08-14-2013, 09:31 PM
http://www.practicalmachinist.com/vb/gen...-a-199836/
That link answers a lot of the questions right off the bat. The main one is that Carpenter 158 is basically inaccessible to many smaller manufacturers, because of ordering volume requirements and cost. Here's the quote that jumped out to me right off the bat, and confirms what I have learned about the AR15 industry especially over the years:
That means, for a machine shop to use Carpenter 158, they have a minimum volume order of $100,000. At this point, we're basically diving into areas of materials selection that most machine shops and rifle manufacturers rarely discuss, for several reasons that are obvious to the savvy engineer, as well as machinist and businessman.
I can tell you that after speaking with Frank, and the steels he has regular access to, we are in great hands, and probably need not worry too much about it. Also, roger that on the Factor of Safety. The bolts need to be able to handle proof loads of no less than 62,000psi, although my understanding is that AA's hard use bolt does that and more with ease.
With 9310, I think phosphorous is the main enemy, but I'm not an engineer.
That link answers a lot of the questions right off the bat. The main one is that Carpenter 158 is basically inaccessible to many smaller manufacturers, because of ordering volume requirements and cost. Here's the quote that jumped out to me right off the bat, and confirms what I have learned about the AR15 industry especially over the years:
Quote:We are currently making bolts for a very large AR-15 manufacturer. I have had several other smaller firearms companys contact me looking to purchase these bolts. But the material that we are currently using is supplied to us by our customer. The Carpenter 158 has to be purchased in 20,000 Lb lots and is roughly $5/Lb.
That means, for a machine shop to use Carpenter 158, they have a minimum volume order of $100,000. At this point, we're basically diving into areas of materials selection that most machine shops and rifle manufacturers rarely discuss, for several reasons that are obvious to the savvy engineer, as well as machinist and businessman.
I can tell you that after speaking with Frank, and the steels he has regular access to, we are in great hands, and probably need not worry too much about it. Also, roger that on the Factor of Safety. The bolts need to be able to handle proof loads of no less than 62,000psi, although my understanding is that AA's hard use bolt does that and more with ease.
With 9310, I think phosphorous is the main enemy, but I'm not an engineer.