The Home Machinist!

I am not sure what you mean by "bow tie" effect?
Do you mean the surface is concave?
A slightly concave surface is acceptical on a finished surface so that the finished surface will rest square and not wobble.
Amything else would result in a convex surface resulting in worse problems.

Find a piece of stock the diameter of the bend you want to make.
Cut a slot in the stock as wide as the 1/2 round is thick and as deep as the 1/2 round is wide.
Bend the 1/2 round in the slot.
Perfect consistent bends ever time

Plated diamond wheels have a single layer of diamond, they can not be redressed.
Green wheels, ie silicon carbide do a very poor job grinding carbide.
Silicon carbide wheels with a strong bond are excellent for grinding some materials but not steel.

Aluminum bronze is plenty strong, expensive, not the easiest stuff to machine. You could use it if you have it, but I would not purchase it if I could buy 7075 aluminum.

Aluminum casting can be affected by porosity, cold shuts and other flaws. Additionally cast aluminum can be weakened by metal contamination of the casting alloy. The same zinc that makes 7075 so strong in a wrought alloy will create an age embrittlement condition in a cast alloy. I have seen failure...

Unhardened gauge stock, most likely ground finished is overkill. Plain old hot rolled steel will not warp and will finish as well as tool steel for far less cost and machine will less difficulty

7075 T6 aluminum has about the tensile strength of mild steel
The color of aluminum is a little different then steel
The color of stainless steel is slightly different also.

The 80" shoes and heads may work for your application.
Regards, HG

I still have to correct some more details in the molds. make and cast waxes. I hope to develop a design that will work. The internal parts can be made on a screw machine. That way I will know the parts are consistent. The casting can be done on a CNC machine. That will require good fixturing and too...

Kap, In order to get the correct hex size I have to mill the hex and then mill the slots from round stock. The nuts are made on a "Swiss" style machine which runs the bar stock through a bushing, not held in a collet. In order to get the least clearence between the stock and the bushing th...

The nuts I made are steel. I would not plate brass nuts.
I will try to post photographs

I have made these nuts in steel 6-32 8-32 and 10-32. These nuts are slotted, not castellated, slightly different. I wil supply them with 1/32 diameter cotter pins for 75¢ each + shipping. The #8 and #10 nuts are electroless nickle plated and the cotter pins are staainless steel. These parts are in s...