Register free!
Search
 
     

The Green Industry's Resource Center


Click for Weather
Reply
 
Thread Tools Display Modes
  #41  
Old 06-02-2012, 06:28 PM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,363
mtmower look at the bottom of page 39 in your owners manual. There is note about pitch and cut quality. If I understand it correctly you are correct about rear pitch creating more vacuum.
Posted via Mobile Device
Reply With Quote
  #42  
Old 06-02-2012, 06:59 PM
Ridin' Green Ridin' Green is offline
LawnSite Fanatic
 
Join Date: May 2011
Location: Michigan
Posts: 8,437
Quote:
Originally Posted by mtmower View Post
What's your reasoning there? I would think any pitch would create less of a seal to the surface causing less vacuum.You don't want that tight of a seal or else the blades lose vacuum, well maybe lose is too strong a word, but they will sure enough have to work a lot harder to gain any vacuum affect. The only reason I could see more pitch creating vacuum would be due to allowing additional air flow to be sucked under the deck at the higher point creating more flow and as a result maybe more vacuum.Exactly right. If this is the case it would seem to make more sense to reverse the deck pitch, making the front of the deck higher than the rear to get the grass to stand earlier within the deck travel/space. Take a good look at your deck, or any commercial Z deck for that matter. They are all designed with the front lip and baffles to be higher than the side and rear skirts to allow the grass to stand more upright before entering the cutting chamber. This would seem to help more in higher ground speeds as well.
Well, I don't have any way to scan them, but several of my Deere manuals show what I am talking about with descriptions and drawings etc. The forwards pitch is so that the blades are only cutting at the front edge of the blade, and it allows the vacuum affect to happen at the rear of the deck as you move forward, which also draws the grass in the direction of travel. The air is being forced out the side chute at high velocity, so drawing it in at the opposite side of the deck (rear) makes perfect sense for maximum air flow to happen. If it drew it all in at the front, it would be immediately redirected out the side chute and you'd have far less, if any, vacuum since the baldes wouldn't have a chance to create any suction anywhere except for the very front of the deck. This is nothing new that I am talking about here. There are lots of recent posts here about this as well.

Last edited by Ridin' Green; 06-02-2012 at 07:05 PM.
Reply With Quote
  #43  
Old 06-02-2012, 07:08 PM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,363
In the Gravely manual it says pitching the deck creates more engine power to cut grass. Heeling the deck creates better cut quality. Gravely recommends a 1/8" pitch for the best balance.
Posted via Mobile Device

Last edited by GMLC; 06-02-2012 at 07:16 PM.
Reply With Quote
  #44  
Old 06-02-2012, 07:14 PM
Ridin' Green Ridin' Green is offline
LawnSite Fanatic
 
Join Date: May 2011
Location: Michigan
Posts: 8,437
Quote:
Originally Posted by GMLC View Post
In the Gravely manual it says pitching the deck creates more engine power to cut grass. Heeling the deck creates better cut quality. Gravely recommends a 1/8 pitch for the best balance.
Posted via Mobile Device
Yea, that's a common pitch number. Deere shows anywhere from 1/8"all the way to as much as 1/2" depending on the exact mower deck and machine. Most manu's show 1/4" as std. A too steep pitch will leave furrows where each blade passes over the grass, but it takes an extrem pitch to do that. Also, remember that manu's show what will work for their decks under any all around conditions/regions. Playing with the pitch can really make a difference in your stripes depending on your exact grass types, and climate. down south, less may pitch may work best, but if you take a poll here, you'll find most guys are pitching their decks 1/4" or slightly more for the best looking cut and stripes (in northern climes).
Reply With Quote
  #45  
Old 06-02-2012, 07:16 PM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,363
Quote:
Originally Posted by Ridin' Green View Post
Yea, that's a common pitch number. Deere shows anywhere from 1/8"all the way to as much as 1/2" depending on the exact mower deck and machine. Most manu's show 1/4" as std.
Yea all my scag manuals recommend 1/4".
Posted via Mobile Device
Reply With Quote
  #46  
Old 06-02-2012, 11:53 PM
mtmower's Avatar
mtmower mtmower is offline
LawnSite Bronze Member
 
Join Date: May 2008
Location: North Western Montana
Posts: 1,106
Well it looks like everything is pointing toward adding more pitch than 1/8' that it's set at now to possibly eliminated the few stragglers I have here and there. I'll give it a try and see what happens. Thanks for the schooling.

