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View Full Version : Double Blades??????????


awagner9
08-13-2007, 09:09 PM
First I have a 07 Scag Wild cat 61" with 30 hp kolher. I assume I have plenty of power to use doubles. What is the best way to set them up and do I have to worry about blades coming off? What angle do I put the blades? And is it really worth it? Thanks Alex

topsites
08-13-2007, 09:12 PM
A few folks swear by it, but my attitude is, if this was such a good idea then why aren't all the mfg's making them like this in the first place?

I don't do it, I don't think much is gained, insofar as investing my time into the cut quality, I can think of many other adjustments that might could use doing. I find NO mower is ever 'ready to go,' thou I did find some used ones are actually readier than the new ones, maybe so because someone adjusted it right, but who knows. Dealers assemble the machine, one spec fits all, I would not recommend taking this out before going over the machine in it's entirety.

lawnboy dan
08-13-2007, 09:31 PM
i aslo feel if this setup is so good -they would come from the factroy with them. it must shorten clutch and spindle life. with the extra drag

awagner9
08-13-2007, 11:06 PM
This is all some people run and they say it destroyes leaves. One account I have they treat thier lawn at least six times a year. With the rain we just got. I'm leaving grass on top. Lawn is about 2 acres. So bagging not an option. And they also only want it cut once a week. The way some talk this would cut down on yard waste.

growabiz
08-13-2007, 11:50 PM
Be careful of unnecessary damage to spindle housings. They are designed for certain standards, excess weight, unbalanced blades lead to premature failure.

Be careful. You also may be setting yourself and your employees up for liability and warranty problems.

MANOFSTIHL
08-14-2007, 01:44 AM
As for the Scag, buy the Hurricane mulch kit. You will not be sorry. BTW, Walker just came out with their NEW 42 inch mulch deck. If you remember they USED to use double blades but their new deck design does not have double blades. To be honest it looks more like your standard 21 inch mulch blade. NO gator teeth or anything extremely aggressive looking about it, but it does an AWESOME job!!! Dean Walker, Bob's brother, spent about 4 years (if I'm not mistaken) designing this deck and said he tried EVERY mulching blade out their, including some that weren't. End result, single did better than double in this case...

LawnScapers of Dayton
08-14-2007, 07:23 AM
I have been running doubles for years, no problems, no extra belt wear, no replaced spindles, nothing. It improves discharge distance, finer clippings and does destroy leaves although I now use Meg-mos for leaves.

D

naturescape
08-14-2007, 09:57 AM
Try running doubles. You can always easily take them off. I have only had one spindle go bad in the last 10 years. Solo op here using machines that are up to 5 years old. I don't think doubles will affect a Scag spindle at all.

Yard-Ape
08-14-2007, 03:27 PM
I use a Dixie Chopper and am looking to try a double blade setup soon to help chop up the discharge a little finer. Most of our grass here is St. Augustine and is growing like crazy right now. It's not uncommon to cut 3 -4" of growth in just a week.

Not sure on the Scag, but I certainly don't buy into the gloom and doom scenarios of ruining belts, spindles, etc. with the Chopper. Doubled X-Blades are a factory option for any chopper and if you would rather double up regular, high lift, or a cobination of these and gators, Dixie sells a double blade kit that holds the two blades in a "+" fashion. Most people just double them up and tighten and swear that you have to really hit something substantial to offset the blades without any special adapters.

bsalter5
08-14-2007, 04:13 PM
I can see where spinning up two blades could cause more wear on the clutch, but doubt it is too significant. Once two blades are spooled up, their inertia will make them harder to slow down, which could extend the clutch or belt life a touch. I'm careful to engage the blades with the engine around 1.2 throttle hoping to minimize clutch loading.

Regarding spindle bearings, doubles won't, or shouldn't increase side loads at all. I can't see where balance is any more of an issue that with single blades either. The extra blade weight, along with a bit more lift (two blades generating lift rather than one), will put some additional down force (axial thrust) on the spindle. If you have tapered roller bearings in your spindle, you have nothing to fear. Ball bearing spindles, on the other hand, might not like the extra load, and could wear a little faster. Ball bearings are inherently poor at resisting axial loads.

