Shop drawings—how much information do you need?

Rectangle tubing frame with small clips welded to the sides. Photo courtesy of Barnes MetalCrafters.

I grew up playing sports and loved being competitive. Soccer was my main sport and still is to this day. I’ve learned a lot about myself and what it takes to be a team player. Always giving your all and leaving nothing on the field was constantly drilled in my head, and it is something I apply to my everyday life.

One thing I liked about playing soccer was my ability to kick the ball hard, especially when taking a shot on goal. I would try my best to render a goalkeeper’s hands useless, or put a hole in the back of the net, whichever came first. Defenders and goalkeepers hated this about me, but I loved it!

As a product designer, I am a little more conservative in my efforts. I honestly don’t give it my all when I am working on our shop drawings. I play it smarter in my role and give just enough information to win or complete the part or assembly. This rule tends to apply only when I am making drawings. I really just want to get the part done correctly and quickly. Before you jump the gun and call me a slacker, I can explain.

I love what I do, and I love 3-D modeling every day using Autodesk Inventor®, although I don’t like making drawings; this probably is my most boring task after modeling parts. Modeling and making a shop drawing are completely different. They go hand-in-hand in a small shop, so I have to do both.

When making most of our shop drawings, I supply just enough dimensions to make the part question-free. This skill took me a while to develop, because it is important to know your shop’s processes and capabilities. I call out data needed for secondary operations such as tapping, countersinking, studs, and finishing, but not detailed hole layouts unless needed. If I mess up on a hole layout on a flat part, that is totally my fault, and I accept that. I should have caught that error on my computer screen. By now that part probably has been laser cut and, most likely, it is too late to fix.

I know exactly what information our press brake operator needs to fold parts up correctly. Recognizing a tricky part on paper comes with my experience as a press brake operator. I usually show the part model to Nick Trueheart, our press brake programmer and shop lead, and we call out a verbal step pattern. Most of the time, I have the necessary information, but Nick T. sometimes throws in some other numbers I need to call out to make his job easier.

One reason that I don’t put unnecessary effort into drawings is time. Time plays a huge factor in a small job shop! Being able to move on to the next job quickly is essential to keeping your shop busy and the work flowing.

I admit that I occasionally miss a dimension here and there. After I give my Homer Simpson “D’oh!” I quickly fix it with a pencil or a talk with one of the fellas. There is an advantage in not chasing the corporate hierarchy for approvals on a mindless change. It’s a decent trade-off for making the Mona Lisa of drawings. We all know that you could spend hours and hours making a drawing pretty, but it is totally unnecessary on certain parts. Would you agree?

Making parts for yourself is so different from asking another shop to make them for you. In that case, yes, you would need to give a bit more information and some quality files. I get some drawings from customers with little to no information. They basically are sending us a pretty picture and no dimensions. I end up opening the drawings in AutoCAD® and pulling some critical dimensions to start the fabrication process. This is usually followed by an e-mail or phone call to the customer because we have questions. This process is very slow and frustrating. I guess it just makes me wonder how some people get things done. If we don’t know their process or application, it is hard to hit a home run with a blindfold on.

Before I hit print, I make sure I am giving what is important. Of course, the more critical the part, the more information I give. Knowing your customers’ needs helps make drawings easier. We are trying to make parts hit the floor and get out the door.

What are some of your small-shop procedures from the part model to completion?

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