main@RealSTMFC.groups.io | bending brass grab irons

Robert kirkham

#107720

I'm working on a Speedwitch model of an Erie 70000 series boxcar.  The ladders have relatively shorter rungs, so I am bending my own (about scale 16" length).  Using DA .008" brass wire, I find some of them break at the bends as a result of metal fatigue.  While I can bend plenty, so will eventually get enough for the model, I'm wondering if heating the brass wire before bending will do anything to make it take the bend with less brittleness?

If you have experience on this topic, I'd like to hear about it.

Rob Kirkham

Anthony Thompson <thompson@...>

#107721

Rob Kirkham wrote:
I'm working on a Speedwitch model of an Erie 70000 series boxcar.   The ladders have relatively shorter rungs, so I am bending my own  (about scale 16" length).  Using DA .008" brass wire, I find some of  them break at the bends as a result of metal fatigue.      No, they're being deformed beyond their limited capacity. One  bend isn't fatigue.

While I can bend plenty, so will eventually get enough for the  model, I'm wondering if heating the brass wire before bending will  do anything to make it take the bend with less brittleness?     If it's ordinary brass, yes, softening it will work. Our brass  wire is cold drawn, consuming most of its capacity for further  deformation (which is why it breaks upon your bending it). Softening  fixes that. But it will also give you ladder rungs that are easily  bent out of shape (think floral wire). You might be best off to try  bending a slightly larger radius and just throw away the failures.

Tony Thompson
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; fax, (510) 540-1937;
e-mail: thompson@...

randy arnold

#107723

Rob
You might try .008" music wire from Small Part Inc, it holds paint better
than brass and should not break.

Randy

On Tue, Mar 20, 2012 at 2:50 AM, Anthony Thompson <
thompson@...> wrote:

**


Rob Kirkham wrote:
I'm working on a Speedwitch model of an Erie 70000 series boxcar.
The ladders have relatively shorter rungs, so I am bending my own
(about scale 16" length). Using DA .008" brass wire, I find some of
them break at the bends as a result of metal fatigue.No, they're being deformed beyond their limited capacity. One
bend isn't fatigue.


While I can bend plenty, so will eventually get enough for the
model, I'm wondering if heating the brass wire before bending will
do anything to make it take the bend with less brittleness?If it's ordinary brass, yes, softening it will work. Our brass
wire is cold drawn, consuming most of its capacity for further
deformation (which is why it breaks upon your bending it). Softening
fixes that. But it will also give you ladder rungs that are easily
bent out of shape (think floral wire). You might be best off to try
bending a slightly larger radius and just throw away the failures.

Tony Thompson
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; fax, (510) 540-1937;
e-mail: thompson@...




--
Best Regards
Randy


[Non-text portions of this message have been removed]

Nelson Moyer <ku0a@...>

#107729

I'm wondering if you're using brass or phosphor bronze. The latter is
somewhat brittle, compared to brass. I've bent grabs from both, and brass is
quite malleable without heating, while phosphor bronze will sometimes break
if the bend goes past 90 degrees or if you try to adjust the bend angle.
I've never used wire from DA, but Tichy makes 0.008 in. phosphor bronze
wire, and I've used it in several sizes for brake details.

 

Nelson Moyer

Show quoted text

-----Original Message-----
From: STMFC@... [mailto:STMFC@...] On Behalf Of Rob
Kirkham
Sent: Tuesday, March 20, 2012 1:00 AM
To: STMFC@...
Subject: [STMFC] bending brass grab irons

I'm working on a Speedwitch model of an Erie 70000 series boxcar. The 
ladders have relatively shorter rungs, so I am bending my own (about scale 
16" length). Using DA .008" brass wire, I find some of them break at the 
bends as a result of metal fatigue. While I can bend plenty, so will 
eventually get enough for the model, I'm wondering if heating the brass wire

before bending will do anything to make it take the bend with less 
brittleness?

If you have experience on this topic, I'd like to hear about it.

