Hinges

[Vinny]

A buddy of mine is rebuilding an old Model T Truck.  Then a Model T car is next.  The windshield is attached with two hinges and when he got these two projects he was only able to find 2 halves of a hinge.  Both in bad shape.  The only place that sells replacements wants $100 for them.  So I told him we'll just make them.  Looks easy enuf as you can see in the pics below.  

Before I get started, tho, I have a few questions.  I figure I'll just use angle stock.  My choices seem to be hot rolled or aluminum.  There's only a couple bucks difference in price at Speedy so is there any reason I shouldn't use aluminum for these?

As you can see in the pics, there are 12 indents for balls to go in.  The originals were done on a press.  I'll be doing these on a mill.  The holes the balls go into are 0.200" at 0.050" deep.  0.200" is about a #7 drill, or should I use a ball end mill instead?  If I do the mill I'll probably go for 1/4" since it'll be cheaper and I can source it locally.  Would I use a 1/4" ball or is there some formula that's supposed to tell me what size?  Never worked with individual ball bearings before (can ya tell?).

Without further ado, here are the pix.





and my scraggly drawing.  Couldn't find the clipboard.


if you want a larger drawing, do a View Image on the drawing and change the location to be hinge4.jpg.

Thanks for reading!!