4-1/2" Electric Grinder recommendation request

Walter A · Nov 26, 2011

I am looking for the possibility of buying some better (longer lasting) grinders for our fab shop. For several years I have been buying the Milwaukee 8.5 amp grinders with only fair luck. It all depends on where they are used but if it's around heavier fab I get about a month before they wear out. Sometimes it's just brushes but most of the time it's armature and/or gear train. Tried Metabo a few years ago and kept having switch trouble. We even used the Home Depot Hitachi but they lasted only a couple of weeks. Year ago we used Black & Decker with fair results. When they became Dewalt the quality was hit and miss.

Milwaukee is now making this model (6148) overseas and upped the amps to 10 amp. It has a 5 year warranty but it's for factory defects only.

Can't use 7" on any but the largest jobs.

Are there any electric 4-1/2" grinders you guys like?

For the record, it's not the wheels or that they are being abused (for the most part). It's just the run time while under load.

Walter

Mark Leigh · Nov 26, 2011

You must be running these things until they smell of hot plastic, alot of heat in the case----------

Why don't you issue 2 per man and cycle them, let them cool off a bit.

Also, are you satisfied that it isn't a small gauge wire or long cheap extension cord issue ?

If going to a 5 or 7 inch isn't acceptable , the problem becomes bigger and heavier 4.5 grinders that are hard to hold onto for long periods of time.

Are you running hard discs on them ? Or soft pads, etc. ? What diameter are they ?

Walter A · Nov 26, 2011

In our cleaning area where a couple of helpers clean up all the fabrications they do have several grinders. As expected the grinders with soft pads or flap disks last longer, while the ones with grinding wheels last the shortest.

I am pretty sure the broken ones with armature trouble are run until they are too hot so maybe more swapping will help. The ones that develop gear or bearing trouble are just wearing out. As I said earlier the average life seem to be a month.

I am thinking of going to pneumatic grinders but those too wear and when they need repair it's more costly.

I know I can tweak the way we are using the tools to stretch the life but what I really would like right now is to find out what other forum members are using and if they get a good life from them.

Walter

joebass · Nov 27, 2011

I use metabo in my shop, Bosch would be my second choice.

jamscal · Nov 27, 2011

Metabo for me.

Bosch is more or less the same (same brushes in the ones I have) I have had to replace a switch on a Metabo, but it's no big deal IMO.

Metabos have the best ergonomics for me, are high quality, and aren't made in China.

Not a big fan of Dewalts, but I have one. Have a big Milwaukee 9" as well.

Here is a CyberMonday Deal for dewalts (Won't be available until midnight tonight) from a dealer on another forum I frequent:

Cyber Monday Free Grinder Special WYL-105

(buy 20 flap wheels and 40 cut offs for $150 and get a free grinder).

Walter A · Nov 27, 2011

The Metabo grinders we used seemed to last OK with the exception on the switch but that was about 5-6 years ago. Maybe they have changed the design?

Walter

adama · Nov 27, 2011

I like the Bosch over the metabo ones. Metabo ones just seam to have a bigger gear box that gets in the way. I like the smaller bosch 4.5" with a flap disc and the larger one with a grinding disc. No side handle fitted. Chances are if you have the side handle on them people are using them to hard!

Above all teach and get them some good 9" grinders + Good free cutting consumables. They can lean on those as hard as they want. Smaller grinders are for tight areas, open corners use a "man's" grinder and make some head way!

Now that said there's no way your allowed to grind in the uk enough to wear a 4.5" grinder out in that time frame before you have contravened health and safety on hand arm vibration levels.

At the end of the day if there wearing small grinders out there not being productive. You need to go to some more friable discs, better ceramic type sanding discs and better faster cutting flap wheels. There's a lot of discs out there and with a truly vast range of property's that make a lot of difference on removal rates. Equaly look at what your welders are laying down, make sure they understand if the welds to be ground smooth not to make a bloody great mountain range to be ground off, that alone can save hours of work a day.

IronReb · Nov 27, 2011

We have had the same problem.Milwauke and Bosch have both been used with not much difference in life span.

Thing to note is we also have a 7'' Black&Decker that is heavy as hell,works the piss out of you but will grind twice as fast as a 4.5'' and has been going strong for over 10 years now.

In a fab shop people would rather use the smaller light grinder and take longer because it doesn't work you as hard,they are not worried at all about burning it up grinding down 5' of weld seam because they do not have to pay for it.

If you can get your people to understand how to make a 7'' work for you using it's own weight instead of it working you and using the small grinder for what it was meant for you production will go up and over head go down.

Ries · Nov 27, 2011

I use Bosch. I buy the industrial, blue ones, they are all made in Germany, the ones I have. I understand they may have a cheaper line from China or Mexico, but the German ones work really well for me. I usually get 3 to 5 years out of em, before a gear box rebuild, and another couple years after that. Of course, cords need replaced more often, and sometimes brushes, but I have found em plenty tough.

they make 9 and 12 amp 5" and 6" grinders that will run 4 1/2" grinding discs just fine, and those would probably outlast the standard 8 amp grinders.

jkilroy · Nov 27, 2011

Like my family in New Orleans might say...

