Flail Mower Sharpening blades

[paulharvey]

I have a very used Ford-917L 48" flail mower. I use it 90% to mow an acre of mixed bahia and nut grass. I've kinda half way sharpened the 39 blades a few times, and it seems to help a little; but this time I've decided to take each blade of, sharpen it, and make sure they are tightened down real good. My question is how sharp to you try to get them?











How much can you grind them down before you replace them?

Do you guys with flails actually like them, cause mine seems to mix the poor quality of cut of a bush hog, with the weak cutting power of a finish mower.

Edit: my complaint is mostly it seems to only knock the seed stocks over more than cut them. In heavy grass I have to go over at least twice to really get it cut.

 

[schmism]

In case you didnt relize, there are various styles of cutter for flail mowers depending on what you want to do.

Your style is for fine cutting, as in finish mow an area. I would not expect them to do well in heavy material. The Y version is the version that is recomended for heavy brush-hogging type activities and from other reports from flail mower owners, they work just as well (some say better) than standard brush hog. (with the right blades for the right condtions)

 

[Halftrack]

Some observations on your flail mower- the blades you are using are not standard equipment for that model of flail. Standard equipment is a blade similar but longer than the reverse "Y" pictured above. They are sometimes referred to as side cutter blades, Ford part #86509415. The blade you have is part # 220398 and is used on the models 907 and 917H and is called a fine cut blade.

The main problem with using this blade is that it is shorter than the side cutter blade and results in a lower tip speed and less cutting ability. The proper blade is a lighter duty blade suitable for grass and light debris but I am not familiar with your grasses to guess whether it is adequate. I would check with the blade supply warehouses with that part number (86509415) for their equivalent. An earlier post mentioned an equivalent blade that the hanger hole had to be slightly enlarged to fit, but the price was right. And don't recycle the fine cut blades, I and a number of other readers always need a few spares.

 

[leonz]

I have a very used Ford-917L 48" flail mower. I use it 90% to mow an acre of mixed bahia and nut grass. I've kinda half way sharpened the 39 blades a few times, and it seems to help a little; but this time I've decided to take each blade of, sharpen it, and make sure they are tightened down real good. My question is how sharp to you try to get them?

View attachment 385932



View attachment 385933



View attachment 385934

How much can you grind them down before you replace them?

Do you guys with flails actually like them, cause mine seems to mix the poor quality of cut of a bush hog, with the weak cutting power of a finish mower.

Edit: my complaint is mostly it seems to only knock the seed stocks over more than cut them. In heavy grass I have to go over at least twice to really get it cut.

About your mower,


What you have are "scoop knives" ment for dual use, brush and grass.

You have hardened knives that should be sharpened with a wet well kitchen knive grinder.

Grinding them without a wet wheel takes the temper out of the steel which weakens the cutting edge.


You will not go wrong purchasing a new set of scoop knives for your mower and new hanging bolts.

You so not want to tighten the bolts so much that it interferes with the knives ability to swing freely.

The other issues are ground speed and engine speed for the Power Take Off.
YOO have to have the Power Take off operating at the 540 RPM engine speed NO SLOWER!!!!

 

[leonz]

ARE YOU GRINGING THE BOTTOM EDGE?????? it looks like it. you have to grind the top edge.

 

[paulharvey]

ARE YOU GRINGING THE BOTTOM EDGE?????? it looks like it. you have to grind the top edge.

Really? Are you sure that's right. I'm not saying your wrong, I just assumed that when looking at the geometry, the bottom would be where you grind.

 

[leonz]

Really? Are you sure that's right. I'm not saying your wrong, I just assumed that when looking at the geometry, the bottom would be where you grind.

View attachment 386051

When new the steel blank is stamped with the mounting holes and separated/sheared
from the continuous steel blank then ground and then bent to create the bend for the
mounting holes to create the scoop/shovel end from what i remember of it.

 

[paulharvey]

Well... I feel really stupid... after sharpening all the blades; adding #00 grease, and tightening the belt banjo string tight, still cut like crap. Adjusted hight of cut; even took the roller off to get lower cut. Still cut like crap. So... I got to looking at it again... then I watched the belt pulley turning, and realized the blades/duck feet/scoops/whatever where actually all on backwards....

I don't know if I put them on backwards after sharpening or if they had been backwards for last 3 years. I think I put them on backwards; and the new tight belt and sharpening is what helped vs couple months ago, but I'm not 100% sure.

 

[gwdixon]

I didn't see anyone else mention it, but the mower sure is missing a number of blades. A blade should be mounted to each of the tab pairs. The mower will not cut cleanly and evenly in that condition.

 

[paulharvey]

I can't seem to see my own pictures; but maybe I had some off to sharpen when I took the picture. It does have all the blades, but thanks. I thought it holds 39, might be 40... 4 rows of 10.