Let's take a look at the six-bladed cartridge that comes as standard with the Stirling
and to get a closer look at it of course I can drop it out really quickly
and take a closer look at it so this is the one that I use on my lawn so it's had quite a lot of
use already but the ultra-change cartridges are a little bit more robust so I've got a thicker
six millimetre thick blade and that's made out of some really special materials to make that
hard and the same applies to the six blades on the cylinder as well these are all special
steels and they're also heat treated. The reason they need to be really hard is we need to keep
a sharp edge as long as we possibly can and also by making the blade stronger they're less likely
to chip or bend when you hit stones which is sort of inevitable. Where do those stones come from on
the lawn that's the question I always have but they always seem to appear and the sure-blade
that we fit onto this like I say is incredibly hard and of course that is where the shearing
action occurs between the rotating cylinder blade and the actual solid sure-blade on the underside.
To get it adjusted this is really ideal if I can get a blade that cuts grass really
cleanly and it really has I'm going to say no contact here and the adjustment is all
done on the screw settings just here which adjust the cylinder down to the bottom blade.
Although it's always really nice when you can show these mowers cutting paper it really
illustrates the scissor action depending on the type of grass that I have and the
time of year that it is I don't actually need to have the cylinder that tight as long as it
cuts the grass cleanly so I always adjust it as lightly as I possibly can but at the same
time knowing 100 percent that it's cutting and shearing the grass completely cleanly .
This six bladed cylinder really cuts well and it mows down to five millimetres height of cut and
that is adjusted on the Stirling with this very clear height adjustment just here. If I use the
right hand scale I can choose exactly how many millimetres height of cut that I can select.
In certain types of grasses the grass benefits from a scalping operation and scalping means
that you take the grass down really really low and it's normally part of a renovation process
and by taking the grass down low it means that when I do any cultivations or over-seeding that
the blades of grass are not getting in the way of the debris throwing into the grass box and
it's not stopping the blades from going down into the thatch layer so I can use this down to five
millimetres high and it's really surprising how cleanly that cuts the grass down very very low.
Another practice that I like to follow as well is in order to keep the blades really
sharp and remember these aren't sharp like knives what they are is really sharp corners
that are working together to actually shear the grass is using a back-lapping
operation and we have a video on that that shows in detail how you back-lap and with
a 24 millimetre socket on a power drill I can turn the cylinder not in the cutting direction
but in the backwards direction that's where the back lapping comes from and I can use a grinding
paste which I apply with a brush and I slowly turn that backwards and what it does on the
rear edge of the blade it puts it really really square and also on the bottom blade as well and
that just means that I can keep a really sharp edge and absolutely minimal contact and at the
same time cut the grass as cleanly as I can so that the injury sight is as minimal as possible
So that's the six-bladed cylinder I think you'll all enjoy that in this
mower and you'll really get a super clean cut with it.
So these are the grass clippings that I've just cut now with the six bladed cartridge
the clippings you can see are quite long I'm looking at 10 to 12 millimetres and that's
that's quite a lot of grass because I'm mowing at 15 millimetres high so in sometimes I'm taking
sort of 50 percent of the grass plant off at any one time which is which is too much you
know we should be cutting a third of the grass plant off at any one time. So these are the six
bladed cylinder handles longer grass clippings really well and you can see that it throws it
all into the back of the box so we're going to tip this out now and then we'll compare this with the
other uprisings that we get from other cartridges. So if I really want to scalp the grass down as
part of my cultivation techniques or if I want to maybe overseed or in certain types of warm season
grasses a good scalp every now and again seems to benefit the grass. So first thing I've done
is taken the actual comb off the front of the machine this will dig into the ground because
I'm now going to be mowing so low that that this would just dig into the ground and the roller will
just spin so a 13 millimetre spanner and remove the screws on both sides put them back in the
rake so that you can find them when you come to put it back on again. Next thing I'm going
to do is lower the height of cut down to five millimetres and I'm going to be using this green
scale on the right hand side I'm not going to be using the cultivation scale that is in white.
I'm going to turn the speed down to slow so that I'm going to go
one click of nine so from off position I'm just going to take it one further
click and then what I'm going to do is start the blades and off we'll go
[Music]
So now you can see that's really scalped down this is 15 millimetres high this is down at
five millimetres high so taking 10 millimetres off and now that's really made it easy if I'm going to
cultivate or overseed now it's really made it easy to be able to get the seed to contact the ground
if I want to mow lower than five millimetres and scalp it even
further down then I'll need to use the 10 bladed cartridge which we'll talk about
later and that ten bladed cartridge because the blade is slightly thinner
at the front means that I can mow that down as low as three millimetres high