Shop Drawing Time per Job

How long does it take to prepare shop drawings for a cabinet job? Here's a thorough and detailed discussion of that question. November 15, 2011

I am trying to set a standard expectation for shop drawings in our shop. Does anyone have a figure they use for estimating time spent on shop drawings (percentage of job, man hours, etc.)?

Forum Responses
(CAD Forum)
From contributor E:
Employers always want drawings done fast, and don't really want to believe the real cost of accurate, detailed working drawings. In my experience, any time spent by a good draftsman, with woodworking experience, will be saved by the people in the shop who are cutting and putting together the project. I have built from my own drawings, and from others, and know there is a wide range of readability and accuracy in drawings.

The other part of the equation is CNC programming and cut-listing from drawings; mistakes cost you time, so whatever time is spent on accurate information is saved many times over in the shop.

With all that said, I believe an accurate estimate of the costs of drawing is 6-10% of the project cost. If you can find someone who is in the low range of that scale, you are lucky, and they deserve top wages. If you think the top end of that scale is too much, look out in the shop, and track how much time people are spending scratching their heads and re-figuring sizes that don't seem to work right. A draftsman who is trying hard, not making too many mistakes, and is still in the top range of that estimate deserves the chance to improve and get a little faster, as they find shortcuts in your system to save time.

From the original questioner:
This sounds realistic to me but the owner's expectation is 2-3% per job. This means that I need to draw a $65,000 project in 32 hours or 4 days! I do not know where he is coming up with these figures and it feels a lot like he is just pushing the expectation to load the shop floor quicker. I can understand but the issues that come with rushing drawings show up later down the line and end up costing more in the long run. Any help?

From contributor D:

In our case, 3-5% is standard. Low end for schools where you get 10 -15 classrooms from one elevation. Whoever said 5-10% must be a draftsman.

From the original questioner:
Obviously there are fluctuations due to repeatable elevations but we do 100% custom where copying and pasting elevations is not possible.

From contributor G:
Efficiency is key in the submittal process. Use every trick in the AutoCAD book to make your company's submittal process faster. Make sure you have a template that works for you, Titleblock with fields, blocks of everything you typically encounter (dynamic as much as possible), use palettes to make it faster, etc. Sheet Set Manager can save you a ton of time if done right. This takes some time to set up, but will pay every time you use this process.

I once heard about 1 man hour of drafting per 1,000 dollars of sale price. That seems to be an attainable average figure for most places that are set up well.

From contributor E:
I was talking about strictly custom work. No real way to use multiples of elevations.

Contributor D, if you are getting 10-15 multiples out of one drawing (maybe with minor changes), then you are right in the ballpark at about half or less work to complete the drawings.

Contributor G, your 1 man hour to $1000.00 of work compares to the questioner's boss's expectations - double his hours and he comes out right at that benchmark. I tracked drawing times for several years in a custom architectural woodworking shop, and think that I am fairly accurate for custom, one-off work. I would appreciate input from others who have the same experience. I hope that managers and bosses will start to realize the real time involved, and value, of accurate and detailed drawings, and give the people drawing them the time they need.

"No time is ever saved by rushing work, when the re-work time is accurately figured."

From contributor O:
I always feel pressure to get the shop drawings done quickly. Less pressure now that what I draw will eventually run the CNC.

I just finished $35,000 of custom millwork drawings for submittal. It took 25 hours over 4 days. I never have time to sit down and draw just one job. Kitchens take less time than complicated commercial millwork. I have templates and sections I can paste into jobs. Accurate, clean drawings are invaluable in the shop and for install. They will save money in the end.

From the original questioner:
Thanks to everyone for the great feedback. I am self taught at AutoCAD and have been using it for the past 4 years. I have learned a lot of tricks through the years and have a solid library and template to work from. It is frustrating to have such unattainable expectations for drawings which drive the shop floor, production, and are key in installation.

From contributor T:
Using a percentage to estimate the cost for shop drawings is quick but it can be tricky. You have to keep a look out for things that could raise or lower that percentage. For most of our customers 5% is a pretty good average for shop drawings, but it's just that - an average. Some examples that could raise that percentage would be lower material cost, desks, paneling, stairs, etc. Some examples that could lower that percentage would be higher material cost, repetition and CAD standards. Since Hardline is in the shop drawings business, we tend to agree with those who say that a well presented and detailed drawing will save time in the shop and during install.

From contributor J:
Please keep in mind that there is a large difference between shop drawings for the sake of design intent and obtaining approval to start fabrication, and engineered drawings from which all part sizes, materials, cut lists, hardware, and machining is already specified ready for fabrication.

