Hi folks,

Happy New Year!

I have a challenge for everyone. I've just bought an old monkey wrench.
I bought it because I couldn't figure out how it had been made, and I
wanted to know. It's marked "Trimo" and was made by the Trimont
Manufacturing Co. of Roxbury, Massachusetts. Someone here might have the
same wrench.

Anyway, the wrench has an approximately rectangular hollow channel in
which the movable jaw slides. The channel has closed sides, i.e., it
isn't a T-slot. The wrench appears to be forged. The movable jaw is
marked "Drop Forged", although the fixed jaw isn't.

There is a line around the whole of the wrench, which appears to have
been made at the junction between the forging dies. The line also goes
down the back wall of the hollow channel.

I'm puzzled because the channel has sharp corners. If the corners were
radiused, I could imagine that the body of the wrench was a solid
forging, which later had the channel cut using an end mill or small
grinding wheel. But the corners are sharp.

There are no visible machining or grinding marks inside the channel.

I can only think that perhaps:
(i) The channel was punched out in a secondary forging operation.
(ii) The channel was created in a complex forging (possibly forge
welding) operation designed to make hollow parts.
(iii) The body of the wrench is actually a sand casting.

I'm inclined to favour option (i). I'd be interested to hear what other
people think.

I even checked the patent listed on the wrench, but it says nothing
about how the body is made.

Here are some pictures:
http://www.mythic-beasts.com/~cdt22/trimo1.jpg
http://www.mythic-beasts.com/~cdt22/trimo2.jpg
http://www.mythic-beasts.com/~cdt22/trimo3.jpg

Best wishes,

Chris

Christopher Tidy wrote:

Hi folks,

Happy New Year!

I have a challenge for everyone. I've just bought an old monkey wrench.
I bought it because I couldn't figure out how it had been made, and I
wanted to know. It's marked "Trimo" and was made by the Trimont
Manufacturing Co. of Roxbury, Massachusetts. Someone here might have the
same wrench.

Anyway, the wrench has an approximately rectangular hollow channel in
which the movable jaw slides. The channel has closed sides, i.e., it
isn't a T-slot. The wrench appears to be forged. The movable jaw is
marked "Drop Forged", although the fixed jaw isn't.

There is a line around the whole of the wrench, which appears to have
been made at the junction between the forging dies. The line also goes
down the back wall of the hollow channel.

I'm puzzled because the channel has sharp corners. If the corners were
radiused, I could imagine that the body of the wrench was a solid
forging, which later had the channel cut using an end mill or small
grinding wheel. But the corners are sharp.

There are no visible machining or grinding marks inside the channel.

I can only think that perhaps:
(i) The channel was punched out in a secondary forging operation.
(ii) The channel was created in a complex forging (possibly forge
welding) operation designed to make hollow parts.
(iii) The body of the wrench is actually a sand casting.

I'm inclined to favour option (i). I'd be interested to hear what other
people think.

I even checked the patent listed on the wrench, but it says nothing
about how the body is made.

Here are some pictures:
http://www.mythic-beasts.com/~cdt22/trimo1.jpg
http://www.mythic-beasts.com/~cdt22/trimo2.jpg
http://www.mythic-beasts.com/~cdt22/trimo3.jpg

Best wishes,

Chris


The channel was broached.

Cheers
Trevor Jones

Christopher Tidy wrote:

Hi folks,

Happy New Year!

I have a challenge for everyone. I've just bought an old monkey wrench.
I bought it because I couldn't figure out how it had been made, and I
wanted to know. It's marked "Trimo" and was made by the Trimont
Manufacturing Co. of Roxbury, Massachusetts. Someone here might have the
same wrench.

Anyway, the wrench has an approximately rectangular hollow channel in
which the movable jaw slides. The channel has closed sides, i.e., it
isn't a T-slot. The wrench appears to be forged. The movable jaw is
marked "Drop Forged", although the fixed jaw isn't.

There is a line around the whole of the wrench, which appears to have
been made at the junction between the forging dies. The line also goes
down the back wall of the hollow channel.

I'm puzzled because the channel has sharp corners. If the corners were
radiused, I could imagine that the body of the wrench was a solid
forging, which later had the channel cut using an end mill or small
grinding wheel. But the corners are sharp.

There are no visible machining or grinding marks inside the channel.

I can only think that perhaps:
(i) The channel was punched out in a secondary forging operation.
(ii) The channel was created in a complex forging (possibly forge
welding) operation designed to make hollow parts.
(iii) The body of the wrench is actually a sand casting.

