View Full Version : Lethal disks

George Hodge
02-28-2011, 10:33 PM
Cutoff wheel disks with no reinforcing mesh. Is there a safe way to use them? I have a bunch that came with a Dremel tool and a stack of 3inch that came in a garbage,(garage)sale. They shatter while in the box. I can't stand far enough away from the grinder to feel safe to use them. They cut fine unless side loaded,but when they break,LOOK OUT! George

02-28-2011, 10:37 PM
They are a little better if you double 'em up, but not much. I use then only on very intricate stuff.....

02-28-2011, 10:51 PM
Are they really, really, REALLY thin? ;)

You may have discs for an arrow shaft saw (http://www.applearchery.com/shop/apple_pro_saw.php).
If you look at them wrong they will snap in half. Have to be super careful when mounting them on the arbor not to over tighten the nut.
Saw blades. (http://www.applearchery.com/shop/apple_archery_quality_saw_blades.php)
They do a wonderful job slicing through thin aluminum arrow shafts though. :)

02-28-2011, 10:58 PM
I use em all the time on my flex-shaft Craftsman tool. Just be very sure to wear eye protection. When they shatter or otherwise come apart during use, I only rarely get a small, sharp tick to the face, arms, etc. Not enough to complain about. Just aggravating that I have to replace the wheel ... again, and again, and again.

If you are talking about the larger ones used on the cut-off saws, just be sure the guard in on just like on your bench grinder and stand off to the side.

02-28-2011, 11:12 PM
Let's see..."Lethal disks"..."Is there a safe way to use them?"..."They shatter while in the box."..."I can't stand far enough away from the grinder to feel safe to use them."

Put em on Ebay and use the above to describe them.

J. Randall
02-28-2011, 11:23 PM
If you don't mind a little wider kerf, superglue 2 of them together with a scrap of material from a castoff pair of pantyhose in between, or just use the glue.

02-28-2011, 11:27 PM
I have heard the non reenforced ones (larger style) are good for cutting HSS blanks, when in a very rigid grinder with a proper work mount to keep everything 100% parallel as you push the work into the blade... Other then that, never heard of anyone using larger non reenforced cut off disks.

The tiny dremel ones.. Ehhh, Maybe if you gotta do a TINY thin cut, Else just buy reenforced ones and stick the crappy ones in the back of a drawer somewhere..

J Tiers
02-28-2011, 11:33 PM
The Dremel ones, they are probably 25 thou thick, and around an inch diameter....

Don't be hatin' on them, those things are great for certain tasks. For instance, I used to use them for de-canning power transistors (failure analysis), but since TO-3 went away, not so much. Still have other similar tasks for them.

When you need a thin cutter, they rule, but you need to brace your hand so you don't get them in a bind, which is when they break.

03-01-2011, 12:07 AM
I have some 1" dia. .025 or so dremel cutoff discs. If you look at them the wrong way they'll crack but they do a great job on cutting small hardened pins or drill bits. I've had a few of them frag on occasions, there is not enough mass to cause any real damage when one lets go, but just wear eye protection or better yet a face shield.


03-01-2011, 03:15 AM
Do not put any side load on them

03-01-2011, 06:41 AM
If they're the usual Dremel disks, they work just fine.... Like somebody said, they don't got enough kick behind them to do much damage. You ARE wearing eye protection, right? :rolleyes:

There's two different thicknesses of un-reinforced 15/16" emery wheels.
One is Dremel part #409 (.025" thick, 36 per pack)
The other is Dremel part #420 (.040" thick, 20 per pack)

I always keep both on hand, and buy them a dozen packs at a time.


I only buy the Dremel-brand disks and grinding stones, I have seen more than once that the generic stuff just isn't made as good.

Your Old Dog
03-01-2011, 08:16 AM
.................................................. ...........................

When you need a thin cutter, they rule, but you need to brace your hand so you don't get them in a bind, which is when they break.

ABsolutly right. You can't be ham handed with these little ones but they are a great tool. I hold my dremel with one hand supporting the other and I use a full face shield. I've had many that I could use right up to the arbor before putting on a new one.

03-01-2011, 09:37 AM
i coat both sides of my dremel discs with super glue. one side at a time of course. seems to help give them longer life. . .

03-01-2011, 11:31 AM
The un-reinforced discs are a lot more likely to shatter when being used, but they do have some advantages.

They don't have fiberglass in them so you don't feel like you have been hanging fiberglass insulation after using them.

They also last longer because they are all grit and no re-inforcement.

We used to use the 2" wheels in air grinders to cut alloy welds by the hundreds when re-working tracking for automation systems that we built.

Our shop eventually dis-continued the use of non-reinforced wheels for safety reasons.

Just remember to use proper safety equipment when using the non-reinforced wheels. Safety glasses with side shields or goggles, long sleeves, gloves, ear plugs. A particle mask is not a bad idea either if using re-inforced wheels to keep the fiberglass out of your lungs.


edit to add:

YOD, good to see you are still posting here. I thought you may have gotten swept up in the mass exodous that included Evan, DP, OldTiffie and a few others.

Sure would be nice to hear from them again too.

03-01-2011, 11:36 AM
The Dremel ones, they are probably 25 thou thick, and around an inch diameter....

I don't see how they're remotely lethal. :) They fly off in little pieces, but other than being an eye hazard, the shrapnel is completely harmless.
That's why they come in stacks of 50 -- 'cause you'll use all 50 off them on a single cutoff job :D