Repair TRUNNION for Caterpillars BIGGEST Dozer! | Milling & Welding
how you going guys Kurtis from Cutting Edge
engineering today's job we have two d11 blade lift barrels in for repair these barrels are
off a d11 dozer and it is caterpillar's biggest bulldozer they manufacturer and what these
do these lift and lower the blade while the machine is in operation and if you remember from
last week's video where we repaired the yolks the yolks attach onto these cylinders so if you can
imagine the barrel standing vertically on the dozer the forks of the yoke go underneath the
trunnion mount there are two caps that then go over the trunnion mounts and get bolted onto the
yoke they're not off the same machine but they do belong to the same customer so these aren't in to
be re-barreled these are in to have their trunnion mounts repaired these mounts are always going to
wear out because it is metal on metal contact you can fit grease nipples to these joints in order
to aid with lubrication but it's just the nature of the way things work and what the machine is
doing they are going to wear out so there are bearings that then get fitted onto the trunnion
mounts they are a sacrificial piece of material that is supposed to wear out but over time the
trunnion mounts do shrink in size because of the constant hammering and the bearings just don't
fit anymore they end up falling off and that's what's happened here but these went a little bit
further than they were supposed to and they are quite worn out and something I did notice these
have actually been repaired before and the reason I can tell that is there is centers in the end of
the trunnion mounts that is not a factory thing that is done from someone doing the exact same
repair we're about to do trying to set up off a surface that isn't round anymore or you've just
welded can be quite difficult so putting a center in each end of the trunnion mounts it's really
going to help with setup and it's also going to help for the next guy that has to repair them so
you may have seen in a previous video where we've done trunnion mount repairs before and that was
because we were doing a complete cylinder rebuild so the cylinder was completely disassembled and
we were able to spin the trunnion in the lathe between centers but in this case because it's
still attached to the barrel we can't do that so ideally you would set these up in a machine
like a horizontal borer where you can access both sides after turning around the table I don't
have a horizontal borer yet and I cannot use the Kitchen and Walker because it is still a work
in progress so we're just going to have to do these in our milling machine so we're going
to be using our shopmade v-blocks that have a key in the bottom of those so they locate into
the table I will then use an edge finder to find the center of the V blocks which will save
me trying to find the center of the barrel because of the shape of the trunnion and how tall everything is
I am going to have to use one two three blocks in order to pack the barrel off the V blocks so
the trunnion is not sitting on the table and because they are all machined surfaces the barrel will automatically
find the center of the v-blocks if you're wondering why I don't
have a v-block set up on each side of the trunnion mount that is because this side of the
cylinder tube is actually a larger diameter than that side so the bottom end is machined down
for the trunnion to slip over it when it is manufactured they do not machine the top side so
it is slightly bigger in diameter and if I was to have a v-block on this side the barrel would
essentially be sitting a little bit on the piss so now I'm just going to use an
alignment center in order to pick up on the center point that has been
drilled into the end of the trunnion and that's just how easy it is to
get a barrel in the center line of the machine when the trunnion mount
has that center hole drilled into it now that's in alignment we're going to
tighten up the clamp so nothing can move the tool we're going to be using is our
adjustable boring head it does have the external part of it so we can go on the
outside of a job and the insert we're going to be using is a ccgt so I know
that does look a little bit shop made I did have to cut and turn the end of the
tool holder because I didn't have the right one for another job and it just happens
to work out perfectly for this one too need a bit more off right so that cleaned up
I ended up removing about a mil off the outer diameter but there's not
quite enough material been removed in order to put a substantial thickness of
a weld layer there so I am going to reduce it just a little bit more so the weld
layer will end up a little bit thicker so yes you could just weld this up and
machine it back to spec but in my opinion that is cutting a corner I prefer to
machine down that surface so everything is nice and round again and I remove all of
that dirty material and then I put a fresh layer of well material there before machining
it back to spec that way you have one material around the entire diameter and you don't
run into hard spots or you don't have a mixed match in materials and their tensile
strengths so that's why I do it this way right so I've got the OD turned to size
before I flip it over I am going to fix up the hole that's been drilled into the end of the
trunnion mount because whoever did it before me did not use a center drill he just used a
jobber drill using a center drill it's much easier to get them in alignment so we'll
clean that up and then we can turn it over so I'm about to flip this it's going to be really
easy to set it up because I do have center holes in the end of my trunnions if you don't have
center holes there are other ways you can do it one of those methods is using the bolt holes on
the head flange and a level screw the two bolts into the head flange sit a level across the top
of it take the reading on what it is you also use a tape measure from the head flange back to the
center point of your tool and when you flip it over as long as you get the measurements matching
up and the level matching up it's going to be good another repair option would be
you could machine the mounts down undersized machine up a custom sleeve to then take
the place of the original bearing but that's not how I like to do things I like to put all components back to an oem specification that way
if anyone is to purchase this machine later on or another repair needs to be done they can simply
purchase OEM parts off the shelf and don't have to worry about getting anything custom made
or modified to get their machine back to work righto guys so that is the other side
machined it didn't fully clean up because there was a fair bit of wear in that particular
