Figuring blade speed

[olddude 10]

My 520H has never cut grass really well. It seems this deck is more like a bush hog than a finish mower. It doesn't seem to mind if the grass or weeds are really tall it will mow them down but that's about it. I have a Zoysia lawn that I like to cut at 3" but when I do it never looks neat. This grass is just around my house about 40' or so all around. The rest of our grass I have to cut is a mixture of grasses but now mostly weeds. The zoysia is slowly spreading out into these areas and does a pretty good job of controlling some of the weeds once it gets established. 

 

When I cut the Zoysia I try to keep the RPM's up and I have been reducing my ground speed but it still doesn't leave the grass like I would like. It sort of looks like all three blades leave a different pattern if that makes any sense. I put on a new set of blades and belts each spring after the second or so cut once all the winter leftovers are all cleaned up but even with new blades it's about the same. It's a 48" deck and I'm thinking that the 48" deck would be the max for the 520. I have a smaller WH with a 42" deck that would cut the grass much cleaner but that old deck is past worn out and I just use that one for a pull tractor. 

 

I'm wondering what the blade tip speed is for the 520 H with a 48" deck. Is there a chart somewhere that will speak to this?

[oilwell1415 563]

Never seen a chart, but it's not hard to figure.  It's just engine speed in rpm x (sum of drive pulley diameters/sum of driven pulley diameters) x blade diameter in inches x 3.14.  That will give you inches per minute.  For feet/second divide by 720.  

[oldlineman 1,481]

That 520 will handle a 60" deck so 48" is no problem. Have you ever checked your tractor RPM's maybe not turning 3600 RPM. 

[gwest_ca-(File Mod) 11,033]

One manual I have states the maximum allowed blade tip speed is 19,200 feet per minute. This one says 19,000.

 

Garry

[Ed Kennell 38,028]

Is the deck adjusted properly?    The front edge should be 1/8-1/4 " lower than the back.    

Is the deck belt and tensioner  and spring clean and working properly so the two outside blades turning at same speed as the center blade?

 

[lynnmor 7,302]

When you say "I try to keep the RPM's up" are you running the engine at full speed?  Is the throttle drifting down as you mow?  Are the blades sharpened at the proper angle with the edge very sharp.  Rotate blades to see if the tips match each other to see if the deck or blades are bent.

[littleredrider 409]

My 520-8 has a 60" deck and even with the wings busted off it still cuts grass beautifully. Even after I used it has a brush hog. Make sure engine is operating at correct RPMs, and as others mentioned the belts are tight and in spec. Should cut like a dream. 

[oliver2-44 9,698]

I suspect Zoysia being a fine blade grass makes it a bit more of a challenge to get a beautiful cut. 

My previous employers main office had a lot of water efficient demonstration landscaping which included Zosia grass.

Reel Mowers are almost never seen in Texas except on golf courses, but the lawn contractor cut the Zosia with a reel mower.

[olddude 10]

23 hours ago, oldlineman said:

That 520 will handle a 60" deck so 48" is no problem. Have you ever checked your tractor RPM's maybe not turning 3600 RPM. 

This tractor doesn't have a tach per say, it has a power percent gauge and it will run at the max hp according to the gauge. 

[olddude 10]

21 hours ago, Ed Kennell said:

Is the deck adjusted properly?    The front edge should be 1/8-1/4 " lower than the back.    

Is the deck belt and tensioner  and spring clean and working properly so the two outside blades turning at same speed as the center blade?

 

I have been over this thing a million times and everything seems to be adjusted. I rebuilt this deck a couple years ago and when I did nothing really changed much it cut about the same as before. I had some problems getting the right parts for some of the things I needed. Looked up the parts then ordered them and some stuff came back that were different than what I had on my deck. They were marked with the same part number but were different. The parts place just said you ordered the parts and they sent what you ordered. I ordered from a couple different places before I got the right parts. I don't know why Wheel Horse/ Toro has to be so difficult. 

 

When I rebuilt the deck I never did get the right Idler pulleys after about 5 try's so the old ones are still on there. I just got tired of messing with it. I'm thinking I would like to replace all the pulleys and probably would if I thought I could get the right ones. It seems that you should be able to give the parts place the deck model number and they would be able to get the right parts for it. Maybe one day.....

[olddude 10]

18 hours ago, lynnmor said:

When you say "I try to keep the RPM's up" are you running the engine at full speed?  Is the throttle drifting down as you mow?  Are the blades sharpened at the proper angle with the edge very sharp.  Rotate blades to see if the tips match each other to see if the deck or blades are bent.

When I'm just cutting my weeds I usually don't run it wide open. This thing has never liked to stay wide open it seems the governor likes it to stay just a little off wide open and if I want to keep it wide open I have to hold the throttle lever to keep it that way. Tried new cable and it still does the same thing. When I'm cutting my good grass I do hold the lever to keep her reved but it still cuts the same. I just put on a new set of blades and belts and no difference. 

