Grading Finish Blade test - the blades

[Charlie_Iliff]

Re: Finish Blade test

John:
I'll be interested to hear how they do on shorter grass. I've generally cut over four feet width of new grass each passs, and often over five feet, so most of mine is essentially single pass. Your multiple pass coverage presumably avoids the possibility of the right-side stripe. I hope it doesn't reappear in the shorter stuff.
It sounds as if the offset on my blades isn't needed with the deflector off. How high did you have the deck set for the cut in the picture?
When you get a chance, post a picture of the blade(s). Since they are reversible, I assume you center drilled them. How thick are they?

 

[Sedgewood]

Re: Finish Blade test

Charlie:
<font color=red>I'll be interested to hear how they do on shorter grass. I've generally cut over four feet width of new grass each passs, and often over five feet, so most of mine is essentially single pass. Your multiple pass coverage presumably avoids the possibility of the right-side stripe. I hope it doesn't reappear in the shorter stuff.</font color=red>
Well, it still stripes if the right side blades pack. but the next pass cleans it right up, much better than the roughcut blades do. A brief test tonight leads me to believe counterclockwise might pack the blades less. It'll cut a couple of inches off, full width, full speed ahead with no stripe. Overall this seems the best setup yet, for both lawn mowing and for my heavy field mowing.
<font color=red>It sounds as if the offset on my blades isn't needed with the deflector off.</font color=red>
No. In fact I think the offset was letting too much wind (and chaff) escape under the skirt.
<font color=red>How high did you have the deck set for the cut in the picture?</font color=red>
One hole down for rear wheels, 4 spacers down for fronts.
<font color=red>When you get a chance, post a picture of the blade(s).</font color=red>
Attached. With the twist these blades are cutting probably 1/2 inch or so lower than the stock roughcuts. Note the "swept tracks" on the bottom of the deck. I must have a close look at them to see what they might tell us about what is happening under there.
<font color=red>Since they are reversible, I assume you center drilled them. How thick are they?</font color=red>
1/8 inch thick. They are cheapies from Home Depot. Box has a Scotts label & says "22 inch Reversible Double Edged Blade".

Soon as I finish mowing the test plot I'll mail them to you for further testing.

John

 

[Sedgewood]

Re: Finish Blade test

<font color=red>Note the "swept tracks" on the bottom of the deck. I must have a close look at them to see what they might tell us about what is happening under there.</font color=red>
Here's a picture of the bottom of the deck after mowing grass and 12 inch weeds for an hour or so. later I went out and finished mowing my test plot which swept the bottom of the deck clean except for just a bit of stuff left around the stump jumpers. Not much to be learned here I guess, the 'swept tracks" are pretty uniform.

BTW, I noticed this morning that I blew the right rear tire on the mower last night. Yeah, the foam filled one. Spun it on the rim and chewed up the beads.

Charlie, I have one small area I want to touch up this weekend (it the blown tire will function well enough) and then I'll mail these blades off to you. And return your custom blades too. John

 

[Charlie_Iliff]

Re: Finish Blade test

John:
No rush sending stuff down here. I'm leaving Thursday to drive to Wyoming. Be back the end of the month, so will be doing nothing on the PT 'til September.

 

[Sedgewood]

Re: Finish Blade test

Charlie:
<font color=red>...so will be doing nothing on the PT 'til September.</font color=red>

September it is.

John

 

[Charlie_Iliff]