I'm inclined to favour option (i). I'd be interested to hear what other
people think.

I even checked the patent listed on the wrench, but it says nothing
about how the body is made.

Here are some pictures:
http://www.mythic-beasts.com/~cdt22/trimo1.jpg
http://www.mythic-beasts.com/~cdt22/trimo2.jpg
http://www.mythic-beasts.com/~cdt22/trimo3.jpg

Best wishes,

Chris

Broach.

Tom

"Trevor Jones" wrote in message
news:fsyej.43598$UZ4.20644@edtnps89...
Christopher Tidy wrote:

Hi folks,

Happy New Year!

I have a challenge for everyone. I've just bought an old monkey wrench. I
bought it because I couldn't figure out how it had been made, and I
wanted to know. It's marked "Trimo" and was made by the Trimont
Manufacturing Co. of Roxbury, Massachusetts. Someone here might have the
same wrench.

Anyway, the wrench has an approximately rectangular hollow channel in
which the movable jaw slides. The channel has closed sides, i.e., it
isn't a T-slot. The wrench appears to be forged. The movable jaw is
marked "Drop Forged", although the fixed jaw isn't.

There is a line around the whole of the wrench, which appears to have
been made at the junction between the forging dies. The line also goes
down the back wall of the hollow channel.

I'm puzzled because the channel has sharp corners. If the corners were
radiused, I could imagine that the body of the wrench was a solid
forging, which later had the channel cut using an end mill or small
grinding wheel. But the corners are sharp.

There are no visible machining or grinding marks inside the channel.

I can only think that perhaps:
(i) The channel was punched out in a secondary forging operation.
(ii) The channel was created in a complex forging (possibly forge
welding) operation designed to make hollow parts.
(iii) The body of the wrench is actually a sand casting.

I'm inclined to favour option (i). I'd be interested to hear what other
people think.

I even checked the patent listed on the wrench, but it says nothing about
how the body is made.

Here are some pictures:
http://www.mythic-beasts.com/~cdt22/trimo1.jpg
http://www.mythic-beasts.com/~cdt22/trimo2.jpg
http://www.mythic-beasts.com/~cdt22/trimo3.jpg

Best wishes,

Chris


The channel was broached.

Probably after being hot-punched in a secondary forging operation. The whole
body could be forged and punched in two hits.

--
Ed Huntress

Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The whole
body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.

Best wishes,

Chris

"Christopher Tidy" wrote in message
...
Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.

Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file -- some
as long as twenty feet or so -- with each successive tooth cutting a
thousanth or three more than the last one, typically cutting on all sides at
once (or not, depending on the job -- some cut on only one side at a time).
They come in two general types: pull-broaches and push-broaches. They were
made from a single piece of tool steel but recent ones have replaceable
inserts.

The broaching likely was done cold. The rough-punched body would be held and
supported in a fixture. Designing a feature for support is an important part
of designing the forging.

--
Ed Huntress

Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.


Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file -- some
as long as twenty feet or so -- with each successive tooth cutting a
thousanth or three more than the last one, typically cutting on all sides at
once (or not, depending on the job -- some cut on only one side at a time).
They come in two general types: pull-broaches and push-broaches. They were
made from a single piece of tool steel but recent ones have replaceable
inserts.

The broaching likely was done cold. The rough-punched body would be held and
supported in a fixture. Designing a feature for support is an important part
of designing the forging.

Thanks, Ed. That's interesting. Does anyone have a picture of one of
those broaches?

How did they make the hole into which the broach was inserted? With a
twist drill?

Best wishes,

Chris

Christopher Tidy wrote:
Ed Huntress wrote:

"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

snip

The channel was broached.



Probably after being hot-punched in a secondary forging operation.
The whole body could be forged and punched in two hits.


Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel
with such thin walls (only about 3/32" thick) without everything
getting mangled. Guess the key must be getting it hot enough.



Production broaching is not much like the kind we do in hobby work.
The broach itself looks more like a long, extremely coarse tapered
file -- some as long as twenty feet or so -- with each successive
tooth cutting a thousanth or three more than the last one, typically
cutting on all sides at once (or not, depending on the job -- some cut
on only one side at a time). They come in two general types:
pull-broaches and push-broaches. They were made from a single piece of
tool steel but recent ones have replaceable inserts.

