Wobbly 9" cutting disc

[DIYalot]

Hi. I've never owned a 9" grinder until today. I also got a 9" diamond cutting disc. The disc is "wobbly" by about 2.5mm on it's outer edge. So, my question is, do I have a faulty disc or is it acceptable to have the 2.5mm "wobble". I would have thought the wobble is unacceptable, but I'm not experienced enough to know for sure. It wobbles from side to side. And brand new. Thanks.

P.S. Came also with two rings about 22mm diameter.

 

[SammyInnit]

It's unacceptable IMO. I've seen wobble up to a mm or two with 1.5mm abrasive cutting discs but a DTB should run fairly true. Try a second disc if you have one, if the problem is the same the issue is with the grinder arbor or friction plates, although I've never seen such an issue cause that much run out.

 

[Tigercubrider]

Is the disc clamp on the right way round?
Is the disc in date?

 

[DIYalot]

The grinder is brand new. Both flanges are the same diameter. The inner flange "locks on" to the arbor, so that is the right way around. The outer flange, that is threaded, it's raised centre is away from the disc, which is correct for a cutting disc apparently. There is no date on the disc. It's a brand new Neilsen CT1028. Secured tightly. It was dropped through the letter box. It came in cardboard sleeve. Disc & grinder never been used

 

[DIYalot]

I've been running the grinder (it's a slow start type) a few times and looking at the flanges. It looks to me like the flanges are wobbling a bit. That would be a grinder problem, not a disc problem. I wonder if I'm due a refund on a faulty grinder. It's a GMC 852949, bought off Ebay for £44.99.

 

[Tigercubrider]

There should be a date on the disc somewhere, albeit small

I doubt it's the issue but try wrapping up some tape on a spindle and spinning the disc to check it

 

[SammyInnit]

I've been running the grinder (it's a slow start type) a few times and looking at the flanges. It looks to me like the flanges are wobbling a bit. That would be a grinder problem, not a disc problem. I wonder if I'm due a refund on a faulty grinder. It's a GMC 852949, bought off Ebay for £44.99.

Best way to check is with a dial indicator but if it's brand new and you're in doubt just take it back and get a replacement. You'll drive yourself mad trying to right it otherwise.

 

[vinn]

Return both the disc and the grinder if possible - dont risk an unsafe tool for a single minute.
If the disc shatters or something flies off the machine, pieces can pierce the average "safety glasses" and do some damage.

I heard a guy tell how a disc flew off an angle grinder and ripped his knee cap. Why it came off he didn't know but he lost a lot of wages.

 

[Roger928]

A GMC what?
When buying power tools stick with either Makita, metabo, bosch, hitachi,hilti, fein, festool, mafell, milwaukee and you won't go far wrong.

 

[Deleted member 174758]

Maybe another point is that it's a Neilsen disc - cheap Chinese carp! As Vinn says, though, return the lot.

 

[chappers]

whatever don't use it could be dangerous

 

[noseall]

I use Bosch blue grinders and pay upwards of £80 for my diamond fellas. Never had any problems since paying proper money for proper discs.

 

[^woody^]

I use Bosch blue grinders and pay upwards of £80 for my diamond fellas. Never had any problems since paying proper money for proper discs.

LOL. I get mine for between £5 and £10 from Amazon or Aldi when they have them. And they last as long as any of the expensive ones I have bought previously.

I just checked, and I bought my first "Blue Spot" disc off Amazon for £2.02 back in 2013. I remember that lasting a hell of a long time on paving jobs and some brick wall cutting. I get them now, but they have gone up a couple of quid.

Two weeks ago, on recommendation, I bought a Norton blade for the stihl saw to cut some hard concrete and tarmac. 15mm of cutting edge, and it cut just about 40m at 50mm depth. I wont be buying them again. The one we had on the saw before that was an Erbaurer from screwfix, and that lasted a long time as I recall.

I don't beleive in the value of expensive blades now. The cheap ones are just as good, but errr, cheaper.

 

[noseall]

LOL. I get mine for between £5 and £10 from Amazon or Aldi when they have them.

The cheap ones I used to buy would be hit and miss. Some would be fantastic and others shoite. The main problem being overheating, warping and gumming up. The expensive ones (I buy) never do any of the above. We cut clay and concrete and some metal so we opt for the general purpose variety. We are not shy with them either.
I got fed up with cheapo ones so I asked my tool hire man for one that would never let me down.

P.S. Apology and correction needed. We are currently using a Makita grinder. Oops

 

[noseall]

The cheap ones are just as good, but errr, cheaper.

No, they most certainly are not.