Milling Fixture

	First I drew up the bottom archbar and added dimensions that would be needed. I used this as a sort of template for the next step, and that is to check how it would fit on the rotary table.
	This is what I came up with to hold the stock on the rotary table. A piece of 3/4" thick MDF bolted to the rotary table.
	Laying the template on the wood confirms that it'll work OK.
	Next the table was mounted on the milling table and zeroed in.
	A quick check to see if I had placed the mounting holes for the piece of aluminum in the proper place showed that I didn't. From the center of the pin to the bottom is 4.128" minus half the cutter dia. of .250 or a distance of 4.003".
	I relocated the holes in the MDF back about .5" and used a new piece of stock plus the old one. Set my distance of 4.003" from center on the "Y" axis. I did this so I could use the power feed of the "X" axis. I'm using the scrap piece on the top so I can check my 1.530" dimension when I cut the angle. This way I won't have to cut and drill another piece in case I make a mistake.
	First cut finished. All looks good.
	I then rotated the table to a setting of 259.5° and made the first pass of about .125" deep. Then I indexed the table to 280.5° and started to cut the second side when it came to me that I didn't compensated for the cutter diameter to either side of the center line. I had to offset the "Y" axis to either side of the center line by the radius of the cutter, that being .125".
	Here's a more clearer view of what that mistake looks like.
	Action shot. Camera froze the cutter in action.
	Milling the second side. Note the bolt sticking up. Had a bit of a scare when the arbor nut hit it. Awful noise at about 700 RPM. Cleared on the first several cut's but not on the last two.
	And here we have the finished part. Note the bolt no longer sticks up.
	Here are the two parts. the one on the left is the bad part. Note the difference at the bottom were the step is on the left hand piece. The dimension won't be 1.530" as it is on the right piece.
	Next step was to mark the 3.300" height of the part. I cheated and use jo-blocks instead of reading the vernier.
	The flat bar will now be cut a little more than half way through, heated to red heat and bent to conform to the shape of the jig. Three more parts need to be made and mounted on another piece of aluminum and the jig will be ready for use.
	The keystone looking part was fastened to a piece of 1/4" thick aluminum plate with 6-32 screws. A small strip keeps the bar up against the bottom of the keystone part.
	The rest of the strips have been added. The bending jig is now done.
	The first bar is cut. I placed the bar in the vice with the line close to the jaw to help keep the saw square and straight while cutting approximately half way through. The are two cuts on this side and two more on the other.
	I then heated the bar at the cut and bend it to fit into the right side of the jig. In this picture you can see the cut on the second side near the top right. The other one is on the bottom left out of the picture. I used a propane torch to heat the bar. It just barely got it to a dull red heat. This is not hot enough. Looks like I'll have to use the oxy/actel torch on the next bend.
	I then noticed that the cut on the other side seemed not to be located were it should have been, like closer to the jig corner. The above picture also shows that up.
	A close view and at a different angle. It looks to be about .250", which is the thickness of the bar being bent.
	Back to the print and I discovered my mistake. I did not deduct that amount from the keystone part at the top.
	Back into the milling machine and remove said amount. Looks OK now.
	Next bend is the left leg, but this time I'm using the oxy/acetl torch to heat the part.
	The left leg bent after heating with an oxy/acetl torch. Note that I've removed some of the line up parts. Makes it much easier to bend the bar.
	Added the right side line up piece and am ready to make the bend.
	Here I'm heating the left portion of the archbar for the last bend.
	Here's the finished part. It will still need a bit of tweaking to straighten it.
	The finished product and the straight bar above it. The cutouts are saw cuts a little more than half way through. This facilitates more accurate bending.
	Checking hole alignment of the bar that will sit on top of the archbar. The holes lined up almost perfect.
	The finished archbar's ready to have the corners welded up and ground.

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