Quick and Easy Grinder Jig

I'm just getting into metal working and I wanted to make a jig to fix the angle grinder to more easily shape metal (like knife blanks). Using basic tools and some scrap material that I already had available, the idea for the Quick and easy Grinder Jig was made!

Materials

1. Angle grinder with latching on/off power switch
2. 120V Foot pedal switch (optional)
3. Piece of plywood approximately 3" x 5" by 3/8" thick (or similar spacer for end of grinder)
4. Four 2x2 pieces that are about 4"long (legs)
5. Two 2" L-brackets (I 3D printed mine, but metal is ideal)
6. 2-1/2" u-bolt
7. 9" x 14" sheet of plywood that is at least 1/2" thick (for jig base)
8. 3" x 5" - 1/2" plywood (vertical support)
9. (16) 5/8" wood screws
10. (8) 1-1/2" wood screws
11. One M8x1.25 approximately 3/4" long (to secure grinder to vertical support)

Tools

1. Wood glue
2. Screw gun
3. Scroll saw or Jig saw
4. Sander (optional)
5. Drill & drill bits

Start by laying the grinder lengthwise on the 9" x 14" piece of plywood with the back of the grinder head about 3" from the back edge of the plywood. Once you have your grinder in place mark a oval shape around the blade (Note: make sure to mark with the flap sanding disc on grinder) keeping a even gap on both sides. Use a 1" drill bit to drill holes on both ends of the oval and then cut the oval out using a scroll saw or jig saw.

Lay your Grinder, 3" x 5" vertical support plywood, and brackets in place. Mark a circle on the vertical support to match the auxiliary handle threaded hole as shown in the picture. Then drill the hole and make sure the bolt fits. Over-sizing the drilled hole slightly and using a washer maybe helpful if your having difficulty lining this up properly. Place the u-bolt over the grinder handle and mark the two holes for the u-bolt as shown (Note: I made a slot for the back hole to provide a little more wiggle room but its totally optional) and then drill them out.

Before we start screwing anything down, now would be the time to sand or paint. I chose to leave mine natural. Bolt down the angle grinder with the u-bolt and screw the vertical support to the back of the grinder head with the M8 bolt. Put the L-brackets in place on both sides of vertical support bolt and screw brackets to the 3x5 piece plywood with the 5/8" screws. Next align the grinder face as close to square as possible with the platform and screw down the bottom of the L-brackets with more 5/8" screws.

Screw the four 2x2 pieces down near the platform corners for the jig legs. Ensure the legs provide enough clearance to keep the disk well away from the surface the jig will rest on. I chose to screw the front right one right behind the oval shaped hole, but it could have also gone in the corner. Glue the 3" x 5" by 3/8" plywood spacer on the left side of the plywood and put some clamps on it to dry. This was strictly to hold the grinder closer to parallel with the base.

To use this jig, latch the grinder into the on position and connect it to the foot pedal switch. If your angle grinder doesn't have a latching switch then perhaps a zip tie could be used to hold the switch in the on position. Ensure the system is bolted down and tightened prior to plugging the foot pedal into a receptacle. Grab your safety glasses, and make sure your area is safe for wandering sparks.

One last word of caution, to ensure your work piece is controlled, make sure not to stick anything in the slot between the disc and the plywood base.

You did it! Now you have reliable,affordable,and easy to make grinder jig to get more precise grinding and shaping. This jig can grind metal and sand wood when using the flap disc. Now power it up and get to work!