Another thing to keep in mind is your serial number. After you finish the passenger side clamping pad, measure and record dimension Bravo. Drawings for all of these items may be found in the back of the book, figures 1, 2 and 3. The other is a little drill guide that takes the heart-burn out of putting in the bolt release pivot pin hole. One is a pair of clamping pads to support and hold the forging for several setups. Dimension ALPHAīefore you start cutting on your forging, there are a some fixtures you will need to make. You may want to take several readings and use the average. Measure across the cheeks and record this dimension. The left cheek is on the driver’s side and is the face where the trigger & hammer pin holes will be. The butt face (don’t laugh) is the face that the buttstock mates against. The deck is the main flat surface that mates with the upper. Name because we will be referring to them often in the text. There are some key surfaces on the lower that will be called by It is also recommended that you have all the parts for your lower on hand to check for fit and function as the project progresses. 6 AR Lower Receiver Step-by-Step Chapter 1 Also a long 1/4” center drill for spotting the buffer retainer hole. Also a long 3/32 drill and a long 1/8 drill. A 1-3/16 x 16 tap for the buffer tube is a must. There are some special tools you will need to follow my method of doing this project. For example, if 0,0 is the pivot pin hole location, then the takedown pin hole will be at 6.375~0.00. The X axis runs left to right and is the long axis on your milling table. When a position is noted it will always be the X axis first followed by the Y axis. Throughout this book I will maintain certain conventions. When setting your position always come to the mark by turning the handle clock wise to eliminate backlash errors. Always touch off your drill and then check with your scale before putting in the hole. You won’t make an error of a few thousands, it will be.
#Solid edge file ar15 receivers full#
Each full turn of the handle is usually 0.200” and the usual method for moving to a position is to count turns. If you don’t have a DRO, you can still do it, but it will take you a little longer and you must guard against positioning errors. With the DRO it is very easy to work using Cartesian coordinates. I use a Bridgport style milling machine with a digital read-out (DRO). We will use 10 setups to finish our lower. These two things together are called the setup. The difficult part is holding the work and locating the cutting tool relative to the work.
First of all cutting metal is the easy part of being a machinist. Now, after successfully machining several, it is nothing more than the combination of many small, simple operations. When I first looked at the blue print for the Colt lower I was overwhelmed by the complexity of it all. I would like to thank the following people for the help they provided in making this book possible: Frank White - Compass Lake Engineering Bruce Funk and all the members of AR15.COMĬontents Chapter 1 What you need to know Chapter 2 The First Setup Chapter 3 Holes Chapter 4 The Passenger Side Chapter 5 The Buffer End Chapter 6 Pivot Pin Details Chapter 7 Finishing the Pistol Grip Mount Chapter 8 Buffer Retainer Hole Chapter 9 The Magazine Well Chapter 10 The Hammer & Trigger Well Chapter 11 Safety Detent & Trigger Guard Chapter 12 Finishing Up Appendix: Tools list and alternate setupsĬhapter 1 What you need to know In this book I will explain in simple terms just how I go about machining an AR15 lower receiver from a forging. This book is dedicated to my best friend and loving wife Vincentine “Ruby” Brandes 1844 Mt Cello Rd Marianna, Florida USA 32448-5365 2 Machining the AR15 Lower Receiver Forging byĬopyright ©2003 Ray-Vin Publishing Co.