Fastening steel cable
 

Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")
in order to hook the cable into a slot. This is a replacement part for a
device I've been using, but due to overload the original factory-made
connection went -- the cable progressively slipped out of the ball.

I had a local workshop make a replacement -- they stuck the cable
through a brass ball, jammed a conical piece of steel into the center of
the open end of the cable, and liberally bathed the whole thing in
solder. Upon my first trial, the joint snapped with a loud pang when it
wasn't even loaded with half of its intended strength (max force in
normal use will be about 700lbs).

My question is: How is this done professionally? Of course I could just
order the original replacement part, but with overseas shipping and all
I'd like to save some time by having this made locally.

The design of the unit, regrettably, doesn't allow any other way of
fixing the cable to the rest.

Thanks,
robert

Robert Latest wrote:
Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")
in order to hook the cable into a slot. This is a replacement part for a
device I've been using, but due to overload the original factory-made
connection went -- the cable progressively slipped out of the ball.

I had a local workshop make a replacement -- they stuck the cable
through a brass ball, jammed a conical piece of steel into the center of
the open end of the cable, and liberally bathed the whole thing in
solder. Upon my first trial, the joint snapped with a loud pang when it
wasn't even loaded with half of its intended strength (max force in
normal use will be about 700lbs).

Where did the new one break? What metal was the original ball?

My question is: How is this done professionally? Of course I could just
order the original replacement part, but with overseas shipping and all
I'd like to save some time by having this made locally.

The design of the unit, regrettably, doesn't allow any other way of
fixing the cable to the rest.

Thanks,
robert

Sounds very much like a Bowden control cable.
That's the type as used on bicycles, motorcycles, cars etc, that have a
multi-strand inner cable with a nipple on the end.
The method you describe for putting on a new nipple (ball) is OK, but
you didn't mention if the nipple had a hollow cone, or double-diameter
made into it. If it's only got a straight hole, I wouldn't expect that
to last long. The larger diameter or cone is where the cable strands can
be spread out into, and optionally a steel "splinter" can be also placed
centrally, before it's all soldered. Using the proper solder, or maybe
silver solder, and cleanliness helps a lot.

Jordan

Robert Latest wrote:
Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")

For high-strength applications, these are usually swedged on under very high
pressure in a shaped die. Bourdon cables for bikes are usually just splayed
out after inserting through the terminal piece and soldered, or the terminal
piece is insert molded in zinc directly onto the cable (zinc shrinks as it
solidifies, clamping very tightly onto the cable as it does). Silver solder
might work better, but only the low-temperature types. Real silver solder
needs a high enough temperture that the heat treatment of the cable will
almost certainly be affected.

--
Bob (Chief Pilot, White Knuckle Airways)


"Jordan" wrote in message
u...
Sounds very much like a Bowden control cable.
That's the type as used on bicycles, motorcycles, cars etc, that have a
multi-strand inner cable with a nipple on the end.
The method you describe for putting on a new nipple (ball) is OK, but you
didn't mention if the nipple had a hollow cone, or double-diameter made
into it. If it's only got a straight hole, I wouldn't expect that to last
long. The larger diameter or cone is where the cable strands can be spread
out into, and optionally a steel "splinter" can be also placed centrally,
before it's all soldered. Using the proper solder, or maybe silver solder,
and cleanliness helps a lot.

Jordan

Robert Latest wrote:
Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")

Jordan wrote:

Using the proper solder, or maybe silver solder

Silver solder is not an option! The steel cable will anneal.
A brass nipple and _soft_ soldering the cable into works for bikes, but
300kg? Uh!

My suggestion:
Make a brass nipple, drill and file a hole in (kind of conical), insert
the wire from the narrow side of the hole, bend the cabe 180deg and lead
it back throug the hole. The hole has to be as close as possible. Pull
on the cable so that the U-bend slips into the nipple and soft solder
the whole construction.

Nick

--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

You should be able to easily find 1/4" steel cable with a rating of
over 3 tons so annealing shouldn't become a major problem. However: Is
this an application where someone could be injured by the end pulling
out? If so I might suggest assembling the cable end into a wedge shape
by brazing, with a central tiny wedge inside (or by bending the strands
inwardly over themselfs) and quenching while it's still hot followed by
a lighter heat to finish temper (a lot of technique needed here). Then
match the cone shape by milling/filing out the ball and finish by
running the cable through the ball and lightly soldering.
Not too stupid sounding, I hope.
Dennis in nca

Hey Robert,

Sounds like your local shop had started along the right track, but
didn't quite get there.

Instead of a cone shaped wedge, make the hole through the ball a
"cone" shape. Doesn't have to be perfect, but definitely the "small
end" of the hole must be the "cable size", just large enough for the
wire rope to pass through. In your case, 9/64" should do", and the
large end as large as you can make it on a 1/4" ball. Nominally,
these are 3 times the cable diameter, but you can't "do" that with
what you have. The cone "finish" should not be smooth, in fact it
should have a surface that is slightly roughened for the last step.

