Hello, all,

I have a Peck, Stowe and Wilcox 30" shear that has a crack in the platen
(The "bed" of the unit that holds the fixed blade). It first cracked
right across where one of the bolts that supports the fixed blade is,
parallel to that bolt. This is the vertical bolt that presses upward on
the bottom of the fixed blade, not the bolts that clamp the blade to the
platen.

Anyway, someone had made a horribly amateur attempt at welding it, and
it cracked immediately. I took a shot at TIG welding the crack, knowing
it had about zero chance of working. Exactly. So, then I welded a
piece of 1/4" steel plate about 6" long, underneath the rib of the
platen, running about 3" each side of the crack. I made a number of
small weld beads there, essentially butt welding the plate onto the edge
of the rib. (The plate hangs straight down from the platen.) I used
TIG at ~100 amps (had the welder set for 150 A max) and went slow so as
to at least partially preheat the area, and then just make a 1/2" long
bead at a time. This weld has held quite nicely!

But (there's always a but) now the platen has cracked again, right at
the end of the welded area. This is right down the center of the platen
too, heading toward the front of the platen, where you stand to stomp
on the pedal. (There is a possibility this crack was already there, or
at least starting to develop, and when the other crack was secured, the
load all jumped to this one. But, the location RIGHT at the end of my
weld is suspicious.)


Well, I certainly don't have a heat treat oven where I can preheat
something as big as this. Has anyone ever succedded in repairing cracks
on a stomp shear like this? Especially if it is a Peck, Stowe & Wilcox,
(not their later PEXTO label) so it must be PRETTY old, I'm guessing
1900 - 1920 at the latest. (Hope this thing isn't made of the same iron
that went into the Titanic! That would explain this damn thing cracking
so easily.) And, of course, the real question is, should I try to
repair this crack, too, or is this a totally lost cause? Without a heat
treat oven, is every weld repair going to end up producing another crack?

Thanks in advance for any thoughts on this!

Jon

Jon Elson wrote:
Hello, all,

I have a Peck, Stowe and Wilcox 30" shear that has a crack in the platen
(The "bed" of the unit that holds the fixed blade). It first cracked
right across where one of the bolts that supports the fixed blade is,
parallel to that bolt. This is the vertical bolt that presses upward on
the bottom of the fixed blade, not the bolts that clamp the blade to the
platen.

Anyway, someone had made a horribly amateur attempt at welding it, and
it cracked immediately. I took a shot at TIG welding the crack, knowing
it had about zero chance of working. Exactly. So, then I welded a
piece of 1/4" steel plate about 6" long, underneath the rib of the
platen, running about 3" each side of the crack. I made a number of
small weld beads there, essentially butt welding the plate onto the edge
of the rib. (The plate hangs straight down from the platen.) I used
TIG at ~100 amps (had the welder set for 150 A max) and went slow so as
to at least partially preheat the area, and then just make a 1/2" long
bead at a time. This weld has held quite nicely!

But (there's always a but) now the platen has cracked again, right at
the end of the welded area. This is right down the center of the platen
too, heading toward the front of the platen, where you stand to stomp
on the pedal. (There is a possibility this crack was already there, or
at least starting to develop, and when the other crack was secured, the
load all jumped to this one. But, the location RIGHT at the end of my
weld is suspicious.)


Well, I certainly don't have a heat treat oven where I can preheat
something as big as this. Has anyone ever succedded in repairing cracks
on a stomp shear like this? Especially if it is a Peck, Stowe & Wilcox,
(not their later PEXTO label) so it must be PRETTY old, I'm guessing
1900 - 1920 at the latest. (Hope this thing isn't made of the same iron
that went into the Titanic! That would explain this damn thing cracking
so easily.) And, of course, the real question is, should I try to
repair this crack, too, or is this a totally lost cause? Without a heat
treat oven, is every weld repair going to end up producing another crack?

Thanks in advance for any thoughts on this!

Jon


I've brazed pretty heavy castings using a space heater (or two) to preheat.

