Ford flail mower 917 advice

[ferds_are_great]

Hi folks!
I picked up this old 6ft Ford flail mower cheap this winter from a local dealer, It was a trade-in and I guess the dealer didn't want anything this old and crusty looking near their shiny new Kubotas. Definitely has some welds and dents on it. Has a few plates and stencils that suggest maybe it was an old highway or county unit? It seems to spin OK, at least it didn't want to tear itself apart when driven. I haven't mowed with it yet, but its mowing time so need to get it in use. I wanted to do some safety maintenance first. Going to run it with my old Ford 860 clipping pastures for livestock and reclaiming old neglected hill pasture, mostly tall shrubby grass with some rose bushes and small seedlings. I don't really care about cosmetics of the cut and I don't own any lawn where it needs to be smooth. I just want it to take the vegetation down and ideally mulch it a bit. I like that it has an offset and that it doesn't stick out so far behind the tractor as my brush hog does. Should make for much nicer mowing across slope and along fencelines. Probably doesn't leave a windrow either I'd guess, from the way it works.

I bought a new belt already though the old one doesn't look terrible.

Knives:
All knives are present but they are very very dull and rusty, they are the one piece Y/duck bill type and I count 33 of them in three rows of 11. Are these fine cut? Or brush knives?
Should I attempt to sharpen the knives, and if so do I have to remove them to do that? I have read that I can swap to the paired Alamo SHD knives, if it comes to taking all of these off would that be a worthwhile investment for my use case instead of dealing with sharpening the old ones? I usually use a coarse flap on my angle grinder for mower blades or occasionally a belt sander. I don't have a wet grinder.

It looks like maybe a rubber drape or deflector could have been hung off of the back cowling, is that necessary and is there any value?

Do I just pump some grease into the roller and drum bearings, change the oil in the gearbox and then call it good or is there anything else I should do before use?

Thank you!

 

[TractorTech]

Welcome to TBN!

The blades are not worth sharpening. Order the the heavy duty FM7 blades from Flail Master. The cut is nice, they are tough and the price is right. Of course you will have to order 66 blades (70 as I think they come in 10 packs). I have a newer 917H, not much different, and I use it for mowing Bulrush sedge, which beats up any mower. The flail takes it and keeps going.
Rubber drape was an option and you don't need it.
Your rings and holders look good.
Change the oil, grease it up and see what you have. Then order the blades.

Flail-Master Catalog

www.flailmaster.com

 

[404nouser]

First post is what I did.
917 7 foot

 

[John0829]

I was using my 918H today cleaning up some areas I had let go, plus mow the shoulders of the county road. The 917 should do what you want just fine and if you want to sharpen the knives a little before replacing them just flip it up on its back and use a 4" angle grinder with a flap disc, it won't take much and you'll have em' done in no time.

 

[ferds_are_great]

I contacted Flailmaster about the FM7 blades, those look perfect.

75w90 GL5 oil OK for the gearbox? The outside is dry so either the seals are good or it leaked out a long time ago.

Thank you all!

 

[dieselscout80]

I’m using the M-108381 blades on my 917, but have used the duck foot ones and both work great.

I think the M-108381 are more durable if you’re chopping up brush.

I resharpen them on the mower (use jackstands) with a small angle grinder (4” or 4.5”). Just don’t get them hot enough to show blue color and you won’t lose the temper.

My first 917 was worn much worse than yours (I only paid $100.00) and I used it from 2010 to 2019.

Keep it grease and gear oil in the gearbox and you’ll have a great mower for years to come.

Keep an eye on the wear skids on the bottom of the sides as they are a wear item.

 

[TractorTech]

Flail Master used to sell the skids for a reasonable price, but no more.

 

[ferds_are_great]

I’m using the M-108381 blades on my 917, but have used the duck foot ones and both work great.

I think the M-108381 are more durable if you’re chopping up brush.

I resharpen them on the mower (use jackstands) with a small angle grinder (4” or 4.5”). Just don’t get them hot enough to show blue color and you won’t lose the temper.

My first 917 was worn much worse than yours (I only paid $100.00) and I used it from 2010 to 2019.

Keep it grease and gear oil in the gearbox and you’ll have a great mower for years to come.

Keep an eye on the wear skids on the bottom of the sides as they are a wear item.

Thanks. I ordered the M-108381 blades and some spares, thanks for the detailed info seems the best bang for the buck in the durability standpoint (heavy duty and forged). $2.65/blade quote before shipping, not unreasonable for 2025 pricing. In the meantime I am going to put a bit better edge on the others with a grinder. I assume I sharpen the "top" of the duck foot, that's the part facing the clevis?

Edit:
My skids are in decent shape though they have been replaced before and are welded on not bolted like I see others. There is some mostly cosmetic damage on the bottom left side of the housing where it wore through from contact before the skid was replaced.

 

[dieselscout80]

I sharpened the bottom of the duck foot knives as that is the factory sharpened surface.

 

[ferds_are_great]

I sharpened the bottom of the duck foot knives as that is the factory sharpened surface.

Thanks. Hard to tell on mine what surface used to be sharp.