Sharpening garden shears with an angle grinder?

[mikeha...@gmail.com]

I recently saw a couple of youtube videos showing variations on
sharpening garden shears with the type of thin disk used on angle
grinders.

The first video
https://www.youtube.com/watch?v=IQ5Fu7TYuGQ
mainly shows how to build a metal jig for holding the angle grinder in
an engineering vice, after which various sharpening and wire brushing
operations are carried out using this set-up.

It looks impressive but I remember hearing several scare stories about
grindstones and grinding disks which disintegrated with quite
destructive effects when not used as intended.

Are there really suitable disks available for angle grinders, on which
the sides of the disk can safely be used for grinding metal objects?

The second video
https://www.youtube.com/watch?v=GgD2O6yj7yM

Shows a more heavy duty bench mounted setup also with a thin, large
diameter disk, which seems to work well for grinding with it's flat
face, rather than the edge.

Which, if any of these methods are considered reasonably safe?
--

Regards,

Mike Halmarack

[Tim Watts]

Dicking around with angle grinders like that is stupid when 20 quid will
buy you a cheap and cheerful bench grinder:

http://www.toolstation.com/shop/p/b/s/d40/sd3353/p27298

OK - it's not going to be a precision bit of kit - but it will do the
job in hand way better and much more safely (they go relatively slowly
compared to an angle grinder).

I don't have a bench so I screw mine to the top of an old flat tree
stump when I have a mower blade to sort out :)

[mikeha...@gmail.com]

On Thu, 17 Jul 2014 16:15:49 +0100, Tim Watts <tw_u...@dionic.net>
wrote:

I do have a normal bench grinder. I find 2 problems with this method
when I want to grind a long blade evenly. One is that the blade angle
and position tends to waver a little during each pass. The body of the
grinder also tends to block a smooth pass of the blade across the
edge of the stone.

With the angle grinder method the large surface area of the disk seems
to help to keep the shear blade at a constant angle steadiness of
pass.
--

Regards,

Mike Halmarack

[Tim Watts]

On 17/07/14 16:40, mikeha...@gmail.com wrote:

> I do have a normal bench grinder. I find 2 problems with this method
> when I want to grind a long blade evenly. One is that the blade angle
> and position tends to waver a little during each pass. The body of the
> grinder also tends to block a smooth pass of the blade across the
> edge of the stone.
>
> With the angle grinder method the large surface area of the disk seems
> to help to keep the shear blade at a constant angle steadiness of
> pass.
> --

I think a more profitable solution would be to make some sort of guide
(mounted either side of the grinder) that would help you pull the blade
over the bench grinder :)

The angle grinder method sounds dangerous - as your face would be facing
the business end of the grinder more than usual.

[Nightjar]

On 17/07/2014 17:23, Tim Watts wrote:
> On 17/07/14 16:40, mikeha...@gmail.com wrote:
>
>> I do have a normal bench grinder. I find 2 problems with this method
>> when I want to grind a long blade evenly. One is that the blade angle
>> and position tends to waver a little during each pass. The body of the
>> grinder also tends to block a smooth pass of the blade across the
>> edge of the stone.
>>
>> With the angle grinder method the large surface area of the disk seems
>> to help to keep the shear blade at a constant angle steadiness of
>> pass.
>> --
>
> I think a more profitable solution would be to make some sort of guide
> (mounted either side of the grinder) that would help you pull the blade
> over the bench grinder :)

+1

--
Colin Bignell

[DerbyBorn]

"Nightjar <\"cpb\"@" <"insert my surname here> wrote in news:Cq-
dnSQbkJsyn1XOn...@giganews.com:

I use a file on my 40 year old shears.

[meow...@care2.com]

Its quick & easy, but much safer to use a grinding disc (6mm or so thick) than a thin cutting disc. If you use a cutting disc, use the edge rather than side, and keep the disc side load to near zero.


NT

[Davey]

I inherited, and still use, something like this:
http://cpc.farnell.com/draper-tools/65787/300mm-sharpening-stone/dp/TL00483?in_merch=Products%20From%20This%20Range
and it works just fine, thank you.

--
Davey.

[mikeha...@gmail.com]

To say there's not much opinion in favour of the angle grinder method
really is an understatement.
--

Regards,

Mike Halmarack

[Phil L]

<mikeha...@gmail.com> wrote in message
news:qmnfs9d77eu5408mt...@4ax.com...

