Yep, I was able to get to it. Very clear and straightforward. Thanks, Glenn! This is a fantastic website, really boosts novice smiths confidence (like mine!)

 

When It warms up, I am going to try and make another header out of spring steel and see how it works.

BP0189 Nails

 

I think I fixed the problem

 

I got it too!  Thanks  :) Good info there.

I was taught to use a ball peen hammer and drive the peen end into the metal to form both the domed top AND a open bottom. Punch a small(ish) hole in the dome. MAKE a taper in the stock size you like the nail to be, and open up the hole to that size. 
 
BP0189 Nails: http://www.iforgeiron.com/page/index.html/_/blueprints/100-series/bp0189-nails-r413
 
Be careful when using spring steel for headers.
 

 
 
Yes, it shattered !! But I got the one nail made in that header that was required for this Blueprint. Upon reflection, I ask where the metal came from for this header. It was from that stack of drops on the far end of the work table, was the reply. Those were the pieces of leaf spring I had cut for use as plates for hardie tools. And in the haste to get the header made and a nail produced, the header was quenched from a nice low orange color directly into cold water.

I have made headers from mild steel and let them cool naturally with no problems. Have two that I have used for several years now. So, choose your steel wisely and choose your quench, if a quench is even needed. I lost an hours work on this one by the wrong choice of materials. But I did get ONE nail made before it failed.

 

I read this when originally posted, but should have read it again yesterday, I made and broke a 5160 header yesterday. I snapped the drawn out handle, hoping to repair the header by adding a new handle, but may just start over.

I don't think anyone has already said this so I'll add a tip. You want to finish the top of the nail so that when you drive it into wood your hammer is hitting the peak of the nail head centered over the nail below. Otherwise it will quickly start bending over. With a domed head on your nail header you can make final angled hammer strikes on each side of the nail. This creates a high point over the center of the nail and also looks decorative. This assumes that the nail head is centered over the nail below. If the nail head ended up off center your finishing strikes should be directed toward salvaging the nail and leave a high point over the top center of the nail.