From Arc Welded Projects, Volume IVThe James F. Lincoln Arc Welding Foundation
This welding project was prepared by Jason Plantenberg of Tomahawk High (Thayer David, Instructor) in Tomahawk, WI as an entry in the James F. Lincoln Arc Welding Foundation Award Program.
A pit cart of this type is used by Motocross and other racers to take tools and equipment from their trailers down into the pits for easy access. The cart is designed to hold heavy objects such as toolboxes, rims and tires, air compressors, tables, and anything else needed in the pits. This pit cart incorporates tables to slide inside the cart from the side for easy access, and doors that fold into thirds to take up a minimum of space.
Building the Frame
Start by cutting the square tubing material into sections using a band saw. Cut eight lengths of 72", four lengths of 32", and 6 lengths of 31". Begin by making the two end rectangles of the frame, with the 32" sections for the height and the 31" pieces for the width. Be sure everything is square and tack-weld each corner of the two rectangles using a MIG welder. Now add in four of the 72" pieces for length. Tack-weld everything together and check that it is square everywhere.
Add in two more sections of 72" tubing, placing them 6" from the bottom of the top section of the frame. (Dimensions may vary depending on the size of tables to be placed inside.) Measure another 6" down and add another two sections of 72" tubing, one on each side for another table. Now tack on the section of angle iron to the inside of the 72" pieces that were just added. This will serve as the table tray. Now add in two sections of 31" tubing to one end, directly perpendicular to the 72" sections that were just added. These will serve as a back support so the tables do not slide out.
Add in the remaining sections of 31" tubing to the bottom of the cart. Spacing will depend on the load requirements for the cart. In the example shown here, the spacing was roughly 8". Finish by welding everything together, checking along the way to make sure that everything is square and making adjustments as necessary.
Assembling the Steering Components
The steering components include the handle bar, spindle bracket, spindle and bracket set, tie rods, axles, and pneumatic tires. To make the spindle bracket, start by cutting all the pieces needed. Sizes will depend upon the specific application, but in the example shown here, all flat steel was 3/16" thick, and the following pieces were cut: one at 4" x 2", one at 2-1/2" x 2", one at 6-1/2" x 2", two at 2-1/2" x 1- 1/2". After cutting the pieces, measure for holes to be drilled and drill them all. Be precise. Measure 1/2" from one end of the 6-1/2" x 2" piece and 1/2" in from the side, and drill a 3/8" hole. Repeat on the other side, but do this to only one end.
On the other end, mark and drill a 5/8" hole in the center and 1" down from the top of that end. Take the 2-1/2" x 2" piece and mark and drill a 5/8" hole in the center and 1" down from the top of the piece. This piece will have to line up perfectly with the 5/8" hole made in the 6-1/2" x 2" piece earlier. In the two pieces of 2-1/2" x 1-1/2", drill a 3/8" hole in each, a half inch down from the top and a half inch in from the side.
Now that all the holes are drilled, take the piece of 4" x 2" and tack weld it exactly perpendicular on the 6-1/2" piece. Then take the section of the 2-1/2" x 2" with the 5/8" hole and tack weld it at 90 degrees to the upright that was just tacked in. The 5/8" holes must match up perfectly so that the pin can fit through them with ease. This assembly now resembles a lower case "h." To finish it, weld in the last two remaining sections to the back side of the only upright when the piece is laid flat on its long side. Tack these pieces in so that all edges match up and the holes drilled in the pieces are on the high side, allowing room for the handle bar to move up and down with ease.
Now MIG weld everything up. To finish up the piece, put it on a vertical mill and using a 3/8" bit, remove 1/2" to the bottom of the handle bar upright supports. This will give room for the tie rods to move more and give the cart a tighter turning radius. Finally, weld the axles from the kit and bolt up the wheel assembly.
Check again that the frame is square and make adjustments as necessary. Paint the frame the desired color. Using a shear or similar tool cut up the sheet metal to size for: two floors, a back, one permanent side, one side that flips down, stainless steel trim around wheel wells, and a front consisting of two doors. Each door will fold up into thirds on piano hinges.