I've sharpened lots of things using a small grinder.
It's not very good as it tends to be a very uneven 'run' - the angle of the
grind changes considerably, especially over a long run like shears.

They're ok for cold chisels, bolster chisels etc, maybe even a rough axe,
but they seem way too fast to me, create too much heat too quickly and
generally don't do a very good job.

[meow...@care2.com]

> To say there's not much opinion in favour of the angle grinder method
> really is an understatement.

I use it, its very fast, and safe if you take the usual precautions, ie avoid side loading the disc, stay out of line of fire, avoid getting the disc damp, use eyewear etc. 10 or 20 seconds a piece makes it practical for bulk sharpening.


NT

[Brian Gaff]

I'd not want to try it I know that much.
Brian

--
From the Sofa of Brian Gaff Reply address is active

<mikeha...@gmail.com> wrote in message
news:qmnfs9d77eu5408mt...@4ax.com...
>

[meow...@care2.com]

On Thursday, July 17, 2014 8:08:49 PM UTC+1, Phil L wrote:

> I've sharpened lots of things using a small grinder.
> It's not very good as it tends to be a very uneven 'run' - the angle of the
> grind changes considerably, especially over a long run like shears.
> They're ok for cold chisels, bolster chisels etc, maybe even a rough axe,
> but they seem way too fast to me, create too much heat too quickly and
> generally don't do a very good job.

Angle really comes down to technique I think. I hold the grinder still and move the workpiece across it.
Way too fast - but if you're doing piles of stuff its great.
Heat: technique. You've got to keep the workpiece moving and the pressure feather light. If removing bulk metal I give the workpiece a break to avoid overheating.
End result: For knives, drill bits etc its great. For planes or razors forget it, for chisels meh but it'll work. Axes aren't ideal due to their weight: quick blade movement, feather touch and a heavy axe don't mix so well, but it can still give a more than sharp enough edge.


NT

[Nightjar]

I have one of those too. However, keeping at exactly the right angle
throughout the sharpening is a fairly skilled job. Putting a guide on a
grinding wheel removes the need for the skill.

--
Colin Bignell

[Tim Lamb]

In message <zu-dnTlVueYrs1XO...@giganews.com>, "Nightjar
<\"cpb\"@" <"insert my surname here>"@?.?.invalid> writes

My method is to fix the tool in the vice.

Angle grinder with grinding rather than cutting disc. Used disc so the
contact face is convex. Visually adjust contact angle and allow time for
heat to dissipate.

Any resulting *wire edge* can be tidied with the dry carborundum stone
above.
>

--
Tim Lamb

[Mr Pounder]

"DerbyBorn" <Some...@Nearhome.com> wrote in message
news:XnsA36DC24F8399ATr...@81.171.92.236...

So do I. The job only takes me 10 minutes and is probably quicker than
finding and setting up an angle grinder.

[Capitol]

meow...@care2.com wrote:
> On Thursday, July 17, 2014 7:56:29 PM UTC+1, mikeha...@gmail.com wrote:
>> On Thu, 17 Jul 2014 11:11:34 -0700 (PDT), meow...@care2.com wrote:
>>> On Thursday, July 17, 2014 3:50:13 PM UTC+1, mikeha...@gmail.com wrote:
>>>> I recently saw a couple of youtube videos showing variations on
>>>> sharpening garden shears with the type of thin disk used on angle
>>>> grinders.
>>>> The first video
>>>> https://www.youtube.com/watch?v=IQ5Fu7TYuGQ
>>>> mainly shows how to build a metal jig for holding the angle grinder in
>>>> an engineering vice, after which various sharpening and wire brushing
>>>> operations are carried out using this set-up.
>>>> It looks impressive but I remember hearing several scare stories about
>>>> grindstones and grinding disks which disintegrated with quite
>>>> destructive effects when not used as intended.
>>>> Are there really suitable disks available for angle grinders, on which
>>>> the sides of the disk can safely be used for grinding metal objects?
>>>> The second video
>>>> https://www.youtube.com/watch?v=GgD2O6yj7yM
>>>> Shows a more heavy duty bench mounted setup also with a thin, large
>>>> diameter disk, which seems to work well for grinding with it's flat
>>>> face, rather than the edge.
>>>> Which, if any of these methods are considered reasonably safe?
>>>

>>> Its quick& easy, but much safer to use a grinding disc (6mm or so thick) than a thin cutting disc. If you use a cutting disc, use the edge rather than side, and keep the disc side load to near zero.

