Hitachi G12SR3 4.5" angle grinder 6.0 amp

I recently picked up a few 4.5" Hitachi angle grinders (each model number G12SR3, rated 6.0 amp) refurbished. Got them from this vendor:
http://bigskytool.com/Hitachi_G12SR3...d)___i967.aspx

Attachment 8793

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So far, the Hitachi grinders seem to be decent. Compared to the Harbor Freight 4.5 amp "drill master" grinders that I'm most used to (which can be had for $10 with a coupon), the Hitachis run much smoother and quieter.

I think a large part of the smoothness and quietness may be simply because the pinion gear is rigidly fastened/secured to the electric motor shaft (via threaded nut) on the Hitachi design:
Attachment 8789

In contrast with the above pic, the pinion gear dsign on the Drill Master "floats" on the keyed motor shaft. The floating gear apparently adds considerable rotational backlash, also imprecisely controlled gear clearance. I feel like it may be hard on the nearby bearing (I've already experienced one failure in this bearing in my fleet of Harbor Freight grinders.)

The gear ratios are quite different between the different grinders (3.9 on the Hitachi versus 3.0 for the Harbor Freight), which would seem to help the Hitachi run at a slower, but more consistent speed. I was impressed by how much grease there was in the gearcases of these refurbished Hitachis:
Attachment 8788

The electric motors between the two different grinders are actually very similar in many respects (same diameter and number of poles, and number of commutator segments) but the Hitachi 6.0 amp motor is significantly longer than the 4.5 amp Drill Master motor. There is no epoxy encapsulation on the motor windings on either.
Attachment 8786

The cooling fan design seems more sophisticated on the Hitachi (curved vanes with conical air diffuser) than on the Drill Master (straight blades and flat air diffuser), which may contribute to the reduced noise of the Hitachi.
Attachment 8785 Attachment 8787

The overall package of the Hitachi feels nice and it doesn't seem overly bulky, long, or cumbersome. However, the 6.0 amp Hitachi unfortunately does add on some significant extra weight compared to the 4.5 amp Harbor Freight.
Attachment 8790
Specifically, the bare Hitachi weighs 3.3 lbs (versus 2.8 lbs for the bare Drill Master). And when the guard, handle, and disc retaining hardware are included, the weight of the Hitachi goes up to 4.6 lbs (versus 3.5 lbs for the drill master). The guard and disc retaining hardware seem overkill in terms of material thickness on the Hitachi.

Although I don't expect to be able to put extra power to work on most flap wheel jobs that I often do (where the speed is usually limited by rate heat in the work can dissipate), I am looking forward to using it on jobs involving using a cutting wheel or disc grinder on thicker metals where the extra power might come in handy. I can see myself however reaching for the Hitachi most of the time, even if only because of how much quieter and smoother it is.

-edit-
Almost forgot to mention another sign of the Hitachi tool having quality is that the spindle lock button on the Hitachi works very accurately, with little slop. (The Drill Master spindle locking button has tons of slop, and racks sideways like crazy.)

Very nice and thorough review! I like Hitachi tools as I can get them cheap here too and their quality can justify the price difference. Unfortunately I don't have a Hitachi small grinder yet. Doing the duty right now is a 4" Powerfist angle grinder. The Canadian equivalent of your HF Drill Master brand I'm think. It's so compact that it'll fit in the carrying case that came with my PA140ST. That's handy! So far it hasn't be lacking power but it's a bear to work with due to the noise and ergonomics.

Can we see the 2 units side by side? How do they compare in size and ergonomics.

I read a lot a reviews on impact drills. They scored high there too. Wouldn't surprise me their grinders are really good.

You must have bought the last one, Jakeru, that link shows they're out of stock! Excellent review with tear-down views, thanks. That looks like a good place to bookmark for future purchases.

Interesting that the title says 6A, but the description and specs list it as 5.0 :confused::confused:

Thanks for the feedback, guys; I'm glad you found this product review to be useful! In due course, I'll make sure to update this thread with longer-term results as well.

Tanh - I'll get some comparison pics with the Harbor Freight grinder. (Maybe I will start another thread to fully and "properly" review the Drillmaster grinders.)

