David Bradly sickle mover. I think I ruined it

1939farmall · Jul 12, 2021

I got this at auction a couple of years ago and finally decided to give
it some use. It would run fine for about half a round then started
slipping. I stopped several time and cleared the bar, the last time
when I started the PTO nothing happened! PTO turning bar not
moving. There are metal shavings all around the slip clutch so Im
sure its stripped. Ive never opened one of these up before so before
I get into it I have a couple of questions. Is the clutch on a splined
shaft of a keyed shaft? I dont hold much hope for finding parts so if
the shaft is not repairable why couldnt I weld it solid and use a slip
clutch right at the PTO on the tractor? As always thanks for your
thoughts and advice.

Steve@Advance · Jul 12, 2021

Not familiar with the model. but is the slip clutch is near the end of the drive drain, they are trying to minimize inertia drive, the sickle needs to stop immediately if something jams it.

Moving the slip clutch to the front will transfer a lot of inertia from the spinning shaft, delay the slip and something will break.

1939farmall · Jul 12, 2021

Hadnt thought of that. Yes the slip clutch is at the end of the drivetrain now. That make sense. Now Im wondering how much of a difference it would make.

wore out · Jul 12, 2021

Is the drive from the upper shaft to the flywheel shaft a chin or a V-belt, I can't tell for sure in the photo.

If NOT a chain, but a belt, if the mower isn't used in real tough going/on lots of acres, running the belt a little on the loose side would be a workaround for the (likely irreplaceable) slip clutch.

My 350 John Deere mower, as an example, is belt-driven and doesn't have a slip clutch.

If the sickle jams the belt slips and you had to be quick on shutting off the PTO or the belt quickly smokes.

1939farmall · Jul 12, 2021

It is a V-belt. That might work. Im only using it on 5 or 6 acres of
grass and clover.

SVcummins · Jul 12, 2021

There isnt much inertia on a sickle mower to begin with its not like a baler or rotary mower

derwen1959 · Jul 12, 2021

Are you traveling too fast?
Is the blade sharp?
Is there too much gap in finger where knife moves back and fo ?

used red MN · Jul 12, 2021

Everything derwen1959 said. There are many types of grasses, many native or prairie type grasses have very tough stems. Say as an example you step up to a sample section of grass a foot tall or so to be cut; take what I call a sharp corn knife or some may call it a farmers machete, see link. Swiftly swing the blade so the tip is about 4 inches about ground level. If all the grass that is 6 inches from the tip of the blade cannot be cleanly cut off in a width of 4 - 5 foot within the swing you have some very difficult grass to cut. To cut this type of grass requires the sickle to be maintained with a nearly razor sharp edge on the sections. And good square edges on the ledger plates the sections run on. If the stroke of the sickle becomes very loud and labored your sickle is not sharp enough or you are moving to fast.
Corn knife example

David Bradly sickle mover. I think I ruined it

1939farmall

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Steve@Advance

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1939farmall

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wore out

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1939farmall

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SVcummins

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derwen1959

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used red MN

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