[olddude 10]

14 hours ago, oliver2-44 said:

I suspect Zoysia being a fine blade grass makes it a bit more of a challenge to get a beautiful cut. 

My previous employers main office had a lot of water efficient demonstration landscaping which included Zosia grass.

Reel Mowers are almost never seen in Texas except on golf courses, but the lawn contractor cut the Zosia with a reel mower.

Yes Zoysia can be a pain to cut but I had a friends Dixie Chopper over here to do service on and that machine cut it just fine even with not so sharp blades. Like I said I've had this tractor since 1997 and it has never cut grass the way I thought it should. Don't get me wrong I love this tractor it's been a great machine for most of what I wan't it to do. My little 416-8 with the 42" deck cut grass so smooth and nice it's a shame this one won't. I have a feeling there was something wrong with this deck all along but if there is I can't see what it is. The dealer I bought it from told me that was just the way they cut and even told me they weren't considered a finish mower. Of course that was after I had bought it.

[oilwell1415 563]

3 hours ago, olddude said:

When I'm just cutting my weeds I usually don't run it wide open. This thing has never liked to stay wide open it seems the governor likes it to stay just a little off wide open and if I want to keep it wide open I have to hold the throttle lever to keep it that way. Tried new cable and it still does the same thing. When I'm cutting my good grass I do hold the lever to keep her reved but it still cuts the same. I just put on a new set of blades and belts and no difference. 

The engine always needs to be wide open when you are mowing.  That may not fix your issue, but it's definitely not helping things.

[lynnmor 7,302]

There are many posts on here about the throttle moving down.  There is a pivot point on the throttle lever behind the dash, to tighten that joint, some smash the rivet, others drill it out and put a bolt thru, I use a small alloy screw with a lock nut.

 

I sharpen new blades, rarely are they really sharp.  Did you compare the blade tips to see if they line up when they tips are next to each other?

 

Run the engine at full speed when mowing, see your owners manual.

 

Did you level the deck with the front being about 1/8" lower than the rear?   I don't go to the maximum 1/4" so that the cut is a bit more even.

 

Are you cutting too low?  These decks often need to be run as high as possible.

 

My 42" rear discharge is no better than my 48"  and 60" side discharge decks.

[oilwell1415 563]

4 hours ago, lynnmor said:

 

I sharpen new blades, rarely are they really sharp.  Did you compare the blade tips to see if they line up when they tips are next to each other?

 

 

Funny you mention that.  I've noticed the same thing with new blades the last several years.  Not only are they not sharp, but they are not made out of very good steel and the edges don't last very well.  I usually do a rough sharpen, then harden the leading edge of the blade, then do a final good sharpening and I have had much better performance and longevity from the blades.

[gwest_ca-(File Mod) 11,033]

The problem of getting the correct parts is likely due to the fact they share a parts list with a similar deck. Most times the 42" and 48" are shared but the online information does not distinguish between the two or identify what fits what. If you follow the item numbers in the list down near the bottom they are repeated with different part numbers. Blades are one item that is different so if you know the correct blade numbers the parts with them are for that size of deck.

If you can find an original parts list the parts are correctly identified.

Click on the picture. Just a guess on the model and vintage.

Garry

[tom2p 2,394]

11 hours ago, oilwell1415 said:

Funny you mention that.  I've noticed the same thing with new blades the last several years.  Not only are they not sharp, but they are not made out of very good steel and the edges don't last very well.  I usually do a rough sharpen, then harden the leading edge of the blade, then do a final good sharpening and I have had much better performance and longevity from the blades.

I use Toro / Wheel Horse OEM blades 

 

I've read there are other quality blades available - but have not tried them 

just based on appearance - the quality of the OEM blades I purchased years ago (early 90's) is better than the quality of OEM blades purchased during the past few years 

the older blades have a rounded edge where the blade is not sharpened (instead of square / unfinished)  -- the sharpened edge is cleaner and more uniform -- and the blade is just slightly thicker ... small amount - half a mil ?

posdible the earlier / older OEM blades were made in the USA - and the more recent / current OEM blades are made ... who knows where ... 

 

Edited May 13, 2020 by tom2p

[tom2p 2,394]

16 hours ago, lynnmor said:

There are many posts on here about the throttle moving down.  There is a pivot point on the throttle lever behind the dash, to tighten that joint, some smash the rivet, others drill it out and put a bolt thru, I use a small alloy screw with a lock nut.

 

I sharpen new blades, rarely are they really sharp.  Did you compare the blade tips to see if they line up when they tips are next to each other?

 

Run the engine at full speed when mowing, see your owners manual.