Insert the cable through this smaller hole, and then seize it with
tape or wire to allow you to splay the end for three times the
diameter.

Turn the end of each of the now separated lays back on itself, bent so
that the ends will meet "inside" the wire rope. Bit of a bitch to do,
but forms a "rosette".

Pull really hard on the cable, attempting to pull the whole bud back
through the ball. It can not pull out, due to you have effectively
"doubled" the diameter of the cable.

While it is under this tension, now you solder it in place. The
solder, babbitt, lead, or what ever, (I've even used epoxy), doesn't
need to "melt into" the cable as though you were tinning or brazing.
It just has to flow around it, so don't heat the cable anymore than
necessary. It doesn't take much heat to damage these now individual
little wires. This "socketing" doesn't stop the cable from pulling
through, but merely keeps it in place so that it can't go the "other"
way and push free when the tension is released.

Done properly, the cable exiting the small end will be "whole" and
still twisted in it's proper lay, and none of the "splay" will be
visible at the small hole end. On the large end, you may find that
the little "loops" are visible. On items where it matters, these MUST
show in fact, so that you know it wasn't just like what your local
shop did.

What is this a part of?? It is quite common for fittings such as you
describe to be Nico pressed, but you need the proper equipment and
expertise to do this. If it is possible to take the cable to a marine
outfitter, they may be able to do provide what you need.

And using a safety factor of 5, you should be using 3/16" cable for a
700 pound load.

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

On 12 Jul 2005 09:42:15 GMT, Robert Latest
wrote:

Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")
in order to hook the cable into a slot. This is a replacement part for a
device I've been using, but due to overload the original factory-made
connection went -- the cable progressively slipped out of the ball.

I had a local workshop make a replacement -- they stuck the cable
through a brass ball, jammed a conical piece of steel into the center of
the open end of the cable, and liberally bathed the whole thing in
solder. Upon my first trial, the joint snapped with a loud pang when it
wasn't even loaded with half of its intended strength (max force in
normal use will be about 700lbs).

My question is: How is this done professionally? Of course I could just
order the original replacement part, but with overseas shipping and all
I'd like to save some time by having this made locally.

The design of the unit, regrettably, doesn't allow any other way of
fixing the cable to the rest.

Thanks,
robert

Funny, I was just looking into this. Suggest you poke around the Web site
http://www.csjohnson.com and find their "catalog request" page where you can
download their architectural hardware catalog as PDF. In there they explain in
great detail all about small wire rope and it's end fittings.

It should have been swaged on using a roller die.

You can buy mechanical fittings that go on with regular hand tools. These are
more expensive, but they develop 100% of the wire rope strength. Or, you can
have McMaster-Carr make you up your assembly.

GWE

Robert Latest wrote:
Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")
in order to hook the cable into a slot. This is a replacement part for a
device I've been using, but due to overload the original factory-made
connection went -- the cable progressively slipped out of the ball.

I had a local workshop make a replacement -- they stuck the cable
through a brass ball, jammed a conical piece of steel into the center of
the open end of the cable, and liberally bathed the whole thing in
solder. Upon my first trial, the joint snapped with a loud pang when it
wasn't even loaded with half of its intended strength (max force in
normal use will be about 700lbs).

My question is: How is this done professionally? Of course I could just
order the original replacement part, but with overseas shipping and all
I'd like to save some time by having this made locally.

The design of the unit, regrettably, doesn't allow any other way of
fixing the cable to the rest.

Thanks,
robert

"Robert Latest" wrote in message
...
Hi folks,

I'm having to fix a steel cable (1/8" dia) to a small metal ball (1/4")
in order to hook the cable into a slot. This is a replacement part for a
device I've been using, but due to overload the original factory-made
connection went -- the cable progressively slipped out of the ball.

I had a local workshop make a replacement -- they stuck the cable
through a brass ball, jammed a conical piece of steel into the center of
the open end of the cable, and liberally bathed the whole thing in
solder. Upon my first trial, the joint snapped with a loud pang when it
wasn't even loaded with half of its intended strength (max force in
normal use will be about 700lbs).

My question is: How is this done professionally? Of course I could just
order the original replacement part, but with overseas shipping and all
I'd like to save some time by having this made locally.

The design of the unit, regrettably, doesn't allow any other way of
fixing the cable to the rest.

Thanks,
robert

I owned and operated a machine shop next to the Denver airport and swaged
cable as part of our services. You need a high impact swager and the right
die for the part to be fitted to the cable. No solder nor welding is
involved. It actually cold fuses the fitting to the cable end. Look for a
shop doing aircraft repair or servicing.

Wayne
www.pueblaprotocol.com

Hi Brian and everybody else,

thanks for all the suggestions. I put the shop back on track; all this
now amounts to is a race between the shop and the $2 replacement part
shipped from overseas.

robert

solder is the wrong stuff. Spelter ( zinc ) is used to attoch fittings
to cables, but if I recall correctly the US Navy does not permit using
slings with fittings attached with Spelter to be used to handle
explosives.

Dan