Grinder Safety Shield

I recently completed an upgraded tool rest for my bench grinder and one of the comments asked about making a safety shield for it. I normally take the factory ones off because I find them pretty useless and prefer to wear safety glasses. But this did get me thinking about a better design for a safety shield, and I decided to design and produce the plans for it. The basic mechanics are copied from a drafting lamp.

While I tried to draw up the design before building this, there were a few parts I needed to figure out as I went. I have updated the plans so you can just print the template out.

1. 3mm thick flat bar
2. 10mm round bar
3. 8mm x 8mm square bar
4. M4 Bolts
5. M4 Nyloc nuts
6. M4 thumb nut
7. Springs
8. Small metal tube
9. Acrylic shield
10. Thin metal
11. Drill press
12. Grinder
13. Printer
14. Glue Stick
15. Hacksaw
16. Small file
17. Tube cutters

The first thing you need to do is print out the attached template. I have made an A4 and a Letter sized template, so just be sure to download the correct one for whatever size paper you use.

Once you have printed out the template, just cut out the parts and then glue onto the metal bar with a glue stick.

Cut out the five support bars from a piece of the flat bar using an angle grinder with a cut-off disc. You can saw these out if you don't have a grinder.

Now drill the first hole in each bar and bolt them together before drilling the second hole. This will ensure the hole spacing is identical between all five support bars. You will be repeating this process for some of the other parts, and keeping the hole spacing identical is very important to make sure everything works correctly.

Lastly, I used a grinder to round the ends of the bar into a semi-circle, basically just grind the final shape to match the template.

The process for making the triangle brackets is nearly the same as the supports. Glue the plans onto some flat bar, cut the triangles out with a grinder, drill the first hole and then bolt all four together, drill the second hole and then place another bolt through that as well and drill the third hole as well.

While not strictly needed the large centre hole helps lighten the frame a little bit and makes it look nicer. I drilled this out to a 18mm hole, but if you don't have a drill bit that large it doesn't matter.

Once again use the template and cut out the two mounts, drill the holes and bolt the two parts together and drill the next hole adding a bolt each time to keep the holes aligned. While the parts are still together grind all the corners into sharp curves.

I then drilled a hole through the grinder safety guard and bolted one of the mounts on. I then aligned mount to the correct location and marked second hole, removed the mount and drilled the second hole.

Ensure the holes are far enough away from the grinding wheel, and remember that a brand-new wheel is larger than an old one so allow for that!

I'm not gonna lie, this part was a pain in the neck to do. If you want an easier way to do this you can just stack up a series of small washers.

The measurements for the spacers are on the plans, you can use a saw or grinder to cut the correct number of spacers of each size. You can either sand or grind the spacers smooth so there are no sharp edges.

The hard part was trying to drill the holes through the spacers in the centre and keep them straight. I ended up reverse-drilling the holes by holding the spacer in the drill press chuck and then holding the drill bit in a spare chuck in the drill vice.

This worked well and I'm pleased with the results, I can't remember where I learnt this but it was somewhere on Intructables. So thanks to whoever it was!

While this looks a little complex, it's fairly easy to make. Using the piece of 8mm x 8mm bar glue the side template onto one side and the top template onto the top of the bar.

Now start by drilling the holes through the bar, flip the bar around in the vice use a hacksaw to cut the slot.

Back on the drill press drill the larger hole through the top of the slot.

You can now thread the holes using an M4 tap, only the bottom of the slot needs to be taped.

The top of the mount was made from a small piece of thin metal (I used aluminium because it's easy to bend). I just bent it around a piece of the round bar with some pliers and drilled a hole at each end. Using a couple of small M4 bolts you can secure the two parts together.

I didn't have any acrylic sheets of the correct thickness but I did have a brand-new grinder shield (I did tell you I don't use the factory ones). I carefully sawed the mounts off, drilled a small hole through the plastic and then bolted in onto the shield mount.

You can make the shield whatever size you want, but I've included a couple of designs in the templates. You can saw the acrylic and sand any edges smooth.

The spring spacers are needed to hold the springs in place and allow them to move around the axis and tighten the bolts that hold everything together. You don't need to use brass tube, that's just what I had on hand.

Use some small tube cutters to cut eight spacers. I used a centre drill bit to de-burr the ends of each spacer.

Lastly, I used a sanding wheel to polish the spacers up. It's easier to hold them with a rod through the middle.

Using the same sanding wheel I gave everything a quick buff to clean everything up a bit. If you want you could spray a paint the parts at this stage, but I'm happy with how it looks now. Spray on a little bit of light oil to prevent rust if you didn't paint it.

You can now do a final test fit for all the parts, at this stage I trimmed the bolts to the correct length. Remember if you cut a bolt you will need to grind or file the cut clean so the nut will go on.

Depending on the width of the grinder safety guards you can pack the spacers on the mounts with a few small washers.