:: Introduction
In this project you will recreate a virtual prototype of a workbench. The workbench specifications a from a book entitled The Boy Mechanic: Volume 1, 700 Things for Boys to Do. The book, originally written in 1913, was published by Popular Mechanics and was a collection of activities to keep young boys (and probably future engineers) occupied in their spare time. Before video games, MTV, and the Internet, young boys actually used their minds to create incredible crafts and useful devices.
This text is an interesting collection of projects that are still very relevant and useful today. We can often learn much from reviewing the past and there are some amazing and practical devices and applications. I recommend a review of this book by all engineering students. Since this book is in the public domain, it is also available in an eText version from The Gutenberg Project and can be found here. I would encourage students to also mine the Gutenberg Project site for other great free literature and reference books.
:: Objective
This project will present the engineering student with a set of very rough notes and sketches and then require them to recreate a virtual representation of the object using SketchUp software. The following learning objectives apply:
- Visualizing a 3D object from a 2D description
- Creating a modern virtual 3D object from historical documents
- Analyzing past designs to understand basic design components and processes
- Modeling and rendering using modern computer-based visualization software (SketchUp)
- View a gallery of images from a completed model
:: Directions
Using the specifications found in the section below, recreate the workbench in SketchUp. This project is worth 200 points. You will be graded on the following:
- File units are accurately selected. (10 points)
- Overall bounding box dimensions of the workbench are included on the final view and are in the correct format including inches and fractional units. (20 points)
- You should have two final isometric perspective, with the front view on the left hand side, views saved using Pages. The first view will be a view called Photo and will include the color and materials using the Display shaded using textures and shadow mode. The second view will be a view called Sketch will use be the same orientation as the previous view but will use the hidden line and shadows mode. This view will contain the overall dimensions. (20 points)
- Auxiliary objects such as fasteners and vise are accurately and proportionally presented. Use your dividers to approximate sizes when a dimension is not known. Screw and fastener holes should also be created to present a more accurate representation of the object. Screws need not contain threads and objects receiving the fastening devices do not need to have pre-constructed holes. Components may be used if available. (30 points)
- Realistic materials and/or colors are used to accurately represent the object. (20 points)
- All object elements are created using accurate and true size. (100 points)
Modeling Tips:
- Create each individual piece as listed in the original description below. Be sure to include your mortise and tenons on pieces that require this fastening technique.
- Organize your pieces by using either Groups or Components. I found these techniques far superior to using layers because I was finding that even though an item was on a separate layer, it was still affecting other objects on other layers. Not the optimal solution. As I did more research online I found that components are the preferred method of maintain part integrity.
- Groups: Once you have a piece created, highlight the entire piece and use the Edit/Make Group menu item. A Group items is created and can no longer be modified without first exploding the item.
- Components: Once you have a piece created, highlight the entire piece and use the Edit/Make Component... menu item. Create components for each items and then assemble the pieces. Be sure to assemble as you go to ensure your pieces all fit together without a big surprise at the end!
- Use extensive use of construction lines to assist in the placement of objects.
You will save the file as workbench.skp and upload to eLearning on or before the due date specified in class.
:: Specifications
A Workbench for the Amateur [The Boy Mechanic page 278-280]
The accompanying detail drawing shows a design of a portable workbench suitable
for the amateur woodworker.
This bench can be made easily by anyone who has a few sharp tools and a little spare time. If the stock is purchased from the mill ready planed and cut to length, much of the hard labor will be saved. Birch or maple wood makes a very good bench and the following pieces should be ordered :
4 legs, 3 by 3 by 36.
2 side rails, 3 by 3 by 62-1/2 in.
2 end rails, 3 by 3 by 20 in.
1 back board, 1 by 9 by 80 in.
1 top board, 2 by 12 by 77 in.
1 top board, 1 by 12 by 77 in.
2 crosspieces, 1-1/2 by 3 by 24 in.
1 piece for clamp, 1-1/2 by 6-1/2 by 12 in.
1 piece for clamp, 1-1/2 by 6-1/2 by 14 in.
4 guides, 2 by 2 by 18 in.
1 screw block, 3 by 3 by 6 in.
1 piece, 1-1/2 by 4-1/2 by 10-1/2 in.
1 end piece, 1-1/2 by 8 by 24in.1
1 end piece, 1-1/2 by 6-1/2 by 24in.1
Make the lower frame first. Cut tenons on the rails and mortise the posts, then
fasten them securely together with 3/8 by 5-in. lag screws as shown. Also fasten the 1- 1/2 by 3 by 24-in. pieces to the tops of the posts with screws. The heads should be countersunk or else holes bored in the top boards to fit over them. Fasten the front top board to the crosspieces by lag screws through from the under side. The screws can be put in from the top for the 1-in. thick top board.
Fasten the end pieces on with screws, countersinking the heads of the vise end. Cut the 2-in. square holes in the 1-1/2 by 4-1/2 by 10-in. pieces for the vise slides, and fit it in place for the side vise. Also cut square holes in the one end piece for the end vise slides as shown. Now fit up the two clamps. Fasten the slides to the front pieces with screws. Countersink the heads of the screws so they will not be in the way of the hands when the vise is used. The two clamp screws should be about 1-1/2 in. in diameter. They can be purchased at a hardware store. A block should be fitted under the crosspiece to hold the nut for the end vise. After you have the slides fitted, put them in place and bore the holes for the clamp screws. The back board can now be fastened to the back with screws as shown in the top view. The bench is now complete, except for a couple of coats of oil which should be applied to give it a finish and preserve the wood.
Detail of the Bench
The amateur workman, as well as the pattern maker, will find this a very handy and serviceable bench for his workshop. As the amateur workman does not always know just what tools he will need, a list is given which will answer for a general class of work. This list can be added to as the workman becomes more proficient in his line and has need for other tools. Only the long run. If each tool is kept in a certain place, it can be easily found when wanted.
1 bench plane or jointer
1 jack plane or smoother
1 cross cut saw, 24 in.
1 rip saw, 24 in.
1 claw hammer
1 set gimlets
1 brace and set of bits
2 screwdrivers, 3 and 6 in.
1 countersink
1 compass saw
1 set chisels
1 wood scraper
1 monkey wrench
1 2-ft. rule
1 marking gauge
1 pair pliers
1 nail set
1 pair dividers
1 pocket level
Footnotes:
1 added by Instructor as these pieces are referenced in the instructions but not listed.