How big is your grinder?

[Whiskeymike]

I'm cleaning slag, dross, and mill scale off steel sheet and plate, most pieces being 1'x1' to 2'x2' in size. I use flap discs on 4.5" grinders but I'm about to upgrade from the HF units to a Metabo. Does a bigger flap disc translate to more done faster?

 

[xela456]

I'd go with a coarser grit before I went to a bigger disc.

 

[trackwelder]

Yes it does

 

[Whiskeymike]

I'd go with a coarser grit before I went to a bigger disc.

I use pretty coarse grit and since it's new steel, it's comes off cleanly as fast as I can touch every inch of the piece. The main issue is that i'll be doing 100-200 pieces at a time so it's a solid couple hours of cleaning. But for the time that it ends up taking, my hands are cramping up, so if I can reduce that time that would be great.

It seems like it's a trade off of more surface area being touched for a larger heavier grinder and I'm not sure the extra weight outweighs the surface area in terms of time to complete.

What I'd really like is a drum sander with conveyor belt. I've been looking at those and they would be perfect. Just need to up the volume before I invest in that. I think I can get situated for $2500 for one of those.

 

[Bobcat753]

The biggest I own is a 6" Metabo. If you are going to be doing that much grinding I'd look at this one from DeWalt. I have one and love it. Very comfortable and has the balls of a bigger grinder. I think anything over a 6" is unnecessary, too heavy and the surface area being ground barely increases.
http://www.lowes.com/pd/DEWALT-5-in..._clickID=b77f776b-c92a-4e76-b7e6-1641e78fcca7

 

[catalytic]

I'm cleaning slag, dross, and mill scale off steel sheet and plate, most pieces being 1'x1' to 2'x2' in size. I use flap discs on 4.5" grinders but I'm about to upgrade from the HF units to a Metabo. Does a bigger flap disc translate to more done faster?

I have Metabos and Milwaukees in most every size and I have spent a lot of time cleaning slag and mill scale off of plate steel.

For this particular job, the 4" angle grinders feel like a waste of time and a lot of extra work.

The 9" Milwaukee makes it about 100x easier, since it not only chews off more at once, but the weight of the tool means you don't have to push down to add pressure -- you just let it do its thing.

That said, the same 9" milwaukee will also eat you if you're not paying attention. Haven't used a Metabo in 9" yet. I love my smaller Metabos, but for this job I would buy Milwaukee just because of the 5-year warranty (they have replaced mine twice after it has been so mercilessly abused that I was shocked any manufacturer would do anything except yell at me when they saw what I had done to their product).

 

[sberry]

4 1/2 with 1/4 grinding wheels. I never use a flap for normal work. Get a hatchet for slag if you need to and chip before grinding. With light plate I do not grind the stuff away but as if you are trying to square it till it breaks off.

 

[larry_g]

But for the time that it ends up taking, my hands are cramping up, so if I can reduce that time that would be great.

.

I'd suggest that you look at the ergonomics of the tool your using. If your one handing a barrel handled grinder then problems. Add a side handle and it gets better. The larger machines have hand sized handles for both hands that will relieve some of the fatigue. I would also suggest that you look into a 'tool balancer' to carry some of the load. All things to ease the work load on the body. Have you set up a bench to the correct height so your not reaching and stooped over? It all helps.

lg
no neat sig line

 

[texasfiremedic]

My biggest grinder is 5'-8" tall and wears a wedding ring.

 

[Know Wosad]

I've a 9" and a 7" Makita.I finally got a good ribbed backer and some 36 Zirconia for the 7". I'm liking it for mill scale.I can weld so I don't have to do much knocking down, if any.Corner rounding. 4 1/2 with a 40-60 grit flap.
If I had enough mill scale issues to warrant considering a drum sander I'd either just buy cold-rolled or setup an acid bath to get rid of it.By the time you got done with the drum and burning paper you could build everything stainless

 

[chilly460]

I have a 9" Makita and Black and Decker Wildcat. I don't need them often, but use them to round corners on thicker steel when I can't get the piece on my belt sander. Just nasty machines, they definitely get your attention while in use. They're too big for most "normal" garage grinding of welds or even bevels for welding, IMO.

 

[SteveCh]

My 7" really goes to town, but for the comfort of using one a lot, a four or five inch is a bit easier on my hands and wrists. Also, the seven is significantly heavier and a bit tiring after a longer session grinding. Not giving up my seven, though.

 

[oldwino]

I have an old Skil industrial unit I bought years ago to grind down fins on horizontal concrete walls. Heavy ******* but runs like a raped ape. Haven't used it in years