Mountfield M28M blade sharpening..Any tips?

sujsuj

managed to remove this blade but the shape cutting edge is bit unconventional. See photos

its not like a sharpened knife's edge shape, where sharpened from both edges and central we have edge used for cutting . but here it is slanted rectangular shaped edge..

I tried to sharpen it with Angle Grinder, but not sure it really made any difference. Any tips on this..?

see photos.

molerat

That blade is goosed and fit for the bin.  It should be straight along the outer leading edge with a 90 deg corner, not rounded, and a 30 deg sharpened edge.  Look up the part number 84109502/0 or 184109502/0

Ajmason42

Plenty of vids on you tube but I would buy a new one as molerat say looks fit for the bin

Eldi_Dos

Bin? come on guys this is a money saving site.

Cut in two at bolthole and you have the makings of two robust patio knifes or weeding tools.

DB1904

When you buy your new blade sharpen little and often using a file. Then all you'll be doing is putting the edge back on and using the original angle. If you lose the angle of the edge then you've left it too long. You shouldn't need the grinder unless you damage the edge.

sujsuj

Thanks for the inputs, probably I will check the edge angle in shop and try to replicate it in this using Angle grinder. Mine is just 1 year old ride on mower so don't want to buy it every year. 

Section62

sujsuj said:

Thanks for the inputs, probably I will check the edge angle in shop and try to replicate it in this using Angle grinder. Mine is just 1 year old ride on mower so don't want to buy it every year. 

The angle isn't particularly critical.  Rotary mowers cut by brute force (like corded strimmers) rather than a precision cut (like cylinder mowers).  They will continue cutting even with the blade completely rounded off, albeit not as healthy for the grass as a clean cut from a sharp blade.

Two questions though...

1) Why did you think the blade needed sharpening?

2) If it is only a year old then how has it got to that shape, rather than the one molerat linked to?  I'm wondering whether the manufacturer has redesigned the blade, or if the mower is being used wrongly.

molerat

I think something other than just grass has done that.  Tops off mole hills and general lumpy ground I suspect, loads of dirt and stones.

Even though they do use brute force there still should be a 30 degree edge on it.  My petrol mower blade is pretty battered but the shape of the edge is still clearly visible.

DB1904

molerat said:

I think something other than just grass has done that.  Tops off mole hills and general lumpy ground I suspect, loads of dirt and stones.

Levelling a tennis court.  https://forums.moneysavingexpert.com/discussion/6355361/any-one-done-diy-tennis-court-in-your-backyard/p1

DB1904

sujsuj said:

Thanks for the inputs, probably I will check the edge angle in shop and try to replicate it in this using Angle grinder. Mine is just 1 year old ride on mower so don't want to buy it every year. 

Since you've decided not to listen to advice and intend to grind it anyway, make sure it's balanced or a new blade will be the least of your worries. 

sujsuj

Section62 said:

sujsuj said:

Thanks for the inputs, probably I will check the edge angle in shop and try to replicate it in this using Angle grinder. Mine is just 1 year old ride on mower so don't want to buy it every year. 

The angle isn't particularly critical.  Rotary mowers cut by brute force (like corded strimmers) rather than a precision cut (like cylinder mowers).  They will continue cutting even with the blade completely rounded off, albeit not as healthy for the grass as a clean cut from a sharp blade.

Two questions though...

1) Why did you think the blade needed sharpening?

2) If it is only a year old then how has it got to that shape, rather than the one molerat linked to?  I'm wondering whether the manufacturer has redesigned the blade, or if the mower is being used wrongly.

I have 1 acre+ land, I had my lawn gone out of control last year because of delivery delays of ride-on mower. It had a rough use last year, I wasn't familiar with the lawn last year as I moved in in that winter only. All contributed to rough use. I could see its damaging grass thats why decided to sharpen it. thanks.