# Serrated VS Standard Mower Knives



## azmike (Jan 4, 2015)

I am studying new knives for our H7220 discbine. I found serrated of about double the cost of standard. Not too experienced but wondering if they are worth the premium?


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## Hayman1 (Jul 6, 2013)

For starters, I switched to a discbine in 2007 and have never looked back and would not consider a sickle machine under any circumstances. That said, before the discbine, I ran a NH489 haybine and before that NH450 and 451 sickle mowers. I made the switch to serrated knives when my dad was still paying the bills in the 80s and thought they were worth the extra to dad's wallet. Only cut grass hay with some clover in it. once I saw the difference, I rebuilt all the knife bars and replaced the smooth knives with serrated and went to all bolt on sections somewhere in that time. As I recall the serrated were more expensive then but I don't remember how much more. When I started paying the bills, I kept serrated. Rebuilt the knife that came with the 489 when I got it and all the new knife bars I bought were ordered serrated


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## Hayman1 (Jul 6, 2013)

another thing, don't know how things in sickle land are built today, but if there are still ledger plates on the guards, they are as important to keep in good order as the sections. dull worn ledgers are a bear and sharp serrated sections don't overcome dull ledgers. sorry, dumb me just realized you were talking about a discbine. I went 7220, wait a minute... good thing it is winter and I am not doing anything important. but will be interested in any feedback you get that is on point. rick


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## mlappin (Jun 25, 2009)

Never seen a need for em, if it's gonna cut that hard either flip the existing knife over or install new ones. But I cut mostly a mix of alfalfa/orchard grass.


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## DSLinc1017 (Sep 27, 2009)

Hayman1 said:


> another thing, don't know how things in sickle land are built today, but if there are still ledger plates on the guards, they are as important to keep in good order as the sections. dull worn ledgers are a bear and sharp serrated sections don't overcome dull ledgers. sorry, dumb me just realized you were talking about a discbine. I went 7220, wait a minute... good thing it is winter and I am not doing anything important. but will be interested in any feedback you get that is on point. rick


It was however a good rant! I was waiting for the realization, glad it came 

I too am curious, As last year was my first year with a Disc mower. I had always had better luck on my sickle mowers with serrated as Hayman pointed out. My new H7220 did come with Non serrated knives as well.


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## slowzuki (Mar 8, 2011)

I'm guessing its a marketing gimmick to appeal to the memory of how much they helped on the sickle machines.


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## Thorim (Jan 19, 2015)

slowzuki said:


> I'm guessing its a marketing gimmick to appeal to the memory of how much they helped on the sickle machines.


 If they improve a sickle bar why wouldn't then improve a discbine? I guess the question

becomes is it worth the extra money????


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## slowzuki (Mar 8, 2011)

They use different cutting actions. Serrations keep grass from squirting out of the closing v of a sickle.

The disc mower is smashing a sharpened blade through a stalk and not sliding it.


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## deadmoose (Oct 30, 2011)

DSLinc1017 said:


> It was however a good rant! I was waiting for the realization, glad it came
> 
> I too am curious, As last year was my first year with a Disc mower. I had always had better luck on my sickle mowers with serrated as Hayman pointed out. My new H7220 did come with Non serrated knives as well.


How expensive are we talking to switch over? Or to try a test run and change out half on a field?

Hopefully someone who has actually used them will give u better insight.


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## Colby (Mar 5, 2012)

The serrated disc mower blades are suppose to last longer in sandy land. But I can't get my hands on any to try it out so I don't know.


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## vhaby (Dec 30, 2009)

My NH haybine came with serrated blades and I was told these blades are self-sharpening.


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## hayman1086 (Sep 16, 2012)

I ran a couple of boxes of the serrated 14 deg blades on my h7450's a few years ago but was not impressed. with them. They did not last as long as the regular 14deg blades in sandy land


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## Grateful11 (Apr 5, 2009)

While we're talking knives, does anyone sharpen their old disc knives during the off season to save a few bucks and to keep from send them to the scrap yard. Also anyone know if NH blades are "through hardened" or "case hardened"?


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## 8350HiTech (Jul 26, 2013)

Grateful11 said:


> While we're talking knives, does anyone sharpen their old disc knives during the off season to save a few bucks and to keep from send them to the scrap yard. Also anyone know if NH blades are "through hardened" or "case hardened"?


I sharpen, especially if it's just small nicks, like from running over a groundhog hole that has loose shale around it. If the blades are starting to lose their square corner, then sharpening isn't very useful.


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## mlappin (Jun 25, 2009)

Grateful11 said:


> While we're talking knives, does anyone sharpen their old disc knives during the off season to save a few bucks and to keep from send them to the scrap yard. Also anyone know if NH blades are "through hardened" or "case hardened"?


Chuck em and put new on or flip em over, ain't worth the time to grind em as they are case hardened, once the edge is gone it won't hold a new one. I've placed a crescent wrench on several bent ones from a field they "picked all the rocks up in", had no problems straightening them, if they were through hardened they would have snapped.


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## slowzuki (Mar 8, 2011)

I sharpen my pottinger knives, works well for me. These ones crack if they are bent very far though so they must be something other than low carbon steel.


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## Hayman1 (Jul 6, 2013)

8350HiTech said:


> I sharpen, especially if it's just small nicks, like from running over a groundhog hole that has loose shale around it. If the blades are starting to lose their square corner, then sharpening isn't very useful.


same here. Touch up with the small dewalt and pliers for nicks, bent or out of square, replaced. Blades are just too cheap and easy to replace to go to the field ragged.


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## slowzuki (Mar 8, 2011)

We have a pile of rocks too so often break knives or completely destroy them part way through a field so I tend to sharpen until there isn't much left of the knive before flipping.


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## azmike (Jan 4, 2015)

$1.59 for standard or $3.49 for serrated, its not the National Debt to deal with. I am ordering a full set of serrated to start. I'll then run a set of standard and let my data be known....


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## mlappin (Jun 25, 2009)

A neighbor swore by having his mower blades cold treated&#8230;..

I ran one half of the mower with standard out of the box 14 degree blades, the other half was cold treated, never seen enough difference to waste money on cryogenic treating again.

If I was going to try serrated, I'd run one half with and the other half without so any difference would immediately be apparent. Start out with all new of course.


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## azmike (Jan 4, 2015)

Guys were cryogenic treating their competition shotgun barrels for several hundred $$, the same fellas had the shaman say a few words over the shotguns also!


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## mlappin (Jun 25, 2009)

azmike said:


> Guys were cryogenic treating their competition shotgun barrels for several hundred $$, the same fellas had the shaman say a few words over the shotguns also!


A former employee swore by having his saw chains cryogenically treated as well, It might have helped a wee bit, but you sharpen them twice or maybe three times and the effect is lost and you need to retreat that chain.

He gave me one to try and again, not enough improvement to waste my time or money on.

He used to be a machinist and worked at a place that cut the gears for helicopters out of magnesium (or something), the management swore by cold treating all they're tooling.


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## slowzuki (Mar 8, 2011)

For high alloy or high carbon steel cryo can harden stuff up a bit similar to quenching from hot. It's pointless on mild steel, doesn't do anything.


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## urednecku (Oct 18, 2010)

Like others, I sharpen mine until the end gets round. Doesn't seem to take any longer than changing them, and these fire-ant beds act just like acourse sandpaper on the blade.


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