 

Did you level the deck with the front being about 1/8" lower than the rear?   I don't go to the maximum 1/4" so that the cut is a bit more even.

 

Are you cutting too low?  These decks often need to be run as high as possible.

 

My 42" rear discharge is no better than my 48"  and 60" side discharge decks.

i cut with 42 RD - 42 SD - 48 SD

 

( currently mounted on three different tractors )

 

the 42 RD ranks the lowest in yard appearance after a cut - primarily because the RD deck does not have the rear rollers (that can provide a better appearance)

 

I rarely run at full throttle - but yard still has good appearance after a cut ... guess there is a benefit to a yard full of weeds ( 'farm grass' )

 

Edited May 13, 2020 by tom2p

[tom2p 2,394]

for RD (rear discharge) deck - I set the front higher than the rear 

 

the clippings are better dispersed - and less clumping when cutting tall grass 

 

this after years (and years) of observation / cutting with RD deck ... going back to mid-70's with a 704 (with 32" RD ?) and then 312-8 with a 42" RD ... 

 

only used SD decks for around 20 years ... started in early 2000's ...

 

[lynnmor 7,302]

7 hours ago, tom2p said:

for RD (rear discharge) deck - I set the front higher than the rear 

 

It actually says that in the owners manual.

Edited May 13, 2020 by lynnmor

[tom2p 2,394]

8 minutes ago, lynnmor said:

It actually say that in the owners manual.

yes - thank you - I believe Garry also mentioned that 

 

years ago I was told to run front lower - but possible they did not realize I was using a RD deck at the time or did not realize can be different for RD and SD 

I also installed a short extension on the 42" RD deck to reduce clippings on rear of tractor ( and better quality idler pulley recommended by Garry )

 

Edited May 13, 2020 by tom2p

[olddude 10]

19 hours ago, oilwell1415 said:

The engine always needs to be wide open when you are mowing.  That may not fix your issue, but it's definitely not helping things.

Thanks.....like I said I do run wide open when cutting my zoysia......the weeds I don't care about.

[olddude 10]

19 hours ago, lynnmor said:

There are many posts on here about the throttle moving down.  There is a pivot point on the throttle lever behind the dash, to tighten that joint, some smash the rivet, others drill it out and put a bolt thru, I use a small alloy screw with a lock nut.

 

I sharpen new blades, rarely are they really sharp.  Did you compare the blade tips to see if they line up when they tips are next to each other?

 

Run the engine at full speed when mowing, see your owners manual.

 

Did you level the deck with the front being about 1/8" lower than the rear?   I don't go to the maximum 1/4" so that the cut is a bit more even.

 

Are you cutting too low?  These decks often need to be run as high as possible.

 

My 42" rear discharge is no better than my 48"  and 60" side discharge decks.

Yeah, I have mashed that rivet and it seems to do ok for awhile but it will loosen up again before the season is over. The motion lever likes to do it also and I have to hold the lever forward when I want to travel at a fast pace. I thought about putting a foot throttle on the ol girl but never have. 

 

Yes sir....I have checked all those adjustments and all are adjusted according to the manual. And no like I said I like to cut my zoysia at 3" which is about all the adjustment I can get out of this deck. That is unless I run with the deck in travel position.

[olddude 10]

19 hours ago, lynnmor said:

There are many posts on here about the throttle moving down.  There is a pivot point on the throttle lever behind the dash, to tighten that joint, some smash the rivet, others drill it out and put a bolt thru, I use a small alloy screw with a lock nut.

 

I sharpen new blades, rarely are they really sharp.  Did you compare the blade tips to see if they line up when they tips are next to each other?

 

Run the engine at full speed when mowing, see your owners manual.

 

Did you level the deck with the front being about 1/8" lower than the rear?   I don't go to the maximum 1/4" so that the cut is a bit more even.

 

Are you cutting too low?  These decks often need to be run as high as possible.

 

My 42" rear discharge is no better than my 48"  and 60" side discharge decks.

I use Toro blades and they always seem to be fairly sharp. I always heard that you shouldn't put a fine edge on mower blades for reasons that they seem to dull so fast. I usually put an edge on them about once a month in summer or sooner if I run over something you probably shouldn't chop up.

 

As I said before I cut as high as the deck will allow which is around 3".

[olddude 10]

I've been looking around for another deck but the ones I have seen have all been fairly well used up and they want too much for what they are. I found one that was in real good shape and went by to pick it up but someone got there just before I did and snapped it up. I still think this deck must have been a late Friday or a very early Monday morning assembly but who knows?? It's probably the reason I have it and not the guy who originally bought it. The old guy bought it and bought it back to the store before he ran the first tank of gas through it and wanted his money back. The dealer never said what the guy didn't like but he offered it to me at a price I couldn't turn down.