This should be post 2998, right?
Resurrecting an old thread. Yesterday I did some comparison testing of blades that John Coxon and I have cobbled up for the 72" rough-cut mower. The PT blades are 3/8" thick, with two swinging on 1" bushings on each of the three stump jumpers. John has had some clogging problems, and both uf us have had a stripe left sometimes on the right side. We've adapted available mower blades to the decks to see if it improves things. I have been trying for a better finish cut, and John for faster cuts in rough stuff, and better clearance of cut grass from the deck.
Results: Both John's 1/8 thick blades and my 1/4" do better finish cuts than the PT rough-cut blades, with the deck low. Both have more lift than the PT rough cuts. When I raised the deck, I expected even better performance, because I thought there was a problem getting air out from under. The cut was significantly rougher, with more tufts uncut, and the right side stripe returning. The cutting, surprisingly, was better when the grass was so high and thick that it choked the mower and occasionally I had to stop to let it spit out a clump. (Despite the drought, we had over an inch of rain two days before the cutting. The grass was extremely heavy and up to 18" high in spots. Neglected pasture /w3tcompact/icons/smile.gif)
Conclusion:
1. John's blades are lighter, and a bit more prone to damage, since they are thinner and sloped downward at the cutting edge, but are reversible, and ultimately will be less expensive than mine. His are from generic lawnmower blades, mine from a gravely hardened set. In similar conditions, it is difficult to see a difference in cut quality.
2. Both sets are significantly better than the factory "finish" blades, which are prone to damage.
3. Both give a more even cut and fewer missed spots with the deck low, even in heavy thick pasture grass. Unfortunately, it's lower than I want to cut the pastures.
3. The rough cut deck will never be as good at finish mowing as a true finish mower, and not as good at cutting trees as a true brush hog. With the factory rough cut blades, however, it does a good job on underbrush, and with either John's or my blades, it does well for pasture cutting. I still need to do a little more testing with deck height and cant to find optimum smoothness.

Tonight, I will give John's a final test, this time on a lawn with only 10 days growth, and the deck set as low as I can get it.
Then -- the 100 hour service.

 

[pajoube]

Charlie,
When all is said and done, will the final product be going back to PT for they’re manufacturing and distributing? Or will your blades be made available to PT owners?
PJ

 

[bubenberg]

Charlie, this may be our next trip ... Tazwell ..... and no hunting this year .... hahahahaha!

 

[Charlie_Iliff]

Last night, I lowered the 72" deck as low as I could get it, and cut my lawn with Sedgewood's blades. The results were great. I had been working on the belief that we had to get the deck up, for air flow underneath with high-lift blades. John's were higher lift than the ones I made, but I had the deck all the way down, and the evenness and smoothness of the cut was as good as I have seen with any mower on my lawn. (It scalped a bit, becasue 72" is too big, but that isn't the deck's fault.)
Bubenberg will chew me out for cutting grass that short, but if the grass survives, the cut quality is better than with the deck higher. It looks as good as my otherwise neglected lawn can.

 

[Charlie_Iliff]

<font color=red>will the final product be going back to PT for they’re manufacturing and distributing? Or will your blades be made available to PT owners?</font color=red>
Paul: I think PT checks this board now and then, and I have talked to Terry about the blades. I hope some time in the next few months to go to Tazewell, and will discuss John's and my tests with them. My hope is they will offer a replacement for the "finish" blades, and perhaps a thinner, higher lift set of rough cut blades. I hope they have been doing some development, as well, but haven't talked to them about it.

 

[pajoube]

Charlie,
Sure appreciate what you and John have been doing.
PJ

 

[Sedgewood]

Charlie: <font color=red>Last night, I lowered the 72" deck as low as I could get it, and cut my lawn with Sedgewood's blades. The results were great.</font color=red>

Oh darn, I just finished mowing my neighbors lawn before reading this post but unfortunately lowering the deck wouldn't have been much of an option on his rough lawn. His mower broke down and he asked me to have a go to keep his grass from getting out of hand while he shops for a replacement. I made up another set of blades for the purpose. This time from some Home Depot cheapie straight blades with high lift. They did a reasonable job but in looking back on it, the humped areas that were nearly scalped were cut much better than the higher areas. Charlie's onto something here.

Drilling these cheapie blades was much easier than drilling the earlier, reversible blades Charlie is testing. The reversibles are hardened and I had to draw some temper out of them to drill them. I suppose they might last longer but they probably take twice as long to make up. I did see at Home Depot some thicker high lift blades that looked as if they too were hardened but being quite a bit more expensive I passed on them for the time being. It occurs to me that in light of the beating blades take on my rough ground that good blades may last no longer than cheap blades and may be a waste of money and extra drilling time.

I also am beginning to sense little advantage to thicker blades. After all high speed string will cut grass quite nicely. And I find the light blades will do a reasonable job on bushes. So other than for cutting really big stuff there may be no advantage to adding weight. Gotta test in the big stuff and see what happens there.

