Ford 917L Special Flail Mower

[wirlybird]

I don't see why not, a lot of flail blades are held on with pins. I figured out the shoulder thing a while ago and gave up. You can probably buy regular bolts just a little longer and cut them down, or not worry about it. Extra length won't hurt operation since they'll all be the same to keep balance. I think 1-1/2" bolts have a long enough shoulder. IIRC the nuts are captive (prevailing torque) types.

Didn't really think about using a longer bolt to get the shoulder.
I'll have to scope out the bolt selection to see what might work as a back up plan.

 

[arto98607]

Question on bolts for the flails.
The ford manual says it uses "special" bolts and that of the shelf bolts won't work.
Anyone have any info on this? What would be special? Is it hardened? Seems to be an 1 1/4 X 3/8 bolt with flanged lock nut.

Thanks for any info.

I bought a bag of 100 bolts (3/8-16 x 1 3/4" Grade 8 Zinc Plated Cap Screw Partial Thread) from eBay vendor for $23.99

(100 bolts left me with another full set for spares and few extras!)

These bolts were just long enough to cover the space in-between lugs where the flails are mounted, but still allow proper compression of the lugs when tightened up a little, but not all the way.

I reused the original flange nuts and afterwards cut off the excess length of bolts with a cutting disc in a grinder.
Piece of cake!

 

[wirlybird]

I bought a bag of 100 bolts (3/8-16 x 1 3/4" Grade 8 Zinc Plated Cap Screw Partial Thread) from eBay vendor for $23.99

(100 bolts left me with another full set for spares and few extras!)

These bolts were just long enough to cover the space in-between lugs where the flails are mounted, but still allow proper compression of the lugs when tightened up a little, but not all the way.

I reused the original flange nuts and afterwards cut off the excess length of bolts with a cutting disc in a grinder.
Piece of cake!

Nice, wouldn't happen to have a link? I'll go search as it could be a good back up for the cost.

 

[arto98607]

Nice, wouldn't happen to have a link? I'll go search as it could be a good back up for the cost.

This is where I got mine from, but there are probably other vendors also:

(Qty 100) 3/8-16 x 1 3/4" Hex Bolt Zinc Plated Grade 8 Cap Screw Partial Thread 82893497051 | eBay

Please double check the length of the non-threaded bolt section your mower needs since it's not neccesary the same as mine is?

 

[arto98607]

I see you used the MH-386 to replace the stock ones. Flailmaster has confirmed this. You had to drill them to 3/8 inch?
When looking at the specs here is what they list. They have a good price on them.
MH-386 Fine-Cut Blade (102086/02988196)
Pin Mounted
.087” Thick
1 1/4” Wide
4.7” Tall
3/8” Mtg. Hole.

Not a big deal, but last summer they had 7/16" holes in the MH-386 flails and I drilled them out to 3/8"

Just be glad if they now have the proper size holes since drilling them was not easy due to pretty hard material but I did it.

 

[wirlybird]

Not a big deal, but last summer they had 7/16" holes in the MH-386 flails and I drilled them out to 3/8"

Just be glad if they now have the proper size holes since drilling them was not easy due to pretty hard material but I did it.

Well it turns out it is a typo!

So I got them all drilled (100) but at first it was taking forever. I was thinking my $45 carbide bit was going to crap out after 20 parts.
Then I stumbled on to something that made a huge difference.
I was loading the flail into the drill press vise with the cutter end pointing up, opposite of in the picture, and drilling like that. It was hard going with lots of heat and took forever to drill the hole.
By accident I loaded one with the cutter end facing down toward the table, like in the picture, and wow what a difference in the drilling. Took 5 seconds vs. a minute before and went so easily.
If you look at the hole in the picture, pre-drill, you can see that this side is where the punch exited while making the original hole. I think drilling from the side where the pinch entered the metal or started the hole does something to the metal. It also makes a sort of beveled hole or rounded edge on the hole. I think the action and pressure of the punch starting through the metal heats it and makes a hard edge around the hole.
As I drill from the side like in the picture it goes right through but you can feel it hit a hard area just before the drill finishes the hole. Night and day difference drilling the holes though.

 

[arto98607]

That's good to know next time.
I drilled two sets 96 each + 48 additional spares last summer hopefully to last few years.

 

[DaveMueller]

For 3/8" bolts under 6" long, the standard calls for 1" of thread. You can figure out what length you need by adding 1 inch to the required shoulder length. I think standard bolts go in 1/4" increments, so if you need an in between value your options are a longer shank with a washer or two, or have a little thread under the hanger.

 

[DaveMueller]

Not a big deal, but last summer they had 7/16" holes in the MH-386 flails and I drilled them out to 3/8"

Must have been an expensive bit

 

[arto98607]

Must have been an expensive bit

Two cheap 3/8" Cobalt drill bits under $5 each for drilling 240 flails so it did not exactly break the budget.
The good news is the flails were only 89 cents / each.