I have a lidl 9 inch , is a feels a bit heaver than the bosh 9" I use. The lower rpm makes them less vibratory than the small grinders I find but generally I will use a smaller one if it will get in there as they are much lighter.
Stu
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I have a lidl 9 inch , is a feels a bit heaver than the bosh 9" I use. The lower rpm makes them less vibratory than the small grinders I find but generally I will use a smaller one if it will get in there as they are much lighter.
Stu
MetalMonkey
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If you do much of it, a concrete saw is hard to beat for that. The Stihl's are great, but the electric ones are a bit more convenient if you have power and are doing lots of stop/starts.
eLuSiVeMiTe
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Don't do much paving/knock through these days or I'd grab a big flexvolt.
My Stihl saw gets used occasionally though so I've not parted with it
8ob
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Its easy to forget how good a 9" grinder/cutter is, because the small ones are always at hand and ready to go there is a tendency to beat one of those to death instead of reaching for the right tool for the job.
Bob
My preference is the 125mm rat tail grinders as they are reasonably powerful but still light, I also have 6" and 9" grinders for cutting/grinding bigger steel. For the majority of work, the 125mm do a good job they are easy to hold due to the Rat Tail handle design and the ones I use are the 1500W Bosch ones, but I also have 3 of the Aldi branded ones, they have 1400W motors and are quite cheap, here in Oz they usually sell for about $30. The Bosch ones are about 8 times that price but they are not 8x better. The 4" ones use a different spindle size, where as all the 125mm and above use the same thread size so the discs are interchangeable, so when the 9" ones wear down I can use them on the smaller grinders at a pinch.
zzr1200
Working at 650 ft on open steel work.
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Same here, got mine when I was 14, it's no scarier than any other grinder. I only really use it for concrete, the weight is fine using it as you describe to cut on the floor but I don't like using it at a bench, it's rare I need to though.
OP was doing a bit of cutting and used a wire cup brush in his 4.5" grinder from my understanding. He wanted a second grinder to save swapping discs for want of a better word. It didn't suggest to me that he needed a 9" grinder at all. I still think the 4.5" and 9" are two very different tools even though one is scaled up from the other. I've never needed to fire up a 9" inside the workshop for anything metal related. Of course I only pratt about. Anyone who asks whether he needs a 9" grinder probably isn't chopping up 25mm road plate in the shed.
Just my 2p.
Just my 2p.
Please do not do this, 9" discs are only rated for around 6000 rpm, smaller grinders turn at up to 12000 rpm! So you could be running the disc at twice its max rated speed a few inches from your body!
Put it this way - your car engine might red line at 7000 rpm. What do you think would happen if you could rev it to 14000 rpm?
selectedgrub
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I think you would win the race.
MetalMonkey
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Please do not do this, 9" discs are only rated for around 6000 rpm, smaller grinders turn at up to 12000 rpm! So you could be running the disc at twice its max rated speed a few inches from your body!
Put it this way - your car engine might red line at 7000 rpm. What do you think would happen if you could rev it to 14000 rpm?
If you think about it logically, it shouldn't really be a big problem providing the discs are undamaged and have been worn down to 5" diameter or under.
The disc of a 9 inch grinder running at ~6000 rpm is around the same surface speed as a disc of a 5" grinder running at 11,000 rpm, so the outer edge of both discs will be travelling at the same speed (72 - 73 m/s).
Same goes for a 7 inch grinder running at 8000 or a 6 inch grinder running at 9000 etc. The maximum speed of the disc is rated in m/s (usually 80 m/s for slitting discs)
Obviously putting a new 9" disc on a 5" grinder means the surface speed is going to exceed the intended design (132 m/s), and that is when there is a real danger of it flying apart.
MikeBs
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I didn’t think this would throw up so many replies, but my toughest cutting job is probably 4mm angle iron.
It was just a general question, since I had never picked up or used a 9” grinder, I had no idea they were so different and when I saw the picture in this thread of the two sizes together I was surprised to see the difference.
Since manufacturers try and standardise parts, as I was looking for a second grinder, I wondered if they were essentially the same body with a larger capacity guard.
Anyway, thanks for all the replies and I have settled on getting another small one.
Thanks Mike
8ob
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Good job you replied when you did, given another week and this thread would have morphed into how to point a chimney stack
Bob
My 9" Grinder (originally for cutting stone, slabs etc with a masonry disc) is now mounted in one of those frames to turn it into a Chop Saw. It's handy for cutting Box, thick Angle, that sorta thing (& can be taken out and used freehand of course - but I'd only do that with masonry).
I've got a 4.5" Bosch 230vac which has been good (still is) and a Screwfix Brand Erbaur Battery 4.5" also (which is very handy, but Battery life with a battery grinder isn't great). I've got the Erbaur Batt Drill and the Impact Driver (which is a really useful good bit of kit).
I've got a 4.5" Bosch 230vac which has been good (still is) and a Screwfix Brand Erbaur Battery 4.5" also (which is very handy, but Battery life with a battery grinder isn't great). I've got the Erbaur Batt Drill and the Impact Driver (which is a really useful good bit of kit).
