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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:

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

dougmacm said:

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.

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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 ?

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:
Attached Thumbnails

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.

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

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.

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

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.

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

No, there is no difference in either blade thickness or cutting angle. The only difference is in the increased surface area behind the tip, which results in more lift for better mulching and bagging, but also requires more power.

MowerMike said:

No, there is no difference in either blade thickness or cutting angle. The only difference is in the increased surface area behind the tip, which results in more lift for better mulching and bagging, but also requires more power.

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Thanks for confirming these facts !!

Doug

OK, so it’s been nearly three weeks gone by, and I’ve mowed my lawn four times with the new HD Unicorn blade. The problem is that it has been so wet that the first three mowings are inconclusive, since all I’ve gotten is wet grass muck that builds up on the deck and forces the mower into continuous high power mode, which dramatically reduces battery run time. The fourth mowing was done yesterday, and although the grass was still not fully dry, I did get enough individual grass clippings to make an assessment of mulching quality. There was also a lot less muck buildup on the deck, so I was able to get a longer runtime with the mower running about 50:50 between low and high power modes.

So, based on this not so precise assessment, I conclude the following:

1) The HD blade does provide a significant improvement in mulching quality over the standard blade. I saw no clippings longer than one inch, and most were less than 1/4”.

2) General cut quality is excellent, level and with virtually no stragglers.

3) Battery power consumption is about 50% higher than with the standard blade, or about a third reduction in runtime.

Well, you got my curiosity going and since I wanted a couple of spare blades for my 2 mowers anyway I ordered 2 regular blades and 1 HD blade last week from Greenworks … they arrived TODAY. To make the shipping cost worthwhile, 3 or more blades is the answer.

I now see the difference 1st hand … both appear to be the same stamping so exact same profile, the std. blade is just trimmed down and not only the lift wings, but the o/a length as well.

The HD blade tip to tip is 20-1/4" long and the std. blade is 19-7/8" … I laid the std. blade on top of the HD blade to show the difference:

Ran the 40V Self Propelled today, bagging with the HD Blade … sounded like a completely different mower and it cut & bagged better.

However, blade motor would kick up to HIGH SPEED and stay there regardless of grass height or thickness … which likely also helped the cut quality and bagging performance.

4Ah battery lasted 1-2/3 full bags and almost 16 minutes which included time to empty the 1st bag (minute or two).

Swapped std. blade back in with 2nd 4Ah battery and went another 1-2/3 bags in 28 minutes (again including emptying 1 bag), 3rd 4Ah battery made it to the end / another 1-1/3 bags and had 1 bar left at 1 Hour 8 Minutes.

So the HD blade also works great on the 40V mower, but is not worth the extra draw / shortened battery run time … still glad I bought it and tried it out though !!

First battery was also too warm to put on charger right away, but was cooled down enough when second battery was done so I put them both on chargers at the same time.


I had mentioned that I had purchased the old style 29423 21" blade by mistake in another thread when I bought my mower. I compared it to the other two and it also has the exact same shape (likely all 3 are stamped on the same die), just trimmed differently on the ends, plus larger center hole & different locating notches:

I bought an amazon warehouse 21" GW mower and wanted a spare blade, so I ordered an HD blade from M and D . But, received a 'normal' duty one - no 'B' on the end of the stamping.

1 Lucky Texan said:

I bought an amazon warehouse 21" GW mower and wanted a spare blade, so I ordered an HD blade from M and D . But, received a 'normal' duty one - no 'B' on the end of the stamping.

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That sucks ! What is their return/refund policy ?

Anyways, you can buy it directly from GW for $20 + shipping at greenworks dot ordertree dot com. The SKU number is SUN-2908902. It is currently in stock.

Their email claims the HD is no longer mads and superseded by this blade. It was $18 and I can still use it so, I'm not gonna pursue a return. If I destroy a blade I would re-visit ordering from GW but, kinda wonder if they are just flushing stock? Might actually become a Unicorn!

UPDATE ... the Unicorn is still out of stock:


Was hoping to buy a couple more for the mowing season, oh well.

Doug

I've been checking stock status every few months and when I saw it still "out of stock" this AM I sent an email to ordertree checking on the HD blade and the reply is encouraging in that it is not "obsolete":

Good Morning:
Unfortunately, the needed item are) currently on backorder and are estimated to be due into our warehouse within 10 to 12 weeks due to factory supply chain issues overseas.

Taba

Ordertree Customer Care

Order Status Backorder of 2908902

thanx doug

would the

GreenWorks 2903402 80-Volt 21-Inch​

have more lift on my 21-inch 40v non-sp than the standard blade? will it fit?

Any reports on Maxpower or Arnold 'universal' blades?

1 Lucky Texan said:

would the

GreenWorks 2903402 80-Volt 21-Inch​

have more lift on my 21-inch 40v non-sp than the standard blade? will it fit?

Any reports on Maxpower or Arnold 'universal' blades?

Click to expand...

Read my post #15 on running this HD blade on my 40V 21" mower.

There is no "universal" blade that fits these mowers due to the chevron shaped cut-outs and I've not searched Max Power or Arnold to see if they offer a direct replacement or not.

