In this Instructable I will be making be making a pedestal bench grinder using Shielded Metal Arc Welding.
Before We Begin
Operations done in this Instructable can be DANGEROUS if done incorrectly! Know how all the equipment you intend to use works before you use it. Read all associated manuals and directions. If you are unsure about anything , DO NOT ATTEMPT.
This Instructable is not intended to be a source on the use of cutting/grinding or welding equipment. Be safe when using all power tools, cutting/grinding tools, and welding equipment. Take all the proper safety precautions including fire-resistant clothing, leather boots, safety glasses, hearing, respiratory, and all other protection. Have a fire extinguisher close by in case of fire.
Every shop needs a good grinder. The shop grinder must be mounted on a level surface at a good working height to ensure safe operation. I TIG weld, so my main use for this grinder will be sharpening my tungsten electrodes. I am tall, so I wanted the table high enough so I didn't need to stoop down to see. I am also limited in space in my garage shop, so I needed something which took up very little floor space. I looked around at what tables I could buy in stores, and I was not impressed. Everything available was flimsy, over-priced, as well as way too short.
I remembered a quote from Ron Swanson—"People who buy things are suckers"—and decided to get to work.
Step 1: The Plan
I looked through a bunch of varieties of grinding stands and tables online and they seem to come in two types: a 4-legged table or a pedestal stand. Each seemed to have an advantage since 4 legs provides more stability while the pedestal-style takes up less floor space. A pedestal stand would use less material and could be customized to a taller height, so it seemed liked a way to go.
I experimented with table heights by putting my grinder on several different levels and I found 36" was comfortable for me to use. I did not want the table top to stick out too far or have sharp corners, so I decided to go with a circle plate as the base to mount the grinder on. For the base I decided to use a piece of square tube and two pieces of channel iron. All dimensions are given in the plan pictured. (Click on the second image to view in pdf).
Step 2: Tools/ Materials
- Miller TIG/Stick Welder Model 320A /BP
- Lincoln 6011 Stick Electrodes (Used on DCEP Polarity , AC would work too)
- Ox-Acetylene Cut Torch with a size "0" Tip (cut through 3/8 channel Iron to serve as base)
- 4.5" angle grinder with different wheels (grind, cut, flap, wire wheels)
- Big Drill with 3/8" cobalt bit
- Cutting oil
- Channel Iron - 1.5" x 5" x .25" 12" piece was around 5 bucks
- Square Tube- 2" x 2" x .25" - 48" piece was around 10 dollars 0.5"
- Plate cut in a Circle 10" - Precut and bought as scrap for around $5
- Nuts and bolts
Getting the Metal You Need
I went to a welding school, so I never really thought about the cost of the metal I practiced on. Our school received donated scrap metal so there was always plenty of metal around for us to use. When I started welding on my own, I had to start pricing the stuff and it can be expensive. Big Box stores (like Home Depot or Lowes) charge a fortune for steel bar stock and their selection is lousy. Look for Metal Yards in your area. Places with the word "steel" in the name are a good place to start. The less of a "store front" the better. These places will be big warehouse-type buildings in industrial areas. The best ones sell "remnants" or scrap, because you can get pieces already cut in reasonable sizes. (Be aware that some places will charge you for 20' pipe, even if you only needed 10' because it comes in 20' sections.) Lots of times, these places will cut material for you too, but it’s usually $2.00 a cut. That can really add up, but if you don't have a good way of cutting your material, it could be a way to go. You will have to look through scrap metal but believe me it’s worth it.
Case in point:
2" Bar Stock (1/4")
Lowes Price : over $4.00 per foot
Metal Yard Price : Less than $1.00 per foot
In total the metal needed for this table was less than $20.00. The Harbor freight bench grinder stand costs around $50 and it is probably less than 10 pounds of material.
Step 3: Cutting and Fit -Up
To cut this material I used two methods. The thicker channel was cut with an ox-acetylene torch. If you decide to use this method, don’t skimp on safety measures. Always test your equipment for leaks before lighting the torch. I like to use a bucket of water. The whole torch (and hoses) can be submerged underwater - bubbles indicate a leak. The bucket of water is also handy to have around in case flying sparks become an issue. I always make sure to have the hose on and ready to go. Before starting the cut, clamp the piece down (I used an old barbeque skeleton). After lighting the torch and adjusting the flame, make the cut. (That is a picture of me making the cut - it was quite spectacular - I am sure the neighbors love me.)
To cut the square tube (and thinner materials generally), I used a zip disk on a 4.5“ angle grinder. With a little practice, you can make very good cuts with this method.
CAUTION: Be sure to wear eye, face, respiratory, and hearing protection. Zip disks can break while in use. Never drop, over-tighten the disks (I tighten mine by hand, easier to feel when its snug), or otherwise abuse the disks. Change the disks frequently as they do wear out.
After making all the cuts, clean up the rough edges with a flapper disk (sanding disk for a 4.5 angle grinder) to ensure a good fit-up. The material is now ready to weld together.
Step 4: Welding the Table Together
Before welding, put on all the required safety gear. Find a level spot in your garage or shop. Turn your welder on and set the amperage by welding on a piece of scrap. ALWAYS check your machine’s settings on a piece of scrap, before welding on your work. Look for good tie in on your edges and a puddle that is not too fluid. Lay a couple of beads to make sure you have your technique right.
Lay the two pieces of channel and shorter piece of square tube out in a cross pattern with the square tube in the middle and a piece of channel on each side. Tack the pieces together and check for level. Then flip the piece over and add four more tacks on the back side. Be sure to tack your piece well because poor tacks can shift of break during welding giving you problems later. After the piece is tacked,weld the base together. Then slag and clean the welds with a wire wheel.
Next put the long piece of square tube in the middle of the base. Find the center of the shorter piece of square tube and measure an inch above and below. Tack the long piece of square tube and ensure it is straight and level. Weld the tube in place. Then slag and clean the welds with a wire wheel.
Find the middle of the circle plate and draw out where the base should attach. Place the circle on the base and tack. CAREFUL when overhead tacking - turn your amperage down slightly on your machine to keep the puddle controllable. Ensure the circle plate is straight and level. Then flip the table over and weld it in the flat position. (The flat position is much easier unless you like a challenge.) Then slag and clean the welds with a wire wheel.
Now we are ready to mount the Grinder!
Step 5: Mount the Grinder
Make a cardboard cut out the same size as your table top. Measure the bottom of your grinder and mark where it would be on the cardboard, make sure its straight, and then mark where the holes are. Poke holes in the cardboard and use it as a jig to mark your plate. Use a Sharpie to mark the holes. Make sure the grinder is lined up with the base.
Using a big drill with 3/8" cobalt drill bit start making your holes. Make sure you have a good grip on the drill, there is a lot of torque and it can get away from you. A better way to do this would be with a drill press, but, alas, you never have every tool you need. Stop every now and then and put a few drops of cutting oil in the hole to aid in the drilling. Take your time and don't force it. After you get the first hole drilled, check and make sure your other mark is correct. It never hurts to double-check!
Place the grinder on the table and bolt down. Now the table is ready to use.
- Painting the table in order to prevent rust.