Has anyone adjusted a 400 series deck yet? I'm also confused on the need for blocking under the deck for the process as it says in the owners manual (not on the edge guard but on the lip of the deck). I just dropped the deck to the 3.5" mark like they recommend and used my new John Deere blade height gauge I bought for less the $7 and adjusted side to side then front and back on both sides and rechecked. The blocking of the deck they talk about in the manual makes no sense to me. If the deck is supported by blocks how in the heck do you get a reading?

By the way I also found that the surface your on has to be dead pan flat or things are thrown off more than you'd think. The concrete surface I'm using I thought was as flat as any and found out differently when I started chasing my tail around the deck adjusters.
Reply With Quote
  #47  
Old 06-03-2012, 03:46 AM
Ridin' Green Ridin' Green is offline
LawnSite Fanatic
 
Join Date: May 2011
Location: Michigan
Posts: 8,437
Yep, I've posted the whole process of trying to use the gauge on cement here several times in the recent past. Almost any cement has small birdbaths that can throw the readings way off. When I built my shop a couple years ago, I made sure that they poured me at least 1/4of it dead flat and as dip/hump free as is possible with wet cement so I do have a good area to check mine over. Still, I lay my 6' trim level across it in several places to reassure myself every time I set a deck for level/pitch.
Reply With Quote
  #48  
Old 06-03-2012, 06:47 AM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,363
Quote:
Originally Posted by mtmower View Post
Well it looks like everything is pointing toward adding more pitch than 1/8' that it's set at now to possibly eliminated the few stragglers I have here and there. I'll give it a try and see what happens. Thanks for the schooling.

Has anyone adjusted a 400 series deck yet? I'm also confused on the need for blocking under the deck for the process as it says in the owners manual (not on the edge guard but on the lip of the deck). I just dropped the deck to the 3.5" mark like they recommend and used my new John Deere blade height gauge I bought for less the $7 and adjusted side to side then front and back on both sides and rechecked. The blocking of the deck they talk about in the manual makes no sense to me. If the deck is supported by blocks how in the heck do you get a reading?

By the way I also found that the surface your on has to be dead pan flat or things are thrown off more than you'd think. The concrete surface I'm using I thought was as flat as any and found out differently when I started chasing my tail around the deck adjusters.
I dont want to confuse things but I think you would want less pitch per the Gravely manual. More pitch is going to give you more engine power(less vacuum). More heel should increase cut quality(more vacuum). At least thats how I understand it after reading the manual. Personally I would try leveling it first before heeling to see if your going in the right direction. Now that I think about it it makes sense. Think of the blade like an airplane wing. If the blade is pitched down in the front it creates down force. If the blade is heeled down in the rear it creates up force.
Posted via Mobile Device

Last edited by GMLC; 06-03-2012 at 06:56 AM.
Reply With Quote
  #49  
Old 06-03-2012, 07:05 AM
ProStreetCamaro's Avatar
ProStreetCamaro ProStreetCamaro is online now
LawnSite Gold Member
 
Join Date: Apr 2004
Location: Gaithersburg Maryland
Posts: 3,772
Quote:
Originally Posted by GMLC View Post
I dont want to confuse things but I think you would want less pitch per the Gravely manual. More pitch is going to give you more engine power(less vacuum). More heel should increase cut quality(more vacuum). At least thats how I understand it after reading the manual. Personally I would try leveling it first before heeling to see if your going in the right direction. Now that I think about it it makes sense. Think of the blade like an airplane wing. If the blade is pitched down in the front it creates down force. If the blade is heeled down in the rear it creates up force.
Posted via Mobile Device

You got it. If the deck is absolutely perfectly level flat it will create the most vacuum and cut the cleanest.
__________________
2013 Gravely 460Z 29EFI
2011 Gravely 36GR
2008 Gravely 160Z
2004 Gravely 34Z
1998 Lazer Z HP 48 (old faithful)
Reply With Quote
  #50  
Old 06-03-2012, 10:22 AM
ProStreetCamaro's Avatar
ProStreetCamaro ProStreetCamaro is online now
LawnSite Gold Member
 
Join Date: Apr 2004
Location: Gaithersburg Maryland
Posts: 3,772
For those interested here is a high lift fusion blade that will fit the 60" X-Factor deck. 20 1/2", 5/8" center hole and 250-250 thickness and width. It is a notched high lift with the extended cutting surface.

491-506

http://www.mowpart.com/p4401/20-1/2%...duct_info.html
__________________
2013 Gravely 460Z 29EFI
2011 Gravely 36GR
2008 Gravely 160Z
2004 Gravely 34Z
1998 Lazer Z HP 48 (old faithful)
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump





Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 08:02 PM.

Page generated in 0.08508 seconds with 10 queries