Use rivets and silicone sealant to secure everything in place. Start by adding in the floors first, and secure them permanently. For the side where the tables go, simply attach a hinge so that the door can fold down. To make the doors, cut the piece in half, and cut each half into thirds. Add hinges with rivets to create two doors that fold into thirds. Put a latch on each of these so that they will not fly open.
Using rivets attach the stainless steel tabletop and add on the vise and anything else needed. The bottom tray may be left as open space, or it can hold plastic containers. Finally, add the tie rod assembly, trim pieces, tables, and handle bar. Clean up everything. Make steering adjustments to the tie rod assembly as necessary.
It is important to use enough ventilation to keep the fumes and gases from your breathing zone. For occasional welding in a large room with good cross-ventilation, natural ventilation may be adequate if you keep your head out of the welding fumes. However, be aware that strong drafts directed at the welding arc may blow away the shielding gas and affect the quality of your weld. In planning your workshop ventilation, it is preferable to use ventilation that pulls fume from the work area rather than blows necessary shielding gas away.
Remember, electric shock can kill. Wear dry, hole-free leather gloves when you weld. Never touch the electrode or work with bare hands when the welder is on. Be sure you are properly insulated from live electrical parts, such as the electrode and the welding table when the work clamp is attached. Be sure you and your work area stay dry; never weld when you or your clothing is wet. Be sure your welding equipment is turned off when not in use. Note that Lincoln wire feed / welders have a relatively low open circuit voltage and include an internal contactor that keeps the welding electrode electrically 'cold' until the gun trigger is pressed. These important safety features reduce your risk of electric shock during any welding project.
It is essential that your eyes are protected from the welding arc. Infrared radiation has been known to cause retinal burning. Even brief unprotected exposure can cause eye burn known as 'welder's flash'. Normally, welder's flash is temporary, but it can cause extreme discomfort. Prolonged exposure can lead to permanent injury.
Workspace - Protection from Sparks
Before you get started on any welding project, it is important that you make sure your work area is free of trash, sawdust, paint, aerosol cans and any other flammable materials. A minimum five-foot radius around the arc, free of flammable liquids or other materials, is recommended. Extra care should be taken in workshops that are primarily used for woodworking as sawdust can collect inside machines and in other hard to clean spaces. If a spark finds its way into one of these sawdust crannies, the results could be disastrous. If your shop area is too small to allow for a safe radius, please use an alternate area like a garage or driveway.
Cylinders can explode if damaged. Always keep your shielding gas cylinder upright and secured. Never allow the welding electrode to touch the cylinder.
It is also imperative to make sure you have all the necessary safety equipment and that you're wearing welding friendly clothes. You should wear:
Welding gloves - dry and in good condition
Safety glasses with side shields
Protective welding shield with a dark lens shade appropriate for the type of welding you do
Head protection - like a fire retardant cotton or leather cap
Long-sleeve cotton shirt
Long cotton pants
Leather work boots
A fire extinguisher should also be on hand during any welding. Also, make certain no children are in the area when you are welding. They may watch the arc and can experience retinal damage from its intense light. There is also a risk of a child getting burned by welding spatter.
Finally, see the instruction manual for your welder for added safety information.
*This project was published in Arc Welded Projects, Volume IV by the James F. Lincoln Arc Welding Foundation. The material has been edited and some of the drawings improved, but neither the projects nor drawings and instructions have been reviewed for accuracy or safety.
*This project was included because it appeared to be interesting, and in some respects, proposed novel applications. However, since the James F. Lincoln Arc Welding Foundation or the Lincoln Electric Company have not tested the material, nor verified the computations or other aspects described, the Foundation or Lincoln Electric cannot, and does not, assume responsibility for the accuracy of the plans or safety of the project. The project was submitted for such use as may appear feasible, but those making the project must assume full responsibility for the results of their efforts to make or use the project described.