John

On Tue, 07 Jun 2005 00:10:18 -0500, Jon Elson
wrote:

Hello, all,

I have a Peck, Stowe and Wilcox 30" shear that has a crack in the platen
(The "bed" of the unit that holds the fixed blade). It first cracked
right across where one of the bolts that supports the fixed blade is,
parallel to that bolt. This is the vertical bolt that presses upward on
the bottom of the fixed blade, not the bolts that clamp the blade to the
platen.

Anyway, someone had made a horribly amateur attempt at welding it, and
it cracked immediately. I took a shot at TIG welding the crack, knowing
it had about zero chance of working. Exactly. So, then I welded a
piece of 1/4" steel plate about 6" long, underneath the rib of the
platen, running about 3" each side of the crack. I made a number of
small weld beads there, essentially butt welding the plate onto the edge
of the rib. (The plate hangs straight down from the platen.) I used
TIG at ~100 amps (had the welder set for 150 A max) and went slow so as
to at least partially preheat the area, and then just make a 1/2" long
bead at a time. This weld has held quite nicely!

But (there's always a but) now the platen has cracked again, right at
the end of the welded area. This is right down the center of the platen
too, heading toward the front of the platen, where you stand to stomp
on the pedal. (There is a possibility this crack was already there, or
at least starting to develop, and when the other crack was secured, the
load all jumped to this one. But, the location RIGHT at the end of my
weld is suspicious.)


Well, I certainly don't have a heat treat oven where I can preheat
something as big as this. Has anyone ever succedded in repairing cracks
on a stomp shear like this? Especially if it is a Peck, Stowe & Wilcox,
(not their later PEXTO label) so it must be PRETTY old, I'm guessing
1900 - 1920 at the latest. (Hope this thing isn't made of the same iron
that went into the Titanic! That would explain this damn thing cracking
so easily.) And, of course, the real question is, should I try to
repair this crack, too, or is this a totally lost cause? Without a heat
treat oven, is every weld repair going to end up producing another crack?

Thanks in advance for any thoughts on this!

Jon

Jon at this point its largely..IMHO a lost cause. Not that it cant be
repaired with replacement parts from another shear.

Drop Leigh at with a question about replacement
parts from carcasses. If he doesnt know where to find them...few
others will either. The dude is good with Pexto stuff.

Gunner

"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown

Jon Elson wrote:

Without a heat
treat oven, is every weld repair going to end up producing another crack?

Did you drill the end of the crack? You should do this!
carefuly check that you drilled out the end of the crack (oil and chalk)
or it will certainly crack again.
Preheating by any means will reduce inner tension.


HTH,
Nick
--
Motormodelle / Engine Models
http://www.motor-manufaktur.de

You can easily heat up the bed to 600 degrees using a propane weed
burner and some sort of metal enclosure. A 30" bed should be about
36"x18", that would fit nicely inside the shell of a 50 gallon water
heater. If you can't find a weed burner, try one of the cheaper gas burners
http://www.harborfreight.com/cpi/cta...emnumber=44895

Jon Elson wrote:
Hello, all,

I have a Peck, Stowe and Wilcox 30" shear that has a crack in the platen
(The "bed" of the unit that holds the fixed blade). It first cracked
right across where one of the bolts that supports the fixed blade is,
parallel to that bolt. This is the vertical bolt that presses upward on
the bottom of the fixed blade, not the bolts that clamp the blade to the
platen.

Anyway, someone had made a horribly amateur attempt at welding it, and
it cracked immediately. I took a shot at TIG welding the crack, knowing
it had about zero chance of working. Exactly. So, then I welded a
piece of 1/4" steel plate about 6" long, underneath the rib of the
platen, running about 3" each side of the crack. I made a number of
small weld beads there, essentially butt welding the plate onto the edge
of the rib. (The plate hangs straight down from the platen.) I used
TIG at ~100 amps (had the welder set for 150 A max) and went slow so as
to at least partially preheat the area, and then just make a 1/2" long
bead at a time. This weld has held quite nicely!