DaveO - I put my order in on these during a "cyber monday" sale at bigskytools, where the "A" refurbished grade for this grinder (which is what I got) was on sale for about the normal cost of a "C" refurbished grade. Bigsky has an e-mail notification feature where they'll e-mail you when they get more in stock (click the "notify me when it's available" link).

Brand new on Amazon, the same model grinder goes for $40 shipped.

Redbeard - Some of the specifications on bigskytools (the amp rating, as well as the no-load speed) appear incorrect. Here are the specs directly from Hitachi North America, which should be more reliable.

The nameplate on the actual grinder indicates 6.0 amps and 10,000 RPM. Also, based on my actual test results, the 3.1 pound weight specification is inaccurate (and IMO, borders on misleading.)

I'm really not a fan of the HF grinder so I may have to give the Hitachi a try when this one quits the bed. The slower speed will be nice but I'm more looking forward to the quieter operation. Even without touching the HF one to metal its ear peircing loud and just annoying.

Just wanted to give an update that I put the Hitachi 6amp grinder though a tube cutting job where I had to make about 30 or so cuts in rapid succession through some 1.5" diameter mild steel downspout type material (fairly thin gauge), but it was thick enough that I was able to press down fairly hard to make it go faster and see how the grinder would perform. I was impressed! It sure went through those cuts fast and the motor never did bog very much, even when pressing down fairly hard.

By the end of the job (which only took a few minutes) the entire 4.5" cutting wheel had gotten consumed down to the nub! I think how quickly the Hitachi 6 amp can wear out the cutting wheel is telling of its power output. I've never seen that kind of cutting wheel wear on the 4.5 amp Harbor freight grinder.

--UPDATE--
I just noticed that it looks like BigSkyTool now has 44 of these grinders in stock now (in "A" grade, for $29 each + shipping).

For anyone look for a good deal on these grinders, now's a good time to jump:
http://bigskytool.com/Hitachi_G12SR3...d)___i967.aspx

"A" grade (top refurbished grade) is on sale right now for $27 shipped. This is a really decent grinder. If you're used to using the harbor freight $10 grinders, the smoothness of the Hitachi will blow you away.

(I will consider actually have to consider stocking up on some more myself!)

I have three of the paddle switch grinders from harbor freight. http://www.harborfreight.com/4-1-2-h...tch-65519.html
One of them runs super smooth while the other two I would rate an 8 out of 10 because of slight vibration. Stay away from the HF grinding wheels... they don't grind, they only heat and polish.

Thanks for the heads up. Just ordered a pair to add to the fleet. I think I will now have more grinders than wheels

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Originally Posted by jakeru

For anyone look for a good deal on these grinders, now's a good time to jump:
http://bigskytool.com/Hitachi_G12SR3...d)___i967.aspx

"A" grade (top refurbished grade) is on sale right now for $27 shipped. This is a really decent grinder. If you're used to using the harbor freight $10 grinders, the smoothness of the Hitachi will blow you away.

(I will consider actually have to consider stocking up on some more myself!)

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Thanks Jake. Will pick up two. I have 4 HF now, but will try a name brand at that price. I have one HF one that has to be around 10 years old. But the lack of a bearing or weird sleve, they are not smooth at all.

Thank for sharing you find.

Jake, it mentions safe slide switch. Does it have the switch you have to hold on?

Thanks for the heads up. I will give two a go, too. If it's anything like my DeWalt the slide switch is spring loaded but can also be snapped to a stay on position. I have DeWalts with both the slide and paddle, and I really prefer the slide. With heavy gloves on, the safety on the paddle is a pain, and If I take the safety off, I can't hardly set the thing down without it going off. If I have a cart or someplace to hang it up, I like the paddle, but for crawling around, over, under, and through stuff, the slide is king.

I love that it comes with a case, too.

I have gone thru a lot of grinder in the shop and on the job site bought a good grinder 15 years ago and it is still working it is German made AEG Grinder WS 1200-125 Spec., 1200 Watts, 11,000 r / min, wheel diameter: 5 inch you cannot stop it, you can push as hard as you can and it will not stop it cost more but worth it in the long run, it probably has over 1000 hrs. on it changed brushes around 700 hrs. The HF (USA)and PA(CA) just go up in smoke in no time. they have been making the same grinder over 20 years just color changes.
Attachment 10134

There is one other plus to the $10 HF grinders (besides the fact that they ARE $10 grinders of course) and that is the return factor. If you use them hard and heavy, it shouldn't be too hard to wreck them within the 90 days. Not to mention the fact that the one I bought 10 months ago looks identical to the one I bought last week. ;)

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Originally Posted by Rambozo

... If it's anything like my DeWalt the slide switch is spring loaded but can also be snapped to a stay on position.

