hi i'm paul brody mitch is behind the camera over my shop welcome
we're back to bicycles this week we're gonna work on a u-break
for my romax i'm on shape number five here i worked on on different shapes over the week
and i had to decide i got some springs off a friend and i have three different kinds
of springs i had to make a choice in which to use these are offer irdu break that's probably
out of the 80s it's hard to find these are our shimano u-brake springs and i don't particularly
like the shimano system but we're going to use these because this seems the best for the project
and i have some cantilever springs and i couldn't figure out how they would fit on the arms so
i bought a piece of metal this is inch one inch by four aluminum at 60 61
32 for this piece of metal i got some bronze we're going to make some bushings it's going to go on to
a tube that fits over the boss so the boss is going to be larger than what's
stock so it's going to be a little bit more more stable and i guess the first thing to do is
to mark out my shape i think there's that the shape that i'm tracing here is a little larger
than it needs to be a little thicker but i can always make it smaller later to save some weight
when you make it too small you can't make it bigger unless you start all over
so i have to do a right in the left so i need to flip it over
i guess that's kind of economical like that and the bandsaw can still sneak past there
i've been looking forward to making these u-breaks for a while
it's the second u-break that i'm making i made a u-break back in
the 80s and that's how the u-brake boost was was made oh how it came to be because
because the brake was so strong it was flexing the posts a lot on the frames we made
for a while i'd say that it was a 50 50 split between u-breaks and the cantilevers because some
riders like one some riders like the other so when when when we did batches of frames
we would always have it on the frame order whether it was canty or u-brake
so we go it's 60 61 it drills quite nicely
i made a drawing it's not a drawing of the whole brake lever but this is the
hole that i have to make that's what holds the bushing that's where the spring goes
and see that tiny little hole right there on the top that's what holds the spring the spring has
to fit into there and then that's the drawing for the bushing which gets made out of bronze
and this is a little smaller at the end because that goes in this end that has to
allow room for the spring there's not a huge amount of extra space in there it's just a
center drill here and then i'll drill a quarter inch hole then we'll go up in size from there
here comes the quarter inch hole
i have to make the little hole off the side now that's where the spring goes into
see how it's really really close to the hole so if i don't do it now and i i sink down the
the larger hole i can't do it so that's why it's happening now
i got a drill that's a little bit larger than the spring just a little bit
okay that looks the same as the other one
okay that's good i'm going to use an end mill to make the hole i've drilled a hole that's almost
as big as the end mill that saves me having to use a boring bar to make a certain size a hole
it's just a little bit easier it took away a little bit of the hole but i think i can still
use it for the spring i haven't made u-breaks in a while so i'm still on the learning curve here
as long as the spring still goes in then that's okay
so this is a large red mill and this is is is what makes the cavity for the spring
so i need to go down
half an inch when the end mill touches down i zero that so now i go down half an inch there
so what we're going to do now is to make the bushings and we press the bushings in
and then we ream them and then we can cut the shape out so everything has to happen in order
so we're going to take some bronze this is a piece of i had lying around we gotta drill
a hole and make a couple bushings they're gonna be a step bushing because one side
needs interference fit for the aluminum and the other side has to make room for the spring
i think i'll make one i'll press it in just to make sure that we're on track
and then i'll make the second one that would be smarter than making two and then trying it
wow
take one more little cut let's go to the hacksaw i'm going to cut this off
and then we're going to see if it fits across your fingers
okay we're going to see if it fits now it's in a piece of aluminum it's not falling in
so let's let's go to the press and see how much of a press fit it is i'm not a super tight fit but
that's going to work that's where the spring has to go maybe we'll check and see if the
spring actually fits now oh look at that fits okay so there's a little bit of pressure
and that's going to hold the hold the u-brake in against the bushing all right that seems to work
you never know if it's gonna work sometimes you make things over again
i've done that many times okay so let's do another bushing i'm going
to make this one a little bit larger so it's a little bit more of a press fit
my lathe cut a little bit undersize you see how it just goes in even though i checked the size
when i first started the cut it took an extra thou off so i'm not very happy with that but
so i'll put a little loctite in it and it'll be good
so i have to let this set up a little bit before it gets reamed can't get reamed right away
there we go so i can bring one hole we can ream that hole right there we'll set up the reamer
and do that let's go over to the bike here my romance and i'll show you what's going on
normally what happens is if you got a shimano you break shimano u-break goes right onto the post
you can see the bushing there it looks like a brass bushing possibly maybe bronze
goes on can you see how it's got a little bit of
a little bit of slop it moves around so on the u-brakes that i'm making
i got some i got some nice tubing it's seamless tubing 7 16 and they put a spacer on there
that's what my my u-brake is going to pivot on so it's a larger diameter it's got
it's a lot longer so it's not going to have it's going to have very very little slop
i think it's a better design so now that this is reamed out
look at that it just goes in
that's a pretty good fit isn't it and that's why i use the rima because the rima makes a beautiful
straight hole that's my plan make a better break let's go to the band saw now we'll do some cutting
and in that time the lock tide is going to set up and then we'll be we'll be moving on
so we have a left and a right so i think i'm going to do some milling now i think i want the
i think i want this one to be cut down this way this is just rough here
it's going to go on on the rotary table that's going to get a nice scoop there
so this is going to go missing then there's going to be a slot there for the cable
because the cable has to go in there so that's the right side and then then on the left side
you still want the slot there but now we need to hollow out or take away this part
so that'll go so that's how the u-brakes cross each other
so this one's gonna i'm not sure what's gonna happen here or probably
maybe something like that i don't know haven't done that before
i'm using a combination square i'm just going to roughly mark how much comes off
so i don't really have to measure too much well basically to the bottom of that look at that
how's that for just using a felt pen in my finger that's my line that's like butter
it's one done
okay a few cups here so that's basically how it's coming along
there's still more more metal to take off you can see how
i take a little bit more than halfway can you see how that's a little bit proud there so if
they both go under the post there's going to be a little bit of a gap there maybe i want more of
a gap i can always put it back in the mill take off a little bit more so anyway that's first step
found a couple washers got an allen screw and that's what's going to hold that down okay
so we're going to put a radius all around here and we can go in
a little bit a little bit closer as well and that'll help me to define the radius
when i do some filing because i can't do all at all machining but can do quite a bit
that's what it looks like it's starting to take shape it's gonna
it's gonna take a little while to figure out what all this shape is gonna look like that's where the
pad goes right here i've got these nice cool stop pads so it's coming along okay number two
that's it
no that's right left and right i'm just thinking that i screwed up but i didn't
because the springs have to go in from the outside not on the inside
so we're good what i think i'll do now is i'm going to mill this flat here
because that's where the pad has to go onto so that's a good step to do
there's a couple you breaks in the process of being made that's all the time we have for today
thank you we both drink coffee mitch and i if you would like to uh click on the link below in the
in our description you could buy us a coffee if you like thanks for watching see you next week