1 Attachment(s)
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Clockwork
I used to angle the slot but now I prefer to bend the dropout.
I tried bending the Columbus style front dropouts from Nova in a vice. Just a really little, very slight bend while clamped, and I felt a fracture. Very uncertain about what I felt, there was no way I was going to use it, so out of curiosity I went to bend it back and it quickly broke in two.
I ordered a new set of dropouts and angled the slots instead.
Perhaps it is a cast vs. forged thing... these were cast.
Attachment 86233
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Michael Gordon
I tried bending the Columbus style front dropouts from Nova in a vice. Just a really little, very slight bend while clamped, and I felt a fracture. Very uncertain about what I felt, there was no way I was going to use it, so out of curiosity I went to bend it back and it quickly broke in two.
I ordered a new set of dropouts and angled the slots instead.
Perhaps it is a cast vs. forged thing... these were cast.
Attachment 86233
I'm a newbie, but I've taken a few materials classes and I would guess that you're correct in thinking it was the casting vs. forging issue.
Re: Brazing Tab Type Dropouts
I can't imagine any sugnificant loss of strength to a steel dropout from bending it some 5-6 degrees or so.
Anyway, I don't know if what I'm doing is right, but I braze the dropouts first and then bend them.
Re: Brazing Tab Type Dropouts
I'd do that prep first. That's a lot of stress on a new joint.
There are a bunch of different ways to skin this cat- I'm generally in the "slot-to-fit" camp.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Eric Estlund
I'd do that prep first. That's a lot of stress on a new joint.
The joint is a couple of times thicker than the dropout, I'm not sure there is any stress to the joint at all. Besides, doesn't brass only get stronger with abuse? =)
Re: Brazing Tab Type Dropouts
I'd be more worried about the thin wall of the chain stay where the brass terminates inside the stay. It may be academic, but if I'm bending things I like to stress them individually.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
waterlaz
I can't imagine any sugnificant loss of strength to a steel dropout from bending it some 5-6 degrees or so.
Anyway, I don't know if what I'm doing is right, but I braze the dropouts first and then bend them.
I was quite shocked when I bent them and had the issue. It was a very slight bend, but it was also right up against the sharp edge of the vice jaw. Regardless, I am now in the camp of slot to fit, braze it up in the fork jig, then make only slight adjustments with frame end alignment tools post braze.
Re: Brazing Tab Type Dropouts
The traditional way is for the slot to follow the center-line of the stay. The dropout angle is produced, or cranked by hand, to mate with the slot. Don't braze the dropout part straight mated to an angled slot. If the part comes straight it's only (ONLY) because the vendor wanted to save a penny or half-second on the labor and machinery.
Re: Brazing Tab Type Dropouts
That's true for softer forged dropouts. The same can't be said for Paragon dropouts and their super thick tabs.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
e-RICHIE
The traditional way is for the slot to follow the center-line of the stay. The dropout angle is produced, or cranked by hand, to mate with the slot. Don't braze the dropout part straight mated to an angled slot. If the part comes straight it's only (ONLY) because the vendor wanted to save a penny or half-second on the labor and machinery.
But surely there are lots of factors affecting the angle, for instance: wheel size, crown width, chainstay length, rear hub spacing?
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
William Chitham
But surely there are lots of factors affecting the angle, for instance: wheel size, crown width, chainstay length, rear hub spacing?
That's always been the case atmo.
Re: Brazing Tab Type Dropouts
Certain dropouts, like Paragon Rockers, can't be bent so at some point you're (a general you, not any "you" in particular) going to have to learn to cut the stays with the appropriate angle.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Will Neide
Certain dropouts, like Paragon Rockers, can't be bent so at some point you're (a general you, not any "you" in particular) going to have to learn to cut the stays with the appropriate angle.
If I were using these types, I'd be more inclined to reroute (as in reshape, curve, or bend) the stay so it engages the part head on rather than slot it at an angle. But that's just me thinking about the stay, the heat, and the asymmetry of the slotted area.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
e-RICHIE
If I were using these types, I'd be more inclined to reroute (as in reshape, curve, or bend) the stay so it engages the part head on rather than slot it at an angle. But that's just me thinking about the stay, the heat, and the asymmetry of the slotted area.
You certainly could do that, but I think you'd be running into heel clearance issues. Especially when you start pushing the rear ends to 150+ mm. I just got a MTB frame in for repair that has a single bend chainstay and you can see he has lots of heel rub issues with the frame. The rear end is 135mm with tabbed sliders. The kind of bends you're thinking of wouldn't work in this particular set-up. This guy could really use an S bend so his heel stops brushing the chainstay.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Will Neide
You certainly could do that, but I think you'd be running into heel clearance issues. Especially when you start pushing the rear ends to 150+ mm. I just got a MTB frame in for repair that has a single bend chainstay and you can see he has lots of heel rub issues with the frame. The rear end is 135mm with tabbed sliders. The kind of bends you're thinking of wouldn't work in this particular set-up. This guy could really use an S bend so his heel stops brushing the chainstay.
Think outside the box. Or build a new box. Only the last several centimeters would have to be rearranged in order for the stay to engage an un-cranked dropout head on.
Re: Brazing Tab Type Dropouts
Old news from 2011: Firefly :: The Beginning :: Part 5 | Firefly Bicycles
Since then majorly upgraded our methods, but this is the basic idea of how we (used to) slot our stays.
Re: Brazing Tab Type Dropouts
What it comes down to is that with longer dropout designs to accommodate for discs pushing the heel interference point towards the bottom bracket, the ability to form/shape a tube to retain a centered slot is drastically reduced.
"Traditional" methods of construction just do not lend themselves to the ever evolving requirements of mountain bike design...the new techniques and designs that accommodate for these needs ARE redefining "the box".
What has not changed is the requirement for solid technical fabrication skills...think through your solutions and execute.
rody
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Rody
<cut>
"Traditional" methods of construction just do not lend themselves to the ever evolving requirements of mountain bike design...the new techniques and designs that accommodate for these needs ARE redefining "the box".
Agreed and fully understood. I was addressing tabbed dropouts and their use.
PS Not to get hung up on words, but "traditional" doesn't mean old, classic, or from the past.
Quote:
What has not changed is the requirement for solid technical fabrication skills...think through your solutions and execute.
Folks need to be reminded of this often.
Re: Brazing Tab Type Dropouts
Quote:
Originally Posted by
Will Neide
Certain dropouts, like Paragon Rockers, can't be bent so at some point you're (a general you, not any "you" in particular) going to have to learn to cut the stays with the appropriate angle.
I have a set of the Paul Track Ends that are pretty thick. Should I assume they also can't be bent?
Re: Brazing Tab Type Dropouts
Those things are short and stout- I'd be slotting at an angle.