My custom frame is being welded this week. Anyone have any
tricks for keeping the bearing holders from coming out of true.
Below is an exerpt from my frame builder in which he mentions this problem.
I thought that maybe there might be a trick out there that someone might know of.
He responded to a comment about my worries that the
frame can come out of true during the welding process.
+++++++++++++++++++++++++++++++++++
Excerpt:
I have made a lot of forks and they always draw in. My
experience is that on a frame it can draw as miuch as 1/2 inch. I use
spacer bocks to over spread to compensate for the draw. For the muni, I cut
a block of wood that I will wedge in between the legs and over spread and
hopefully have it draw to size. I plan on having to tweak it a little
afterwards. What I am really worried about is the bearing clamps drawing
upor down uneven. If is easy to spread it sideways, but im to possible drop
or raise a clamp after welding. So… slow is the way to go.
Keep you fingers crossed.
Nickel filler rod may work. If I remember correctly, nickel alloy is used
to weld cast iron since it doesn’t shrink nearly as much as other metal
alloys. Less shrinkage is less stress, etc, etc.
The nickel filler material will have less strength than most other filler
rods. This could be OK since the weld of the bearing housing should be more
compression than tension.
Your results may vary. Let us know what your welder decides to do.
Pictures Please
Doug
“teachndad” <teachndad.61qnz@timelimit.unicyclist.com> wrote in message news:teachndad.61qnz@timelimit.unicyclist.com…
>
> HI,
>
> My custom frame is being welded this week. Anyone have any
> tricks for keeping the bearing holders from coming out of true.
>
> Below is an exerpt from my frame builder in which he mentions this
> problem.
>
> I thought that maybe there might be a trick out there that someone might
> know of.
>
> He responded to a comment about my worries that the
> frame can come out of true during the welding process.
> +++++++++++++++++++++++++++++++++++
> Excerpt:
> I have made a lot of forks and they always draw in. My
> experience is that on a frame it can draw as miuch as 1/2 inch. I use
> spacer bocks to over spread to compensate for the draw. For the muni, I
> cut
> a block of wood that I will wedge in between the legs and over spread
> and
> hopefully have it draw to size. I plan on having to tweak it a little
> afterwards. What I am really worried about is the bearing clamps
> drawing
> upor down uneven. If is easy to spread it sideways, but im to possible
> drop
> or raise a clamp after welding. So… slow is the way to go.
> Keep you fingers crossed.
>
> ++++++++++++++++++++++++++++++++++++++
>
> Working the maze
>
>
> –
> teachndad - The Munieer
>
> Rod Wylie
> ------------------------------------------------------------------------
> teachndad’s Profile: http://www.unicyclist.com/profile/56
> View this thread: http://www.unicyclist.com/thread/18619
>
When welding my frame we [mr.tig and myself] held the [home-made] bearing caps in place by mounting them on a “fake hub” which I turned down to 40mmOD from some bar stock we had lying around. This stayed in place for the whole welding process and meant that when the [suzue] hub went in, all was straight and true - i borrowed the idea from here:
It all worked very well [the bar did sink a far amount of heat tho’]
I am sure that a Nickel filler rod will do as I have seen frames only brazed
and they cope perfectly well, but be warned this IS a high stress part on a
unicycle frame and quite prone to failure. The problem is that there is a
high torsional force at that point and the joint just above the bearing
housing tends to sheer if anywhere on a frame.
Roger
The UK’s Unicycle Source
----- Original Message -----
From: “Doug Massey” <dvm@mmcable.com>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Wednesday, June 12, 2002 3:36 AM
Subject: Re: Need frame welding tips
> Nickel filler rod may work. If I remember correctly, nickel alloy is used
> to weld cast iron since it doesn’t shrink nearly as much as other metal
> alloys. Less shrinkage is less stress, etc, etc.
>
> The nickel filler material will have less strength than most other filler
> rods. This could be OK since the weld of the bearing housing should be
more
> compression than tension.
>
> Your results may vary. Let us know what your welder decides to do.
>
> Pictures Please
>
> Doug
>
>
> “teachndad” <teachndad.61qnz@timelimit.unicyclist.com> wrote in message
> news:teachndad.61qnz@timelimit.unicyclist.com…
> >
> > HI,
> >
> > My custom frame is being welded this week. Anyone have any
> > tricks for keeping the bearing holders from coming out of true.
> >
> > Below is an exerpt from my frame builder in which he mentions this
> > problem.
> >
> > I thought that maybe there might be a trick out there that someone might
> > know of.
> >
> > He responded to a comment about my worries that the
> > frame can come out of true during the welding process.
> > +++++++++++++++++++++++++++++++++++
> > Excerpt:
> > I have made a lot of forks and they always draw in. My
> > experience is that on a frame it can draw as miuch as 1/2 inch. I use
> > spacer bocks to over spread to compensate for the draw. For the muni, I
> > cut
> > a block of wood that I will wedge in between the legs and over spread
> > and
> > hopefully have it draw to size. I plan on having to tweak it a little
> > afterwards. What I am really worried about is the bearing clamps
> > drawing
> > upor down uneven. If is easy to spread it sideways, but im to possible
> > drop
> > or raise a clamp after welding. So… slow is the way to go.
> > Keep you fingers crossed.
> >
> > ++++++++++++++++++++++++++++++++++++++
> >
> > Working the maze
> >
> >
> > –
> > teachndad - The Munieer
> >
> > Rod Wylie
> > ------------------------------------------------------------------------
> > teachndad’s Profile: http://www.unicyclist.com/profile/56
> > View this thread: http://www.unicyclist.com/thread/18619
> >
>
>
>
Nickel filler rod may work. If I remember correctly, nickel alloy is used
to weld cast iron since it doesn’t shrink nearly as much as other metal
alloys. Less shrinkage is less stress, etc, etc.
The nickel filler material will have less strength than most other filler
rods. This could be OK since the weld of the bearing housing should be more
compression than tension.
Your results may vary. Let us know what your welder decides to do.
Here is the response from my builder taken from two different emails. Hope this answers the questions:
The welding rod
is 80 asd. I may have the asd letters wrong but it is a mild steel 80,000 tensile strength.
also
Yes, I did clamp a tube in the clamps…after tacking and clamped it all
flat to a welding table too… and seat tube was clamped via spacer I
milled flat so if my fixture was straight it should not have moved, but it
did a little, but it is OK.
