It doesn't fit

Hazza · 31 Mar 2009, 21:37

So in the absence of being able to find good woodworking plans on the net I have borrowed a few woodworking books from the local library. One of them is "Build your own contemporary furniture" (ISBN number 1-55870-610-0) from plans published in the Popular Woodworking magazine.

I have made one model from the plans already:

The next plan I did was the Modern Console from that same book and it would not work, the measurements would not line up. I followed the directions and the cutlist but some pieces were too small and others were too large. I double checked all the measurements but I had to adjust quite a few pieces.

Now when making a SU model it is just a matter of a few clicks and hey presto the piece is bigger and actually reaches. In real life if you followed the cutlist you would have trim some pieces and to go get a new piece of timber because some pieces were too short.

I just goes to show that plans even from the pros like Popular Woodworking are not always perfect.

Dave R · 31 Mar 2009, 23:50

Yes, this is a common problem with plans. Some dimension or dimensions get missed or are incorrect. Frequently angles are rounded off and important dimensions are omitted. I have found a number of errors as I've redrawn plans from various woodworking magazines in SketchUp. Curoiously I rarely ever see comments on the woodworking forums about these errors and I wonder if they are being found. Maybe only a few of the projects ever really get built so the errors are not noticed.

Boatbuilders take time to draw out the lines of boats full size before building them. It's called "lofting" and one of the things it is used for is to check the "plans" for erors. It isn't uncommon to have to move points on the lines to get the curves to be fair. I suspect a lot of woodworkers would benefit from doing the same sort of thing. SketchUp can actually do that if it helps you find the errors as you did.

Hazza · 1 Apr 2009, 22:59

Ha, I worked it out, I have SU7 on my laptop in my room but I am not allowed to connect it to the work network. I just saved the model as a SU6 file and then ran SU6 from my external HDD and uploaded it here:

Roger · 25 Apr 2009, 07:51

I have run into the same problem, but I just put cardboard under the the short leg (just kidding).

Where I did have a problem was assembling an IKEA plan-cabinet-like thing.

The factory had the static part of the drawer runners already installed. However a bored Swede wanted to know what would happen if he shifted the screw holes on one side one screw hole from the runner on the other side.

It drives some poor American nuts.

I was getting ready to smash the whole thing with a hammer when I got out my flash light and counted holes on both sides. I should have taped the whole thing and put it on YouTube. You just expect mechanical perfection from the Swedes.

Sawduster · 25 Jun 2009, 15:54

Every now and again you will run across a correction to a plan in a later issue of the magazine. Doesn't help the fella who jumped right in and went to making the project, and I suspect that is how many of the problems are discovered.

I've never been very successful at cutting all of the pieces of a project to the cutlist, then assembling the project. Incorrect dimensions in a plan is only one of the problems with that method of building. A bigger problem is that there is some small amount of error in every measurement and cut that you make. Some of this is due to the measuring device being used, and then there is parallax error. Even the thickness of the marks on the measuring device can throw you off sufficiently to cause a visible seam where two parts come together. And, as Murphy would have it, these errors are cumulative rather than canceling each other out.

Over my years of wood working I have developed the attitude that dimensions in the plan are no more than suggestions and approximations. When actually building, I use the plan dimensions for the perimeter parts, then more or less toss the measuring devices aside. These perimeter parts are then dry assembled, squared and clamped, and I use a story stick or the actual workpiece held partially in place to mark them for use in setting up for making the final cuts. This is an old hand tool method that lends itself well to machine work.