>
>> To say there's not much opinion in favour of the angle grinder method
>> really is an understatement.
>
> I use it, its very fast, and safe if you take the usual precautions, ie avoid side loading the disc, stay out of line of fire, avoid getting the disc damp, use eyewear etc. 10 or 20 seconds a piece makes it practical for bulk sharpening.
>
>
> NT

Works for me too.

[F Murtz]

mikeha...@gmail.com wrote:
>
> I recently saw a couple of youtube videos showing variations on
> sharpening garden shears with the type of thin disk used on angle
> grinders.
>
> The first video
> https://www.youtube.com/watch?v=IQ5Fu7TYuGQ
> mainly shows how to build a metal jig for holding the angle grinder in
> an engineering vice, after which various sharpening and wire brushing
> operations are carried out using this set-up.
>
> It looks impressive but I remember hearing several scare stories about
> grindstones and grinding disks which disintegrated with quite
> destructive effects when not used as intended.
>
> Are there really suitable disks available for angle grinders, on which
> the sides of the disk can safely be used for grinding metal objects?

Angle grinder disks are usually thicker and are designed to grind on the
side and edge, the thin ones are cutting disks and are not designed to
use on their sides.

[DerbyBorn]

Surely for a proper shearing action you don't need "sharp" edges - a close
contact between the blades is more important

[Roger Mills]

On 18/07/2014 18:05, DerbyBorn wrote:
> Surely for a proper shearing action you don't need "sharp" edges - a close
> contact between the blades is more important

I think you'll find that if you rounded off the edges, they wouldn't cut
too well!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

[DerbyBorn]

Roger Mills <watt....@gmail.com> wrote in
news:c2v141...@mid.individual.net:

> On 18/07/2014 18:05, DerbyBorn wrote:
>> Surely for a proper shearing action you don't need "sharp" edges - a
>> close contact between the blades is more important
>
> I think you'll find that if you rounded off the edges, they wouldn't
> cut too well!

True - but not "sharp" in the usual sense of the word. Shears usually have
quite a large angle rather than an acute edge.

["Pet @ www.gymratz.co.uk ;¬)"]

On 17/07/2014 15:50, mikeha...@gmail.com wrote:
>
> I recently saw a couple of youtube videos showing variations on
> sharpening garden shears with the type of thin disk used on angle
> grinders.

*HOW TO SHARPEN GARDEN SHEARS*

Garden shears have hollow ground and curved blades.
If you look at the inside face of blunt shears you'll see where the
mating surfaces have become "flat" and shiny. You can't rectify this by
grinding the bevelled face it's completely wrong and even if it does
make the shears cut a bit better they'll be useless again in no time
(and jam up)

You need to sharpen the back (hollow) of the blade not the front side.
Obviously this needs to be done on a proper fixed grinding wheel (with
support plate) so you can lightly and accurately shape the hollow
bringing it back into the cutting edge.
Once you've done both blades they might need a little "tweaking" with
the aid of a vice to adjust the very slight "curve" on the blade. This
is a curve in the direction of the hollow ground face. it has the effect
of ensuring the cutting edges have the right pressure at the blade
contact point throughout the whole of the cutting stroke. It's this
curve/pressure that dulls the blade over time but it's how they're
supposed to work and it stops the shears jamming with vegetation etc
when in use.

Just because someone in overalls in a workshop does an "instructional
vid. and puts it on youtube doesn't mean it's correct. :)

Tip from my Agricultural mechanic apprenticeship years.
Grinding the WRONG face will trash a good pair of shears.

Cheers
Pete@
--
http://www.GymRatZ.co.uk
Commercial Gym Equipment and So much more...

[mikeha...@gmail.com]

Evenly distributed hollow grinding on that scale is a bit of a tall
order for a d-i-yer of my skill level. Would it be almost as good to
rub the "flat" sides with a flat stone, placing extra pressure on the
back edge?
--

Regards,

Mike Halmarack

[stuart noble]

Or pop into Wilkos and get a new pair for �3.50? Not obviously different
from more expensive brands

[www.GymRatZ.co.uk]

On 21/07/2014 10:05, stuart noble wrote:

> Or pop into Wilkos and get a new pair for �3.50? Not obviously different
> from more expensive brands

which is why the shear and scissor man in the van that used to come
round once a month in my youth no longer exists and the way to sharpen
shears has been forgotten.

