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  #31  
Old 06-02-2012, 09:43 AM
Razorblades Razorblades is offline
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Originally Posted by GMLC View Post
Right now Im still running OEM blades. But yesterday I bought a set of Stens blades from my dealer which are factory replacements (Gravely owns Stens) but are thinner than the stock blades. He claims you get a little more blade tip speed and has had good results. I kinda gave him the look and said I will give them a try. Im going to put them on this weekend and will cut with them on Monday and report back. I have never run thinner blades. Have you ever heard of better blade tip speeds with them?
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Blade tip speed should be the same as with other blades because that engine should have a max. rpm setting of about 3600 loaded (with blades engaged)or unloaded. That is one function of the governor on these engines with carbs is to get the engine to max rpms under load and to help keep it operating at that rpm whenever possible.

If you put a tachometer on the engine and check the rpms (not a bad idea anyway to make sure it is running at the 3600 rpm setting) unloaded and then after you engage the blades, you should see the engine have a short drop off in rpm's and then it should gain back the rpms back to within 50 rpms of original reading, if the governor is set properly.

With the bagger going, I'm not sure if the governor will be able to compensate for that much extra rotational mass being turned.
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  #32  
Old 06-02-2012, 09:51 AM
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GMLC GMLC is offline
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Originally Posted by Razorblades View Post
Blade tip speed should be the same as with other blades because that engine should have a max. rpm setting of about 3600 loaded (with blades engaged)or unloaded. That is one function of the governor on these engines with carbs is to get the engine to max rpms under load and to help keep it operating at that rpm whenever possible.

If you put a tachometer on the engine and check the rpms (not a bad idea anyway to make sure it is running at the 3600 rpm setting) unloaded and then after you engage the blades, you should see the engine have a short drop off in rpm's and then it should gain back the rpms back to within 50 rpms of original reading, if the governor is set properly.

With the bagger going, I'm not sure if the governor will be able to compensate for that much extra rotational mass being turned.
Thanks, I thought he was blowing smoke. I had never heard that claim before and I have heard some good ones over the years!
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  #33  
Old 06-02-2012, 01:59 PM
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mtmower mtmower is offline
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Originally Posted by ProStreetCamaro View Post
Are the stens blades he gave you flat on the bottom? The stens blades I buy are flat blades and don't have that small arch to them. I actually think the flat blades might cut a little better than the oem blades. BUT the oem blades do hold an edge longer because they are marbane. The stens have a longer cutting edge also.

Here are my stens laid next to new G6 blades


This is my cut quality with the stens blades. This was done with my 160Z but it has the same deck as our new 400 series. Nice clean smooth cut.

I think your on to something. My SZs and a lot of others like Exmark have long gone with the flat blade (no hump) and the longer cutting edges. I understand the longer cutting edge is not so much for cutting as it is to add more lift like an airplane wing. I also see many of these blades with good results using a notched lift wing instead of rolled. I still have not heard a good reason why a slight hump in the blade would have any positive effect. Plus they're a little harder to sharpen when using a dedicated blade sharpener. I'll be looking for a long lasting, flat, notched lift I think. Maybe Oregon offers something in a fusion. If your picky don't forget to readjust your deck for the slight difference in cut height due to difference in blades being flat or humped.
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  #34  
Old 06-02-2012, 03:45 PM
Ridin' Green Ridin' Green is offline
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mtnmower-

a humped blade serves three purposes that I am currently aware of. One is to help protect the spindle bolt by mere the fact that it is recessed in relationship to the cutting edges/height. If they'll clear, so will the spindle bolt (as in going on or off the trailer or over a root, shallow small stumpe etc). Also, a spindle designed to run flat blades has to be longer to keep the blade in the lower part of the deck where most machines run their blades.

The main reason though is to help eliminate the drag on the grass surface by the entire length of the blade which can only reduce power, and cause extra wear to the spindle bearings.

Last edited by Ridin' Green; 06-02-2012 at 03:50 PM.
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  #35  
Old 06-02-2012, 04:14 PM
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mtmower mtmower is offline
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Originally Posted by Ridin' Green View Post
mtnmower-

a humped blade serves three purposes that I am currently aware of. One is to help protect the spindle bolt by mere the fact that it is recessed in relationship to the cutting edges/height. If they'll clear, so will the spindle bolt (as in going on or off the trailer or over a root, shallow small stumpe etc). Also, a spindle designed to run flat blades has to be longer to keep the blade in the lower part of the deck where most machines run their blades.