But (there's always a but) now the platen has cracked again, right at
the end of the welded area. This is right down the center of the platen
too, heading toward the front of the platen, where you stand to stomp
on the pedal. (There is a possibility this crack was already there, or
at least starting to develop, and when the other crack was secured, the
load all jumped to this one. But, the location RIGHT at the end of my
weld is suspicious.)


Well, I certainly don't have a heat treat oven where I can preheat
something as big as this. Has anyone ever succedded in repairing cracks
on a stomp shear like this? Especially if it is a Peck, Stowe & Wilcox,
(not their later PEXTO label) so it must be PRETTY old, I'm guessing
1900 - 1920 at the latest. (Hope this thing isn't made of the same iron
that went into the Titanic! That would explain this damn thing cracking
so easily.) And, of course, the real question is, should I try to
repair this crack, too, or is this a totally lost cause? Without a heat
treat oven, is every weld repair going to end up producing another crack?

Thanks in advance for any thoughts on this!

Jon

On Tue, 07 Jun 2005 11:41:48 +0200, Nick Müller wrote:

Jon Elson wrote:

Without a heat
treat oven, is every weld repair going to end up producing another crack?

Did you drill the end of the crack? You should do this!
carefuly check that you drilled out the end of the crack (oil and chalk)
or it will certainly crack again.

That's what I was thinking too, Nick. I've drilled out the end's of cracks
in fiberglass panels to prevent them from cracking further before repairing
them. Works like a charm.

How do you use oil and chalk to find the end of a crack?

"Artemia Salina" wrote in message
news snip----

How do you use oil and chalk to find the end of a crack?


It's much like a spray penetrant inspection. The crack holds some oil, which
is wicked out by the chalk and is easily visible from the discoloration.
It defines cracks quite well.

Harold

Artemia Salina wrote:

How do you use oil and chalk to find the end of a crack?

Pour some thin oil on the suspect place, let it penetrate, whipe it
carefuly off, and dust some powdered chalk over the place. The chalk
will suck the oil out of the crack and will get dark. voila!
Well, you can also buy expensive super space science spray for that ...

Nick

--
Motormodelle / Engine Models
http://www.motor-manufaktur.de

Nick Müller wrote:
Jon Elson wrote:


Without a heat
treat oven, is every weld repair going to end up producing another crack?


Did you drill the end of the crack? You should do this!
carefuly check that you drilled out the end of the crack (oil and chalk)
or it will certainly crack again.
Preheating by any means will reduce inner tension.
The new crack is 3 inches away, and parallel to the old crack. It is at
the end of the gusset patch, where stess may have been concentrated both
by the application of the patch and by the patched area now being
stiffer than the rest of the platen.

So, this has nothing to do with the end of the crack propagating farther.

Thanks,

Jon

Hello Jon,

Somebody posted this URL here a while ago:

http://www.locknstitch.com/

It seems to me that what you are experiencing agrees pretty well with their
explanation as to the mechanisms involved, though I'm only going on
recollection. It may be that either their products or their data could help.

BTW your EDM power supply worked exactly as I hoped on eroding a square
socket into the hardened stud we were discussing a while back. So, thanks
once again on that.

Regards,

Adam Smith
Midland, ON

"Jon Elson" wrote in message
ervers.com...
Nick Müller wrote:
Jon Elson wrote:


Without a heat treat oven, is every weld repair going to end up producing
another crack?


Did you drill the end of the crack? You should do this!
carefuly check that you drilled out the end of the crack (oil and chalk)
or it will certainly crack again.
Preheating by any means will reduce inner tension.
The new crack is 3 inches away, and parallel to the old crack. It is at
the end of the gusset patch, where stess may have been concentrated both
by the application of the patch and by the patched area now being stiffer
than the rest of the platen.

So, this has nothing to do with the end of the crack propagating farther.

Thanks,

Jon

Adam Smith wrote:

Hello Jon,

Somebody posted this URL here a while ago:

http://www.locknstitch.com/

This stuff seems to be about sealing leaks in the non-structural part of
engine blocks. Maybe I was reading the wrong part of the site. The
problem I
have is this is in the highly stressed part of the platen, where it
experiences
great tension loading!