:)

[www.GymRatZ.co.uk]

On 21/07/2014 09:33, mikeha...@gmail.com wrote:

> Evenly distributed hollow grinding on that scale is a bit of a tall
> order for a d-i-yer of my skill level. Would it be almost as good to
> rub the "flat" sides with a flat stone, placing extra pressure on the
> back edge?

A flat stone on the flat (hollow ground)? side will reduce the hollow
even more making them worse (more blunt)
You could simply try putting the blade in a between to open(ish) jaws of
a vice and giving a bit extra bend on the blades so each blade is curved
in towards the other a little bit more. Just tweak a little in one point
then move the blade along a bit and tweak again and so on to give an
even curve along the blade length.

I've done this on a few pairs of shears to get them working again in the
absence of doing the job properly.
:)

[mikeha...@gmail.com]

Tempting but I'm getting fed up of throwing such things away.
--

Regards,

Mike Halmarack

[mikeha...@gmail.com]

Thanks. I'll give it a go.
--

Regards,

Mike Halmarack

[Davey]

On Thu, 17 Jul 2014 15:50:13 +0100

mikeha...@gmail.com wrote:

>
> I recently saw a couple of youtube videos showing variations on
> sharpening garden shears with the type of thin disk used on angle
> grinders.
>

> The first video
> https://www.youtube.com/watch?v=IQ5Fu7TYuGQ
> mainly shows how to build a metal jig for holding the angle grinder in
> an engineering vice, after which various sharpening and wire brushing
> operations are carried out using this set-up.
>
> It looks impressive but I remember hearing several scare stories about
> grindstones and grinding disks which disintegrated with quite
> destructive effects when not used as intended.
>
> Are there really suitable disks available for angle grinders, on which
> the sides of the disk can safely be used for grinding metal objects?
>

> The second video
> https://www.youtube.com/watch?v=GgD2O6yj7yM
>
> Shows a more heavy duty bench mounted setup also with a thin, large
> diameter disk, which seems to work well for grinding with it's flat
> face, rather than the edge.
>
> Which, if any of these methods are considered reasonably safe?
> --
>
> Regards,
>
> Mike Halmarack

My Dremel kit came with a jig to hold the tool at the right angle for
sharpening something.

--
Davey.

[meow...@care2.com]

On Sunday, July 20, 2014 10:45:42 PM UTC+1, Pet @ www.gymratz.co.uk ;¬) wrote:

Its very unclear what you mean.


NT

[Tim Lamb]

In message <bd56b0e9-2e5c-40e4...@googlegroups.com>,
meow...@care2.com writes

I think he makes a few points... quality scissors and garden shears have
their inside faces *hollow* ground. Grinding a *knife* edge will destroy
the intended shearing action. Wear with use will flatten the hollow
ground finish at the contact point.

Even the ubiquitous angle grinder will not restore this outside a
factory set up.

A cheap single line strimmer will do lawn edges; used vertically:-)
>
>
>NT

--
Tim Lamb

[Dennis@home]

On 27/07/2014 10:02, Tim Lamb wrote:

8<

>> Its very unclear what you mean.
>
> I think he makes a few points... quality scissors and garden shears have
> their inside faces *hollow* ground.

That contradicts my experience, if you use a stone to flatten them and
then sharpen at the correct angle they cut better and stay sharp.
AFAIK they are hollow ground because its easy and cheap.

Quite often the blades aren't bent correctly and then they don't cut.

[Tim Lamb]

In message <53d4dda7$0$54507$c3e8da3$4e33...@news.astraweb.com>,
"Dennis@home" <den...@nowhere.invalid> writes

>On 27/07/2014 10:02, Tim Lamb wrote:
>
>8<
>
>>> Its very unclear what you mean.
>>
>> I think he makes a few points... quality scissors and garden shears have
>> their inside faces *hollow* ground.
>
>That contradicts my experience, if you use a stone to flatten them and
>then sharpen at the correct angle they cut better and stay sharp.

OK. I am not a mechanical engineer or much of a mathematician... try a
limiting case where the blades are ground perfectly flat, the edge
bevelled appropriately and the blades curved slightly such that the
cutting point travels outward from the pivot as the handles are closed.

Contact between the blades is the full width such that any debris
prevents the cutting edges actually meeting. You can cheat by twisting
the blades slightly to give a clearance. This leads to wear and an
adverse bevel inside the blades which you cannot easily sharpen out.

>AFAIK they are hollow ground because its easy and cheap.
>
>Quite often the blades aren't bent correctly and then they don't cut.

Quite often someone else has used them for cutting grass laden with
abrasive soil:-(

--
Tim Lamb