Refurb a Sickle Bar mower

[kbuegel]

I just bought a Sickle Bar mower - I'm pretty sure its a NH 450. Its fairly rusty, but I hooked it up and it works. So I want to rebuild it and clean it up so it will be reliable for Spring hay cutting in a couple weeks.

Thankfully, the pully and PTO parts seem in good condition, so just greasing them and blowing out debris will do there. But, there is a lot of rust on the bar and cutter blade sections. I have a "new" blade I can put in, but its just as rusty. The mower works but clogs up within 10 feet of cutting heavy grass. I assume this is because everything is rusty and the cut grass is sticking to the rust. I've seen recommendations to pour motor oil over the bar, but I think it will need more than that.

Also the cutter sections look fine except for the rust (no nicks or broken rivets) but sections do not sit down agaist the bar very well. I think it may have been sitting in a field for a long time and grass grew up and bowed up the blade between each of the "keepers" on the bar (not sure what all these parts are called). Or maybe there is debris under the cutter bar that is lifting it up. But it seems like the sections need to ride right on the bar for it to scissor correctly, and in some cases they sitting up about an 1/8 of an inch or more.

Lastly, I'm a bit unsure on the operating speed when using a sickle. I can run it at 540 rpm and it slides back and forth so fast that only the tips of the cutter sections are doing all the work. And they seem to push and hold torn grass into the spaces under the guards. There are scerated edges further down the sections, but the Grass never really makes it back that far (you can tell from the moisture left behind). So I might assume that I should drive faster through the grass, but that seems to flatten the grass down. So if I drive slow, and lower my RPM's to run the cutter slow, is that a good idea? Or should I always use it at 540 RPM?

Thanks in advance for everyone's advice on this. I'm sure I'm not the only one trying to get a finicky sickle mower to work well.

 

[zzvyb6]

Your 450 is clearly shown on the New Holland parts web site. It should be easy to refurbish the sickle cutter because parts are all over the place (TSC for example has guards, hold down clps, knife sections, rivets, bolts, etc.

That being said, you can hammer the hold down clips to get tighter contact between the knives and the cutter bar. Pound then down until the knife is in contact with the guard surface. They may break only because they are all worn away. Unbolt the guards and put new bolts and clips in.

As for cutting, if the knives are not sharp, pull the bar and hit then with a grinding wheel. For mostly grass, I recommend a over-serated knives. This helps rip the grass blades. Putting new knives in is a neat skill to learn. If rivetted, put the bar loosly in a vise with the knife noses down. Then blast the back edge with a heavy hammer to shear the rivets. Install the new rivets with a ball pein hammer or buy a rivet tool. I prefer the bolts myself, but that's your decision.

Don't worry about the rust on the knives or cutter. After mowing a few acres, it will be all shiney again. Stones, ant hills, a few mice or a woodchuck are good polishing materials.

 

[kbuegel]

Now that I'm looking at the NH website, it looks like my mower is a NH 45, not a 450. Its pretty old! Its a full-mounted version, no support wheels. The 3-pt hitch has lots of extra clamps and bars to keep the mower from twisting on the hitch. I did not seem to need those on my newer NH 29DA tractor. I guess the lower arms on 3-pt hitches used to move independently.

I got this mower as part of a package deal: a NH super-68 baler with a Wisconsin engine (engine was recently rebuilt, works great), a NH side-delivery pto-driven rake-appears to be 8 foot or so and has rubber tires in decent shape, a ground-driven bale picker for throwing bales into a truck, and this NH sickle mower. All these had been sitting in a field for 4 years, but prior to that they were used regularly. Got a couple boxes of spare parts too, including 3 cutter bars for the sickle mower, one appears to be brand new, but rusty from sitting.

When I get home, I'll attach a couple pic's. Picked all this up for $2000.00. Seemed like a decent deal, even if the equipment needs some TLC. We have a horse ranch and plan to cut and bale some volunteer rye grass that is on neighboring land.

The hold-down clamps on the cutter bar do seem to keep the knife sections pushed down on the bar, but those hold-downs are about 18 inches apart. So all the sections in between are lifted up for some reason. But now that I'm looking at the parts diagram, there looks to be a long metal strip that all the knife sections attach to, and perhaps that is what is bent. When I take the bar apart, that should be obvious. I'm just hesitant to take apart something that is working - if I can just tweak it, that may be better.

That's good to know that all the rust will get buffed away from an acre or two of mowing. Then I will just brush it to get rid of any scale, oil it generously, and let the grass do the rest. Out here we have moles, so they raise up some dirt which the cutter digs through now and then. Its very sandy soil, no rocks and fairly flat but somewhat marshy. Grass seems to grow very well with little help. This year, local bales of orchard grass are going for $25/each. So we plan to use some rye hay to strech out our feed.