 

[Charlie_Iliff]

Today, my wife asked :"Oh, did you get the Jacobsen fixed, the grass looks great?"
That is validation of my observation about the cut quality with the deck low and Sedgewood's blades.
Please don't anyone assume that we will be recommending 1845s with rough-cut decks for golf course use. My lawn is rough, hilly and otherwise neglected, so I can't claim yet that the grooming quality will match a 425 with 60" deck, or an Exmark ZTR. It is great to see some improvement, however, and there is even a possibility I can avoid buying a Jacobsen replacement, and can look at something smaller (and cheaper) to do places a 72" deck is too clumsy.

 

[Charlie_Iliff]

Re: Finish Blade test - results

The first post in this thread has a picture attached comparing the PT rough-cut blade with one I made by cutting a Gravely blade in half and getting a 1" hole drilled in it. I did some comparison testing, which was reported earlier. and Sedgewood (John Coxon) made up some blades from thinner lawnmower blades and did comparison tests with mine. He then sent me a set of his, and I did some mowing with both.
The result, John's blades are the best so far. They beat the factory blades and mine in each type of mowing I did. With the deck at its lowest setting, they do a finish cut that is acceptable on my lawn - but not Bubenberg's customer lawns or golf courses. Set a little higher, the blades do a good smooth pasture cut, with almost no missed area. The factory blades, and to a smaller extent my blades, leave a stripe and some tufts.
The attached photo shows one of my blades and one of John's, with his on the right. His is reversible, and has the whole blade area twisted, so the whole blade outside the stump jumper lifts. Mine has a level leading edge, and bends up at the trailing edge, also creating lift, but not as much.
So, now all I have to do is wear out two sets of my blades, and I can make some like John's.
I am going down to Power Trac with Bubenberg in November, and will see what they have in the works, and give them a bit more detailed report. Maybe they'll offer a revised finish blade set for the 72" rough cut.

 

[Sedgewood]

Re: Finish Blade test - results

Charlie <font color=red>So, now all I have to do is wear out two sets of my blades, and I can make some like John's.
I am going down to Power Trac with Bubenberg in November, and will see what they have in the works, and give them a bit more detailed report. Maybe they'll offer a revised finish blade set for the 72" rough cut.</font color=red> Take one of my blades along. The new set I made up from generic hi lift lawn mower blades is straight with the back upturned edge and cuts about the same as your custom set. The reversibles are still the best so far by a fair margin, even in full grown unmowed weedy fields. And they do a surprisingly good job on saplings too - I may never put the roughcuts on again.

 

[Sedgewood]

Re: Finish Blade test - results

Charlie <font color=red>So, now all I have to do is wear out two sets of my blades, and I can make some like John's.
</font color=red> Naw, toss 'em in the junk pile in the back of the shop with PT's finish blades and all the other experimental stuff that never quite worked and see if you can improve on the reversibles. Hmm... I wonder what happens with 4 reversibles per spindle... Four per spindle had a negative effect with the roughcut blades but maybe, just maybe... naw, the power consumption issue would still be there. I think.

 

[Charlie_Iliff]

Re: Finish Blade test - results

<font color=red>Take one of my blades along.</font color=red>
John: I will take one of your blades and one of mine to Tazewell with me, and then send your set back. Even with a bit of distortion, the blades are good. A couple of them did eat major grooves in two of PT's expensive bushings. I was a bit surprised that the blades were so much harder than the bushings. I mounted them with a 1" flat washer, so they only had a little vertical play. Unfortunately, I had them all off and scrambled before I noticed the bushings, so I don't know which two caused the wear.
I've only used one side of your set, so expect a set with 50+% life to arrive by mid November.

 

[Sedgewood]

Re: Finish Blade test - results

Charlie <font color=red>I was a bit surprised that the blades were so much harder than the bushings</font color=red> Those suckers are hard! I had to draw some temper to get a drill to touch them and it was still a long slow process. guess I could have heated them some more but at the time I thought a little hardness might be a good thing. But maybe not - bushings and drilling time being as hard to come by as they are. The new hi lift set were very soft and a hole saw cut through them like butter.

And if PT wants to keep a blade for development purposes thats fine with me. It wouldn't bother me a bit if they got all the blade making fun.