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Yep, that pretty much describes it. A slider that locks with a bit of a rocking motion, which you rock the other direction to make it turn off. Takes a few tries before getting totally used to, but works well and I can do it with a gloved thumb pretty easily.

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Originally Posted by Rambozo

Thanks for the heads up. I will give two a go, too. If it's anything like my DeWalt the slide switch is spring loaded but can also be snapped to a stay on position. I have DeWalts with both the slide and paddle, and I really prefer the slide. With heavy gloves on, the safety on the paddle is a pain, and If I take the safety off, I can't hardly set the thing down without it going off. If I have a cart or someplace to hang it up, I like the paddle, but for crawling around, over, under, and through stuff, the slide is king.

I love that it comes with a case, too.

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Good point about the paddle. I was thinking about getting a paddle grinder but I never thought about safety and the paddle getting depressed. Grinders with slop physically wear me down with all of their vibration. I always wear ear plugs so the noise doesn't bother me (my neighbors though are a different matter though).

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Originally Posted by redbeard

There is one other plus to the $10 HF grinders (besides the fact that they ARE $10 grinders of course) and that is the return factor. If you use them hard and heavy, it shouldn't be too hard to wreck them within the 90 days. Not to mention the fact that the one I bought 10 months ago looks identical to the one I bought last week. ;)

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Well I bought 2 (will see what Jake sees soon; ground shipping free), 3 would have been better (cut, flap and grind). But not going to dump the OLD HF grinders all the way around (other can use them). Was a little over $58. My old orange HF one has to be 10 years or older, one set of brushes (that came with it) as I recall. Still uses to cut many times a week.

I was in HF one time (I have been in there way to many times I can assure you) and I guy had about 5 broken, dirty grinders with the boxes. Covered in grind dust of some kind. They swapped him out and the guy had on a body shop shirt no less covered in the same looking dust :D So you are right there. I laughed inside when I saw him do it and with a straight face too.

Re-read the OP, Jake you need to write for a couple magazines. Take it apart, weigh it, abuse it, review it. Or have a show on discovery channel.

Did you get a second Everlast machine still using the Super 200P?

I picked up another Dewalt grinder on Craig's List because I got tired of changing wheels to brushes and back. Even though its a model similar to my older dewalt, it sounds and feels very different. changes in manufacturing or country of origin or whatever, i guess.

With all that dust I hope that guy at the HF had a circle around his nose and mouth, from where he took the mask off.

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Originally Posted by everlastsupport

Well I bought 2 (will see what Jake sees soon; ground shipping free), 3 would have been better (cut, flap and grind). But not going to dump the OLD HF grinders all the way around (other can use them). Was a little over $58. My old orange HF one has to be 10 years or older, one set of brushes (that came with it) as I recall. Still uses to cut many times a week.

I was in HF one time (I have been in there way to many times I can assure you) and I guy had about 5 broken, dirty grinders with the boxes. Covered in grind dust of some kind. They swapped him out and the guy had on a body shop shirt no less covered in the same looking dust :D So you are right there. I laughed inside when I saw him do it and with a straight face too.

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It is kind of surprising they don't have a "no commercial use" clause in the warranty. Talk about gaming the system. :D

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Originally Posted by DaveO

I picked up another Dewalt grinder on Craig's List because I got tired of changing wheels to brushes and back. Even though its a model similar to my older dewalt, it sounds and feels very different. changes in manufacturing or country of origin or whatever, i guess.

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The Makita I got in the 90s was my only grinder for the longest time, I too got really tired of switching wheels and brushes. Started amassing the HF ones about a year ago when I discovered the $9.99 coupons for them. So far so good, but they do quiver a lot, especially with the knotted wire cup brush. It will be nice to have a new quality tool in hand again.

