hi i am paul brody this is my shop welcome i was on facebook recently and i discovered
that we have a situation locally anyway we have a shortage of brake boosters you break boosters
i know that no one else except me is going to fix that problem right now anyway so that's our
that's our mission today i have metal we have metal and i have laid out a couple here
we're going to do a very small run i made i was in my shop yesterday i made up a fixture this
is the fixture that's going to get used on the lathe and the mill to make you break boosters and
you will see how that works a little bit later so the first step is to drill
four holes one two three four and these holes are at the very end of the slots
so let's head over to the mill and mark out some holes what i've done is i got a red felt pen
i marked a circle there because if i just go off the slot like that it's hard to know if i'm in the
middle of the of the radius on the end when i mark a circle i'm going to the middle of the circle
in 1988 i was making brake boosters and this is basically how i was made how i was making
them i've used a fixture the lathe and the mill and and then we hired a consultant and he says
you're doing all that by hand basically you need a cnc so that's when we got cnc
up until then i had no contact with cnc shop so what i'm showing you now is how i used to make
brake boosters back in 88 over 30 years ago this is what i did so this is the six millimeter hole
okay now we go back to the mill let's go here it's not a very long walk at all i'm going to use this
little end mill this is a 3 16 end mill can you see how it's smaller can you see how there's space
there see how i can rock it back and forth what i'm going to do is i'm going to i'll take a
cut right down the middle it'll join those two holes make a slot and then i'll go up one side
and then i'll go over and down the other side and i'll have a nice six millimeter slot
that's a pretty nice slot
so
i confess i was in my shop yesterday i made eight more yesterday so now we have
a total of ten we're doing a run of ten so i've drilled two holes here and i'm
going to put the bolt the allen screw through and the allen screw goes at the very far edge
and so we're going to bolt these down and then we're going to machine them
all at the same time that's the plan so let's see how this works out
our first step on the lathe is to do the outer radius it's going to
be an interrupted cut because halfway there's going to be nothing and then it's going to cut
so we'll do the outside cut and then we'll i'll take off this this piece of round stock
and we'll hold this in the middle of ice and we'll use a cutter on the inside that's the plan
i can still see my felt pin mark on the outside so i've got a little bit more to go maybe another
i'm going to say 50 thou
i'm taking cuts of half that 25 thou cut that's how much metal is being removed at a time
okay that's all the machining and the lathe so we'll take this off now we'll go to the mill
can you see how that's basically on the line now i bring it over to this side that's on the line
so that's i think that's close enough to start and i can make adjustments as i go all right
that's going to be good so i've got the tool right out to the line i need to i need to back it in
just a little bit because i don't want to take that big of a cut right off the bat
if i turn this half a turn that's a 50 thou cut there we go 50 thou cut
if i just go off the felt pen that's not very accurate so what i want to do is to
measure somewhere around there it's kind of hard because this is on a taper but i can get an idea
call that zero and then go to this side and this side is less
50 thou less because if i lock that see it doesn't go in there
so this side is 50 thou less so i'm going to move everything over there half that i'll go i'll go 25
so handy having a digital readout there we go
see that it's a carbide end mill and the end is a bit worn but it's got the flutes
long enough that it's going to going to make a nice cut there it's taking a small
cut
i'm climb milling going this way
it's going to make a smoother finish that's what the end mill's done it's made that smooth
but there's still a little bit there so i've got another 15th hour to take off
i think that's as about as good as we can get i want to drill some holes to add some lightness so
what i'm going to do is to bolt this existing booster that i have
on top of these and then i'll just i'll start the holes that's what i'll do
wow almost looks like i know what i'm doing
that's not bad this one's cnc and these are all manual and you can see how
how it matches up this little little fender hole in the middle so that's a
5 mil thread so the tap drill is 4.2 you knew that i'm starting the holes only and
then after i start the holes i'll take off this booster and then i'll drill them through
we need to round around the corners now so what i have here is a tool i bought years ago it's kind
of like an end mill except it's got a radius we're going to take these boosters off the fixture we're
going to put a couple bolts through hold that in the middle of ice then by going back and forth
you see how that mat well it's not a perfect match of the radius but this is cnc
this is going to work fine on the boosters that we're making right now
let's go to the mill and uh
we'll see how how well i can use this tool
i've got a very small ridge there but i'll just see how my nail is catching that ridge
but i can file that off that's not going to take much at all
so i've got a little bit there to file see how my thumbnail hangs up and then over here
don't have my good pointer see how this one here is a little bit higher
so that's a pretty good average a little bit of filing but not much
fresh out of the fixture they got oil on them and stuff but you get the idea
i have a small smooth file i'm just gonna
do a little bit of blending i'll call it blending not really taking much off at all
it's a pretty smooth file
so that's what it looks like it's pretty smooth there's no sharpness that i can see
so what i'm going to do now is to i have to knock this is pretty sharp on the edge
so i'm going to knock off all the corners give them a little bit of a radius
and then i just got to
take the burrs off there i could hold this in the vice too but there we go
this is anchor lube it works well on aluminum for tapping
put a little bit on there there we go so with my eye chromometer i want to hold it at a right angle
get it started and that looks good so then i just wind down i got a spiral point tap
so i don't have to go back and forth i can just go straight down
and the chips all come out the bottom and that's it that hole is tapped
on the surface we got a few little scratches nothing major but a little bit of scotch brite
it'll polish it up fairly well you can also use some fine sandpaper or emery cloth like 400
so you can see still see there's a few little marks there but
i'm not going for perfection right now i'm just trying to show you how we would often finish up
yeah if i was building a show bike i'd take some
400 paper and i'd sand out all those little marks there but for this it's it's fine it'll work
and that's how we build a brake booster that's how i used to do it thank you for watching if you like
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you