Sickle Blades serrated or smooth

[Ken(Ark)]

I bought a 9' Deere 350 sickle mower , belt drive . I run it with a Ford 3000 3 cylinder diesel . It works great but seems a little heavy , but it really does a nice job for what I need .

I have about 30 acres of clear fields that I have kept mowed ( 5" rotary mower ) and have managed to get most of the bigger bushes eliminated . About 10 acres are nice and smooth with a mix of grasses , maybe half is clean Bermuda and the other half is heavy with sage grass . I have the sickle mower going this year and hope I can mow / bale often enough to get rid of most of the sage grass . I have a small 4x4 round baler .

I usually mow once or twice a year and plan on using the rotary mower on the rougher areas until I get them under control .

My question is about the sickle mower blades . I have replaced all of the bad rock guards ( singles ) and they have serrated blades on them . I received two extra Pittman arms ( if that is the correct term for the long bar with the teeth riveted on it ) . One has fair serrated blades , one has blades that have been ground down a lot , and one has smooth blades .

Is there a big difference in performance between under serrated , top serrated , and smooth blades ?

It is not a bad task for me to change the pittman arm section . I hit a small bush and buckled one , broke a few guards , and had to change it . The 20v 1/2 drive impact did most of the work for me .

I would not mind using one arm just for cutting hay and keeping it sharp , another for cleaning up the rougher stuff ( briars , etc ) if that is even necessary . Would I even want different style blades .

I have not used one before and all replies are welcome . I can sort through an find what works best for me , Thanks - Ken(Ark)

P.S. Yes I have spent hours picking up those golf ball sized rocks .

 

[Mike(NEOhio)]

If the guards are serrated I think you should go with smooth sections (what you call teeth) on the knife (what you call the pitman). Others may have different opinions. Smooth and underserrated can be sharpened with a grinder, not top serrated.

 

[hd6gtom]

Your guards have serrated ledger plates to help cut the hay. I
run serrated sectioned on all sickles. Make sure you get the
chromed sections. They are tougher and stay sharp longer than
the mild steel sections. I have gone to all bolt on sections.
To do that you need the tall hold down clips. This stuff is
aviliable at most farm and home type stores. You don't have to
pay JD prices to get quality in mower rebuild parts.

 

[SVcummins]

If you go to the double guards you will like way it
cuts a lot better than the old single guard
Untitled URL Link

 

[SVcummins]

Link to some of the work I did on my no.8 John
Deere
Untitled URL Link

 

[Leroy]

Smoth are for lawn quality grass, not any hay type. Everything was smoth orignally as it was part of a learning prosses. Underserated sections were developed for heavier hay grasses and legumes like red clover or alfalfa. Top serated were developed for crops like whead with a heavier but dried out stem. And all 3 can be sharpened. The top serated just not as offten as the underserated sections. And you don't grind as much to get them sharp. I have done it many a time on top serated on combine knives as well as underserated mower knives. And what you are talking is the knife, the pitman is the part that drives the knife and fastens to the knife head. Each cutting piece is called a section and what they are fastened to is just knife back.

 

[Dan in North Houston]

A pitman arm is a wooden stick used to drive the knife section back and forth. Wood because it will break if you hit an obstruction and not damage anything more valuable. A pitman arm mower only works if the bar is relatively level.
Your 350 mower does not have a pitman, it is a belt drive to a balanced head. As such, it can mow with the bar at any angle - including when the mower is in the upright transport position - so always keep your hands clear.
There are several grease zerks on your mower, including one hidden down in the head that is very easy to miss. You want to keep everything well greased, because repairs to the balanced head drive are difficult and expensive.
If you don't have a manual for your 350, suggest you get one. In addition to maintenance info, there is a wide setting and a narrow setting for the mower, depending on your tractor and how you have your tires set. Do a search on this site for postings from James Howell, he has posted many good photos discussing how to set up these mowers.
I just use mine to mow around the stock tanks, so smooth versus serrated is not an issue for me. I use serrated because that's what Dad always used.

 

[Bob]

As Dan said, you have a "pitmanless mower".

The "sickle" is called a "knife" by John Deere, and the part the sections rivet to is called the "knifeback".

 

[James Howell]

"[b:654c4848f0][i:654c4848f0]Is there a big difference in performance between under serrated , top serrated , and smooth blades ?[/i:654c4848f0][/b:654c4848f0]"

It depends on the type of crop being cut.

You mentioned above "[i:654c4848f0]About 10 acres are nice and smooth with a mix of grasses , maybe half is clean Bermuda and the other half is heavy with sage grass.[/i:654c4848f0]"

We use top serrated sections to cut our Coastal Bermuda and Bahiagrass.

Take a look at the photo below of a top serrated section.

The top serrated sections should also cut sage grass with no problem.

Hope this helps.

 

[paul]

Aggressive serrated sections work best in stem my crops, like soybeans or alfalfa. Smooth sections work best in very fine grass and with serrated ledger plates.

Under serrated sections are often a good all around choice, not too aggressive if you get in fine stuff, works on bigger stems too.

Paul

 

[Ken(Ark)]

Thank You All for the replies .

They will help me to get going in the right direction . I have a manual , have watched a few videos , and read a lot of older posts .

