Mountfield M28M blade sharpening..Any tips?

sujsuj

DB1904 said:

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

I didn't use ride-on to level land rather connected a heavy roller on the back and run with blades UP. Thanks

casper_gutman

From what you say about the exceptionally rough use the blade has seen in the last year, it doesn't sound like you'll be needing a new blade annually. 

I'd replace it this time, but then mow more regularly and maintain the new blade by sharpening little and often as others have suggested. There's no reason to think you'll then find yourself in the same position next year.

benson1980

I used a dremel and a grinding stone attachment to sharpen our mower blade. They seem to come pretty blunt from factory (might be a H + S thing), and certainly dull quite quickly.

All I know is that I'd have a new blade working well for a few months on the mulching mower before it would start leaving clumps everywhere. Regular sharpening with the dremel has given much better results. So perhaps some kind of rotary tool and grinding stone attachment rather than angle grinder to get the edge sharp; if the blade hasn't been deformed.

Bendy_House

sujsuj said:

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.

The answer is, to keep on going with the angle grinder - gentle repeat passes, with the blade firmly clamped down, and the disc at around 30o (I understand?). I don't understand what you mean by the A-G making little difference? Are you sure it's a 'metal' disc that's in it?

The main part of the blade seems to be pretty much there, so you 'just' need to continue that edge profile to the very (round...) end. Why isn't this working for you?

Yes, that's an incredibly worn blade, but as S62 points out, most of the cutting is done simply by the blade's speed; the blade sharpness is largely to make the cuts 'clean' and better for the grass's health. Also, most of the cutting takes place on that outer few inches of blade (the part you haven't ground...) as it's the fastest-moving.

Just keep going, and give that whole edge, but especially the end part - tho' no need to go around the bend beyond the front curve - as even a 30o slope as you can. It doesn't have to be actually 'sharp', just a big sod better than it currently is.

When it's looking good, but not quite finished, clamp a screwdriver or similar, sticking out, to the top of a bench, and slip the blade on to it - see how well-balanced it is. Grind some more.

Although we are ideally money-saving, new blades are cheap, aren't they - around £15? You shouldn't have to replace the next one for years, but it does look as tho' this one has had a very tough time, so perhaps best to start again?

I wouldn't - I'd always grind... :-)

(That reminds me - when I mowed last week, it ended with me going over a rock hidden along the side. Must check blade...)

stuart45

DB1904 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. 

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. 

A friend of mine is a mobile tractor and mower mechanic, and he's got scales in the van to balance the blade. He reckons it's really important when sharpening the blade.

DB1904

Bendy_House said:

sujsuj said:

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.

The answer is, to keep on going with the angle grinder - gentle repeat passes, with the blade firmly clamped down, and the disc at around 30o (I understand?). I don't understand what you mean by the A-G making little difference? Are you sure it's a 'metal' disc that's in it?

The main part of the blade seems to be pretty much there, so you 'just' need to continue that edge profile to the very (round...) end. Why isn't this working for you?

Yes, that's an incredibly worn blade, but as S62 points out, most of the cutting is done simply by the blade's speed; the blade sharpness is largely to make the cuts 'clean' and better for the grass's health. Also, most of the cutting takes place on that outer few inches of blade (the part you haven't ground...) as it's the fastest-moving.

Just keep going, and give that whole edge, but especially the end part - tho' no need to go around the bend beyond the front curve - as even a 30o slope as you can. It doesn't have to be actually 'sharp', just a big sod better than it currently is.

When it's looking good, but not quite finished, clamp a screwdriver or similar, sticking out, to the top of a bench, and slip the blade on to it - see how well-balanced it is. Grind some more.

Although we are ideally money-saving, new blades are cheap, aren't they - around £15? You shouldn't have to replace the next one for years, but it does look as tho' this one has had a very tough time, so perhaps best to start again?

I wouldn't - I'd always grind... :-)

(That reminds me - when I mowed last week, it ended with me going over a rock hidden along the side. Must check blade...)

It's a ride on so about £50.

Eldi_Dos

stuart45 said:

DB1904 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. 

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. 

A friend of mine is a mobile tractor and mower mechanic, and he's got scales in the van to balance the blade. He reckons it's really important when sharpening the blade.

In Cambrils where we go on holiday there is a chap of retirement age who has a Vespa kitted out for sharpening and polishing knife's,turns into quite a social occasion when all the householders and chefs are gathered round while he does the work.It is something we look forward to seeing and I always think what a great retirement job.

stuart45

He could be an ex mod. It is still covered in mirrors?

Eldi_Dos

stuart45 said:

He could be an ex mod. It is still covered in mirrors?

Give him his due he is always well dressed, it's a work of art the little mobile workshop with the grinders and polishers powered off the engine. Must be a company in the Med somewhere who does the conversions.

stuart45

Out of interest I googled Vespa knife sharpener and got a few pics and a short YouTube video I would say look like Italy. 
Used to amaze me how people would take out the whole family on a scooter over there.