Repair SUPER SIZE Tilt Bracket for 90T Excavator | Line boring & Machining
how you going guys Kurtis from Cutting Edge
engineering so today's job we have a head bracket off a tilt Bucket from a 90-ton excavator
so you did hear correctly this actually suits a zx890 Hitachi Excavator this is a special purpose
machine it does have three different attachments that it uses it has a standard tooth bucket for
the heavy bulk earthwork it also has a ripper used for ripping the ground to loosen things
up so it can then be loaded into a truck and then it has its tilt bucket for doing final
nice precise trimming work and they are all attached to the machine using a quick hitch it's
not very common to see a quick hitch on a machine this size because they are generally used for
bulk earthworks by adding a quick hitch onto any excavator you do decree increase the digging power
of the machine because you have essentially made the Dipper arm longer so when you go and add
a quick hitch plus a tilting bucket like this you do decrease its horsepower and its breakout
force the way this is sitting on the floor it is actually upside down so in real life when this
is attached to the bucket it is up the other way these two pins connect the head bracket to
the quick hitch and this position here connects the head bracket onto the bucket so the repairs we
need to do we do have some line boring to be done on the main pivot of the hitch and we also have
some cracks to repair and one boss to weld back in place and then line bore that position as
well so the main pivot position is not actually totally destroyed like we usually have to repair
it is simply just worn out and the reason it's worn out is maybe the bush wasn't tight enough
in the main pivot position to start with so it's no wonder it's worn out because there is a all
the machines horsepower going through this part of the hitch and the repairs we need to do up
here this is where the Tilt cylinders attach to the Head bracket and then attach to the bucket
in order to tilt it left to right so we do have these spaces on the inside of the ears one of them
is cracked and one of them is completely missing these aren't really a structural part these are
just to hold the cylinders in the center of the hitch and the reason one of them broke off is the
pin actually broke and then everything started working itself loose and it broke the spacer
off so to get started on the repair I need to gouge out the crack on this spacer I then need
to remove the weld material on this side and then reattach that spacer so we'll take it outside
to our outdoor welding area and get started righto guys so we're going to start the line
boring now I need to set up the boring bar central to the services we are going to be
boring I can't use the outer areas because they are slightly worn out so I am going to
use the inner shoulder where the bush actually stops against because it will be the closest
concentric machine surface that we can use so to do that I would generally use my centering
cones Unfortunately they are about three mil too small in diameter to actually pick up on
that surface so what I'm going to have to do I'm going to have to machine up two new centering
cones so we can get this repair started [sqwuaaaak] just wait [sqwuak] sit stay leave it ah [giggle] [sqwuak] oh no [Laughter] righto guys so we're about to get our line borer
set up I could go and use my standard sir meccanica mounts in order to do this
but I just got my new shop made mounts back from nitriding so we're going
to put those together and use them so you can see the nitriding came out really good on these
I'm really happy with the outcome so we're going to take them over to the press
we're going to install all the bearings install the snap rings and then we can
finish assembling the bearing mounts so I'm going to be installing four bearings
in each of the mounts that is different to the way the sir meccanica mounts come
standard they come with two bearings and then a sleeve that joins those two bearings
to act as support for the boring bar but over time debris and grit and stuff like that
gets down inside the sleeves and it does end up opening them up and they do end
up a little bit loose so I've actually changed out the standard mounts with four
bearings because it lasts longer the machine is more accurate in my opinion so let's get
stuck into fitting all the bearings so that is our shop made bearing mounts fully assembled
we've put all the bearings in put the snap rings in and attached all
the standoffs I'm really happy with how they turned out now I get to use
them so let's go and get them set up righto guys we've completed our bore welding
on either side of the hitch while they are cooling down I'm going to get on to welding
up the crack that I gouged out earlier so we've gouged out that one it just needs
to be welded but the spacer on this side was totally missing ideally I would just
replace the spacer but because it is only a spacer it doesn't really matter what sort
of condition the old one is in so I'm going to quickly clean that up so we can then
reattach it once it's welded back on there it's still going to serve its purpose so
we're going to get stuck into that so now that we've got that repair completed we can
get back onto Line boring the main pivot position oh come on where have you been the last couple of days [chirp] haven't seen you for a while [squawk] what's this what's that that's it dude no more for today [squawk]
no go catch a bug [chirp] yep righto guys so we have completed the repairs
on this hitch so we have line bored the main pivot position we did repair the crack in that
spacer we reattached the one that was broken off and we line bored that pin position as well
so there is one more thing that I need to do and that is to freeze fit the bushes that go in
the main pivot position these are the bushes that I need to fit I will be using liquid
nitrogen to get them to shrink down enough to then be put into the hitch there is about
0.2 of a mil interference fit which is about eight thou so I don't want to get this
wrong because these bushes are about fifteen hundred dollars each and I don't want to have to
go and cut one out today so let's get on to that yup that shrink enough righto so that went about as good as you could possibly
hope it to go we did have a bit of a binding issue on the other side but all in all it went in really
well the job is now completed thanks for watching pheeww [giggle] my hat on straight
it's a bit munted is it really yeah there's like a crease on that side
you should go get one of the new ones this is the tilting part of the
this is a head bracket that does the tilting oh [ __ ] me I've lost it right so this bucket is actually for a ZX
this is not a bucket oh [ __ ] me swinging ah what what are we calling this wait how'd you start that right oh what are we saying [ __ ] where are we going with that
oh my lord and the the hmmm [giggle] huuuh well yeah it's pretty much it are you gonna restart I am yeah ready right oh so that went really really well
you couldn't have expected uh [ __ ] can you try and avoid the really's
yeah right oh so that went re just one really
[Laughter] yeah one really is enough right ready so now I get to use them so let's go attach them [giggle] yeah well what happened what happened
I lost it you ready
right so these two pins here the hmmmm
[giggle] right so these two pins connect the Tilt oh for
my Jeebus help me lord [Laughter] he can't I got it I just said it wrong I'm just going to start again again generally the weakest link's going first
so this is the weakest link goodbye [Laughter] oh right
[wet fart car] you've got to be [ __ ] kidding me huuuuh
I was not doing that on purpose what the hell he's trying his best it's never gonna die this thing's strong I'm impressed that is a strong squeaker hello did you kill it yet hang on where you going oh oh still squeaking come on let's go
