1mm cutting discs

[zeppelin builder]

pferd horse 125x2 or 3m cubitron is wot the big boys use

 

[fixerupper]

Anyone used any of the 9" 2mm slitting discs?
Another 'why haven't these been available before' moment.

....I bought a couple of thin nine inch Rhodius discs, but I could not get on with them, when I switched on I could see the edge of the disc flexing as it got up to speed ,,,, I tried to cut a bit of light box and it kept wanting to jam up ... So I went back to the standard 3mm for the nine inch ... the thin Rhodius discs for the 4 1/2 inch grinderette are fine ,cut fast , accurate and last for a long time.... if you let the tool do the work .jeff

 

[jordan1]

I also use mainly Smith and Arrow, but prefer the 0.8mm thick ones, as already said a light touch makes them last a lt longer.

X2

 

[Bill Edwards]

....I bought a couple of thin nine inch Rhodius discs, but I could not get on with them, when I switched on I could see the edge of the disc flexing as it got up to speed ,,,, I tried to cut a bit of light box and it kept wanting to jam up ... So I went back to the standard 3mm for the nine inch ... the thin Rhodius discs for the 4 1/2 inch grinderette are fine ,cut fast , accurate and last for a long time.... if you let the tool do the work .jeff

9" slit disks do flex a lot - first time I used one I stopped thinking it was loose - and they require thought as to where to hold metal as they trap easily. But, after only a few minutes with one you soon learn to control it without flexing the disk and to think about the cut and I just cannot use an ordinary disk these days, life is too short for that.

 

[gordon stephenson]

Just recently jot a load of Flexovit and Kennedy 125mm x 1mm cutting discs, Both excellent at cutting and long lasting too

 

[normspanners]

I use 9" x1 all the time and luv them, can do some complex radius cuts with them, then when the get down to 5" they go in the small grinder the only thing is you have to be carful when picking up or putting down the grinder to save the weight bending the disc and breaking it.
I bought some 5" from aldi few years ago and they where crap but they were practically giving them away few mths ago so tried them and the latest ones are ok and are lasting well.

 

[TechnicAl]

Id be scared of the Silverline

 

[armalites]

I've done the whole putting worn down discs in a smaller grinder but stopped doing it after reading stuff like this

http://www.mmsonline.com/articles/grinding-wheel-safety-respect-the-maximum-speed

 

[Kent]

I use 9" x1 all the time and luv them, can do some complex radius cuts with them, then when the get down to 5" they go in the small grinder the only thing is you have to be carful when picking up or putting down the grinder to save the weight bending
the disc and breaking it.

I bought some 5" from aldi few years ago and they where crap but they were practically giving them away few mths ago so tried them and the latest ones are ok and are
lasting well.

Don't do this it's very dangerous

 

[normspanners]

Whilst I am not arguing with you, re the speed I have never had a problem doing this since the 9" became available, the make up of the disc is the same, it is the diameter of the disc that creates the force and limits the maximum speed of the disc at its max dia. hence why 1" wheels can run at 22000rpm
the fact is the 9in discs are usually very good quality to stand the forces that a 2400 watt machine puts on them at the speed they run , I have only had problems with cheap 5 inch disc which are supposedly designed for the extra speed of the 5inch and find the cheap 5inch much more dangerous than a 9 inch, I am certainly not going to throw away a disc because it is down to 5".
But as all my 5 " machine have speed control anyway the disc can be used at their rated speed.

 

[brightspark]

ive done it for years and never had one go. smaller the disk the less the surface speed so can take more rpm

 

[normspanners]

just sat here and checked my dremel tool and I was wrong---------- that runs at 35000 rpm on the 1" discs!!

 

[armalites]

I must admit I've never had one go either but I can fully see the reasoning. I supect it is far more of an isssue if you just sit with the disk running flat out. When cutting the disk slows down.

A 9" disc has a circumference of 28.27
A 4.5" disc has a cirumference of 14.13

So thinking about this a bit more the speed limit is probably related to edge speed and not rpm and that seem to relate roughly to the fact that a 9" is around 6K and 4.5" is 10K.

The process for making the 2 diameters I'm sure will be exactly the same so if that is the case then theory would say that once the disk gets to 4.5" it will will fine on a faster grinder as the edge speed will be the same as in it's original use.

I suspect the big issue would be putting a full 9" on a 10K grinder.

A quality manufacturer will have quite a bit of safety margin too.

So if it's all about edge speed it is probably absolutely fine given that a 9" is only restricted due to it's circumference

I may start doing it again

 

[Kent]

Guys there was a thread on here not long back about how a worker got killed using worn down discs from a bigger machine
Don't do it
My 6 " is rated 10200
The 115 is 13300 rated
The chop saw 4400
The 9" 6600

It's crazy just coz you got away with it up to now is not reason to carry on- check those speeds

 

[Robotstar5]

Most of the discs I've seen have the speeds marked in rpm and m/s - example

 

[Bill Edwards]

Whilst I am not arguing with you, re the speed I have never had a problem doing this since the 9" became available, the make up of the disc is the same, it is the diameter of the disc that creates the force and limits the maximum speed of the disc at its max dia. hence why 1" wheels can run at 22000rpm
the fact is the 9in discs are usually very good quality to stand the forces that a 2400 watt machine puts on them at the speed they run , I have only had problems with cheap 5 inch disc which are supposedly designed for the extra speed of the 5inch and find the cheap 5inch much more dangerous than a 9 inch, I am certainly not going to throw away a disc because it is down to 5".
But as all my 5 " machine have speed control anyway the disc can be used at their rated speed.

I too take the view it's about the speed at the cutting edge of the disk, and so once the diameter reduces the speed can safely increase keeping the edge speeds the same.

I've been using worn down disks for as long as I've been round grinders. Now, I'm not using the fact that I have never had a worn down disk shatter from over-speed as a means to say it is safe (could technically all be luck) but what I can say is I have smashed a lot of 9" slit disks, nearly all from cutting things which have closed the grind gap and jammed it. It typically rips the centre out of the disk, or sometimes takes a chunk from the edge.

If the disks break, they do so on the machine they're supposed to be on, not once I put them on a smaller, faster machine.

 

[Ton-up]

3M Curbitron discs are fantastic. Yes they cost more, but last forever and cut like a knife through butter!

Used to use Dronco ones and they are good for the money.

 

[Kent]

If you look at the safety guidance on grinder wheels it's very specific about not using worn down wheels in smaller grinders

I have had quite a few wheels bust even when on the right grinder
Have never been injured much as I can remember from a break
This is through good management ppe and luck. I don't want to push that look

It's was only a few months back someone posted the report on the guy that died - direct result of a wheel off a bigger machine! Yes they had done it for years also

I will leave this now - just replied on the grounds that a new wheel is a lot better than an injury or death