface so that it becomes perpendicular to the axis of rotation (of the cutting tool). Facing could be used as a datum, a reference surface assumed to be perpendicular and flat within a few thousands of an inch.
*Note to keep in mind: In order to achieve near perfect perpendicularity, the cutting tool used for facing must be right in the middle of the diameter. If the cutting tool is a bit off, this will cause a small dimple, and when put in a flat surface, this dimple will cause the part to be off from perpendicularity. The farther away the cutting tool is from the middle (of the diameter), the bigger the dimple.
Dimple tips: To make the cutting tool perfectly in the middle of the diameter, hold your 6 inch metal ruler with the cutting tool and the aluminum bar. The more perpendicular the ruler seems to be from the ground, the more perpendicular your facing will come out (perfectly without a dimple). It is easy to determined by optical inspection withing a few thousands, and the better you get at it, you could get near perfection just by looking at the ruler and see how straight it is.
**Note: depending on how bad the extrusion came, you might have to make several runs in the lathe when facing your part. The face should be come out smooth with an evenly circular pattern,
>>how to face in the lathe machine?
Grab the chuck key and use it to insert your part in the lathe, try using the one with most accuracy ( in this case, always use the "67" chuck insert).
Important note: since the lathe requires high speeds, the part will loose rigidity as it goes far away from the chuck, if you are cutting your part far away from the chuck (more than 3 in) then the aluminum rod will easily bend and this could cause an accident if it brakes off. when facing, keep the part as inside the chuck as possible without letting the cutting tool touch the lathe (duh!). If the part has to exceed 3 in, then you'll have to add support to the other end by drilling a cone-shaped hole and use it as a support point for the Quil. This eventually takes care in the lack of rigidity in the part, and this process will later be used, as explain in 1C.
During the first runs, you will notice "the face" will have two kinds of patterns: 1) a linear, crystal like surface pattern, and 2) a circular, smooth surface. Keep facing up to 0.050 inches at a time until the face only has the circular pattern on its surface. If the surface is not that rough, then you might would like to go by 0.010 or 0.020 inches at a time.
*Cutting Tip: big cuts get the job faster, but they also heat up the part faster, this could cause an imperfection due to heat expansion, which will cause measurements to be off when it cools down. Your final cuts should be using WD-40 as well as thin cuts to achieve flat, shiny surfaces.
1B-2> optical inspection: at this point it should be clear weather you have a dimple right in the middle of the face, or if it is perfectly smooth. There are 2 causes of a the dimple: 1) the cutting tool didn't go far enough into the part, or 2) if the tool did go far enough, then the cutting tool is not right at the middle of the diameter (and thus the ruler might not have been perfectly straight).
1C) The Shoulder
1C-1) With your Vernier Height Gage already set up, grab your ink and make a mark around the rod where the cutting too will be reaching. Then use your Vernier Height device to mark the desire length you will use as reference.You will need 2 marks: The overall length, and the end of the housing body where the fillet begins.
1D) Center Drilling
At this point we are ready to start center-drilling so that you use such hole as a support when making the diameter smaller.
