Rotary Mower blades sharpening

[elmerinva]

On my Land Pride rotary mower, the blades needed sharpening which was done OK. I noticed the ends were rounded so that the actual width of cut was reduced by several inches. Has anyone tried welding on to the blades to "square" them out? Or is this just not smart because of the heat/temper,etc. I have only 60 hours on this set of blades.

 

[rancar]

Elmer,

<font color=blue>I noticed the ends were rounded so that the actual width of cut was reduced by several inches.</font color=blue>

Wow....only 60 hours on the blades and you lost several inches. Is this normal??

<font color=blue>Has anyone tried welding on to the blades to "square" them out? Or is this just not smart because of the heat/temper,etc.</font color=blue>

I've never done this kind of welding but my sense is these blades, when manufactured new, are of high tempered steel. I don't believe welded ends will produce the strength you need to maintain effective cutting capability. You may also find these ends will snap when you hit the first rock or sappling.

Bob

 

[Slamfire]

While you could extend the length of the blades, how would you handle tha balance problem? Rotating equipment is pretty fussy about that.

 

[elmerinva]

rancar, i probably wasn't clear about the rounding. The corner of the square blade tip has been rounded so that the radius of the rounded corner is about an 1-1 1/2 inch. When mowing the speed of the blades flattens the grass and leaves a row of tufts. The welding would just restore the corner to square up the blade. the rounding occurs i guess from rocks, dirt, saplings, etc. i guessed the steel on the blades is mild steel since it would have to deal with severe shock loads. maybe new blades is the easiest way.

slamfire, the balance would be a problem but would have to be worked. After sharpening, i have the balance problem to deal with anyway which i do with moving shim washers on the blade bolts.

thanks for the replies

 

[Anonymous Poster]

I am putting new blades on my Woods M5 cutter...it's got to be 30 years old...I think I may be only the second owner (had it for 9 years). The blade kit from Woods, with shipping to the local dealer was only around $45. Probably cheaper, and less time consuming than sharpening if the current blades are real bad.

 

[JerryG]

M5 blades are inexpensive. That's about what I pay for mine. They aren't worth the work of sharpening them.

 

[djradz]

I just sharpen them, including the rounded edge, and call it good. If they get too bad, then replace. I've mowed for years with the tips rounded and as long as you can get some sharpness to them, still get satisfactory results.

 

[Anonymous Poster]

Yes, it can be done, in fact I've built mine up a couple times.
NO, I'm not going to post the technique here cause it isn't something that should even be attempted by anyone who isn't fully versed in welding techniques. Mine did shatter a bowling ball the neighbor's kid threw into the tall grass, after being rebuilt, and there was no evidence of damage to the blade, but it sure shook me and the machine when contact was made.
By the way, it isn't a hard surphace process you want to use, how would you ever sharpen that?

 

[patrickg]

Franz, Is this one of those "if you have to ask, you won't understand the answer" things? Sharpening a hardened surface? Uh, use my diamond surfaced angle grinder wheel.

OK, don't give actual specifics of the technique, just mention the rod you use.

Just out!! The bowling ball test for brush hog blades and gearboxes.

Patrick

 

[JimMc]

Actually, for those of you who are interested in such things, one of the 4 standard tests we use on a new cutter design is to lower the cutter while running at 540 PTO RPM onto a 2" diameter steel stake buried 3 feet in the ground and sticking out of the ground 8 inches. Makes an unbelieveable racket, but fully checks cutter integrity from blades to PTO shaft.

 

[JohnMiller3]

Hi Jim,

That's interesting... What are the other 3 tests...?

In fact, can you start a new post on the mfr. testing and designing of implements in general... That would make great reading... /w3tcompact/icons/smile.gif

Thank you...

 

[Inspector507]

I can see it now........"Try the First Choice Fence Post Mower" /w3tcompact/icons/laugh.gif

 

[Kodiak]

I haven't mowed any t posts with mine. But it only took a couple of seconds to wrap 35' of old barb wire around the spindle, in an incredibly tight mess. It was also time for a new pair of shorts after that wire started whipping under the tractor.

 

[Slamfire]

A few stratigically placed jack stands keep them mowers up in the air.

 

[JimMc]

The other tests involve running the cutter at full RPM with only one blade, checking a standard template representing a human leg and foot to check blade clearance from openings, and last, dropping nails through the deck into the spinning blades to check that the ejection of nails falls below a certain level. These tests are meant to check basic safety levels in rotary cutters. I can supply the specifics if anyone is interested.

 

[JimMc]

Russ, I did the same thing on a new property once. Unfortunately, the cheap posts came with the wire and it got very intense until I got the tractor shut down. One thing I knew for sure, I wasn't about to get off that tractor with all that wire and posts whipping around!

 

[jhburke]

When I clean and or need to work on the under side of my rfm, I hook a come along to the top link and to the back of the deck. First I disconect the pto shaft then I crank the deck to about 45 %. This makes inspection and maintenance easier.

 

[Anonymous Poster]

Patrick, you kind of hit the nail right square, it ain't anything I'd recommend to someone cause I flat know somebody else with a 120 volt wirefeeder is gonna figure he can do the process with his "machine" too.
I'll also tell you it doesn't involve a hard surface process. Just take a file to your blade and see how hard that is. Hard surface and abrasoweld really aren't designed for this type of application.
The first time I did it, I wondered if I was nuts for doing it, but I had the recommendation of a fellow I had complete trust in, so I figured why not try. After building up close to 1/4" of edge, and sharpening, I ran the machine for a few hours, and looked at the blade edges. The buildup was still there, and had performed as well as the original blade.
Now, if anyone wants to know how to rebuild rototiller blades, since they travel slow, I'll spill the beans on that. Just cut old leaf springs from a car to the original tooth profile and weld it onto the stub tooth with stainless rod. No, I don't do buildups on mower blades with stainless.

 

[Ozarker]

Think that was a mess? I was on a training exercise in Germany once when at about midnight we got word to break bivouac and move to a different site. In the process, a guy ran a 5 ton cargo truck through a concertina line wrapping an entire roll of it around the rear differential. It cut the tires to pieces and mangled the brake lines.

We had to move and couldn't do anything with the truck so I had it winched onto a low boy behind a D7E (it almost fit and didn't hang off the end too far) and away we went. Took two days to get all that wire cut off, replace the brake lines and get it back on the road.

I worked that driver to death for those two days. I didn't waste any of the maintenance guys time on getting that wire cut off.