jd5000
Well-known member
I bought an old Wissota bench grinder. The grinder is fine but is missing the side guards. Could I cut out a piece of acrylic/plexiglass and use that for some side guards?
Bench grinder missing side guards - make with acrylic?
- Thread starter jd5000
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RoninB4
Well-known member
-Not knowing the size of the motor:
-If it's safety that concerns you then no. Polycarbonate/Lexan/Plexiglass can shatter easier than you think, depending upon thickness and stress raisers. When it shatters the shrapnel edges will be like knives.
-If it's spark control then it's decidedly not as good as sheet metal. Sparks will soon begin to cloud the transparency and it will look like an amateur home-shop effort.
-I'm not knocking you for asking I'm just trying to steer you into a safer solution than Plexi. Ask yourself why OEM doesn't use plastic sideguards? The larger the motor the greater the risks. JMO
-If it's safety that concerns you then no. Polycarbonate/Lexan/Plexiglass can shatter easier than you think, depending upon thickness and stress raisers. When it shatters the shrapnel edges will be like knives.
-If it's spark control then it's decidedly not as good as sheet metal. Sparks will soon begin to cloud the transparency and it will look like an amateur home-shop effort.
-I'm not knocking you for asking I'm just trying to steer you into a safer solution than Plexi. Ask yourself why OEM doesn't use plastic sideguards? The larger the motor the greater the risks. JMO
RoninB4
Well-known member
-Plywood has a chance of catching on fire so I wouldn't use that either. Davefr had it right, trace the outline on a sheet of steel or aluminum (which is easier to cut/drill) and drill the mounting holes. Knock off the sharp edges with a file, paint, and it will not only be safer but also look professional. It's a nice grinder you have there, might as well make it look good too.
MushCreek
Well-known member
Plexiglass and Lexan are very different materials. Lexan (polycarbonate) would probably work, but I'd use metal.
Black300zx
Well-known member
Agreed with everything above. You're dealing with a pretty simple shape here. If you can cut plexi or wood to that profile, you can cut some sheet aluminum or steel and have a much more effective guard.
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seber
Well-known member
You may need to cut a hole in the middle to clear the shaft. I would opt for steel. Aluminum will eventually look pretty beat up. As others have said, stay away from plastic. If you intend to use a wire wheel however, no end cap is needed and will in fact hinder use.
You could probably get away with plexiglass but it would get pitted up or impeded with metal bits. At least you've got decent clearance. One of mine the wire wheel side cover is iff because it rubs.
It would be easy enough to cut them out of sheet metal.
It would be easy enough to cut them out of sheet metal.
Firebrick43
Well-known member
Absolutely no to acrylic/plexiglass/perplex. It’s brittle and therefore terrible idea.
Lexan/polycarbonate is what some bullet proof windows are made from. It might crack(rare) but I have never seen it shatter.
As @MushCreek stated they are not the same material and people should know better before advocating for plexiglass/acrylic.
We use a lot of lexan for machine tool windows and it was pretty effective at stopping pieces of shattered carbide drills and framers when they blew up.
One idiot didn’t know the difference and put in plexiglass. Luckily when a tool blew up months later no one was standing at the HMI directly in front of the window. They wypall box at the door jamb was peppered with shards of plexiglass. The chunk of 7/8” solid carbide drill that Went through it was found 25’ across the isle.
The guard and rest on the wire wheel side should be removed entirely
Lexan/polycarbonate is what some bullet proof windows are made from. It might crack(rare) but I have never seen it shatter.
As @MushCreek stated they are not the same material and people should know better before advocating for plexiglass/acrylic.
We use a lot of lexan for machine tool windows and it was pretty effective at stopping pieces of shattered carbide drills and framers when they blew up.
One idiot didn’t know the difference and put in plexiglass. Luckily when a tool blew up months later no one was standing at the HMI directly in front of the window. They wypall box at the door jamb was peppered with shards of plexiglass. The chunk of 7/8” solid carbide drill that Went through it was found 25’ across the isle.
The guard and rest on the wire wheel side should be removed entirely
2 Wissota 7" bench grinder buffing wheels guards & rests light US made tool | eBay
Because of this, they are sold AS IS, as found. WE WILL NOT!
www.ebay.com
rlitman
Well-known member
You are confusing two VERY different materials.
Polycarbonate = Lexan = shatterproof, but also has the scratch resistance of jello unless coated. This is what your typical ANSI Z87 face shields are made from. Polycarbonate suffers badly from stress cracking, but will never crack under impact, no matter the thickness.
Plexiglass = acrylic = shatters into shards, but slightly more scratch resistant. Acrylic is actually what's used in most bullet resistant windows (and all non-glass aquariums), but only in thick sections. It's also what you find in submersible windows, because polycarbonate is way too soft and flexible. Acrylic is a little bit more impact resistant than non-tempered glass.
For the purposes of a grinder, I don't think I'd be comfortable with acrylic under 1/2" thick to withstand an impact and not throw dangerous shards. For thin see-through safety windows, not much beats polycarbonate, but it's going to haze pretty fast.
Lexan is used in forestry equipment windows and gets hit with branches all day. Optioned for skid steers for safety of rocks hitting it, like with a bush hog or fecon mulcher
Also used in race car windshields... maybe not now, I haven't followed NASCAR in ~25 years.
RoninB4
Well-known member
-As a former mold maker I'm well aware of the fact that they're different materials. You're stating technical definition but ignoring the context of my reply. I purposely lumped them all together for the benefit of the OP, or anybody else reading, that probably wouldn't know the difference of one plastic to another. The fact that the next suggestion was for plywood certainly supports that theory.
-However, I do appreciate you being diligent enough to point out a perceived mistake but not offering much in the way of a helpful suggestion for the OP.
RoninB4
Well-known member
-Yes, I've made many safety shields from Lexan that would survive impact. Despite the impact resistance of the material there's still a tendency for fracture propagation at stress raisers. For an unskilled person to try crafting a guard from Lexan there's a good chance several stress raisers would be present in the form of poorly drilled holes and sharp edges. Furthermore, the OP is not likely to know one plastic from another and substitute whatever is available. I don't like to offer advice that I think may lead someone to injury and I'll attempt to offer a safer solution.
-You are correct in your reply and I appreciate your input but I still don't advise the unskilled to use it in this application when sheet metal is a safer, readily available option.
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