SCREW DAT!

Go to harbor freight, buy 20 of these for the price of 2 *nice* grinders...

4-1/2" Angle Grinder

When they start to give you trouble, CHUNK THEM IN THE TRASH and grab another one. I promise you they will outlast the two good ones many times over. I did that two years ago and have only chunked three of them and I am hard on them, grinding lots of 304.

doug6949 · Nov 27, 2011

I worked in three shops that bought and replaced Dewalt grinders on a much too regular basis. The assumption seems to be that if it has a good American name then it must be the best. The switches fail, the gears fail, the motors go up in smoke. IMO, they are junk.

The newer Milwaukee grinders aren't any better. And their lithium battery drills never lasted more than six months at my last shop. Even my cheapo Ryobi drills have lasted longer than the Milwaukee drills. So have the batteries.

I managed to acquire a Makita grinder at my last job and a Metabo at the job before that. Neither gave me any problems with daily use for a combined five years and I am hard on grinders.

My personal Makita grinders have gone thru at least 100 disks each and they both work perfectly.

If I needed another grinder I would choose Metabo for the ergonomics.

They are all made offshore so you might as well get one that lasts.

Doug

adama · Nov 27, 2011

One thing that has just occurred to me, im use to using 240 volt tools over here in the uk. Your 110V doubles your current requirements which does nothing to help keep things cool. Add in some long extension leads and 110V is going to be a lot more current. That's not going to help motor life at all. Yes i know there wound differently with diffrent gauge wires, but IxIxR=P still applies. Due to the size of the tool they have got to be dumping more heat from the resistive heating effect than a 240V tool would. That might at least begin to explain your tools over heating far easier. especially with long extension leeds and hence voltage drops.

Might well be worth trying making up some heavier gauge extensions and see if that sorts the issue.

Walter A · Nov 27, 2011

We do have a few 7" Milwaukees and a big old B&D with rock mounted on it. They get used when we are working on stuff where there is room to work. Most of what we work on is pretty heavy but compact with not much room for a 7" grinder. Parts for heavy equipment as well as structural work.

Just to set the record straight we are not wearing out these grinders in one day or on one job but the ones that are used every day are wearing out faster than I want. It might be the best I can do but that has never stopped me from attempting to improve.

I keep a couple of Northern Tool cheap grinders for use at out cutoff saw. One time a welder snagged one when he went out on a job. It lasted all of 15 minutes. One the saw they last a couple of months.

Also for the record we use Metabo cut off discs, Sait grinding disks and Metabo flap discs. Gave up on Norton when they went to China.

This is not a monster problem for us but it never hurts to ask what others are using. Based on the comments I think I will toss a couple of Metabo and Bosch grinders into the mix. As for a Makita I have a couple of cordless drills by them I really like so I need to check them out. I always thought they made a lighter duty tool.

Walter

TKassoc · Nov 27, 2011

I'm a big fan of the Hilti 4.5" grinders. I had a DC500 that lasted so long (~6years) the brushes got obsoleted before I could put another set in. I've never bought one since the started showing up at Home Depot though...can't be sure it they're making a cheaper line of stuff just for the big box stores.

Winterfalke · Nov 27, 2011

I definitely agree with Metabo and Bosch, and I have an older US made Milwakee that is rock solid. Can't vouch for the newer stuff, mine is over 10 years old. You might want to make sure they are treating those grinders their tools with respect, I have been in multiple shops where the welders just toss them to the floor and then drag them back by the cord. And management couldn't figure out why the Metabos weren't lasting any longer than the Dewalts.

Mud · Nov 27, 2011

Metabo is constantly upgrading their grinders, the recent 4.5" I bought is a world ahead of the old one I have. I also have an old 5" that seems to have 2X or more power of the old 4.5", has a governor and an overload slip clutch, but only about 15% more weight. I just looked at the Metabo website and they list 4.5 and 5" grinders from 705 watts to 1450 watts. proper selection could make a difference maybe. - Product catalogue Metabo Metal hand-held power tools - Metal - Metabo worldwide

fortyonethirty · Nov 29, 2011

I like my big makita, it's the strongest and coolest running grinder I've ever used. I was so pleased with it when I first got it that I posted on weldingweb, you can see that here: http://weldingweb.com/showthread.php?t=57159&highlight=makita+usa

Walter A · Nov 30, 2011

Thanks to all of you for the suggestions.

I am planning to get at least one 10 amp minimum of a different brand and put it in the cleaning area of a fab shop. The guys in there take care of the tools but use them hard. I should get a clear comparison to the Milwaukee.

Walter

Mark Leigh · Nov 30, 2011

Walt, how thick are your cut off wheels ?

Walter A · Nov 30, 2011

Mark Leigh said:
Walt, how thick are your cut off wheels ?

.040" to .045"

Metabo Slicers...

Walter

4-1/2" Electric Grinder recommendation request

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