The Unicorn that wasn’t

MowerMike

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Let me explain.

in March, 2017 I purchased a Greenworks 21” 60 volt cordless lawn mower that mentioned in the manual an optional heavy duty blade that promised improved bagging and mulching performance at the expense of higher power drain on the battery. So, I searched the internet and queried Greenworks in a vain attempt to purchase one. Nothing at all could be found for a year, but then in March, 2018 I purchased a switch for my Greenworks Twin Force from a new greenworks.ordertree website, and decided to try again. This time the part number for the heavy duty blade showed up and the website accepted my order. But then there was silence, so after a week I emailed customer service to inquire on the order status, and was told the the item was backordered and there was no information as to when or even if the item would ever be available. Since I had not been billed, I just left the order in place and forgot about it. Anyways, a few days ago about four months after placing the order I noticed a charge on my credit card from ordertree, and when I checked my greenworks.ordertree account later that day I saw that the status had changed to “shipped”, and there was a UPS tracking number. The blade showed up yesterday, and I tried it out today, although with my lawn dried up from the summer heat and drought, I have no way to tell how much of a difference it makes. The only apparent difference between the stock blade and heavy duty blade is the shape of the tips. Whereas the stock blade has a substancial taper at the ends, the heavy duty blade has almost none, which I assume creates more lift to improve mulching and bagging, but also consumes more power that reduces runtime.

The difference between the two blades can be seen in the attached photo:
 

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dougmacm

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I'm guessing you've got the pusher (non-SP) 60V mower, as this manual calls out both the std. 2903402 & HD 2908902 blades as you state.

The manual for the Self Propelled 60V model only calls out one blade: 333041179 which is the same blade my 40V pusher and 40V SP manuals call out (no HD option).

Interestingly, the non-SP 80V manual only mentions the std. 2903402 blade … no mention of the HD blade.

However the 80V SP manual calls out the std. 2903402 and the HD 2908902 blades just like the 60V non-SP manual.

These are all 21" deck mowers, and my 40V 21" blade (measures 20" long) has the same arrow notches in it and looks a lot like the std. one in your pic.

Makes me wonder if 333041179 & 2903402 are the same. If not, you would at least ways expect the 60V pusher & SP models to call out the same blade like the 40V & 80V mowers do.

That HD blade looks much straighter … like a normal lawnmower blade, which will be easier to sharpen.

Doug
 

MowerMike

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Makes me wonder if 333041179 & 2903402 are the same. If not, you would at least ways expect the 60V pusher & SP models to call out the same blade like the 40V & 80V mowers do.

That HD blade looks much straighter … like a normal lawnmower blade, which will be easier to sharpen.
Yes, indeed, they are the same. The 2903402 number is shown in the manual and is the Sun product number for ordering. The 333041179 is shown in the parts list and is stamped on the blade with a “GLB” (Greenworks Lawn Blade ?) prefix. The heavy duty blade is stamped GLB333041179B, and weighs less than an ounce more than the standard blade. As to the hd blade being straighter, it is not, that is just an optical illusion of the photo I took. Anyways, I have no doubt that the hd blade should fit just fine on your 21” 40 volt SP mower. Does the blade on your mower attach with a big 27mm plastic hex head on the bolt ?
 

dougmacm

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My mower is the non SP version MO40L01 that I bought for my wife's office that has a real small yard (maybe 15 minutes of cutting). I've been researching the 40V SP version … as well as all the 40, 60 & 80V versions that GW offers and also makes for Kobalt, Snapper, & Dewalt that I've found so far … for home use. This yard is about 15k sq-ft. and takes about an hour to cut with my Lawn-Boy 10525 in 3rd gear (= approx. 3.5 MPH).

Amazon had the MO40L02 priced under $300 a few weeks ago (currently $308 and was quite a bit higher than that between then & now), so if it again dips below $300, I might jump on one.

It's been a while since I took off the blade, so I don't remember what the bolt looked like. I took a picture of the blade mounted with bolt removed though:
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MowerMike

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That looks just like mine, so no doubt you have the same bolt. The bolt head has a flange that spans the full width of the blade, which is clearly shown in your photo. Also, the fan and blade carrier looks the same.
 

dougmacm

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Was just on the SUN partstree site and when item 333041179 is displayed it mentions (2900402) not 2903402.

A google search for 2900402 brings up nothing, a search for 2903402 brings up blades and on the SUN partstree site it does state that 333041179 supersedes it.

Could they make things even more confusing ??


Now to add more confusion to Greenworks mower blades I've got another story to share:

At the same time I ordered my mower I jumped the gun and ordered a GW replacement 21" blade # 29423 from Tyler tool, that various sites state it fits all GW 21" mowers … WRONG !! This blade has the round & half round cut outs instead of the arrows and is only 19.38" long (vs. 20" for the correct blade). It was a special 4th of July sale and was only $9.89 & free shipping, so I jumped on it. Box does say 21" Mower blade but must be for older models.

Doug
 

MowerMike

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The 29423 blade that you bought fits the old Greenworks 21” 13 Amp corded lawn mower models 25112 and 25213. That was before Greenworks even offered any cordless 21” deck lawn mowers. Anyways, if you decide to buy the hd blade, make sure to order it with the 2908902 part number. That is the correct Sun P/N, and it is what is shown on the pick ticket that was included in the package with the blade. Something is a great deal only if it works with your equipment.
 

dougmacm

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So have you had a chance to use the Unicorn / HD Blade ??

Does it cut any better ??

How does it effect run time ??

Now that I have two of these mowers (MO40L01 & MO40L02) I'm thinking about getting some spare blades … the HD being only $5 more ($20 vs. $15) and both are now stock I'd be tempted to order one to try out.

Thanks,

Doug
 

MowerMike

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I’ve not had a chance to try it out so far due to a combination of first no grass to cut, then health issues and recently continuous rain. When the rain clears up this weekend there will be some decent growth to cut and my little old body should be able to push the mower again.
 

dougmacm

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It's been pretty dry up here too, but obviously not as dry as Texas as I've still been cutting grass every week. Sorry to hear about your heath issues and glad you are feeling better. I'll be 55 in two weeks and have all sorts of muscle & joint pain to deal with but otherwise healthy at the moment.

Anyway, I've been thinking about getting a lawn mower blade sharpener from these guys …
https://www.allamericansharpener.com/shop/
… and one of the things you need to consider is the sharpening angle.

All my Lawn-Boy blades are ground at a std. 30Deg angle, where the GW 333041179 is at a 45Deg angle. In communicating with AAS, we're both guessing the 45Deg angle is due to the GW blade being "thinner":

Oregon L-B 21" Gator = 3/16" thick
OEM L-B 21" Tri-Cut = 0.127" thick
GW 333041179 = 0.119" thick (incl. paint)

To be able to grind the 45Deg angle, I'd have to buy their most expensive $205 adjustable model … vs … $160 for their fixed 30Deg model. They also have a $185 two stop model for grinding bi-level mulching blades similar to the GW blade but with a 30Deg std. cut not 45Deg. My thinking (as well as theirs) is the 30Deg angle cuts better than 45Deg, but would re-grinding the GW blade to 30Deg effect how long it remains sharp ?? It is quite a bit thinner than the Oregon blade, but really not that much thinner than the OE L-B blade.

So … all this got me thinking again about the this Heavy-Duty "Unicorn" blade.

You don't mention a change in thickness or cutting angle nor does your comparison picture show a noticeable difference, so I'm now curious if there is any difference in either the thickness or cutting angle.

Let me know … thanks,

Doug
 
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