Rob Kirkham

Robert kirkham

#107732

It would be nice if the solution was that easy Nelson, but no, it is brass - from DA.

Rob

--------------------------------------------------
From: "Nelson Moyer" <ku0a@...>
Sent: Tuesday, March 20, 2012 5:45 AM
To: <STMFC@...>
Subject: RE: [STMFC] bending brass grab irons

I'm wondering if you're using brass or phosphor bronze. The latter is
somewhat brittle, compared to brass. I've bent grabs from both, and brass is
quite malleable without heating, while phosphor bronze will sometimes break
if the bend goes past 90 degrees or if you try to adjust the bend angle.
I've never used wire from DA, but Tichy makes 0.008 in. phosphor bronze
wire, and I've used it in several sizes for brake details.

Nelson Moyer

Robert kirkham

#107733

Thanks Tony & Randy,

So the better choices seem to be either .01" brass or .008 music wire (I assume that is stainless or something of that sort).  Or to muddle along with a high failure rate using the .008 brass.

I think I'll give the music wire a try next.

Rob

--------------------------------------------------
From: "Anthony Thompson" <thompson@...>
Sent: Monday, March 19, 2012 11:50 PM
To: <STMFC@...>
Subject: Re: [STMFC] bending brass grab irons

Rob Kirkham wrote:
I'm working on a Speedwitch model of an Erie 70000 series boxcar.
The ladders have relatively shorter rungs, so I am bending my own
(about scale 16" length).  Using DA .008" brass wire, I find some of
them break at the bends as a result of metal fatigue.      No, they're being deformed beyond their limited capacity. One
bend isn't fatigue.

While I can bend plenty, so will eventually get enough for the
model, I'm wondering if heating the brass wire before bending will
do anything to make it take the bend with less brittleness?     If it's ordinary brass, yes, softening it will work. Our brass
wire is cold drawn, consuming most of its capacity for further
deformation (which is why it breaks upon your bending it). Softening
fixes that. But it will also give you ladder rungs that are easily
bent out of shape (think floral wire). You might be best off to try
bending a slightly larger radius and just throw away the failures.

Tony Thompson
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; fax, (510) 540-1937;
e-mail: thompson@...

Dennis Storzek

#107735

--- In STMFC@..., "Rob Kirkham" <rdkirkham@...> wrote:

Thanks Tony & Randy,

So the better choices seem to be either .01" brass or .008 music wire (I
assume that is stainless or something of that sort).  Or to muddle along
with a high failure rate using the .008 brass.

I think I'll give the music wire a try next.

RobOr try .008 brass from a different source. Brass work hardens as it is drawn into wire; what we typically use for model building is rated "half hard". IIRC, the hardness of the finished wire is controlled by annealing it at intermediate points in the drawing process; it would seem DA got a batch of wire that is harder than optimum.

As Tony said, you can anneal brass by heating it. Unfortunately, this will return it to its dead soft state, and is not reversible by further heat treatment as steel is.

Dennis

Steve SANDIFER

#107736

I use .010 Detail Associates Stainless wire.
______________
J. Stephen (Steve) Sandifer
mailto:steve.sandifer@...
Home: 12027 Mulholland Drive, Meadows Place, TX 77477, 281-568-9918
Office: Southwest Central Church of Christ, 4011 W. Bellfort, Houston, TX 77025, 713-667-9417

Show quoted text

----- Original Message ----- 
  From: Rob Kirkham 
  To: STMFC@... 
  Sent: Tuesday, March 20, 2012 9:33 AM
  Subject: Re: [STMFC] bending brass grab irons


    
  Thanks Tony & Randy,

  So the better choices seem to be either .01" brass or .008 music wire (I 
  assume that is stainless or something of that sort). Or to muddle along 
  with a high failure rate using the .008 brass.

  I think I'll give the music wire a try next.

