which angle grinder to sharpen mower blade?

[seneca]

hello folks,
I've been given an old cylinder mower with a worn out rusty blade, and was wondering if I could use my angle grinder (small one, can't remember size details) to sharpen the blades. The thing is I've only ever used it to cut stone and metal, but not to sharpen anything. Could someone please advise me on what I need to get and preferably point me to a few links to help me out.
Many Thanks

 

[Burnerman]

The only blade you can sharpen is the bottom one.....the cylinder needs to be ground.
Something you can do.......notice to either end of the cylinder are adjustment screws.....turning them clockwise lowers the cylinder onto the bottom blade.
Do this ( machine running) until the cylinder just touches, and then back off a fraction. That's the adjustment set.
Then, machine tipped back on its handles - engine off- rotate the cylinder slowly by hand.....the cylinder must clear the bottom blade by the same amount all the way along. If it's miles out, then it's regrind time.
Unless you are adept with the angle grinder, a new bottom blade is probably best, but there's nothing to stop you giving it a go!
John

 

[seneca]

Thanks John.

I have a few old tools with rounded, blunt and chipped edges and thought I could have a bash at improving them. Some of the tools have a bit of a sentimental value and whilst they don't work perfectly, they're still good for a few more years.
I have an angle grinder and have heard some folk use them on worn blades, so thought I would have a go. Only thing is I've never used them for such a purpose, only ever cut with them. Looking at a few websites they all tell which blades cut what, but none mention sharpening. Hence, I thought I had better ask, as I've only got cutting blades. Any advice on the right disk would be appreciated. Thanks.

 

[Burnerman]

A typical grinding (not cutting) disc is the one to use......typically 115mm diameter and 6mm thick.
Hold the bottom blade tightly in a vice, and grind it to an edge following the original angle. You haven't much to lose by giving it a try!
Do check the cylinder clippers though.....on the cheaper mowers they seem to be made of plasticine and bend even if a twig is picked up.
John

 

[EddieM]

hmm, personally I think using an angle grinder will make an absolute pigs ear of it.

 

[Burnerman]

With care, you can get by, Eddie - so long as the cutting edge remains straight, and the blade isn't curved.
It's an old machine after all - but a replacement blade is usually around the £20 mark.
For rotary mowers it's much the same, but if the grinding is heavy, there's the balance to consider.
John

 

[Dave54]

The other old tools you say about, depending on what they are, probably would be better grinding on a bench grinder, and the tool brought to the grinding wheel. Angle grinder isn't really the tool. If you do try grinding edge tools they need to be kept cool by not pressing too hard, and by dipping in water if necessary. It they get hot enough to discolour the steel it spoils the hardening.
Lidl had some bench grinders for under £20 recently. I notice our local shop still had some yesterday.

 

[Bilabong007]

To sharpen anything I would use a good quality bastard file. Only ever apply pressure with the forward stroke of the file. Clean it often with a file card.

This way you can take out most of the nicks carefully. It takes time but finishing with a stone gives a great edge. I use a Lansky stone that allows me to bring the stone to the tool.

Can pretty much shave with my axe. Good thing as missus uses the damn razor for her legs...

Graeme