The other thing that occured to me is the height of the cut - this mower has skids at both ends and it does not appear to be adjustable in height. I can raise up the inboard end by raising the 3pt, but the outboard end still rides on the ground. But I assume that is on purpose so I could cut pond banks and have the bar swing downhill (as long as it doesn't break the pitman). There is a heavy-duty spring that appears to stop the bar from lowering too far, but it looks like about 25 degees or so below level is where it stops. So anyway, I cannot lift up the outboard end of the bar without getting off the tractor and lifting it all the way up. Would be nice if I could set it to be level and just use my hydraulics to lift the whole thing up 1 foot or so, to get past obstructions. Maybe I'm missing something that locks the bar into a level position?

 

[zzvyb6]

I think a lot of us would like to see the ground bale pickup elevator. I used to have one, never used it, and scrounged the chain sprockets off of it for other uses. Maybe I should consider resurecting it.

My old New Idea mower had a rope to pull when you wanted to raise up the cutter bar. Also, as I recall, the side view angle was adjustable, thus allowing you to change the cutting height. This was a manual operation. Be careful when picking up the cutter bar. Lots of people got their fingers caught in between the knives. When you raise it up, the knives slide across the ledger plate. With good sharp knives you'll never realize its happeneing...

 

[Solo]

You might be able to find a manual for your mower on ebay. I've seen several there. For the Rivets I always use a grinder to take the heads off. To reinstall I just bought a rivet tool from www.smithtoolinfo.com/r3030.htm. I've seen these on ebay as well.

Solo

 

[Farmwithjunk]

On the gaurds, you'll notice a serrated piece that's integral to the gaurd. That's the ledger plate. When they wear out, no matter how sharp the sections are, grass will bunch up rather than cut. The sections cut against that serrated edge on the ledger. Simple fix? Replace gaurds. Sections should ride CLOSE to the ledger but not TIGHT against them. Both cutting edges wear really fast if there's too tight of a fit. Not sure if that old of a mower has wear plates UNDER the hold down clips or not. If you're doing a total rebuild, replace them too (IF they're indeed used on a 45) Tension on the knife bar is regulated by the hold down clips. As mentioned, they can be bent to proper adjustment.

One of the most misunderstood concepts with a sickle bar is, people tend to move along too SLOWLY with them. They cut better if the ground speed isn't too slow. A GOOD, well adjusted sickle bar mower can easily handle 5 to 7 mph in a heavy crop.

About the only height of cut adjustment on a lot of older mowers is with lengthening or shortening the top link. That makes a very small difference. There MAY be some adjustmet to the skids themselves. I've got a NH 451 (owned it since 1975) The skids on that model do have some height adjustment.

 

[kbuegel]

Turns out it is a NH 501 sickle mower - it was hard to identify from the drawings since many of the sub-assembly parts are similar to 45's and 451's.

I rebuilt the bar over the weekend, but did not try riveting new cutter knife sections - only one section is broken so I let it be. But the guards are fairly worn and bent, several have been replaced with JD and MF guards which apparently fit but don't fit perfectly. The plates on the guards do have serrated edges but they are rounded over and not sharp at all. But they may still hold the grass, which seems to be their purpose.

Overall, I think I'm going to have to buy a better mower. This one has mowed many, many acres and will do for now, but its pretty worn out.

If you see anything I should fix in these pictures, please say so. Here are the pics:

 

[kbuegel]

Here's some more pics showing the grass buildup at the tip of the guards, one of the guards removed, and the shims. I guess the shims are sacrificial, rather than wearing out the guards or the bar itself.

 

[kbuegel]

Also here are pics of the bale-picker. Its tipped down for towing, normally it runs with the chute sticking up in the air, and the opening (currently at top of pic) rides along the ground and guides bales into the chute. The chain going up the chute has teeth sticking up about 3 inches, about one per foot, that grab onto the bale. The chute has a floating top bar that keeps pressure on the bale against the chain with teeth, and is adjustable for various sized bales. But the baling machine, and probably this bale-picker, are designed for 50-60 pound bales, somewhat smaller than normal bales these days.

The chain is driven by the tires, and a solid axle (no differential) so it doesn't turn corners very well. There are several welded spots, presumably repairs, and it looks like somebody added a guard on the towing side, probably to keep it from running into the truck or trailer it is loading.

 

[Farmwithjunk]

Actually, that'd be a F.O.R.D. 501. They pre-date the current "New Holland" tractor brand and go back to a time when New Holland and Ford had absolutely NOTHING to do with each other.

The Ford 501 is a pitman style mower, a totally different concept from a NH451.

Still a good mower though.