Spent some time working with the MF Dynabalance 41 7' sickle bar mower...

keegs · Jul 28, 2013

I know a lot of you aren't big fans of the sickle bar mower but right now it's all I have and I'm trying to make the best of it. I cut probably 30 acres with it so far....mostly timothy but there's some weeds and some fescue and a variety of smaller trees and shrubs, particularly nearer the property boundaries. The sickle bar seems to have no trouble with the timothy and the smaller woody plants but it does seem to struggle with the softer, denser fescues of which fortunately there isn't too much. It's great for cutting into culverts and along the edge of the pond. It seems setting the tractor speed to 3mph is about as fast as the old sickle bar can handle...any faster and the blade bogs donw or the bar begins to traveling over the grass rather than cutting it. Frequently the hay accumulates on the bar to where it seems it may bog down the blade if I don't back up to clear it off...The buildup on the bar seems to be worse if I don't leave enough of a margin between the newly cut row and the row I'm cutting. The knives seem to be in pretty decent shape but I notice that the fescues seem to bind up between the blade clips and the blade sometimes. This doesn't affect the cutting speed but it may block some of the cutting action. I think I'm going to pull the cutting bar and over the winter replace all the knives. I've also got a few blade clips that are wearing out on the outboard side. I've been greasing regularly and from what I can tell the bearings in the drive system seem to be OK.

I'd appreciate any tips or tricks, recommendations, adjustments ....that you may have for getting the most out of this old girl.

I know allot of you recommend the drum mower for cutting hay. I have no experience with the drum mower or a bush hog. There's some money in the buget for something better ....maybe next year but for now I'm going to continue playing with this old Dynabalance. TIA.... Chris

wmonroe · Jul 28, 2013

My dad has always cut with a sickle bar and while it might not be the most efficient, it does work. Keeping all the cutter sharp, guides in place, basically keep everything on the bar in top shape, find the speed where it is most efficient and you shouldn't have much trouble. Like you said try to go over already cut grass, that seems to either clog it or get caught up on the bar and will cause a clog. His always seemed to clog less if the grass was at its driest, if it was a little damp it seemed to hang up more.
Good luck.

donjdgt · Jul 28, 2013

If the cutterbar is maintained properly, speeds over 3mph should be possible. Are your knives smooth, underserrated, or overserrated? Smooth and underserrated can be sharpened. A high speed disc grinder works ok for this. Symptoms sound like the hold down clips may not be tight enough down to the knives. With the knife bar out, take a new section and slide it under each clip. New knife section should have slight drag. Tap down with hammer if too loose. On that mower, the knife register should be ok, but check by manually moving the knife bar to full extent each way. A given knife should travel equal amounts past the guard. True, a sickle bar mower requires more maintenance, and doesn't like fire ant hills or groundhog mounds, but if maintained properly, will do a fine job and require a lot less fuel than any of the rotary type mowers. Hope this helps.

keegs · Jul 29, 2013

donjdgt said:
If the cutterbar is maintained properly, speeds over 3mph should be possible. Are your knives smooth, under-serrated, or over-serrated? Smooth and under-serrated can be sharpened. A high speed disc grinder works ok for this. Symptoms sound like the hold down clips may not be tight enough down to the knives. With the knife bar out, take a new section and slide it under each clip. New knife section should have slight drag. Tap down with hammer if too loose. On that mower, the knife register should be ok, but check by manually moving the knife bar to full extent each way. A given knife should travel equal amounts past the guard. True, a sickle bar mower requires more maintenance, and doesn't like fire ant hills or groundhog mounds, but if maintained properly, will do a fine job and require a lot less fuel than any of the rotary type mowers. Hope this helps.

Thanks Don ...It absolutely helps ..hearing someone else's experience... I'm back at our perm res now so I can't say for certain but as I recall it there's a mix of different knives on the blade but a majority I'd say are under-serrated. I think the rock guards have serrated edges also but most if not all are pretty well worn down. I check the clips with a ratchet wrench when I grease the machine which is I guess about every 4 or 5 hours of operation. Some of the clips at the end of the bar are wearing down from the inside where they come in contact with the surface of the knives. Clips and knives are still available at the local dealer so next trip up I'm going to pick up a set of new knives and some clips. I'll check the knife register to see how the knives travel past the guards. I had to replace the spring bar (this is the bar the attaches the dirve to the blade bar) The new spring bar was fabricated by a local repair guy ... I'm pretty sure the length of the new bar is the same as the original.

redman135 · Aug 1, 2013

One thing that no-one has mentioned is that you should find out and check that you have the correct "lead" on the cutter bar. ie the bar should be slightly forward of the 90 degree line to cut properly. It will feel dragy if the lead is wrong.
2)sharp blades
3) dry grass. damp grass is a recipe for clogging
My father used to run a sickle mower, MF532 (6 ft bar)

donjdgt · Aug 1, 2013

I agree that lead is very important as described. As for damp grass, yes it can increase clogging, but if all the cutterbar components are up to snuff, then the dampness can actually be a lubricating component to the knives. Others have mentioned keeping the guards tipped slightly up to help ride over obstructions, but if obstructions are not a problem, the cut is better with the guards tipped down slightly because the pulling action of the cut crop tends to further hold the knives down to the ledger plates. There are a lot of issues to contend with, with a sickle bar, but I still think they are a worthwhile crop cutter in many conditions.

sweettractors · Aug 1, 2013

If your rock guard ledger plates are worn, replace them ($2-$3 each and some time) or the rock guard ($8-$9 each).........If your triangular knife sections are wearing to a pointed tip...... replace them with 11 gauge under serrated sections as needed. Make sure all the ledger plates on the rock guards are the exact same level from the cutting head to the end of the bar.....if not level....adjust with hammer. Adjust the toe clamps to where you have no more than 1/32" clearance between the knife sections and the ledger plates. Be sure to have a swath board on the bar tip. Keep the correct tension on the drive belt tight. Keep the cutterbar angled up 5-10 degrees to allow skipping over ant hills, gopher and crawdad mounds and rocks. Never mow until the dew has left the field (usually 10-11 AM on a sunny day). When the dew falls just before dark in the PM, stop mowing for the day. Keep your inside and outside cutter bar skid shoes adjusted to cut 3-4 inches above the ground level. Ken Sweet

keegs · Aug 1, 2013

Ken, You've given some information that's going to take me some time to interpret/understand. I know you have a lot of experience with these machines so I'll review your directions carefully. Thanks Chris K.

Ken,

If your rock guard ledger plates are worn, replace them ($2-$3 each and some time) or the rock guard ($8-$9 each).........

The rock guards have a serrated edged plate that the knives pass over. These plates can be replaced? Is this correct?

Make sure all the ledger plates on the rock guards are the exact same level from the cutting head to the end of the bar.....if not level....adjust with hammer

....meaning the rock guards should line up evenly down the cutting bar?

Adjust the toe clamps to where you have no more than 1/32" clearance between the knife sections and the ledger plates.

The toe clamps (AKA low/high arc knife clips in the MF parts catalogue) are the clamps that hold the knife back to the cutting bar....these can be adjusted with shims to 1/32" or less?

Be sure to have a swath board on the bar tip

I have an outboard shoe but I think some bits are missing. The catalogue shows some parts that I don't think I have on mine.

Some questions:

Do you always run the mower with the inboard shoe riding on the ground or do you adjust with the conditions?
When starting a new row, do you place the inboard end of the blade on ground that's already been mowed?
What strategies do you have for reducing material buildup on the mower? I spend a lot of time unclogging the mower blade.

I like the old girl....she's slow but steady.