Doug

they seem to bypass the proprietary shape hole thing with slots - dunno about other fitment issues - just wondering......

1 Lucky Texan said:

they seem to bypass the proprietary shape hole thing with slots - dunno about other fitment issues - just wondering......

Click to expand...

Here is my take on trying something "generic" ...

1. The GW Blade mount is PLASTIC, personally I want maximum engagement with the blade, which you will not get with universal oversized openings.

2. The motor shaft on these mowers is not very large nor is the blade retaining bolt, so I would not want to mount a blade that is any heavier than an O.E. blade. Also, the bearings in the motor that the shaft spins in are sized to match the small shaft too.

3. The O.E. GW blades are also thinner steel and not as wide as a typical lawnmower blade, so I doubt there is a generic one out there as THIN or as NARROW as the GW blades. Thicker and/or wider is only going to ADD weight which will drastically reduce run time and shorten motor life.

4. The GW locating chevrons also "center" the blade, where these generic blades use washer spacers to reduce down to the mounting bolt size ... it would be pretty tough to get a generic blade perfectly centered without the chevrons to avoid any unbalance.

Bottom line is any added weight is only going to overwork the batteries / motor and any unbalance will probably wreck the light duty electric motor pretty quickly.

Doug

well, seems kinda like there's a move to make blades incompatible like the batteries.

Just ordered up 6 HD 2908902 blades ... $138.00 shipped / $23 each. Got 4 for myself and two for a friend that just picked up a Kobalt 80V just like mine after trying it out at his house.

Based on the 10-12 weeks they told me on 08/24 (post #20), they should ship by mid-November. Will not matter to me if they ship even later, as mowing season will be done anyway.

Doug

dougmacm said:

Just ordered up 6 HD 2908902 blades ... $138.00 shipped / $23 each. Got 4 for myself and two for a friend that just picked up a Kobalt 80V just like mine after trying it out at his house.

Based on the 10-12 weeks they told me on 08/24 (post #20), they should ship by mid-November. Will not matter to me if they ship even later, as mowing season will be done anyway.

Doug

Click to expand...

Looks like you bought them out >>> https://greenworks.ordertree.com/heavy-duty-blade.html

MowerMike said:

Looks like you bought them out >>> https://greenworks.ordertree.com/heavy-duty-blade.html

Click to expand...

No ... they are out of stock, but they let you still place an order and they will ship when they get them in. Unlike many sites that don't let you put items in your cart if out of stock, this is nice in that I don't have to keep checking back to see if they are stock or not.

Doug

dougmacm said:

No ... they are out of stock, but they let you still place an order and they will ship when they get them in. Unlike many sites that don't let you put items in your cart if out of stock, this is nice in that I don't have to keep checking back to see if they are stock or not.

Doug

Click to expand...

So, have you received them yet ? Looks like they are in stock now, and the price has dropped to $20 each.

MowerMike said:

So, have you received them yet ? Looks like they are in stock now, and the price has dropped to $20 each.

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My Sept order was CANCELED by them (site probably has a time limit on open orders), so I'll just have to re-order. They were $20.00 back then too, $23.00 was with shipping.

Thanks for checking the site and letting me know.

Doug

Ordered 5 blades and they shipped me only 2 ... they are again out of stock. They charged me the full shipping cost for 5 blades, and it appeared that they reduced the order to 2 blades with no back order.

I emailed them saying they needed to refund me around $9.50 for the shipping overcharge and got a reply saying my back order is still open and it will ship in 10-12 weeks. We'll see, if the B.O. is indeed open, my guess is they will cancel it as they did before at some point.

Doug

ordered a HL blade from ebay, $30 . Hoping it reduces the stragglers...

seller claims to have 2 more, c.more4lesssales , in case anyone else is interested.

I've still not received the 3 on Back Order from January ... guess I should be contacting them again.

dougmacm said:

I've still not received the 3 on Back Order from January ... guess I should be contacting them again.

Click to expand...

Look on it from the bright side, at least they haven't let your credit card get stolen.

dougmacm said:

I've still not received the 3 on Back Order from January ... guess I should be contacting them again.

Click to expand...

maybe I got one of yours....?

MowerMike said:

Look on it from the bright side, at least they haven't let your credit card get stolen.

Click to expand...

They might have actually ... CC contacted me about some suspicious activity early June ... it was nothing we did so charges got denied and we got new cards.

Doug

1 Lucky Texan said:

maybe I got one of yours....?

Click to expand...

Probably not ... I looked at the listing and those are shrink wrapped and a different P/N is mentioned, where the ones from SUN/GW come in a box. Guessing those are a retail / store version.

Doug

first use today, seems like a little advantage with a little more energy use. I'll know more later as we are under watering restrictions and it's hard to say how that affects straggler/mulching comparisons.

after a few more uses, It seems like only 5-10% better performance for 30% or more energy use. If I could force the 'normal' blades to run at high power as often as this HD blade runs at high, there might be little noticeable difference.

of course, I'm on St. A and Bermuda grass. The blade seems to cut bermuda slightly better, but not St.A ....
northern grasses may respond better.