Sickle Bar Maintenance Questions

I'm looking over my sickle bar mower I picked-up recently and am wanting to refresh the cutter bar assy.

Presently the guards have serrated ledgers on them and the sickle sections are also serrated. I am to understand that having serrated ledgers and sickle sections in combo is not good - is this correct? The preferred arrangement is s serrated and smooth combo? Does it matter if the serrated part lives with the ledger plate and the smooth with the sickle section or vice-versa?

When should the guards be replaced? Other than the ledger plates being worn and needing replaced, I don't really see any damage to the guards other than a few of them have the very tip bent slightly and that could be easily ground or tapped into shape again. Are guards typically replaced when they break or are they a wear item like a ledger plate?

With the sickle bar, I got a box of spare parts. In it are about 15 new guards with serrated ledger plates on them. The cutter bar has at least 2 of these new guards on it. My question is - should I replace the existing guards/ledger plate assemblies with the 15ish new ones I've got and buy the remaining new guards or just keep the new guards in the box and replace only the ledge plates?

If I replace the new guards completely with what I have and finish out the cutter bar with additional new guards - I would continue with serrated ledger plates and on the knife use smooth vs serrated sickle sections. Is serrated ledger plates and smooth sickle sections an OK combo?

If it is OK and/or advisable to just keep the guards I've got and replace the ledger plates plates, I'd put smooth ledge plates on and go with bottom serrated sickle sections on the knife.

I would consider double guards, but since I have a box of single guards, I'd like to use them if I can.

The next thing is the hold down clamps for the knife. The sickle sections presently are about 1/8 inch standing off the ledger plates vs setting on them. How should I deal with the knife hold down clamps. Is this something I need to shim or beat into position with a hammer or replace or something else?

I assume there are some wear plates - don't know their condition and to what extent they are potentially out of wack.

Not trying to be cheap on this round of refresh on the sickle bar mower, but if I could use the new guards I've got, it would certainly save me some $$$'s, but I'm not opposed to redoing the whole cutter bar assy with new bolt-on double guards and serrated sickle sections - basically new everything on the cutter bar.

BTW - the mower is a MF32 pitman with a 7 ft cutter bar.

Any advice would be much appreciated.

Thanks!
Bill

Been over 30 years since I made hay but I do not buy that serated section and smooth guard. Always had serated on both with no problems. Fact is I don't think could even get smooth guards around here. Last couple of years redid some old horse mowers for Amish and Amish mower dealer uses serated on what he does and sells. Any smooth guards were always wore out guards.

Any advice would be much appreciated.

Since you asked, I think you are over-analyzing this.
Serrated guards and sections are a good match. I would use smooth sections only if you were mowing very heavy bluegrass.

Assuming you have one or two spare sickles, you might make one of them with smooth sections, and then choose which knife will work best for what crop you are cutting.

The knife back needs to be straight - if you have to beat it with a maul to get it into the cutter bar, you are starting with a problem.

The hold down clips should do exactly that -but not bind the sickle. They can be bent with a hammer when the sickle is NOT underneath. Use shims to raise them.

I use an angle grinder to "sharpen" the guard tips. Even a little burr on the tip will catch damp foliage.

Check that all guards (really the ledger plates) are lined up. If a guard is low or high, use your BFH - then check the bolts for tightness.

I like the section and a half for the outer section - made by _____?

Make sure your mower is in registry, and the outer tip has 3-5" lead standing still.

There are wear plates under the hold down clips that do two things. They hold up the heal of the knife whitch in turn makes the cutterbar sections lay on the sector plates in the guards. They also suport the back of the section bar itself and hold it forward away from the main bar. You should loosen the hold down clip bolts slightly and tap each plate ahead till it just contacts the back of the section bar under the knves. Some plates are flat and can be flipped over to provide a new wear surface and others have a bent over lip that gives them more wear surface but you can't flip them over.

Serrated on both guards and sections will be ok. If guards are serrated then maybe a sharp smooth section in fine grass hay.

The guards are worn out when the gap is more than 3/16 inch, ot the ledger plate is worn smooth. Check the gap on all the old guards. replace with new ones with serrated sections. Buy a box or two of smooth sections and replace any worn or chipped serrated sections with those
Sections should have about .035 gap to the guard plate.. Use a 6 foot pipe to bend guards to this tolerance.

[b:654c4848f0][i:654c4848f0]Presently the guards have serrated ledgers on them and the sickle sections are also serrated. I am to understand that having serrated ledgers and sickle sections in combo is not good - is this correct?[/b:654c4848f0][/i:654c4848f0]

The previous owner may have needed serrated sections and serrated ledgers to cut the type of grass he was growing; this combination was “correct” for him for the job he was doing.