area so rather than cut the entire diameter down just to clean that up I'm going to grind
that area there and I'll just put a little bit of heavy weld in that spot if I was to
machine it down so it cleaned up that would mean a lot more welding around the entire
diameter and that's just not necessary so we'll get this out of the machine and
get the other one up to the same stage so that's our second one done we're going to take them over to our welding area
and get them set up for welding right oh so there's a couple of ways I can
weld these up I can put them flat on a pallet and weld horizontally across the mount or
I can stand it up on the trunnion mount and then walk around it and weld it up but
this time I want to try something different so ideally having this in a more vertical
position and me standing in front of it would be perfect but the machine is struggling
a little bit to rotate it around because one end is slightly heavier than the other
rather than break the machine I'm just going to weld it the way it is I'm going
to use the forklift tyne as a steady for my hand to rest on and I have an extra
long handpiece for my MIG welder so I can stand out of the way this can spin and
we'll get a nice even well build up so the wire we're going to be using it is er70 S6
copper free we will be backing that up with Argo Shield Universal which is 80 percent Argon
10 percent CO2 and 10 percent oxygen we're running that at around 20 volts
and about 4.7 meters of wire a minute righto so that actually went really
really well although it might have looked uncomfortable it was actually not too
bad so let's crack on with the rest of them righto so that is our second trunnion fully
welded using the positioner is definitely a good way of getting consistency in the
weld layer I would imagine doing a d10 or a D9 would be a lot more comfortable and
a little bit easier because they are a shorter barrel so these are far too hot to
machine at the moment we're going to give them a couple hours to cool down and then we
get them set back up in the mill go outside ready hey whose a good boy good boy go on on your bed righto guys so the welding has cooled down
enough we can get the first barrel set back up in the milling machine and then we can
start machining the OD to suit the bearing so we are aiming for a 0.1 interference
fit our finish size is going to be 88.53 which will give us our 0.1 Crush so I'm
going to take a roughing cut so I can get a measurement so we can then determine how
much I need to remove to suit the bearing righto so after our first roughing cut we landed at
93.8 mil so we've still got about five mil to come off because the tool is hanging
so far out of the boring head I'm going to take each pass at half mil depth of cut
which is one mil overall if I tried to go anymore I would probably end up breaking
an insert and getting too much chatter so I'm about to do my final cut but before
I go and adjust the boring head to the final dimension I am going to take a spring pass
because the tool is hanging out so far it can cause tool deflection so rather than over
cut it or undercut it I'm just going to take a spring pass at its last dimension I
will run it down the job a little bit to clean up the surface then I can take
my measurement and adjust it from there our current measurement is 88.72
we do need to remove about 0.15 of a mil in order to bring it
to the crush size for our bush righto so our final dimension come
out spot on I'm really happy with that what I'm going to do now is change out
the tool so I can put a chamfer on the top edge which will act as a lead for the
bearing to be fitted onto the trunnion mount and then I'm going to flip it over and
get the other side up to the same stage righto guys so that is the machining completed on
our first barrel I still need to clean up the radius in the bottom corner of the
trunnion mount but I can't do that with the milling machine I don't have the right
tooling so I will end up doing that with a poly curve wheel on a grinder so let's get this
one out of the machine get the second one set up and I've gone ahead and completed the
machining on the second barrel as well with all of that done I can now grind
up the barrels and install the bearings because we can't shrink down the trunnion
mounts with liquid nitrogen we do need to expand the bearing in order to get
them to fit so using an oven is a nice controlled way to get an even heat
throughout the entire bearing and while that's heating up we're going
to clean up the bottom radius around the trunnion mounts we're going to be using
a wheel called a poly curve sandpaper goes all around the edge of the wheel and
they're really good for cleaning up welds for handrails and lots of other things they're
just a very handy wheel for this sort of work righto so I've tried that twice and it's just not going on
to the trunnion mount so I'm going to give it a little bit of help using
the oxy and LPG it's not going to take much to expand it just a little bit
further so it'll just slip straight on so that's this one completed unfortunately the
customer only supplied us two bearings there is supposed to be four in order to do both of the
barrels we don't keep them in stock so we're just going to grind up the other barrel ready to go
and the customer will fit the bearings themselves right oh guys so the job is done for about a day's
work this has been a very economical solution for our customer and this repair should last as long
as the genuine parts would providing they keep up with their preventative maintenance and change
out these bearings when they do wear out these components should last the life of the Dozer so
that's another job done thanks for watching right you ready yeah ready yep you ready sure
ready yeah just and and what wait how am I starting that
wait what how'd you start that ummm hmmm ohh [ __ ] meee [ __ ] where'd I go with that what the [ __ ] did I call that wait for the train to [ __ ] off it's [ __ ] off but in my opinion that is
a half-assed job that is cutting a corner [air compressor] I'll put a bit of a heavier
weld layer there and then [air compressor again] I'll put a bit of a ugggh I'll pita uh pit
I'll pita ohhh PIT [laughter] what
[Karen] hang on that got confusing so [brain offline] [Karen] I need 10 years to edit this I'm just gonna say it all again
okay ready yeah [ __ ] yeah that was it size matters [tick tock tick tock] [DING] [GASP]
[wheezing laugh] [sigh] [BANG] ohhhh [gasp] [Karen went to church] [Karen] what the hell it's not on there [giggle] [Karen whispers] looks like a face [giggle] [Karen whispers] he's looking for this [Karen] what color
purple [Karen] how long
a metre [Karen] so you mean this one
that's the one [laughter] [giggle]
can you see OH [laughter]
