The small passive solar greenhouses I make requires cutting 4’x8’ and 4’x12’ sheets across the four foot width with accuracy. A panel saw will cut this type of sheet good but they are expensive and large, too large to move easily. The commercial panel saws are 10’ to 12’ foot wide and six feet high and cost more than $1500.
Step 1: Why Make a Portable Panel Saw?
With these limitations, I decided to make a panel saw that could hold 8’ to 12’ sheet goods and cross cut them accurately. A panel saw differs from a table saw because the sheet goods are held and clamped on edge and the saw moves across the sheet. The saw, similar to a skill saw, moves along a fixed track with a counter balance that allows the saw to move smoothly up and down.
The panel saw I made folds up to a five foot by one and a half foot by five inch box and unfolds to form a rigid eleven foot wide panel saw. It takes about ten minutes to assemble the saw and makes accurate four foot cuts across sheet goods square to within 1/32 of an inch.
Step 2: List of Materrials
1 sheet ¾ Baltic birch
½ sheet ½ Baltic birch
½ sheet ¼ Baltic birch
½ inch by 6” steel rod
2 pieces of Aluminum extruded track the “T” slot 1” by 2” by 60”long
6 x 3/8” bolts
1@2” pulley and 1 @ ¾” pulley
1@ 2” EMT 60 inches long
1@ 1 ½ by 20 long steel pipe
12 @ ¼ “ sliders
16” by 16” by ¼” aluminum plate
10/24 x 1 ½ stove bolts
2@ 1” x ¾“x 16” UHMW Polyethylene
Step 3: Making the Saw Base With Guides
The base of the saw is aligned to the ¼“ aluminum base leaving ¾” along both sides of the plate. A ¾” shim places the aluminum base level with the bottom of the guides. Two pieces of ½” x 2” x 16” pieces of Baltic birch are attached to the UHMW Polyethylene guides using flush fitting 10 20 stove bolts. The guides are placed, drilled and secured while installed in the aluminum tracks. This insures a proper fit to the guides. The orientation and installation of the aluminum tracks establishes the square cut. .
Step 4: Layout of Wood and Aluminum Tracks
The base of ¾” Baltic birch is cut to the width of the saw base plus the width of two of the aluminum tracks. This makes the base 13” by 60” base. A 9” by 22” by ¾” base is screwed and glued perpendicular to the base extending 4 ¼” from the base bottom. This forms the legs for the base and the base to which the folding arms are secured. A 4¼” by 22” is glued and screwed onto this at the bottom of base. This forms a shelf the stops the arms from spreading beyond level. Two 13” by 4 ¼” by ¾” and one 13” by 4 ¼” by ¼” are glued into a block. This forms the support for the aluminum tracks leaving a space a little more than 1 ½” for sheet goods. A similar block is formed for the top of the base.
Step 5: Folding Arms
The arms that support the sheets of material when extended but are design to swing up parallel to the base when in the portable mode. The right and left are made form a sandwich of Baltic birch. The base of the arm is made from a 4” by 60” by ¾” piece. On to this, two pieces of 1 ½” by 55” by ¾” and one piece of 1 ½” by 55” by ¼” are glued then trimmed in place. Then a piece of 4” by 48” by ¼” is glued on the front surface and the face to the arm that keeps the sheet good in place.
Step 6: Bracing for Arms
The arms need additional support to ensure they are level and perpendicular to the saw path. This is done by using ½” sheet bracing. These sheets are supported to be flush with the edge of the base and are held in place by “T” nuts and threaded slides. The sheet bracing then supports a 3” by 40” by ½” that attaches to the fold out arm. The sheeting brace keeps the system rigid.
Step 7: Bracing the Main Rack
The main base is supported by a tripod with a hinged 2” EMT pipe that also seconds as the saw counter balance column. The top of tripod is hinged on a ½” steel rod held in place by a sandwich block of plywood. The tripod is supported by two 2” by ½” by 30” plywood sections supported on the main base so they can fold against the base. When folded down, the secure to two bolts attached to the base of the EMT pipe.
Step 8: Counterbalance for Skill Saw
The saw needs to be counter balanced so that it moves up and down freely. A pulley is set into the block at the top on the main base so that a cable may be passed over the pulley and attached to the counter weight that is housed within the 2” EMT tripod pipe. The counter weight holds a smaller pulley so the cable attaches to the top of the EMT pipe, passes through the counter weight pulley and back to the top, over the upper pulley then attaches to the saw. The counter weight needs to be twice the weight of the saw because of the pulley arrangement.
Step 9: Setting Up the Portable Panel Saw
The panel saw is set up by first setting the tripod in place. Fold down the two arms Next, the sheet braces are fastened to the “T” nuts on both sides using the threaded sliders. Then the brace is folded down to secure to the arm. This makes the arms rigid and holds then in line with each other and perpendicular to the saw track. Setting up the portable panel saw takes about ten minutes.
Step 10: Using the Portable Panel Saw
Once the saw is set up, slide the sheets to be cut along the arms trough so that the saw cut will be at the marked place. Clamp the sheets to the saw main base so tat it does not move while being cut. For repeated cuts, place a clamp at the appropriate distance from the saw cut and slide the sheets into the trough up to the clamp. The panel saw will cut up to 1 ½” of sheet goods accurately at one time. This is a real asset to our greenhouse business.