[b:654c4848f0][i:654c4848f0]The preferred arrangement is s serrated and smooth combo?[/b:654c4848f0][/i:654c4848f0]

The combination of serrated and smooth will depend on the type of grass being cut.

On our farm we have two types of grass: Coastal Bermuda and Bahiagrass.

We cut both types of grass with a <a href="http://youtu.be/Zn_KlD_irWY?list=PLCUEeGboEbi9lZeitHoI9GA2HKYB2_Zyg">9ft JD 350 sickle mower</a>. It has serrated sections and smooth guards.

We have a <a href="http://youtu.be/rnH8n4KOYoU">7ft. JD No. 5 sickle mower</a> with smooth sections and serrated ledgers; it will only cut Coastal Bermuda.

[b:654c4848f0][i:654c4848f0]Does it matter if the serrated part lives with the ledger plate and the smooth with the sickle section or vice-versa?[/b:654c4848f0][/i:654c4848f0]

Not sure what you are asking here.

[b:654c4848f0][i:654c4848f0]When should the guards be replaced?[/b:654c4848f0][/i:654c4848f0]

Replace any broken guards and ones without ledger plates.

[b:654c4848f0][i:654c4848f0]Are guards typically replaced when they break or are they a wear item like a ledger plate?[/b:654c4848f0][/i:654c4848f0]

Replace a worn ledger plate on any guard.

[b:654c4848f0][i:654c4848f0]My question is - should I replace the existing guards/ledger plate assemblies with the 15ish new ones I've got and buy the remaining new guards or just keep the new guards in the box and replace only the ledge plates?[/b:654c4848f0][/i:654c4848f0]

If you can replace the worn ledger plates and get both rivets secure, then this will be less expensive than replacing guards.

If the new ledger plates are installed with loose rivets, then the section will probably knock it off and damage the section.

[b:654c4848f0][i:654c4848f0]If I replace the new guards completely with what I have and finish out the cutter bar with additional new guards - I would continue with serrated ledger plates and on the knife use smooth vs serrated sickle sections.[/b:654c4848f0][/i:654c4848f0]

Use the sickle knife you have to determine if it will cut the grass you have.

If the new serrated guards and serrated knife don’t cut as desired, then consider using a knife with smooth sections.

[b:654c4848f0][i:654c4848f0]Is serrated ledger plates and smooth sickle sections an OK combo?[/b:654c4848f0][/i:654c4848f0]

Yes.

[b:654c4848f0][i:654c4848f0]If it is OK and/or advisable to just keep the guards I've got and replace the ledger plates plates, I'd put smooth ledge plates on and go with bottom serrated sickle sections on the knife.[/b:654c4848f0][/i:654c4848f0]

The OEM smooth guards on our mowers do not have a ledger plates; bought smooth guards from TSC and they do not have ledger plates.

[b:654c4848f0][i:654c4848f0]I would consider double guards, but since I have a box of single guards, I'd like to use them if I can.[/b:654c4848f0][/i:654c4848f0]

Either double guards or single guards should work just fine.

[b:654c4848f0][i:654c4848f0]The next thing is the hold down clamps for the knife. The sickle sections presently are about 1/8 inch standing off the ledger plates vs setting on them. How should I deal with the knife hold down clamps. Is this something I need to shim or beat into position with a hammer or replace or something else?[/b:654c4848f0][/i:654c4848f0]

To insure a shear cut, the point of the section must set on the guard plate.

The knife hold down must fit down snug on the knife, but not binding.

You might consider using a pipe wrench to bend the end of the knife hold down clip.[b:654c4848f0][i:654c4848f0]

I assume there are some wear plates - don't know their condition and to what extent they are potentially out of wack.[/b:654c4848f0][/i:654c4848f0]

I would recommend changing all the wear plates.



[b:654c4848f0][i:654c4848f0]Not trying to be cheap on this round of refresh on the sickle bar mower, but if I could use the new guards I've got, it would certainly save me some $$$'s, but I'm not opposed to redoing the whole cutter bar assy with new bolt-on double guards and serrated sickle sections - basically new everything on the cutter bar.[/b:654c4848f0][/i:654c4848f0]

On a sickle mower with a pitman, you will need to “register” the knife.

This means at the sections center in the guards when the pitman is at the inner or outer end of its stroke.





I would strongly recommend that you get an owner’s manual for your mower.

The manual will explain in detail how to register the knife.

Hope this helps.

Great info everyone - THANKS!!!!!!!!!!!!!!!!!

Bill