RPM for a 22" residential push mower

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GearHead36

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slomo said:
The grass police won't be by to arrest you.
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I'm not worried about the grass police. But I WOULD like my mower to work as designed. It's been a reliable workhorse over the years, but I've never been particularly satisfied with the cut quality.
 
C

*CPB*

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GearHead36 said:
Is there a balancer out there that is better than the cones, but doesn't cost a fortune? I'm just a homeowner. I have several blades to maintain each year, but I don't have a need to balance hundreds of blades like a shop would, so I can't justify a top of the line balancer.

It's definitely NOT running at 5800, so I'm pretty sure the tach is giving the right readings.
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All American Mower Blade Balancer — All American Lawn Mower Blade Sharpener

Made in the USA, our mower blade balancer is a great combination of practical, functional, and simple. It works as a typical cone balancer, but with more precision. Our balancers are made with anodized aluminum and stainless steel. They are built to last a lifetime (just like our sharpeners). The bl
www.allamericansharpener.com www.allamericansharpener.com
 
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Dwayne Oxford

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kbowley said:
The spec is 3100 to 3200 RPM's for a 21 or 22 walk behind. Those cone balancers are useless. Simply drive a large nail in the wall and wipe a bit of grease on it to balance. If it is a star hole, simply place a similar sized socket in the blade hole to balance. Balance is important on the long blades; even new blades are off many times. I simply grind a groove on the lift/back side of the blade to balance. I have a busy outdoor power equipment shop and use the this tool to balance. You simply can't beat one of these tachometers for small engines.
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..."can't beat one of these tachometers"...??
 
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thesilentone

thesilentone

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You are chasing the holy grail.

Specification is one thing, regulation is another.

Despite a machine having an optimum design efficiency, it must also comply with a whole raft of regulation, such as hand arm vibration, noise and emissions.

In many cases, equipment leaves manufacturers set up to meet regulations as opposed to operate at optimum.
 
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BTBO

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kbowley said:
The spec is 3100 to 3200 RPM's for a 21 or 22 walk behind. Those cone balancers are useless. Simply drive a large nail in the wall and wipe a bit of grease on it to balance. If it is a star hole, simply place a similar sized socket in the blade hole to balance. Balance is important on the long blades; even new blades are off many times. I simply grind a groove on the lift/back side of the blade to balance. I have a busy outdoor power equipment shop and use the this tool to balance. You simply can't beat one of these tachometers for small engines.
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I too have a Magna-Matic blade balancer. It works like nothing else---very accurate. I have a ZTR and bought the MM thinking it was worth the price vs having to replace spindles prematurely.
 
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beeev

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BTBO said:
I too have a Magna-Matic blade balancer. It works like nothing else---very accurate. I have a ZTR and bought the MM thinking it was worth the price vs having to replace spindles prematurely.
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Ditto here.
You can even check them for straight before wasting any time sharpening with the MM.
As far as the tachometer you bought, is it a quality piece or a Scamazon cheapie?
I would have trust issues on some knock offs.
When it comes to tools, get the best quality you can afford.
Buy once, cry once. The proven good stuff gives a lifetime of use/reliability imo.
 
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W

Wrenchit

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GearHead36 said:
I know that the blade tip speed is limited by ANSI to 19000 FPM. Which, on a 22" blade, equates to 3299RPM according to my calculator. I recently bought a tachometer, and found that my residential push mower, with a 22" blade, is running at 2750 RPM. So I started increasing it. When I got to 2950, it seemed like it was running really fast, and had a lot of vibration. So I backed it down to 2900, and the vibrations seem to get better. So my question is, of course, what speed should I set my engine to?

Engine: Briggs 128T05-5123-B.
Mower: 2011 Toro Recycler w/Personal Pace.

I still have the owner's manual and the engine manual. Neither mention engine RPM settings.

Not sure if this is the right forum, but the only other blade tip speed discussion I could find was in this forum.
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The maximum torque achieved for your engine is between 2600 and 2800 RPM. It drops after that.
A slightly bent crankshaft will cause vibration even with a perfectly balanced blade.
 
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GrumpyCat

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I don't think HP/torque is the primary concern about RPM. In general the cut is better at higher speeds, so while the big deck of a rider has it's disadvantages the faster blade speed over a walk-behind has advantages.
 
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