The main reason though is to help eliminate the drag on the grass surface by the entire length of the blade which can only reduce power, and cause extra wear to the spindle bearings.
I guess I can see the spindle bolt protection but the drag issue I've heard and dispute. If the deck pitch is set correctly the front is lower than the rear so in most cases the grass is cut to length prior to the rest of the blade coming in contact with any grass. This would also keep added stress of the spindle. IMO the added lift gained from a flat blade would out weigh the possible damage to the spindle bolt.

The X-Factor blade hump is so minimal that I don't know if it helps much even for your purposes stated. You can see pics of the oem blades here.

http://www.lawnsite.com/showthread.php?t=379728 post #16
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  #36  
Old 06-02-2012, 04:23 PM
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ProStreetCamaro ProStreetCamaro is offline
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Originally Posted by GMLC View Post
This is one of the Stens blades...looks the same as yours. Your cut looks great!! I like the OEM blades but if my dealer and you are right these may be even better!


I think you will like them! You will find that they dull out faster. I have thought about trying a set of high lift fusion blades to see how they cut. Tons of 60" mowers use the same dimension blade. 20 1/2" and 5/8 bolt hole and they will fit and work.
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  #37  
Old 06-02-2012, 04:30 PM
Ridin' Green Ridin' Green is offline
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Even though I'm not a member of "the club", I have been following all of these threads, so I have seen your pics already. Your aren't humped as much as my OEM blades for sure, but the hump is quite visible.

As far as the drag issue, let's think about it for a minute. If the deck is pitched 1/4" front to rear as most guys seem to do, that's over the length of an approximately 21" blade. That's a pretty shallow angle, and you can bet your hinnie that the grass blades will still be dragging the blade's bottom surface. Think about all the turbulence under the deck surrounding the grass blades as they are cut. Too, when the blades actually make contact with the grass blades they tend to bend over slightly before being cut off, which means that they spring back up enough in all probability to drag the bottom of that shallow pitched blade.
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  #38  
Old 06-02-2012, 05:08 PM
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mtmower mtmower is offline
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Originally Posted by Ridin' Green View Post
Even though I'm not a member of "the club", I have been following all of these threads, so I have seen your pics already. Your aren't humped as much as my OEM blades for sure, but the hump is quite visible.

As far as the drag issue, let's think about it for a minute. If the deck is pitched 1/4" front to rear as most guys seem to do, that's over the length of an approximately 21" blade. That's a pretty shallow angle, and you can bet your hinnie that the grass blades will still be dragging the blade's bottom surface. Think about all the turbulence under the deck surrounding the grass blades as they are cut. Too, when the blades actually make contact with the grass blades they tend to bend over slightly before being cut off, which means that they spring back up enough in all probability to drag the bottom of that shallow pitched blade.
Yea I'd agree with you. I got plenty of power which I'm sure I'm paying for with the 31 Kaw. So power is not an issue in my case but lift seems to be. I check my blade balance and deck height/pitch new. The MB blades were quite close but I only use a cone balancer. The deck they recommend a pitch of only 1/8" which is super minimal. I may try pitching it more to see if it effects the stragglers I'm seeing. But I would think more pitch would also = less vacuum so I may be going in the wrong direction.
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  #39  
Old 06-02-2012, 05:39 PM
Ridin' Green Ridin' Green is offline
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I believe that more pitch (within reason of course) creates more vacuum because it allows air to be sucked in at the rear of the deck easier, which is also what helps with striping. I would think that pitching your deck more should help to get rid of the stragglers.
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  #40  
Old 06-02-2012, 07:05 PM
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mtmower mtmower is offline
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Quote:
Originally Posted by Ridin' Green View Post
I believe that more pitch (within reason of course) creates more vacuum because it allows air to be sucked in at the rear of the deck easier, which is also what helps with striping. I would think that pitching your deck more should help to get rid of the stragglers.
What's your reasoning there? I would think any pitch would create less of a seal to the surface causing less vacuum. 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. 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. This would seem to help more in higher ground speeds as well.
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