Tuesday, October 30, 2012

Simple Sturdy Assembly Bench

For some years I have been using a small Sears Craftsman bench for woodworking assembly. Recently, I started working with a local group which was in the process of creating a MakerSpace. One item that this operation will require is a number of general purpose sturdy, inexpensive benches. As a prototype bench, I designed and constructed the largest assembly bench that my shop could accommodate. The bench has a 24" by 48" by 33" base with a 54" by 30" surface, 1 1/2" thick. The base is constructed of 2x4's and the surface, MDF.

The construction of the base started with the H shaped end sections, shown below. The section is assembled with Kreg screws and wood glue. The bottom cross piece is placed 4" from the bottom of the leg. During assembly, check squareness using a carpenters square since the 2x4's are knotty. If not square, loosen screws slightly and adjust. Don't worry about a weak joint, since there will be overlap at all joints which will more than strengthen the joint.

Base H section
The next step is to attach the cross pieces between the H sections. Once again use the carpenters square to square up the pieces. This is important since once the base skeleton is assembled squaring will be too late.

Attaching cross members
 Use glue and Kreg screws for the joints.

Base skeleton assembled
Note in the above picture the addition of a second 2x4 glued to the top cross member for strength. Click the picture for a better view. Now glue additional 2x4's to all skeletal members as shown in the next picture. Note the Kreg holes drilled in the top member for fastening the top to the base. Set the Kreg for 3/4" thickness.

Shown below is the completed base. If you enlarge the picture, you can see the Kreg screw hole for attaching the top.

Completed base
The top is constructed of 3/4" MDF with a 4 1/2" edging of MDF. A thin coat of glue was spread evenly on the MDF edge  pieces and then lightly clamped. The inner pieces are scrape 3/4" plywood for attaching the top. I had HomeDepot cut the MDF to 54" by 30" with the 54" vertical cut made first. The 4 1/2" edge pieces were cut on my table saw and then cut to length with the miter saw.

Bottom of bench top.
Using a 1/8" round-over bit, all edges were dressed and sanded. The top was then sealed with SealCoat. Three layers of oil based polyurethane were then applied and sanded between coats.

Completed bench.