So now we have our program loaded and we need to veryify it. There are a lot of repetative steps, but it's better than destroying a $300+ wheel or not doing it right and finding out at the end and having to redo it. So the machine runs the profile for you on the screen, like so.
So we have verified that the program is not only the correct number the the profile matches up. So now we chuck the wheel back up on the lathe. This time I will indicate off the back side of the front bead for two reasons. Number one we cut the back so even though it is super close to the front bead it's still not as accurate. The second reason is because the face has a break in the spokes so it makes it goofey and we don't want to scratch the paint in the pockets with the dial indicator.
So once the wheel is indicated we put on the cutting tool. This is a straight bar with a slight back angle on it, for cutting down the straight bead edges. We then move the tool up to set the parameters of the tool. Now there are two axis. X and Z. If you are standing infront of the lathe X would be tword you and away from you and Z would be left and right. We need to find Z's zero point. This is shown below in the picture of the screen and zero is where the gray line is.
Then we bring the tool to it and tell the computer it is at zero.
You can see now that the Z axis is set to 0, under tool 2. That is the diamond tip. Tool 1 is the probe. Tool 3 changes, some wheels will have a steep up slope near the center cap that we can not cut with tool 2, so we set up tool 3 and put it at an extreme angle and then cut it. Tool 4 is actually set up for one degree off from tool 2 just for the Toyota Sienna wheel. It is the only wheel that can be cut with that angle. It does not have a traditional bead edge but it has a part near the center that is just barely too steep to cut with tool 2. Any way now the computer recognizes the tip of the tool, which is the white dot on the bead edge line, is at zero.
Now we need to find X. I know again, from getting these often, that X is supposed to be set at +.385. When you add to X it pulls it tword you, when you take away it pushes away from you. When you add to Z it goes right or holds it away from the wheel and when you take away from Z it will go left, or cut into the wheel. If you didn't know what X is supposed to be however, you would look at where the white dot is on the screen when you zero it and then try to get it as close as you can to where the tool is in relation to the graph, then just start the program and modify the coordinate from there, usually only .020 or so. So I have gotten X right and we start the program. As soon as it starts cutting and we know for a fact X is right, we go tell the machine how much to cut off next.
You can see I am going to take off .010 on the next cut. The initial cut always cuts a little uneven and funky because it is so light, so taking of ten thou is pretty standard for a second cut.
Action shot.
So the next cut finishes and it's good! We have cut all the paint off the face of the wheel.
Cut wheel.
Now we do a clean up cut. I usually take off .002 as a clean up cut. The purpose of a clean up cut is to make the cut lines on the face of the wheel as small and unnoticeable as possible. We use a diamond tip to cut, and that is what gives it that shiney look. Those who have used a lathe or mill or anything of the sort will know that a carbide tip does not leave a real great looking finish.
So we use this stuff from Zep, it's actually a degreaser, we use it for that in cleaning the lathe, but we also use it for coolant while cutting. It is very slick fluid and helps prevent what is called chip drag. Basically a little piece of aluminum that is cut could get stuck between the tip and the wheel and cause little white scratches.
My invention.
I used to have a little spray bottle where I would mix the solution, but you need to pump a lot of this stuff on these wheels, so I would have to refill it every other wheel. It got old quick, so once I found an empty bucket laying around and I had some extra fuel hose, and presto chango I've now got a five gallon spray bottle.
Any way. We do our clean up cut, and here it is. It is not a real noticeable difference in the picture, but it looks much better.
So then we pass the wheel off to the painter who dunks it in the acid bath.
The purpose of the acid bath is to open the pores of the aluminum so that when we pre-heat the wheel it will let all those nasty gasses out so that when we powder coat it the gas does not escape and bubble the powder.
So after the acid it gets rinsed with cold water and dryed with the air tip.
After this, we put the sucker in the oven to preheat for 45 minutes.
Then we wait...
*yawn*
Is it done yet?
*yawn*
Okay time to powder the wheels. Powder coating is pretty easy stuff. You hold the powder gun a certain distance away from the wheel and take a couple sweeping passes over it. Give it a squirt on the back side to protect the spokes from the back and you are done.
Then back into the oven for 45 minutes to cure.
45 minutes later and after cooling, remounting the tire if it needs it, and balancing....
Just like new.
So that is the story. There are little tiny unimportant things I left out but you get the gist I am sure. If not feel free to ask.
That's my job. Not the most glamorus or exciting gig in the world, but I like it.