I'm currently playing around with one high lift and one mulching blade on each spindle. It seems to work pretty well, but I haven't convinced myself it is better than two "regular" or one "regular" and one high lift blade on each spindle.

My next test might be with two mulching blades - I didn't like the way a single mulching blade worked as much as any of my double combos.

bes

lawnmaniac883
08-14-2007, 05:49 PM
I can see where spinning up two blades could cause more wear on the clutch, but doubt it is too significant. Once two blades are spooled up, their inertia will make them harder to slow down, which could extend the clutch or belt life a touch. I'm careful to engage the blades with the engine around 1.2 throttle hoping to minimize clutch loading.

Regarding spindle bearings, doubles won't, or shouldn't increase side loads at all. I can't see where balance is any more of an issue that with single blades either. The extra blade weight, along with a bit more lift (two blades generating lift rather than one), will put some additional down force (axial thrust) on the spindle. If you have tapered roller bearings in your spindle, you have nothing to fear. Ball bearing spindles, on the other hand, might not like the extra load, and could wear a little faster. Ball bearings are inherently poor at resisting axial loads.

I'm currently playing around with one high lift and one mulching blade on each spindle. It seems to work pretty well, but I haven't convinced myself it is better than two "regular" or one "regular" and one high lift blade on each spindle.

My next test might be with two mulching blades - I didn't like the way a single mulching blade worked as much as any of my double combos.

bes



The clutch is responsible for starting AND stopping the blades. Not only will you face increased wear upon engagement but also upon disengagement.

IMO doubles would be best used if you could find two blades that when stacked cut at the same height. See if you take two standard high lifts and put one ontop of the other then ones cutting surface will on top while the other a quarter inch below it. If you ask me it would be better to find a blade with a quarter or half inch drop from the center to the ends so that each blade surface was cutting at the same height.

bsalter5
08-14-2007, 06:13 PM
The cut height think is an interesting theory - that is why I'm using a high lift and mulching blade. My mulching blade has a 1/4" drop, which, when stacked on top of the high lift, yields two blades with one cutting height.

It doesn't really seem to work noticeably better that two blades with 1/4" difference in cutting height though. When I stacked two straight (no drop) blades, the lower blade did dull faster. Annoyingly, my mulch blades seem to be made from a steel/peanut-butter alloy - they dull much, MUCH quicker than the high lift.

I don't fully agree with your theory about clutch damage upon disengaging. While there is a little slippage, after the first tiny bit of movement, no drag or load. I'd guess that engaging the clutch is where at least 90% of your wear happens - the engine loading up and the mower torquing or jerking indicates that something is picking up a big load. I don't feel anything like that when I disengage the blades - at any throttle setting. Naturally, I could be wrong...

bes

lawnmaniac883
08-14-2007, 07:13 PM
Its not that you would necessarily feel the load comming to a stop as you feel it start up but it is that while most clutch wear surely comes from engagement, the clutch doubles as a brake to stop the load when you disengage the blades. Wear occurs at both cycles.

bsalter5
08-15-2007, 01:33 AM
"the clutch doubles as a brake to stop the load when you disengage the blades"

Not trying to beat this to death, but, at least on my last three mowers, there is nothing even pretending to be a blade brake. When I disengage the blades, they take at least a few seconds to spool down. I can turn them off at mowing speed and cut anywhere from a few feet to about 15 feet (depending on the length and thickness of the grass).

Do some ZTRs have blade braking? I can see where that would add some clutch wear, but it could also save me time. I have to cross about 6 feet of tattered landscaping fabric in one yard to get to another part. If I don't disengage the blades, then wait at least 5 seconds or so before crossing, I can suck up bits of cloth, which can cause some problems. I hate having to slow down or stop, disengage, wait, cross, then re-engage the blades.

bes

David Gretzmier
08-23-2007, 01:43 AM
There is no blade brake on clutches I am aware of. it you engage the clutch, 12 volts goes to it and it locks down. belt engages, blades spin. disengage, no voltage, and it unclamps or releases. wears out when materail is not able to clamp anymore. I am not aware how that it releases so much that it slows things down, and then is not on at all when the blades stop...