Describing machining operations: Educate a tyro please!

[Eddyde]

Yeah, I really had two completely separate goals here. In both cases to clearly and concisely:

• Summarize a plan for myself, to follow or to modify on purpose while making a part, in a way that's easy to follow when I'm standing at the lathe and mill.
• Communicate with other (hobby, in my case) machinists about the process I used to make a part, to help learn from each other.

When I was actively flying (personal, not professional) I was used to a standardized shorthand for air traffic control clearances that let me unambiguously write down a plan, or a change in plan, with one hand, while flying the airplane with the other. Another pilot in the right seat would be able to glance at my notes and immediately and unambiguously know exactly what the plan was.
Of course. My question was for making my own parts though. ☺ I'd like to be able to say "Here's the print, here's a picture of the part, and here's how I made it" competently.

I have a dry erase board by each machine. I do a simple sketch of the part or just the operation at hand, with all the target dimensions clearly noted. sometimes, especially on mill operations, I'll do a separate list of points eg, #7 hole @ X 1.625-Y 4.375, X 3.500-Y 2.25,--- Tap ¼-20 @ X 1.625-Y 4.375, X 3.500-Y 2.25 and so on etc... that way I only need to crank to those points on the DRO and not look at the drawing or have to figure any math on the fly.

IMHO Pictures with some written description is the best way to convey how I made or understand how someone else made, a project or part.
We love to see exactly that here at HM. Please post some project pics soon!

 

[higgite]

As a non-pilot, the major difference I see between running a hobby lathe and flying a plane is If you forget to face a work piece before center drilling it, your lathe won’t fall out of the sky and crash in a cornfield somewhere in Iowa.

Tom

 

[pontiac428]

Hear me out before you scoff: I think you should learn some basic G-code. There are commands for all types of operations that you can use as shorthand. G01 (startpoint, endpoint) is an unambiguous mill or cut from point to point. G02 with center point and radius is a clockwise circle. G33 is a tapped hole and G84 is how one is made. Coordinate systems can be specified (local, global, feature, etc) for bolt patterns or pockets. Gear changes and tool changes can be specified. If you're looking for a sytax to communicate in, this is a professional system for making steps and movements using logic.

 

[higgite]

That probably makes sense for CNCers communicating with other CNCers, but I think the OP is looking more for terms that one might find in a machinist’s glossary to communicate his thoughts and processes to others. If you handed me a list of G-codes, I’d look at you like a deer in the headlights.

Tom

 

[vtcnc]

You benefit by Googling the following terms:

1. Job Instruction,
2. Job Breakdown Sheet

This is a program of a logical sequence training and instruction worksheet laid out in three columns...

1st Column, Important Steps (Sequence of Operation) WHAT you are doing....

2nd Column, Key Points, (Make or Break the Important Step [quality, safety, tricks or knacks]) HOW you do the Important Step....

3rd Column, Reasons for Key Points, (understanding of the quality, safety or knacks) WHY you are doing the HOW a certain way.




Sent from my iPhone using Tapatalk

 

[mcdanlj]

As a non-pilot, the major difference I see between running a hobby lathe and flying a plane is If you forget to face a work piece before center drilling it, your lathe won’t fall out of the sky and crash in a cornfield somewhere in Iowa.

Actually, I often describe lathe work as like flying an airplane, in that it requires similar long-term focused attention in order to stay alive, except that in most cases it is easier to get in trouble more quickly on the lathe; airplanes are way more forgiving in almost every respect. A spinning chuck with almost-invisible jaws is a lot like a spinning propeller with almost-invisible blades, except that you expect to have your hands relatively near the chuck often as part of normal operations, whereas I keep my distance from the prop even when it's not spinning.

Hear me out before you scoff: I think you should learn some basic G-code.

No scoffing. I sometimes hand-write G-code for my CNC router, or write a custom program in a normal programming language to generate custom G-code. But G-code says only what, and doesn't communicate the purpose, or the relationship between the steps. And as far as I know, G-code doesn't contain instructions for (say) fixturing, which would be important for at least one of my purposes here.

Incidentally, when people ask whether my lathe is CNC, I usually tell them "No, it's HNC." "Oh, what's that?" "Human Numerical Control!"

2. Job Breakdown Sheet

This is what I was looking for! Separating what/how/why will let me be concise where no verbosity is needed, and reading examples will help me understand what machinists have found useful to write up for themselves in the past.

 

[vtcnc]

This is what I was looking for! Separating what/how/why will let me be concise where no verbosity is needed, and reading examples will help me understand what machinists have found useful to write up for themselves in the past.

PM me if you need any help with some examples. I use this at work and in normal life. It is a logical way to think and plan.

 

[mcdanlj]

Thanks @vtcnc ! From my open source software development background where people post lots of concrete detail publicly, I was expecting to find lots of filled-out examples on line to learn from, but so far what I'm seeing is examples based on everyday actions like folding clothes.

The concept makes sense to me; I already write outline-form plans for most complex tasks that have "what" at the top level, have one or more levels of "how", and in some cases remind myself of "why", so this form clicked quickly.

I've been busy with family duties over the holiday, but I'm looking forward to watching the videos @Chewy linked to soon, hoping to see more concrete examples of job breakdown sheets for machining complex parts, to learn from complete, complex examples.

 

[vtcnc]

Thanks @vtcnc ! From my open source software development background where people post lots of concrete detail publicly, I was expecting to find lots of filled-out examples on line to learn from, but so far what I'm seeing is examples based on everyday actions like folding clothes.

The concept makes sense to me; I already write outline-form plans for most complex tasks that have "what" at the top level, have one or more levels of "how", and in some cases remind myself of "why", so this form clicked quickly.

I've been busy with family duties over the holiday, but I'm looking forward to watching the videos @Chewy linked to soon, hoping to see more concrete examples of job breakdown sheets for machining complex parts, to learn from complete, complex examples.

Folding a T-Shirt is a great example. I do an old school Fire Underwriter's Knot in my Job Instruction sessions and we break down that job when I show people how to write a Job Breakdown Sheet. It's the original example I use from the old WWII Job Instruction Manual. It's very effective.

 

[mcdanlj]

Note 13, you are touching off to end of shaft on a mill, but, you didn't say how to position the dividing head and shaft on the table. You assumed the person would orient it in the X axis. Also nothing said about dialing it inline with the bed. If it is .050 out of line all of your operations will be crooked.

Yeah, that's where this sequence assumed my own shop practices; my dividing head won't fit on my PM-30 oriented tin Y even if I wanted to, and I have made slot keys to orient the dividing head and spindexer quickly and accurately on the bed.

Me, I would have turned all the straight diameters at one time and the taper last because you have to change the compound, but that's me.

I cut that rear surface last, after the taper, for maximum rigidity while cutting the taper, and the overall length isn't a critical dimension.

Now that I got a chance to watch the first two videos, I see that he also focuses on preserving rigidity in ordering operations.

In any case, now I have two different form suggestions to choose between, and can combine them however I like. This is better than just prose.

Thanks y'all!