  Rob

  --------------------------------------------------
  From: "Anthony Thompson" <thompson@...>
  Sent: Monday, March 19, 2012 11:50 PM
  To: <STMFC@...>
  Subject: Re: [STMFC] bending brass grab irons

  > Rob Kirkham wrote:
  >> I'm working on a Speedwitch model of an Erie 70000 series boxcar.
  >> The ladders have relatively shorter rungs, so I am bending my own
  >> (about scale 16" length). Using DA .008" brass wire, I find some of
  >> them break at the bends as a result of metal fatigue.
  >
  > No, they're being deformed beyond their limited capacity. One
  > bend isn't fatigue.
  >
  >> While I can bend plenty, so will eventually get enough for the
  >> model, I'm wondering if heating the brass wire before bending will
  >> do anything to make it take the bend with less brittleness?
  >
  > If it's ordinary brass, yes, softening it will work. Our brass
  > wire is cold drawn, consuming most of its capacity for further
  > deformation (which is why it breaks upon your bending it). Softening
  > fixes that. But it will also give you ladder rungs that are easily
  > bent out of shape (think floral wire). You might be best off to try
  > bending a slightly larger radius and just throw away the failures.
  >
  > Tony Thompson
  > 2906 Forest Ave., Berkeley, CA 94705
  > (510) 540-6538; fax, (510) 540-1937;
  > e-mail: thompson@...

Andy Carlson

#107739

Details associates packaged a lot of their brass wire about 20 years ago which
were from a bad batch. Wire from these batches would break when brought to any
near a right angle. Since the DA packaging seems unchanged over these years,
swap meet purchased DA wire may very well be a relic from these poorly drawn
wires of the past. Throw away any of these bad wires, as they are useless for
our needs.

-Andy Carlson
Ojai CA




________________________________
From: soolinehistory <destorzek@...>
To: STMFC@...
Sent: Tue, March 20, 2012 7:48:24 AM
Subject: [STMFC] Re: bending brass grab irons




--- In STMFC@..., "Rob Kirkham" <rdkirkham@...> wrote:

Thanks Tony & Randy,

So the better choices seem to be either .01" brass or .008 music wire (I
assume that is stainless or something of that sort).  Or to muddle along
with a high failure rate using the .008 brass.

I think I'll give the music wire a try next.

RobOr try .008 brass from a different source. Brass work hardens as it is drawn
into wire; what we typically use for model building is rated "half hard". IIRC,
the hardness of the finished wire is controlled by annealing it at intermediate
points in the drawing process; it would seem DA got a batch of wire that is
harder than optimum.

As Tony said, you can anneal brass by heating it. Unfortunately, this will
return it to its dead soft state, and is not reversible by further heat
treatment as steel is.

Dennis

albyrno

#107740

Another source for music wire is guitar strings,they are sold by diameter,if you know someone who plays guitar ask them for the old strings next time they change them or go to a music store and tell them what size wire your looking for and get it there.Strings straighten out when you remove coiled spring from envelope.
          Alan

________________________________
 From: randy arnold <61mkii@...>
To: STMFC@...
Sent: Tuesday, March 20, 2012 2:22 AM
Subject: Re: [STMFC] bending brass grab irons

Rob
You might try .008" music wire from Small Part Inc, it holds paint better
than brass and should not break.

Randy

On Tue, Mar 20, 2012 at 2:50 AM, Anthony Thompson <
thompson@...> wrote:

**

Rob Kirkham wrote:
I'm working on a Speedwitch model of an Erie 70000 series boxcar.
The ladders have relatively shorter rungs, so I am bending my own
(about scale 16" length). Using DA .008" brass wire, I find some of
them break at the bends as a result of metal fatigue.No, they're being deformed beyond their limited capacity. One
bend isn't fatigue.

While I can bend plenty, so will eventually get enough for the
model, I'm wondering if heating the brass wire before bending will
do anything to make it take the bend with less brittleness?If it's ordinary brass, yes, softening it will work. Our brass
wire is cold drawn, consuming most of its capacity for further
deformation (which is why it breaks upon your bending it). Softening
fixes that. But it will also give you ladder rungs that are easily
bent out of shape (think floral wire). You might be best off to try
bending a slightly larger radius and just throw away the failures.

