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3067 posts

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# 261448 28-Nov-2019 09:42
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I remember the chainsaw tooth style grinder discs being discussed somewhere but can't find the thread. It possibly came up off topic. I've never tried them but thought well if you took care you could manage it. After watching this video by an experienced woodworker I know I won't be.



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  # 2362189 28-Nov-2019 10:53
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Yeah...

 

With grinder safety, I think about scenes in gangster movies, the "we're going to take you for a ride" up some side road miles from anywhere, the victim always seems to make the same plea "not in the face - I want an open coffin".  It's somewhat worse (IMO) than having a finger or two cut off to teach you a lesson.


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  # 2362251 28-Nov-2019 11:30
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I've never seen a chainsaw type disc on a grinder before. I definitely wouldn't try using one.

 

The scariest tool I have for my angle grinder is a wire wheel. I can't use the safety guard with it as the ends of the wires hit it. I've often thought how bad it would be if I accidentally let go of the grinder while it's going! Oh and I always use eye goggles with the wire wheel as I've had numerous wires from it break off and embed themselves in my flesh.


 
 
 
 


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  # 2362257 28-Nov-2019 11:40
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DarthKermit:

 

I can't use the safety guard with it as the ends of the wires hit it. 

 

 

Well you probably got the wrong wire wheel, maybe the guard is for 115mm and the wheel is 125mm,  There's a second problem with this, the rpm rating for disks etc usually goes down as the diameter increases, a 115mm grinder may turn at higher rpm than a 125mm disk is rated for, that may be part of the reason why wires come loose.


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  # 2362266 28-Nov-2019 12:03
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Fred99:

 

DarthKermit:

 

I can't use the safety guard with it as the ends of the wires hit it. 

 

 

Well you probably got the wrong wire wheel, maybe the guard is for 115mm and the wheel is 125mm,  There's a second problem with this, the rpm rating for disks etc usually goes down as the diameter increases, a 115mm grinder may turn at higher rpm than a 125mm disk is rated for, that may be part of the reason why wires come loose.

 



This.

It is a pritty common example at workplace safety training (in the construction / industrial sector). Operator has run out of blades for the little angle grinder, and there are blades for the big grinder available (but that grinder is in use). Operator fits a big disk to the little grinder, assuming that the big gear is stronger, and hence fine with the little grinder. Operator needs to remove guard to fit the bigger disk.

 

Operator does not check RPM rating of big disk against speed of smaller grinder, and the disk shatters when in operation due to massive over speed, flinging high speed fragments.


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Ultimate Geek


  # 2362452 28-Nov-2019 22:42
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Jeesz, no wonder that guy is called Stumpy Nubs!

 

Having said that, I appreciate the video. That is fricken terrifying! I'd seen those blades before and thought they looked dicey but that video really emphasises it.


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  # 2362490 29-Nov-2019 05:52
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Fred99:

DarthKermit:


I can't use the safety guard with it as the ends of the wires hit it. 



Well you probably got the wrong wire wheel, maybe the guard is for 115mm and the wheel is 125mm,  There's a second problem with this, the rpm rating for disks etc usually goes down as the diameter increases, a 115mm grinder may turn at higher rpm than a 125mm disk is rated for, that may be part of the reason why wires come loose.



I seriously doubt this, unless he has significantly modified either the grinder or the wire wheel.

115mm grinders have a much smaller centre mounting hole than 125mm, specifically to prevent the interchanging of discs between the two.



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  # 2362492 29-Nov-2019 06:16
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Scott3: This.

It is a pritty common example at workplace safety training (in the construction / industrial sector). Operator has run out of blades for the little angle grinder, and there are blades for the big grinder available (but that grinder is in use). Operator fits a big disk to the little grinder, assuming that the big gear is stronger, and hence fine with the little grinder. Operator needs to remove guard to fit the bigger disk.


Operator does not check RPM rating of big disk against speed of smaller grinder, and the disk shatters when in operation due to massive over speed, flinging high speed fragments.



RPM ratings of 100 -125mm discs are often similar. A quick survey finds 100mm grinders typically 11,000rpm and discs rated 13,000 - 15,000rpm. While some 125mm grinders are ~7000rpm there are others that match the smaller model 11,000rpm. 125mm discs are typically rated 11,000 - 12,500rpm.

Some people use worn down discs on smaller grinders. Maybe by that stage the disc has already suffer some abuse and it is age rather than speed rating.

 
 
 
 


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  # 2362680 29-Nov-2019 10:06
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Ge0rge:
Fred99:

 

DarthKermit:

 

 

 

I can't use the safety guard with it as the ends of the wires hit it. 

 

 

 

 

 

 

Well you probably got the wrong wire wheel, maybe the guard is for 115mm and the wheel is 125mm,  There's a second problem with this, the rpm rating for disks etc usually goes down as the diameter increases, a 115mm grinder may turn at higher rpm than a 125mm disk is rated for, that may be part of the reason why wires come loose.

 



I seriously doubt this, unless he has significantly modified either the grinder or the wire wheel.

115mm grinders have a much smaller centre mounting hole than 125mm, specifically to prevent the interchanging of discs between the two.

 

Yes - but many of the accessories sold come with a brass ring to insert so you can fit a standard 125mm disk on the smaller arbor.  Now maybe that adaptor is okay with the accessory it's sold with - but it probably ends up loose in the toolkit. Then there's the chinese cheaply made factor, with both cheap grinders and the cheap accessories.

 

 


gzt

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  # 2362694 29-Nov-2019 10:21
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Some of the stuff described in that video is just crazy and the wrong tooll for the job.

Apart from that there are specialist carving tools gone through several design iterations. Still dangerous, not as dangerous:


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