The Streaker

[Ed Kennell 38,048]

 

I have this real nice 42" SD that has no rust and has never been welded on, but it leaves streaks even on the straight runs.  

 

I have sharpened and balanced the blades and adjusted the front to rear height with no change.

 

The blades have a 1/4" overlap when parallel  and have a 1/8" clearance at closest point.   The spindles are good with no slop.

 

I have bolted and welded liners in many rotted out decks and they all cut fine.       Apparently this one for some reason is flexing causing the streaking.

 

       Any ideas?

 

I gave it the Greasy  @peter lena  treatment and left it in the 90F sun to bake for a few bays.

[squonk 41,040]

Those blades look shot for one thing

[Jeff-C175 7,199]

41 minutes ago, squonk said:

Those blades look shot for one thing

 

They do?  Why you think so?

 

They do look like high lift though.

[Handy Don 12,174]

I agree the blades are near end of life. Rounded ends, even if sharp, deflect grass more easily than they cut it. You might get another season out of them if you can file them back so the cutting edge is perpendicular to the direction of the cut for its full length.

 

To me it looks like the center blade is spinning strongly  but the outer ones are not spinning as strongly. Are you sure the deck belt isn't slipping? Tensioner not frozen? Correct belt in good shape?

I'm going to assume you've checked that the blades are not bent and are on in the right direction (wings up, i.e. closer to the shell).

 

Are all the blades at the same height off the ground? At both ends?

 

In the extreme, I'm wondering if you've got a bent shell that is leaving one or more spindles out of plumb? It wouldn't take much to get ½" at the end of a blade.

Edited July 27, 2022 by Handy Don

[squonk 41,040]

7 minutes ago, Jeff-C175 said:

 

They do?  Why you think so?

 

They do look like high lift though.

Look at the edge on the blade next to the straight edge.

[Jeff-C175 7,199]

28 minutes ago, squonk said:

Look at the edge on the blade next to the straight edge.

 

Maybe I should look on my desktop.

 

I see some chips but I've cut with way worse than that and not gotten any stripes.

 

Can't see enough of the blades to tell how much they are 'daggered' at the ends.

 

OK, on the desktop now...  they are a bit worn, but I've used way worse and not striped.

 

 

 

Edited July 27, 2022 by Jeff-C175

[peter lena 8,589]

@Ed Kennell looks to me like you have a number of things going on , think those blades have to go , what do those bearings sound like ? mule drive noisy ?  think there is a slower speed involved , with your discharge issue , agree with @Handy Don  on possible belt tensioner issue , not a fan of S/D  decks , but it should still put down a smooth finish . have to go after every function , pull the belt cover off , and verify drive function . pto lever engagement smooth / firm?  if any of those related bearings are noisy or resisting easy movement , can't give you a definite , too many possibles . let us know what you find , done a number of decks , has to spin free and easy , blades square and fine filed sharp, detail build every step , interested in what's found , pete  

[skrusins 128]

Can the deck be warped?

[lynnmor 7,302]

Ed, I planted some new grass and left it and the assorted weeds grow to a considerable height.  Just this evening I mowed it for the first time using a lightweight brand X 42" lawn tractor.  The stripes looked just like yours, I think it may be the hot weather conditions making for some tough grass/weeds in our area.

[gwest_ca-(File Mod) 11,036]

Blades are measured diagonally from cutting tip to cutting tip so any rounding shortens them up quite a bit.

 

Any chance the center drive pulley can be installed upside down? Is the diameter of the center pulley the same as the left and right?

If it could be turned over the blades would run faster.

[Pullstart 62,812]

 No matter what, I’m glad to see green streaks and not Ed Dog’s streaks 

[Ed Kennell 38,048]

The deck tensioning is clean, The slide is free, spring is strong, idler is free. and the belt WH belt is good.

The top drive pulley is larger than the three blade pulleys.   There is a chip broken out of the flange of the drive pulley.  I have smoothed the broken edge and it does not affect the drive or damage the belt.

The PTO and mule drive are good.   There is never any indication the blades are losing RPM with even heavy grass.