It seems to me that what you are experiencing agrees pretty well with their
explanation as to the mechanisms involved, though I'm only going on
recollection. It may be that either their products or their data could help.

BTW your EDM power supply worked exactly as I hoped on eroding a square
socket into the hardened stud we were discussing a while back. So, thanks
once again on that.


Hey, great! Glad it worked out for you. How long did it take?

Jon

Jon Elson wrote:

The new crack is 3 inches away, and parallel to the old crack.

OK, this seems to have to deal with thermal tension from welding. I am
_not_ a welding instructor, so don't read my answers like a bible.

What could you do to reduce thermal tension?
- use MIG/MAG
- weld quick and not make the fillet in one pass (we call it "pilgrim's
step", one back two forth)
- weld on both sides intermittent
- leave time between welding passes
- preheat

One last resort might be MAG-brazing*). But if that fails, your piece
might be ruined. MAG-brazing is a "welding" with a CuAl-alloy wire (Or
CuSi, about 95% Cu) in your MAG with Argon. The wire is quite expensive
but will be more flexible. But I don't have enough experience to stand
full behind this advice! Maybe someone else has something to say?

*) That's how about how I would translate it from German, your naming
might vary.

HTH,
Nick
--
Motormodelle / Engine Models
http://www.motor-manufaktur.de

Nick Müller wrote:
Jon Elson wrote:


The new crack is 3 inches away, and parallel to the old crack.


OK, this seems to have to deal with thermal tension from welding. I am
_not_ a welding instructor, so don't read my answers like a bible.

What could you do to reduce thermal tension?
- use MIG/MAG
- weld quick and not make the fillet in one pass (we call it "pilgrim's
step", one back two forth)
- weld on both sides intermittent
- leave time between welding passes
- preheat

One last resort might be MAG-brazing*). But if that fails, your piece
might be ruined. MAG-brazing is a "welding" with a CuAl-alloy wire (Or
CuSi, about 95% Cu) in your MAG with Argon. The wire is quite expensive
but will be more flexible. But I don't have enough experience to stand
full behind this advice! Maybe someone else has something to say?
I've also heard of using pure nickel rod, and peening the weld before
the part cools. I used some stainless steel filler wire, as it has SOME
nickel in it. That weld has held! I did do the weld slowly, ie. in a
small spot at a time, then working on the opposite end of the patch.

What's really driving me crazy is why this platen keeps cracking when
I'm cutting thin aluminum sheet. I am operating at half or less the
capacity the shear should be able to handle.

One "plan B" solution is to remove my patch and make a patch that runs
the full length of the platen, welding it in just to the side of the
two cracks. And, then jam in shims or weld on little blocks that
support the platen along the full length. That ought to work, and
should prevent any more cracking, but it will be a lot more work.

Thanks to everybody for the help with this.

Jon

On Tue, 07 Jun 2005 21:24:46 -0500, Jon Elson
wrote:

What's really driving me crazy is why this platen keeps cracking when
I'm cutting thin aluminum sheet. I am operating at half or less the
capacity the shear should be able to handle.

One "plan B" solution is to remove my patch and make a patch that runs
the full length of the platen, welding it in just to the side of the
two cracks. And, then jam in shims or weld on little blocks that
support the platen along the full length. That ought to work, and
should prevent any more cracking, but it will be a lot more work.

Silly wild-ass guess non-expert off the cuff analysis from a hundred
miles away comment... In other words, Feel free to ignore me, I'm
just thinking out loud here. ;-P

(Oh, and after a quick bit of research... From here to your address
in Kirkwood MO [www.pico-systems.com - I'm not psychic] Mapquest says
it's 1838.67 miles, 27.5 hours. Seems my initial silly guess of 100
miles was a /bit/ low. But I digress...)

