Double blades... Should I?

[balconio 606]

I needed to sharpen the blades, and I have lots of spares. It's a 312-8 42" rear discharge deck in great condition. Should I run double blades? Anyone have experience positive or negative, I've searched on some other forms and folks seem to be all over the place on this topic...

[Pullstart 62,811]

What keeps them from spinning and eventually riding together?

[balconio 606]

2 minutes ago, pullstart said:

What keeps them from spinning and eventually riding together?

right now just the tightness of the bolt. i figure if i like it i could put a tack weld on each side and double check them for balance. in researching folks were saying to engage/disengage the PTO at low speed anyhow and definitely with this mod- i have never done that but will start immediately since it makes sense to treat your PTO clutch/brake nicely. 

 

also i realized maybe i should move this to the implements section of the forum...

[Pullstart 62,811]

Maybe a star lock washer would help between them... or build a + shaped plate that sandwiches between and bends up/down alternating?

[Stepney 2,325]

I went the star washer route. 
Honestly can't say I noticed any difference .. outside the deck cutting even painfully lower..

[tom2p 2,394]

19 minutes ago, Stepney said:

I went the star washer route. 
Honestly can't say I noticed any difference .. outside the deck cutting even painfully lower..

lol

 

[prondzy 3,881]

1 hour ago, balconio said:

I needed to sharpen the blades, and I have lots of spares. It's a 312-8 42" rear discharge deck in great condition. Should I run double blades? Anyone have experience positive or negative, I've searched on some other forms and folks seem to be all over the place on this topic...

What is gained by this? Engineers developed this deck and they function very well, not saying things cant be improved upon. If you ask me your looking for trouble if those blades come loose while mowing you will have a pair of throwing knives flying across the lawn at a couple thousand rpm. Goodbye to who ever or whatever is in their way.

[JoeM 7,871]

I set up a 36" like that and It cut very nice. Very fine clippings. Used more, noticeably power. I had it on a 10 hp. Nothing in between blades. no special washers, just the nut tension and they held up good. 

 

[JoeM 7,871]

1 minute ago, prondzy said:

What is gained by this

I was looking for finer clippings.....and it did work. I would think before a blade would fly off the blades would spin on the shaft. No different than one coming loose. The deal breaker for me was the power consumption. A good 12 HP gear drive would have been more better.

[skrusins 128]

I have a 48SD and a 42RD with 6 blades for about 3yrs. now and love it. I use no washers and they stay together unless I hit something really hard like a big rock or turf it. I think it happened only once a long time ago. I have a regular and a gator blade on each spindle it pulverizes the grass. I Hope this helps.

Edited April 30, 2020 by skrusins
sp

[skrusins 128]

Forgot to mention I use a electric impact never a cresent wrench.

[ZXT 2,401]

1 hour ago, skrusins said:

I have a 48SD and a 42RD with 6 blades for about 3yrs. now and love it. I use no washers and they stay together unless I hit something really hard like a big rock or turf it. I think it happened only once a long time ago. I have a regular and a gator blade on each spindle it pulverizes the grass. I Hope this helps.

From what I've read, using one regular and one gator blade produces the best results. I've considered trying this myself.

 

1 hour ago, skrusins said:

Forgot to mention I use a electric impact never a cresent wrench.

Yeah, a Crescent isn't going to tighten it near enough.

[balconio 606]

I think I'm going to try the more is better approach and see how it goes. Being a rear discharge I feel like the clippings don't spend as much time getting chewed up on the way out like a side discharge. I'm looking for finer clippings and more lift basically. Definitely impact drove the nuts on and then some. I will be keeping and eye on them for sure. Thanks for all the input fellas.

[balconio 606]

i tried it this past weekend- worked great! the clippings are definitely finer and i didn't notice any kind of vibration or undue strain on the engine or clutch. i did start slowly engaging/disengaging the PTO just off idle and that makes the clutch scream a whole lot less- but didn't kill the engine or anything. i used to jam the lever forward at full throttle- and regret every time i've ever done that... I mowed a section of my field with the deck all the way up (still too low but oh well) and that turned out really well too.

[sgtsampay 117]

Any update on this? Do you still think the 42in RD works well with Double blades?

[OoPEZoO 513]

I've been running my 36" RD deck like this for probably 10 years.  One set of standard blades and one set of gator blades.  I think it works great.  I'm very happy with the cut quality.  I don't have anything between the blades, just tightened the spindle nuts down with an impact wrench.  Only difference with my deck is that it has the arching baffles in the front.  The previous cut quality was OK, but the dual blade setup was a noticeable improvement.  That being said, the most important thing for a nice cut with my deck is sharp blades and making sure there isn't grass built up underneath.  My deck is horrendous for that.......my property runs along a creek and doesn't drain well.  My grass is always wettish, and will pack the underside of the deck almost solid......then it cuts like crap

[balconio 606]

I ran it like that for most of a season but came to the conclusion it produced only marginally finer clippings and the cut was too darn low even at the highest deck setting. I had sticker shock at the price of new spindles and decided not to stress out the old gals. I have a field which I mow periodically and the double blades definitely didn't work well in the high field grass. It bogged down the 312 where the single blades were able to power through it.

[kpinnc 11,936]

On 4/29/2020 at 8:13 PM, tom2p said:

outside the deck cutting even painfully lower..

 

I've had better luck by adding taller guage wheels. There is a limit of course, but 6 or 7 inch wheels will raise the cut quite a bit.

[peter lena 8,588]

@OoPEZoO  that under deck issue is treatable , NONE OF MY DECKS HAVE BAFFELING  , terrifying to many , I am aware of the intended benefit . the built up solid clogging is your obvious issue , and enhanced rotting . that was my original intended removal of the baffles , they did little to help on the lawn.  regularly drop my decks for light cleaning / lubrication spray down and most important  , hot sun angle drying  , like this , been doing this for years , none of my decks have any rot , blades are sharp , they are soaking in oil now over winter, upside down to hold lubricant to metal . grass cutting is very good , questions ?  just ask , pete