 

I used a straight edge and positioned all six blade tips to each other and all three blades are on the same plane with 1/8" clearance.

 

The blades do have a  slight rounding on the tip, but have only been sharpened a couple times.

 

I did find a mark on the rear deck skirt where the two outside blades made contact with the turned up blade tip.   For this to happen, the deck has to be flexing.

 

Here is the blade number.

 

 

When it cools down tomorrow, I will swap blades between my two 42" SDs and see if the streaking moves with the blades or stays with this shell.

 

Thanks to all for your input.    More to come tomorrow.

[squonk 41,040]

That blade is pretty whomped on that right side! 

 

[ineedanother 1,369]

9 hours ago, Ed Kennell said:

The blades do have a  slight rounding on the tip, but have only been sharpened a couple times.

 

I did find a mark on the rear deck skirt where the two outside blades made contact with the turned up blade tip.   For this to happen, the deck has to be flexing.

 

I agree that the blades are not in good shape and think they are definitely suspect. I would be more concerned with the spindle bearings though. Have you checked them with the belt off? The blades should not hit the deck EVER, but if a tree or something was bumped while mowing it might cause enough flex to do what is pictured. Otherwise I would suspect play in those bearings along with the condition of the blades to be where your troubles are.

[Ed Kennell 38,048]

OK, here's todays test results.      

I removed both sets of blades from my two 42"SDs.     

The streaker blades are on the left.    #6693 REX 504      They are  higher lift than the other set .   About 1/4" higher curl.    IMO, they are worn more than the other set.

The set that cuts fine on my older patched and welded up deck is on the right.   #HEF 1536   1106     These blades do have a more blunt cutting edge.

 

 

 

 

 

I swapped the two blade sets with the two decks and mowed a patch of grass.

 

The streaks stayed with the HL( high lift) blades.       Is it possible the HL blades cause a back draft off the deck roof that somehow blows the grass down in the area between the blade tips?     

 

My next step will be to alter the HL blades by cutting off some of the lift curl to the same height as the old blades that cut fine.    And rebalance of course.

[rjg854 11,354]

waiting to see what your results are 

[Jeff-C175 7,199]

2 minutes ago, Ed Kennell said:

blows the grass down

 

Sounds like they are creating a vortex and not 'lifting' as much as they are blowing the grass over and down.

 

3 minutes ago, Ed Kennell said:

cutting off some of the lift curl

 

That ain't gonna be easy!  Maybe better to get your blacksmith forge up and running and "beat your swords into plowshares"...  heat 'em up red hot and hammer 'em back down.

 

 

[Jeff-C175 7,199]

Maybe it's the lighting, but this one appears to have a whole lot less roll to it...

 

[Ed Kennell 38,048]

16 minutes ago, Jeff-C175 said:

Maybe it's the lighting,

Lighting , shadow and camera angle.    The curl on the other end of that same blade looks vertical.   They are all the same and are extremely steeper than the other set.

 

A radiac cut off wheel should zip off some of the curl.

[Handy Don 12,174]

Very interesting. I know the HL blades are intended for decks that have the power vac attachment. The top edge of the blade being taller also explains the touches to the shell that you found.

 

Trimming the lift and then balancing seems like a lot of work, but I know you have all kinds of nifty tooling at your disposal.  Good luck!

[Jeff-C175 7,199]

30 minutes ago, Handy Don said:

blade being taller also explains the touches to the shell

 

Yes... and the reason that the Gator blades won't work on my 48" SD.  I almost bought them, right length, etc, but when I looked at the lift wing I realized they would not work.

 

 

[peter lena 8,589]

@Jeff-C175  agree with you on a number of issues , that end of blade to shell contact says it all , when I regularly drop/ check mine , always verify easy smooth total function , have a number of blade sets to try/ swap if needed ,  @Ed Kennell  love to see that oil soak on that metal , that also helps deck stay clean , rarely have anything stick to my decks , that a light swipe does not remove it . would definitely go to a shorter blade , or time to retire that deck . that blade drag is your  answer ,  deck swap , no big deal , pete