Angle Grinder cut-off Wheels / Flex

In relation to angle grinders, what is a "Flex" wheel? Is it the same as a "cut-off" wheel?

Yesterday I purchased a Makita 7060 Angle Grinder (7" / 180 mm) and some cut-off disks for a job that it too big for my 5" models. It came with 2 sets / 4 pieces of mounting flange, back up pad and lock nut which the instruction booklet show to be used for 2 different wheel types. 1) Depressed center or flap disk and 2) "flex" wheels. "Flex" appears to be a descriptive term for a type of wheel, but I can't find a description of what this actually is.

The disks I purchased are all 1.6 mm cut-off wheels, however some are depressed center wheels and the others just flat disk wheels. When I asked the salesman which wheels were best suited to the machine he said I could used either. :? maybe, or just doesn't really know. Benefit of the doubt, this may be the case, but I'm not really sure since there is no actual information regarding this in the user manual. They both physically can be used but should they be?

???? Are the flat disk wheels considered to be "flex" and thus requiring the use of the larger diameter flange and backup pad for safe mounting? (Or are they something different altogether? See below.)

The depressed center cut-off wheels obviously can't be used with the additional diameter support flanges, but should the flat ones have the extra support if it's possible to do so?

The word "flex" appears to be associated with brands and variety rather than a type of wheel in a Google search, or as in Europe, the whole tool is called a flex in reference to company that invented it. Google images show that many wheels that contain the word flex in the naming are actually depressed center wheels and some of these are grinding wheels up to 6 mm thick. Now it's me who's :?. I can't see that using the larger diameter flange where possible is a bad thing, other than slightly reducing the depth of possible cut. When it comes to safety though, particularly with larger angle grinders, this is an important consideration.

From Above: Perhaps this is all irrelevant or incorrect, since on page 11 of the user manual there is instruction on using abrasive cut-off / diamond wheels and the requirement to use the fully enclosed wheel guard (optional accessory). Apparently in some European countries the use of the diamond wheels with the standard guard is allowed but I'm not sure about abrasive cut-off wheels. The instruction manual says to follow the regulations for your country. ????? What are they for Australia does anybody know?

I guess I'll look into the availability of the fully enclosed guard anyway.

EDIT: I should have read the whole booklet. Apparently the large diameter flanges are provided in Aus / NZ only, which sort of suggests they are required here. So this then begs the question, what is the back up pad needed for "flex" wheels and I still want to know what a "flex" wheel is.

A webs search doesn't turn up much in relation to "Flex" as a cut off wheel

There is a well known brand of grinding and cut off wheels called Flexovit. They make excellent think kerf cutting wheels and I use these a fair bit.

Pferd make something called a CC-GRIND-FLEX raised hub wheel is a semi flexible grinding wheel that can take a much more side strain that and are deliberate designed for use on the side face and not recommended for edge cuts. They are supposed to be good on welds. For optimum performance =they do recommend (but nit mandate) using their clamping flange set. Pferd's thin raised hub cut off wheels are sometimes labelled as "SG - elastic"

I contacted the store this morning. The guy asked if it was for private use or onsite and I told him private but my son may want to use it in his work onsite. To this he said that they are banned on many sites because of being too dangerous. Anyway apparently the Australian rules do not apply to personal use so it's up to the user.

The full double sided guard is available for an extra $35. Putting it on the machine will naturally reduce it's ability to cut into corners and close up to other metal edges to a degree.

"Flex" wheels are apparently a very flexible abrasive disk. They are probably similar to what I consider to be a sanding disk that is usually used over the top of a rubber support wheel. These are usually cloth or heavy cardboard / paper construction. They don't give you that backing pad referred to in the manual. I doubt I'll use these so I'm not too concerned.

Quote:

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Originally Posted by glivo

"Flex" wheels are apparently a very flexible abrasive disk.

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If you ever find a web link describing these it would be appreciated.

I'd say they are probably similar to the Pferd discs you described. The KGS semi-flexible abrasive disk and on eBay searching for Semi Flexible abrasive discs brings up similar in Bosch, Flexovit and ZEC brands, etc. These are all Semi-flexible.

Here is a flexible grinding wheel with back up pad made by 3M.
https://www.ebay.com.au/itm/20-X-3M-...0AAOSwkFZcLEPa

Something like this?
https://www.bunnings.com.au/norton-1...p-pad_p6328226

For use with flat sanding pads. The back-up pad is flexible.
I prefer these to flap discs... get good life, can get some very nice ceramic grain abrasives (norton blaze for example).

As for grinders...
9" and 7" fell out of favour with big industry due to high wattages, heavy mass (and difficulty to control and fatigue leading to loss of control).
As far as abrasives... they are rated to a speed (RPM). You don't want to over-spin them, or they can come apart/fail. This goes off the optimal surface speed for the cutting operation as many of the machinst types would know...
IIRC smaller grinders (4" for example) need a faster spinning motor to get that surface speed over a smaller disc diameter than a 9".

If you want to talk tech / regulations, jump on the blower and have a good old fashioned yarn to someone in the tech department for any of the abrasives companies- Flexovit/ Norton Abrasives, Pferd, 3M, Klingspor etc.

I would not normally have even considered an AG above 5" but unfortunately this just wouldn't have done the job in this instance. The 7" worked beautifully and gave the depth of cut I required. It's manageable but the 9" are crazy big for a hand tool. Job done, now what to with it.

I guess I'll use it again now that I have it.

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