After 25+ years in the millwork industry, I’ve seen shop drawing mistakes from both sides. I’ve been the guy on the floor trying to make a bad drawing work, and I’ve been the guy at the desk trying to prevent it. Here are the five most common errors I still see—and what you can do about them.
1. Assuming Field Dimensions Match the Architect’s Plans
This is the most expensive assumption in millwork. Architects design to ideal conditions. Job sites don’t have ideal conditions. Walls aren’t plumb. Floors aren’t level. That 36″ opening on the plan? It’s 35-3/4″ on one side and 36-1/8″ on the other.
The fix: Always note which dimensions are field-verified and which are taken from plans. If your drawings don’t distinguish between the two, your shop is guessing—and guessing costs material.
2. Missing or Incomplete Hardware Specifications
“Hinges: TBD” on a shop drawing is a problem waiting to happen. The type of hinge affects boring locations, overlay dimensions, and minimum stile widths. If your drawings leave hardware as an afterthought, your CNC programs are based on assumptions.
The fix: Lock down hardware selections before production drawings begin. Every hinge, slide, and pull should have a manufacturer, model number, and mounting spec on the drawing. No exceptions.
3. Ignoring Material Thickness in Joinery Details
This one catches even experienced drafters. You swap from 3/4″ plywood to 19mm melamine and suddenly your dado depths, edgeband reveals, and drawer box clearances are all off by a fraction. A fraction is all it takes.
The fix: Build your drawing standards around actual material thickness, not nominal. If your shop runs metric sheet goods, your drawings need to reflect that—not round to the nearest fraction.
4. Section Views That Don’t Tell the Whole Story
A plan view and a front elevation aren’t enough. If your installer is standing in front of a 12-foot reception desk and can’t figure out how the panels connect behind the waterfall edge, your section views failed.
The fix: Think about who’s reading the drawing. The CNC operator needs different information than the installer. Good shop drawings include sections at every critical joint, transition, and connection point—not just the ones that were easy to draw.
5. No Revision Tracking
Revisions happen on every project. The architect changes a finish. The GC moves a wall. The client wants the grain running vertical instead of horizontal. If those changes aren’t tracked on the drawing with clear revision clouds and notes, your shop is building to an outdated version.
The fix: Every revision gets a number, a date, a cloud, and a description. Every sheet in the set gets updated, not just the one that changed. This is basic, but the number of shops still working from unmarked PDFs is staggering.
The Common Thread
All five of these mistakes share the same root cause: the person creating the drawings didn’t understand what happens after the drawing leaves the desk.
That’s what makes MillworkIQ different. We’ve built the cabinets. We’ve run the CNC machines. We’ve been on job sites when things don’t fit. Every drawing we produce is built from that experience—not just CAD skills.
If your current drawings are creating problems downstream, we should talk. Get a quote and see what production-ready drawings actually look like.