I only use paddle switch grinders after one with the lock on switch sliced me across the thigh and shin when the cutoff disk broke and snatched it out of my hand.
The grinder fell between my leg and the benchwith 60% of the cutoff disk still spinning at 10,000 rpm. It went across my thigh at a shallow angle, cutting through my pants and leaving a one inch wide abrasion with lots of fiberglass bits embedded, then flipped over and sliced through the front of my shin about three inches below the kneecap, almost to the bone.
Three years later another cutoff disk broke, jerking it out of my hand again. No cuts this time (except my pants) but having a tug of war with my underwear wrapped around the broken disk as smoke bellowed out of the grinder convinced me to toss it and buy three paddle switch grinders and a plasma cutter before I lose my junk.

I find the safety lever on HF paddle switches easy to operate with gloves on.

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Originally Posted by redbeard

It is kind of surprising they don't have a "no commercial use" clause in the warranty. Talk about gaming the system. :D



The Makita I got in the 90s was my only grinder for the longest time, I too got really tired of switching wheels and brushes. Started amassing the HF ones about a year ago when I discovered the $9.99 coupons for them. So far so good, but they do quiver a lot, especially with the knotted wire cup brush. It will be nice to have a new quality tool in hand again.

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Yeah wire cups are a challenge for HF, like drill bits. hahaha..

Looking forward to mine.

Didn't really "need" another grinder, but I ordered one just because.

I have had nothing but trouble with the HF $10 grinders. The HF $20 "Heavy Duty" grinders are not bad.
If you open them up when you first buy them, and grease the gear in the head, they are half as loud, and last twice as long.

Always use a coupon.

Attachment 10139

Thanks for the coupon incognito. That will come in handy. I've got a couple of things I need to pick up from there.

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Originally Posted by sportbike

Didn't really "need" another grinder, but I ordered one just because.

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I can relate. I have a spare grinder (backup) in the box, and the three we use, and bought two more. Just because. Late fathers day gift I guess...

Hey all - on the Hitachi grinders, one tip I've developed is is that substituting the lower 5/8"-11 threaded nut (that holds the wheels on) from the $10 harbor freight grinder onto the Hitachi grinder is an upgrade because it's less bulky/cumbersome (to better fit depressed center flap wheels better, and stick out less) than the original Hitachi nut. (It gives a wee bit of weight savings to boot.) That's how I prefer to setup my Hitachi grinders now.

The Hitachi grinders (decked out with their carrying case and new grinding wheels) also make great gifts.

Regarding the $10 harbor freight grinders, I've successfully combined two broken ones to make a good one. ;-)

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Originally Posted by everlastsupport

Did you get a second Everlast machine still using the Super 200P?

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Thanks for the kind words, Mike. :) Oleg has me on the list to be one of the first to receive a 255EXT, as a prize from my prior contest winning. I'm looking forward to reviewing that, too!

My Super200P is still performing like a champ, though, and you might even say that it's getting better with age. I modded its AC Balance circuit to support higher %EN capability - turning the knob fully counter clockwise now gives ~95-98% EN, instead of the unit's original 80% EN limit.

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Originally Posted by incognito

I have had nothing but trouble with the HF $10 grinders. The HF $20 "Heavy Duty" grinders are not bad.
If you open them up when you first buy them, and grease the gear in the head, they are half as loud, and last twice as long.

Always use a coupon.

Attachment 10139

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I was beginning to think that the 25% coupons were mythical, then within a couple weeks of getting an airless sprayer and a day after buying a bandsaw, I find one of my very own and now this one. Phooey.

I'll have to try greasing the $10 ones and see if that helps; guess it is like many things from HF, "lubricant not included". :D

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Originally Posted by incognito

I have had nothing but trouble with the HF $10 grinders. The HF $20 "Heavy Duty" grinders are not bad.
If you open them up when you first buy them, and grease the gear in the head, they are half as loud, and last twice as long.

Always use a coupon.

Attachment 10139

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I've had no bad luck, but mine are old models.

Bigger companies seem to sometimes make it cheaper over time, smaller ones sometimes make it better (to get to be a bigger company; like Everlast). So maybe the old HF ones were stronger. But I've had great luck with the old ones I have. The backup is like a year old $9.99 one (not good). Well, the Hitachi ones will be here before the old ones break on me :D

Thanks also, I used two of the coupons today. I only have 20% ones in the wallet.

