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As promised, Monday found me in the machine shop finishing up the spool.

I started out by removing the chuck and grabbing the part by the hub that was left from the previous step with a collet. The other end of the spool is supported by a brass insert I turned up and the tail stock. I didn't get a picture, but I checked the run-out before I started cutting and it was less than .0002". Not bad for just slapping the part in the machine.



Getting ready for some serious stock removal. This 1/4" wide tool will get me most of the way.







Because of the large amount of cutting area in contact with the part, the 1/4" wide tool wanted to chatter pretty bad if I stuck it out too far, so I had to switch to a narrower tool to get the rest of the way to the middle. This is just a 3/32" parting tool.





Next the compound is turned to 94 degrees to make the 4 degree taper on the left side of the spool. I had to take the handle off the X-axis feed to be able to turn the compound handle.



A cutting tool with a radius ground on the edge is used to make the final cut.



I was expecting the part to chatter at this stage since the wall is only .055" thick, but the angle and the small rim on the outer edge went a long way to stiffen it and chatter was pretty much non existent. I ended up getting a beautiful finish.



The compound then gets swung to 86 degrees to make the 4 degree taper on the right side of the spool and a mirror of the previous tool is used to finish the cut.



To cut the radii on the edges of the spool I used a corner-rounding end mill. It's not the ideal tool and it required some hand work with a file and sand paper to blend it in perfectly, but I didn't feel like spending two hours at the grinding wheel trying to make a custom tool for such a non-critical feature.



Finally the lathe work on the spool is finished!


Now here's the part where I cheat a bit...
Since the spool gets a hex shaped pocket and a gear profile cut directly into it I turn to CNC. I know many here consider CNC a four letter word, but I'll wager most of them have never run one. Just because you don't have to crank a handle doesn't mean you can eliminate the machinist!

Here's the spool in the CNC machine, held in a set of soft jaws being indicated in. These operations have to be aligned to the center of the spool very closely.



I didn't get a picture of most of the process as it was flooded with coolant the entire time it was running, but here's the first tool.



This end mill cuts the hub down to the final size. Then a smaller end mill comes in to cut the hex and rough the tooth pattern. A third smaller end mill then comes in to finish the profile. And now we have a finished spool.



I spent a few hours yesterday at my small lathe at home sanding then polishing and buffing all the aluminum pieces. By the time I was done buffing I was covered in a thick layer of greasy black soot. Once I cleaned myself off I took them to the anodizer. The face plates will be black anodized, while th spool and rings will be clear anodized. I didn't get the drag knob done and I held the foot back from anodizing as I want to engrave it first, but they will go with the next batch.

I spent today working on some of the various small pieces which I should have done by Friday. If all goes well I will be doing some field testing at Grey Reef on Saturday!

Mark

Mike,

The spool is being driven by a collet holding the hub that later gets turned into the clicker gear.

Mark