From the original questioner:
You have a good point. Our shop drawings are all encompassing to include specs, engineering, and all information needed to fabricate the project. The intent is to hand off to the production team and input directly into CNC and machining to ensure there is not a lot of head scratching. We have a very demanding clientele and architects who want to see exactly how product is fabricated and engineered in some cases where weight and structural integrity is paramount. Thanks for your input. Oh, did I mention that in between all of this I am the lead estimator on projects ranging from $50K-$2M? Makes for an interesting work week!

From contributor P:
This is a good thread. I was wondering if any of you guys/gals are drawing in 3d and how that affects your estimates of time on drawings?

It seems to me that the 2 hour per 1000 is about right for custom (cash wraps, receptions desk, etc.) one-offs.

From contributor G:
It would be an unusual product mix to warrant 2 hours per $1,000. I regularly draw custom one offs, cash wraps, window units, paneling, etc. Like I said before, the key is efficiency in the process. That said, allow me to clarify... 1 hour per thousand is for drawing and submittals. I need up to another hour per thousand to revise redlines, revise to field dimensions, and engineer/process/optimize and package for the shop floor release.

From the original questioner:
We only use 3D for prototyping of large production runs and custom furniture for product lines. This is usually done in Inventor and has different expectations (the owner is usually much more understanding of this process).

From contributor P:
Contributor G, is that applicable when drawn in 3d?

To the original questioner: With production runs you can amortize the drawing time over many, so the time spent on the drawings is almost moot.

From contributor W:
I would have to add that when taking all things into consideration, the last thing you really care about is the time detailing. If an extra hour or so there will save many more hours later in the shop, installation, etc., as compared to another detailing system that can't reach that efficiency, then the hours are irrelevant under most circumstances. I was thinking it would be nice to express it as a formula, but I am no economist. How about this? Formula = Common Sense.

From contributor G:
Contributor P, historically for me, this has been applicable when I draw in 3D. But I'm careful not to waste my time drawing things that aren't required. I once had a job where they wanted to see everything, and while I was able to, and it looked nice, it wasn't anywhere near the budget. I also only draw things in 3D if somehow 2D drawings don't cut it. For residential kitchens for instance, I'll draw in both 2D and 3D (Microvellum helps big time here) as well as more complicated millwork like a curved reception desk or something.

From contributor Z:
Imagine the shop conversations that used to take place 130 years ago...

Click here for higher quality, full size image

From the original questioner:
That is an interesting piece of history there. Can you imagine the drawing time for a guy on a board with pencil and straight edge, and then the revisions if someone changes the design?

From contributor I:
Regarding your questions about "estimating time spent on shop drawings." Are you talking about the time to produce shop drawings, or the time spent estimating shop drawings? Both seem to be an issue wherever you go.

I have been in the world of custom woodworking for 34 professional years with at least half of that in general management or consulting. This estimating situation is typically the crux of operational problems that exist in too many operations.

First... price estimating. After many years of evaluation I have come to the understanding that most operations manage estimating haphazardly. They expect a great deal in less time. They would prefer you to shoot from the hip and just get it done, but do not spare you the whip when they lose money on projects. Many do not understand the function and true capacity of estimating, coming or going.

Since I link my entire systems on scientific input and data and require this information to ultimately manage total operations, I choose to manage this on a scientific and exact set of circumstances.

After all of my years of benchmarking I have discovered certain relevant factors. Let's just say that my rule of thumb as a manager is: be compelled by your best scenario. There is a bottom line. Whatever it is you have access to, is certainly part of your bottom line. Should this be dictated by a frantic principal or manager solely based on urgency? No. But all too often it is.

There is a cost of doing business. Managing those costs appropriately sure helps put everything in proper perspective. I once helped an owner that would draw estimates as if speed reading. He would rough draft 300K estimates in one hour, and send his notes to bookkeeping to submit contract by the end of day. He wouldn't hesitate to stop their work in progress to accommodate the estimate. He hired me to discover why he was losing 30% or more on projects and posting year end losses.

When I improved his estimating position on the next project (only a cost out study in comparison between him and I) at the rate of about 1 hour per each 10K based on the drawings/information he was receiving. Let's call it a 40 hour week for the same that he did in an hour. The man required a mild sedative waiting for my workup. When all was said and done, and the project transpired, he would have cleared a 10% profit (10% below target of 20% he actually wanted, which led me to other areas). He lost 32.45% or about 64K, slightly higher than I informed him he would. Not everyone is that bad, but too many are in similar circumstances.

Estimating doesn't stop there. It is up to the manager of the company to monitor his company's capabilities and pulse. It is his responsibility to make or create a winning proposition.

All incoming drawings and information are not created equal. Some can chew up your entire process, others can flow smoothly. Price estimating through these drawings is not the only challenge. Now to the drafting department.