If this area is cast iron that gets shock-loaded in tension during
use, it won't take much to make it crack again. Since you tried a
fishplate on the bottom side, and it just cracked where the loads were
moved to one end of the fishplate, I'm thinking there may be an
inherent design weakness in the platen. (Bet you when they changed
over from "Peck Stowe and Wilcox" to "Pexto" they made it heavier...)

How about putting a tension rod through or under the platen, right
below the shear throat edge, thread the ends and use some fine thread
nuts to put some external compression on the platen? Maybe even a
V-block (or two on the webs) at the center like the tensioning rod on
your garage door, to counter any downward forces in the unsupported
center of the platen? THEN you remove the old fishplate, drill the
ends of the cracks, preheat and weld them up again.

You can check the finished side of the platen for bowing, and stop
tightening the tensioning nuts when it gets a very slight positive
arch from the preload.

Better than throwing it out.

-- Bruce --
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

Bruce L. Bergman wrote:

If this area is cast iron that gets shock-loaded in tension during
use, it won't take much to make it crack again.
Yes, that's the main problem.
Since you tried a
fishplate on the bottom side, and it just cracked where the loads were
moved to one end of the fishplate, I'm thinking there may be an
inherent design weakness in the platen. (Bet you when they changed
over from "Peck Stowe and Wilcox" to "Pexto" they made it heavier...)

Maybe, this is a 30" shear, I can't find a gauge rating on it, and it
only weighs 150 Lbs. It has 18 (nameplate) 90 cast into the upper blade
support, so it must be a very early design.
How about putting a tension rod through or under the platen, right
below the shear throat edge, thread the ends and use some fine thread
nuts to put some external compression on the platen? Maybe even a
V-block (or two on the webs) at the center like the tensioning rod on
your garage door, to counter any downward forces in the unsupported
center of the platen? THEN you remove the old fishplate, drill the
ends of the cracks, preheat and weld them up again.
It seems to me that compressing the piece first and then welding is
going to cause even worse problems (unless you never remove the
preload again). If you do ever remove the preload, it might just
crack right then. I arranged to leave the first crack slightly spread
(maybe .020") before doing all the welding. After I was done, the crack
had closed up quite nicely.

You can check the finished side of the platen for bowing, and stop
tightening the tensioning nuts when it gets a very slight positive
arch from the preload.
I'm not sure this is going to be stiff enough. I think having a thick
piece of steel sheet that supports the platen along the entire length
would be a lot stiffer than a rod. It might not even need to be welded
to the platen at any point, just attached to the legs.

Jon

On Tue, 07 Jun 2005 19:24:47 +0200, Nick Müller wrote:

Artemia Salina wrote:

How do you use oil and chalk to find the end of a crack?

Pour some thin oil on the suspect place, let it penetrate, whipe it
carefuly off, and dust some powdered chalk over the place. The chalk
will suck the oil out of the crack and will get dark. voila!
Well, you can also buy expensive super space science spray for that ...

Ok, thanks. That almost sounds like my "dirty thumb" method of crack
detection: Clean suspect area well, then wipe with dirty thumb.

As an retired farmer I used to keep a stream of water running on my
chunks of cast iron , always able to hold it in bear hand. Can be very
slow filling in.

I have a friend who uses nickel. I have also had engine blocks nickel
welded.

Who knows why it keeps breaking, perhaps it is jus old!

If you fix it, try bolting the legs to each other, or bolting it to the
floor really well. Stopping leg spread under load may reduce the
cracking. MAybe

I have had good results welding cast iron with two different rods- the
nickel tig rod, and silicon bronze- tig brazing the cast iron.
With the nickel, a preheat really helps, but just using the rosebud on
the oxy fuel torch will do it- 500 or 600 degrees is plenty, you dont
have to get it red.
The silly bronze rod is more forgiving, as you dont have to get the
base metal as hot.

The small Pexk Stow and Wilcox 30" shears were 18ga max. And most of
those weighed in at 400lbs. My guess is yours is a No. 30, or a No.
130- the only difference is the 130 had little fold down tables left
and right. My guess is years of people ignoring the 18ga rating, and
cutting 16ga stressed the machine out.