For the machinists on the site

[Dani]

I am in the process of helping to redo our training manual at work. Machining practices and knowledge of how they work to remove metal is very important to what we do. One of the required readings is Modern Machining Technology published in 1987. There have got to be much newer texts and they likely will touch on newer machining practices that may not be covered in the 1987 edition. Are there newer texts out there that y'all would recommend? I thought about contacting local trade schools to see what they use but I figured a stop in here first might be quicker. The other challenge is getting a hold of a text to review (and compare to the older version) without having to pay textbook prices. I have access to a few libraries and will check them out but if someone has a newer text that they wouldn't mind me borrowing, I don't mind paying the shipping to be able to borrow it.

Thanks a lot,

Dani

 

[Eric Patterson]

Dave McCann customer needs help on aisle five, Dave McCann aisle five...

 

[John Ki]

https://www.researchgate.net/profile/Viktor-Astakhov/publication/284530412_Turning/links/5d4446494585153e5935c5aa/Turning.pdf

Printed 2011 full PDF, hope it is useful.

 

[Huntindave McCann]

The other challenge is getting a hold of a text to review (and compare to the older version) without having to pay textbook prices.

Dani,
The PDF John linked is a very good start.

Machining practices and knowledge of how they work to remove metal is very important to what we do. One of the required readings is Modern Machining Technology published in 1987.

Hard for me to address this without knowing a bit more about what aspect is critical to what you (your employer) does. The basic principles of material removal have not changed. Yes there are certainly additional newer technics available to a machinist but the understanding of the basics is still the foundation.
The whole concept of "Machining practices and knowledge of how they work to remove metal" is a bit more complex than what one might expect to cover in a training manual.

As maybe a poor analogy is "how to carve a duck decoy in 1906 or how to carve a duck decoy in 2024". Given the same base material, lets say white cedar and a steel cutting edge. In 1906 the steel cutting edge was most likely driven by hand and guided by a craftsman who was personally aquatinted with the anatomy of a duck. In 2024, the steel cutting edge may be fastened to device which is guided by a computer program.

Both methods require a knowledge of how to apply the cutting edge to the work at a proper angle to lift a chip of wood, without undue wear or stress on the blade, as well as not doing damage to the work piece. The same can be said about machining and metal removal. (over simplified for sure)

 

[Dani]

Thanks Dave.

Basically, we need to understand all the different types of machining processes that may be used to make the parts that a bullet or cartridge case might come in contact with. How to recognize those machining processes and how likely the marks left behind during manufacturing are individual marks or subclass marks.

Drilling, reaming, swaging, hammer forging, cutting, CNC, EDM, ECM, turning, milling, broaching, stamping, investment casting, metal injected molding, tumbling, polishing and other finishing processes....I think those cover the majority of the processes that makes the various parts and pieces that come into contact with a bullet/cartridge case/shotshell during its life inside of a gun. As you say, advances in technology can influence time honored processes of manufacture. And there may be new processes that have come out to make various parts and pieces that aren't covered in older texts.

I agree that it is more complex than just "machining practices and knowledge of how they work to remove metal." But the need to understand chip formation and those machining processes and how microscopic marks/defects can be left on the surface of something is paramount in my job. We are supposed to be able to identify bullets/cartridge cases/shotshells to a gun. So we have to be able to distinguish between subclass characteristics and individual characteristics. We have to be able to recognize the types of machining that may have been used to make a particular part and then take that into consideration before we make the conclusion on whether something is identified to a gun or not.

Currently, the training module that deals in manufacturing is only 24 hours long. 3 freaking days! I and the rest of the training manual revision committee are aiming to lengthen that training because manufacturing processes are so important to what we are doing. We aren't trying to become machinists or metallurgists but for something that is so critical to understand, the training needs to be lengthened. And our texts need to be updated.

To be fair, we do get to visit firearms manufacturing plants to get to see how all of these parts and pieces can be made. We get to ask questions and speak with folk who do this everyday. My tour was two weeks but I think this group of trainees is only going for a week. So, manufacturing is not limited to just those three days....there is an in person learning environment that is included in the training.

I hope that helps some....

 

[Dani]

Oh yeah... 3D printing is being added to the manufacturing portion of the training and I know that was not covered in our old texts when I went through training....so things are coming out that are new and not addressed yet that I need to learn about

 

[Huntindave McCann]

Thanks Dave.

Basically, we need to understand all the different types of machining processes that may be used to make the parts that a bullet or cartridge case might come in contact with. How to recognize those machining processes and how likely the marks left behind during manufacturing are individual marks or subclass marks.

Drilling, reaming, swaging, hammer forging, cutting, CNC, EDM, ECM, turning, milling, broaching, stamping, investment casting, metal injected molding, tumbling, polishing and other finishing processes....I think those cover the majority of the processes that makes the various parts and pieces that come into contact with a bullet/cartridge case/shotshell during its life inside of a gun. As you say, advances in technology can influence time honored processes of manufacture. And there may be new processes that have come out to make various parts and pieces that aren't covered in older texts.