I have drawn quite a few with pencil before CAD, and I have managed quite a few CAD draftsmen in my days. First, I always shoot for a review of the provider's electronic documents CAD file. If my CAD draftsman can blow and go with these, that is one thing... If I was to develop these from scratch, that is another. The same factors apply here as in estimating. The better the info, the faster the drawings. In a reasonable scenario and in my systems... I would estimate that the CAD draftsman requires 1 hour per 1K of development time. Heads up, because this can also direct you to unrequired or unwarranted challenges in incoming information.

300,000 job is 300 hours in my world. That seems to be about 4-5% of the job estimate between 9-10K in direct cost. This might not work for everyone as prices do fluctuate from place to place. You must monitor and benchmark your realistic scenarios and provide your workforce with real demands because that too is a factor that weighs on success.

I have been called bad names by some that could not understand why I would pass on certain projects or only offer services at an elevated additional cost to the customer for drafting requirements due to the very high difficulty level that their plans and business practice represented. On the other hand my managed operations post planned and targeted profit margins at will!

The sum of it is... You can not expect that all submittals for review will represent the perfect scenario for an estimator or a draftsman, or your bottom line. You must be able to evaluate which you prefer and how to deal with those that do not comply with your requirements or program.

My general rule of thumb through years of monitoring and benchmarking these situations is about 1 hour per 10K for cost estimating and 1 hour per 1K in drafting for custom work in my system.

Depending on the drawings and information, this may or may not be comprehensive with buyouts and materials listed out, though I shoot for this. That is purely custom and what I understand as my average and acceptable time requirements.

From contributor U:
A percentage of the job would be a dream for me. I've been doing shop drawings for 2 different companies for about 5 years and I've always charged by the hour. It's not constant work, a few drawings every other month or so. I use AutoCAD and have used a table as my timecard. If I were to charge a percentage of the job, the people I work for would take their business elsewhere. As for estimates, unless it is a real big job like a hospital floor or school, it usually just takes me 3 to 4 days and I try to keep the cost under $500. I have only had a few mistakes brought to my attention, which I gladly fixed for free. It might seem silly to most of you, but this works for me. My shops are all custom commercial. Some things I can copy and paste, some I just redesign.

From contributor F:
On the subject of 2D/3D, I have been using Inventor alongside AutoCAD in production over the last 18 months. Producing drawings takes about the same amount of time with Inventor as with AutoCAD, but with the bonus that your cut sheets are already done.

The plus points are that it is much easier to spin out more details and it is much easier to make changes (a change to the model changes all the drawings, and the cutting sheets at the same time).

Virtual prototyping using a 3D model isn't necessarily faster at the design stage (unless you do a lot of similar work) but it does give you a much more complete overview of what you are building (which can be passed on to others). The speed comes after the sign off, because there is no time spent booking up. The drawings go straight into the shop and you are free to get on with the next drawing.

From the original questioner:
I am also looking to Inventor in the near future, as we need prototyping that is efficient and complete for a custom furniture line. There have been so many great responses to this thread and I thank you all for the input.

From contributor K:
I have been drafting for over 25 years and I can tell you the process and scope of responsibility have changed tremendously. I have been operating a millwork drafting service for the past 15 years and I stick with small shops who still have craftsmen on the floor and not just factory workers. This requires a good 2d drawing that gives that man everything he needs to build the project. I draft mostly high end residential projects. The final product is a handcrafted work of art that is produced from a drawing where everything fits.

I charge by the hour, but the final cost is generally around 5% of the project total. A lot also depends on revisions for design changes by the architect, which often are not billed by the millworker.

Charges will vary on the size of the project. A 10k project will run a higher percentage than 500k. Remember, the way to make a small fortune in the millwork business is to start with a large one.

From contributor Y:
I have been drafting/engineering for the last 12+ years in a custom millwork shop. We have kept track of the time and cost of all of the projects that we have worked on for the last 8 to 10 years. Since we started keeping track of the cost vs time we have seen a change in the relationship of the two. We are now at 2 to 3% of the job cost, and that is with a fully engineered and compete set of drawings ready for the shop to fabricate.

From contributor Q:
Contributor Y, what CAD software are you using? What do you think has caused the change in the relationship between to two? Do you use any type of log software to keep track of the time spent on a client's job?

From contributor X:
So I'm curious... Everyone is speaking about basing a project's drawing costs on the project's total cost, but how do you find this information out? I currently work as a project manager at a custom residential cabinet company and while we rarely source out our drawings, the times we have I never remember being asked what the project's total cost was. Would shops not shy away from this information thinking that you will be price gouging? It seems like shop owners prey on the weak and any opportunity they have to benefit from a subcontractor's mistake, they jump on it. I know at our shop we have never told a customer, sorry you paid us too much for a job that was easy. Or the other way around, sorry subcontractor, I know you are losing money but that's the price you gave us. So I ask, how do you find out the project total when calculating drawing costs?