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Originally Posted by jakeru

Thanks for the kind words, Mike. :) Oleg has me on the list to be one of the first to receive a 255EXT, as a prize from my prior contest winning. I'm looking forward to reviewing that, too!

My Super200P is still performing like a champ, though, and you might even say that it's getting better with age. I modded its AC Balance circuit to support higher %EN capability - turning the knob fully counter clockwise now gives ~95-98% EN, instead of the unit's original 80% EN limit.

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I thought you won a contest, but saw you signature still reflected the 200P, why I asked. Cool on the 255EXT. Bet you will love that.

On the 95%+ EN mod, well, you are out of the 5 year warranty by at least a year, so I guess that's OK. hahahaha.. Mark would be on you otherwise.

2x on congratulations on the 255EXT jakeru. That is a fine catch and I can't wait to hear what you have to say about it. I'd have to save up for quite a while before I can afford a digital welder so I'll have to live vicariously through you when you receive one.

I might use the 25% coupon for my grinders, drill press, router, etc. on this:

Attachment 10140

http://www.harborfreight.com/momenta...tch-96619.html

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Originally Posted by Mr120

2x on congratulations on the 255EXT jakeru. That is a fine catch and I can't wait to hear what you have to say about it. I'd have to save up for quite a while before I can afford a digital welder so I'll have to live vicariously through you when you receive one.

I might use the 25% coupon for my grinders, drill press, router, etc. on this:

Attachment 10140

http://www.harborfreight.com/momenta...tch-96619.html

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I use one of those momentary foot power switches on my drill press so I can use both hands and if something goes wrong let it go and the foot pedal and it stops you don't have to reach around the drill press to shut it off been there done it not again. Will have to get a few more thanks Mr120.

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Originally Posted by Kempy

I use one of those momentary foot power switches on my drill press so I can use both hands and if something goes wrong let it go and the foot pedal and it stops you don't have to reach around the drill press to shut it off been there done it not again. Will have to get a few more thanks Mr120.

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No problem Kempy. One of my biggest fears is running a table saw or drill press with both hands occupied and not being able to shut it off quickly if something goes wrong. That is until I read about zoama585 and the grinder falling between his legs while still running ... . I think that scares me more! LOL

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Originally Posted by Mr120

No problem Kempy. One of my biggest fears is running a table saw or drill press with both hands occupied and not being able to shut it off quickly if something goes wrong. That is until I read about zoama585 and the grinder falling between his legs while still running ... . I think that scares me more! LOL

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I should have had two hands on it... cutting with one hand while directing the sparks away from you usually means the open side of your hand is facing down. I use both hands while cutting now.

I'd never thought about that foot switch as an inline safety device but I will now. Zoama's story made me cringe.

I have bad mental images of one of those thin cut-off wheels shattering during operation.

When I've turned off any grinder/cutoff they spin for quite some time, so I don't see how the foot switch will fix the couple seconds of damage either way.

Best to wear gloves and proper clothing, use both hands, be out of harms way of the disk and unit (body and face wise), do NOT remove the guard. When I turn on the gas to weld, I do not stand in front of the gas line, and turn and lean away from it on the opposite side. Just me, but better safe than sorry.

Just keep alert and be smart and you should be fine.

Mine are here. Mint looking, and 10 grinding discs worth $20 of the $58 purchase.

Thanks Mr Russell, not much on the commission side I bet. hahaha

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Originally Posted by everlastsupport

I've had no bad luck, but mine are old models.

Bigger companies seem to sometimes make it cheaper over time, smaller ones sometimes make it better (to get to be a bigger company; like Everlast). So maybe the old HF ones were stronger. But I've had great luck with the old ones I have. The backup is like a year old $9.99 one (not good). Well, the Hitachi ones will be here before the old ones break on me :D

Thanks also, I used two of the coupons today. I only have 20% ones in the wallet.

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I agree that companies often have various levels of quality over a timespan. Harbor Freight takes it to a level I have never seen before. They sometimes have 2 products, with different item numbers, for the same price, that look the same on the outside yet are different on the inside, for sale at the same time. This can go on for years.

Enjoy the Hitachi grinders. I'm well stocked on grinders, but I still picked up one of the Hitachis, at that price I couldn't pass it up. It will get into the rotation eventually.