This is the grinder I'm using.
Well I was untill I wore out the carbon brushes. Which I can't find & because 'Supercheap' are a Aussie company, they don't really give a hoot about ol' NZ & muck me around for trying to get a set.
Rockwell Shopseries Angle Grinder - RS4703, 2350W, 230mm - Supercheap Auto New Zealand
On the other hand, the guy said "If I could give them a receipt they could give me a brand new 9 inch Grinder". But I brought it 2nd hand in new condition.
They are worth NZ$129. About US$85 each.
If you get one, the brushes are cheaply made, very porous. I'd search for another 'brand name' set of quality brushes.
Also. Make sure the 4 bolts that hold the head together are tight, actually I'd drill & retap the threads out, replace the screws with bolts & use 'tabwashers' or use wire to wire the bolts in place.
The brushes started arcing, I thought it was the moter shorting out, but it turned out to be that the brushes had worn so much they were loose in their fitting & moved around untill the started shorting against the wrong contacts.
Quality grinders/brushes have a spring & plastic pin inside them. Once they have worn down to the plastic pin, the spring pushes the pin out against the contacts, removing the brush from the contact, stopping the grinder.
Thats when you get another set of brushes, or order them, pull the pin & spring out, replace the brush & use the grinder till the parts arrive & then put them in.
Along with getting a 9 inch, I'd get a 4 1/2 inch as well. If you are welding & grinding, I'd get a 5 inch & 4 inch instead of, or as well as, the 4 1/2.
Mark the bigger grinders guard at the 4 1/2 inch dia mark, then as soon as the wheel has worn down to the mark, take it off & put it aside for the smaller grinder.
How to max the effiency of grinding stones is to keep them at the maximin surface speed, ie the actual speed of the outer surface of the grindstone.
To do that, use the biggest wheel designed for the grinder & replace it as soon as it has worn down to the size of the next smaller grinder you have.
Also, very important. Let the grinder get up to full speed before doing any work, you will hear it 'ring out' when its up to full speed.
It'll then stay at that speed all the time & catch up between grinds. If you start grinding before it rings out, it'll never get up to full speed & the stone will never get to its maxamim effiency.
Same with chainsaws, thats where I learnt it.
When working as a welder I used a. 9 inch cutoff grinder, 9 inch grinder, 7 inch grinder & a 4 1/2 inch grinder.
9 inches for work & 7 for dressing & prep & 4 1/2 for touching up welds.
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I used the 4 1/2 today to cut apart two compressors. Took 4 mins each & really used up the disc.....
Oh, cut above or below the weld mark, you can see where its two layers thick & you only want to have to cut thru one layer..
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