I had problems getting the lever hooked to the draw bar and staying out of the way of the pto shaft , but after seeing a few pics and videos I don't think I will have any problem there .

I watched a video and saw I do not need to disassemble a lot if I remove the knife section by pulling it under the frame . I also saw James Howell's post about the shims on the end .

There are a few things I need to work on to get it as it should be , even though it is doing a great job already .

On the single vs double guards , what makes them smoother ? I would guess the double being bolted in two places would keep the vibration down and the alignment would be straighter ?

I just bought 10 new singles for $75 delivered . The doubles looked looked like twice the price with half as many needed but if a double breaks one side the whole unit needs replaced ?

I would bet that I go through a lot of guards this first year , but I would have no problem setting it up with doubles for next year . Murphy law says if you have a pile of extra guards you wont need them , it is when you have none that you break a few .

 

[Leroy]

You are wrong about the pitman being wood on all mowers. All mowers made by Detroit Harvestor and carried the Dearborn, Ferguson and some models of Case name mowers had steel. No more problems with them than wood and if you ever broke a pitman stick it was because something else was wrong as hitting somthing would not break a wood stick. Wood was easier to make back in the 1800's and companys just got used to it so they stuck with it as the same parts for that 1880 mower would work on the last pitman mower made. The wood was also I believe cheaper to make than the steel pitman. So it was personal prefference as to wood or steel for the manufacture. The steel pitmans had the knife head ball built into the pitman and the clamps were on the knife instead of the ball on the knife as with wood pitmans. I liked that better.I mowed for years with that wood stick and NEVER broke one but our mowers were kept inside so the wood did not rot as the rot is what would make most of them break. Just got rid of 4 Detroit Harvestor mowers as I had no place to keep them after I lost the farm. I have bought several horse drawn mowers for the Amish over the years and unless you found a barn stored unit the stick was rotted away.

 

[RickB]

It also depends on the guard style. Guards with no separate ledger plate generally require under serrated sections. Guards with serrated ledger plates can use smooth sections or top serrated sections.

 

[James Howell]

"[b:654c4848f0][i:654c4848f0]if a double breaks one side the whole unit needs replaced ?[/i:654c4848f0][/b:654c4848f0]"

Have never had a double guard to break, but have had a double guard loose both bolts and nuts and fall off.

Would highly recommend using nylon lock nuts to secure the two bolts on a double guard.

Same recommendation for single guards.

Hope this helps.

 

[Ken(Ark)]

(quoted from post at 15:20:35 03/24/19) "[b:dcaa44d1e5][i:dcaa44d1e5]if a double breaks one side the whole unit needs replaced ?[/i:dcaa44d1e5][/b:dcaa44d1e5]"

Have never had a double guard to break, but have had a double guard loose both bolts and nuts and fall off.

Would highly recommend using nylon lock nuts to secure the two bolts on a double guard.

Same recommendation for single guards.

Hope this helps.

I just ordered 10 singles but plan on giving it a good overhaul this fall after the hay season . I plan on buying all new doubles and saving the rest for spares . Here in Arkansas I am doing great growing rocks and ragweed . I just bought 100 7/16 nuts with a shoulder and serrated teeth but I think I will add them to the nut and bolt bins and get nyloc nuts . I watch my money closely but loosing one nut could easily run up a good size repair bill .

 

[Leroy]

Think you would be better off with the nuts you bought. You do not want a long bolt sticking out to catch hold of the stems. I think those lock nuts will require a longer bolt. And in mowing since I bought me first mower in 59 and mowed with dads before never had any problem with guards comming loose with factory nuts. What will make them come loose is not having all surfaces properly cleaned. I don't know on the new guards and mowers but what I had used nuts the shape of a lug nut on a car with the beveled side. The nuts did not stick out over 3/8" from rest of surface.

 

[SVcummins]

I went cheap and used just plain old fashioned 7/16
nuts I torqued em down with my big half inch ratchet
and have never lost another guard after that . If you
have correct nuts and run em tight you?ll never have
a problem
John Deere no.8

 

[Bob]

Here is what DEERE officially recommends as a nut for the guard bolts, a type of locking nut.

I think tossing the serrated flange nuts into the bolt bin id s good idea, I've never had any luck with them staying tight on tough applications.

<img src = "https://i.imgur.com/KLbQSbw.jpg">

 

[Leroy]

That nut has the cone shaped side to it and that is what helps keep them tight the same as the lug nut on your car. The flange type are for on a flat surface and I have never had a problem with them comming loose when used in proper conditions.

 

[Bob]

(quoted from post at 09:25:34 03/26/19) That nut has the cone shaped side to it and that is what helps keep them tight the same as the lug nut on your car. The flange type are for on a flat surface and I have never had a problem with them comming loose when used in proper conditions.

The nut I posted about is a self-locking nut that is "crimped" at the top to deform the threads a bit to lock it, and is "shorter" than a nyloc nut.

It's not at all like a tapered wheel nut, in this case, the tapered surface faces AWAY from the flat surface that's tightened down to.

In other words, it can be used with a shorter bolt than a nyloc, so the nut and bolt don't stick up as much above the cutterbar.