I agree that it is more complex than just "machining practices and knowledge of how they work to remove metal." But the need to understand chip formation and those machining processes and how microscopic marks/defects can be left on the surface of something is paramount in my job. We are supposed to be able to identify bullets/cartridge cases/shotshells to a gun. So we have to be able to distinguish between subclass characteristics and individual characteristics. We have to be able to recognize the types of machining that may have been used to make a particular part and then take that into consideration before we make the conclusion on whether something is identified to a gun or not.

Currently, the training module that deals in manufacturing is only 24 hours long. 3 freaking days! I and the rest of the training manual revision committee are aiming to lengthen that training because manufacturing processes are so important to what we are doing. We aren't trying to become machinists or metallurgists but for something that is so critical to understand, the training needs to be lengthened. And our texts need to be updated.

To be fair, we do get to visit firearms manufacturing plants to get to see how all of these parts and pieces can be made. We get to ask questions and speak with folk who do this everyday. My tour was two weeks but I think this group of trainees is only going for a week. So, manufacturing is not limited to just those three days....there is an in person learning environment that is included in the training.

I hope that helps some....

Dani,
I kind of figured that was the crux of the matter.

I would suggest a slightly alternate approach to your desired end goal. It seems the concern is not so much the actual "machining process" but rather the resulting "surface finish" produced by the various machining processes. There are comparison charts showing the different surfaces produced. These charts are used by the machinist on the floor, to confirm that the part being produced, conforms to the specs on the engineering print. Different features of a gun, would require a different degree of acceptable surface roughness for that part based on function.

As you say, it is the surface roughness which will impart marks onto the case and projectile.
This is a very basic article on surface roughness and does not cover some of the newer processes, but it may help you towards your goal.

How to Use and Choose Surface Roughness Comparators - Practical Machinist

How to use and select a surface roughness comparator to ensure the surface finish has met project requirements.

www.practicalmachinist.com

I truly think information gathered from the gun manufacture engineers would be paramount and focused to your goal.

I would tend to agree that 24 hours of instruction, is only going to touch the "surface" of "surface roughness in manufacturing firearms".

 

[Ed L.]

Hi Dani,

I am in the process of helping to redo our training manual at work. Machining practices and knowledge of how they work to remove metal is very important to what we do. One of the required readings is Modern Machining Technology published in 1987. There have got to be much newer texts and they likely will touch on newer machining practices that may not be covered in the 1987 edition. Are there newer texts out there that y'all would recommend? I thought about contacting local trade schools to see what they use but I figured a stop in here first might be quicker. The other challenge is getting a hold of a text to review (and compare to the older version) without having to pay textbook prices. I have access to a few libraries and will check them out but if someone has a newer text that they wouldn't mind me borrowing, I don't mind paying the shipping to be able to borrow it.

Thanks a lot,

Dani

Hi Dani,

As I'm sure you are learning this subject has become quite a science. I was a designer for LMT. A manufacturer of AR style firearms and accessories. My area was mainly design/revisions of lowers, trigger mechanism, forearm, stocks, grips and accessories placement when they were introducing the 308 caliber version. I was not in Quality Control but their procedures were very precise. Here are some things you may find interesting in regards to detection and classification of defects in gun barrels and ammunition. These are not links but you can highlight, copy and search for the references.

Hope this helps,

Ed

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  Friction and wear at high sliding speeds​

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• B. Lawton
  

  Thermo-chemical erosion in gun barrels​

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• L. Barelli et al.
  

  A non-conventional quality control system to detect surface faults in mechanical front seals​

  Eng. Appl. Artif. Int.​

  (2008)
• Y.C. Chiou et al.
  

  Flaw detection of cylindrical surfaces in pu-packing by using machine vision technique​

  Measurement​

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• Y.C. Chiou
  

  Intelligent segmentation method for real-time defect inspection system​

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• Y.C. Chiou et al.
  

  The feature extraction and analysis of flaw detection and classification in bga gold-plating areas​

  Expert Syst. Appl.​

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• S. Ravikumar et al.
  

  Machine learning approach for automated visual inspection of machine components​

  Expert Syst. Appl.​

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• X. Zhang et al.
  

  Automatic classification of defects on the product surface in grinding and polishing​

  Int. J. Mach. Tools Manuf.​

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• T.H. Sun et al.
  

  Electric contacts inspection using machine vision​

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• F. Timm et al.
  

  Novelty detection for the inspection of light-emitting diodes​

  Expert Syst. Appl.​

  (2012)

 

[Dani]

Thanks a lot Dave and Ed. You have given me much to think about and research. I really appreciate the help!

 

[Richard Lathrop]

Dani,

Sounds like you work in forensics? From your description I would focus on specific machining operations that impact the cartridge\bullet. For example firing pin manufacture versus a trigger group manufacture. That may limit the amount of knowledge necessary to teach.

Rick

 

[Dani]

Yes I work in forensics. Many if not all processes that are used to make internal parts that do not contact a bullet or cartridge case can also also used to make firing pins, ejector, extractors, bolt/breech faces, cylinders and barrels. Depends on the manufacturer on what process they choose to make various parts.

For example trigger group parts as I recall are mainly made thru stamping, metal injection molding or cut out from sheets of metal using CNC machines. There are some manufacturers that use breech face inserts as opposed to manufacturing the breech face itself as part of the slide. Those inserts can be stamped, MIMed and also cut out using CNC machines.

So sadly, pretty much we have to have a working understanding of every manufacturing process that may be used to make a gun.