Tony Thompson
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; fax, (510) 540-1937;
e-mail: thompson@...

--
Best Regards
Randy

------------------------------------

Yahoo! Groups Links

[Non-text portions of this message have been removed]

Jim Barnes

#107746

Another alternative to brass wire would be phospher bronze.  This wire bends very well and makes great grab irons.  You can find some at: http://www.tichytraingroup.com as well as other sources.  Jim Barnes

________________________________
 From: Alan Kilby <albyrno@...>
To: "STMFC@..." <STMFC@...>
Sent: Tuesday, March 20, 2012 9:38 AM
Subject: Re: [STMFC] bending brass grab irons

Another source for music wire is guitar strings,they are sold by diameter,if you know someone who plays guitar ask them for the old strings next time they change them or go to a music store and tell them what size wire your looking for and get it there.Strings straighten out when you remove coiled spring from envelope.
          Alan

________________________________
From: randy arnold <61mkii@...>
To: STMFC@...
Sent: Tuesday, March 20, 2012 2:22 AM
Subject: Re: [STMFC] bending brass grab irons

Rob
You might try .008" music wire from Small Part Inc, it holds paint better
than brass and should not break.

Randy

On Tue, Mar 20, 2012 at 2:50 AM, Anthony Thompson <
thompson@...> wrote:

**

Rob Kirkham wrote:
I'm working on a Speedwitch model of an Erie 70000 series boxcar.
The ladders have relatively shorter rungs, so I am bending my own
(about scale 16" length). Using DA .008" brass wire, I find some of
them break at the bends as a result of metal fatigue.No, they're being deformed beyond their limited capacity. One
bend isn't fatigue.

While I can bend plenty, so will eventually get enough for the
model, I'm wondering if heating the brass wire before bending will
do anything to make it take the bend with less brittleness?If it's ordinary brass, yes, softening it will work. Our brass
wire is cold drawn, consuming most of its capacity for further
deformation (which is why it breaks upon your bending it). Softening
fixes that. But it will also give you ladder rungs that are easily
bent out of shape (think floral wire). You might be best off to try
bending a slightly larger radius and just throw away the failures.

Tony Thompson
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; fax, (510) 540-1937;
e-mail: thompson@...

--
Best Regards
Randy

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

[Non-text portions of this message have been removed]

Michael Watnoski

#107750

Hi Rob,

    I always bend my own grab irons.  It seems that the commercial never match exactly.  Many of them use too heavy wire or a material that is too hard to clip without chipping my good wire cutters.  Also drop grabs have the wrong dimensions or wide radius bends.

    I use a pair of needle nose pliers with a piece of tape on the inside of the jaws.  Just set the wire against the tape and roll the jaws on a hard surface for a sharp bend.  bend with fingers for a slightly larger radius.

    You have found the main problem with Detail Associates wire.  It develops a temper in the wire making process.  Bending it adds work hardening which makes it brittle.  It can be annealed by heating it slightly with a butane lighter at the bend point.  Unfortunately, there is very little control of the amount of softening.  You also don't want to soften the whole grab as it won't hold its shape when handling.

    My suggestion is to skip the DA brass wire and use the Tichy phosphor bronze wire.  This has a consistent hardness that will not change if heated.  It can be bent multiple times without cracking.  It holds a straight line well and bends easily.  The springiness is handy for making electrical pick ups.

Michael

Show quoted text

On 3/20/2012 2:00 AM, Rob Kirkham wrote:
I'm working on a Speedwitch model of an Erie 70000 series boxcar.  The
ladders have relatively shorter rungs, so I am bending my own (about scale
16" length).  Using DA .008" brass wire, I find some of them break at the
bends as a result of metal fatigue.  While I can bend plenty, so will
eventually get enough for the model, I'm wondering if heating the brass wire
before bending will do anything to make it take the bend with less
brittleness?

If you have experience on this topic, I'd like to hear about it.

Rob Kirkham





------------------------------------

Yahoo! Groups Links