The broaching likely was done cold. The rough-punched body would be
held and supported in a fixture. Designing a feature for support is an
important part of designing the forging.


Thanks, Ed. That's interesting. Does anyone have a picture of one of
those broaches?

I think I found one:
http://www.ohiobroach.com/index/broaching2

Chris

"Christopher Tidy" wrote in message
...
Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.


Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file --
some as long as twenty feet or so -- with each successive tooth cutting a
thousanth or three more than the last one, typically cutting on all sides
at once (or not, depending on the job -- some cut on only one side at a
time). They come in two general types: pull-broaches and push-broaches.
They were made from a single piece of tool steel but recent ones have
replaceable inserts.

The broaching likely was done cold. The rough-punched body would be held
and supported in a fixture. Designing a feature for support is an
important part of designing the forging.

Thanks, Ed. That's interesting. Does anyone have a picture of one of those
broaches?

How did they make the hole into which the broach was inserted? With a
twist drill?

Best wishes,

Chris

Here are some photos and descriptions. Google "pull broach" and you'll get
more than you ever wanted to know:

http://www.ohiobroach.com/index/broaching2

http://www.americanbroach.com/tools.htm

http://www.kingsfordbroach.com/products.htm

http://www.millerbroach.com/engineering.html

http://cgi.ebay.com/STRAIGHT-SPLINE-...QQcmdZViewItem

Pull broaches are a lot longer, but you can search "push broach" to round
out the picture. Your wrench likely was push-broached.

The holes in forgings like that are usually pierced with a piercing punch
while the metal is red hot. That was the "second hit" I was talking about.
This is a carryover from the days of blacksmithing. Hot-piercing is a common
process in forging all sorts of products, whether by hand or by machine.

--
Ed Huntress

Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

"Christopher Tidy" wrote in message
...


Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.


Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file --
some as long as twenty feet or so -- with each successive tooth cutting a
thousanth or three more than the last one, typically cutting on all sides
at once (or not, depending on the job -- some cut on only one side at a
time). They come in two general types: pull-broaches and push-broaches.
They were made from a single piece of tool steel but recent ones have
replaceable inserts.

The broaching likely was done cold. The rough-punched body would be held
and supported in a fixture. Designing a feature for support is an
important part of designing the forging.

Thanks, Ed. That's interesting. Does anyone have a picture of one of those
broaches?

How did they make the hole into which the broach was inserted? With a
twist drill?

Best wishes,

Chris


Here are some photos and descriptions. Google "pull broach" and you'll get
more than you ever wanted to know:

http://www.ohiobroach.com/index/broaching2

http://www.americanbroach.com/tools.htm

http://www.kingsfordbroach.com/products.htm

http://www.millerbroach.com/engineering.html

http://cgi.ebay.com/STRAIGHT-SPLINE-...QQcmdZViewItem

Pull broaches are a lot longer, but you can search "push broach" to round
out the picture. Your wrench likely was push-broached.

The holes in forgings like that are usually pierced with a piercing punch
while the metal is red hot. That was the "second hit" I was talking about.
This is a carryover from the days of blacksmithing. Hot-piercing is a common
process in forging all sorts of products, whether by hand or by machine.

Thanks, Ed. I've now got the explanation I wanted.

Best wishes,

Chris

"Christopher Tidy" wrote in message
...
Christopher Tidy wrote:
Ed Huntress wrote:

"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

snip

The channel was broached.



Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.


Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.



Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file --
some as long as twenty feet or so -- with each successive tooth cutting
a thousanth or three more than the last one, typically cutting on all
sides at once (or not, depending on the job -- some cut on only one side
at a time). They come in two general types: pull-broaches and
push-broaches. They were made from a single piece of tool steel but
recent ones have replaceable inserts.

The broaching likely was done cold. The rough-punched body would be held
and supported in a fixture. Designing a feature for support is an
important part of designing the forging.


Thanks, Ed. That's interesting. Does anyone have a picture of one of
those broaches?

I think I found one:
http://www.ohiobroach.com/index/broaching2

Chris

Yeah, that's it. I've seen them as big around as your thigh, and nearly 20
feet long. That one machined the internal teeth on the ring of a planetary
gearset in one pull -- maybe five to ten seconds.

--
Ed Huntress

That isn't a monkey wrench. It is the tool before a Crescent.
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Life; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


Christopher Tidy wrote:
Hi folks,

Happy New Year!

I have a challenge for everyone. I've just bought an old monkey wrench.
I bought it because I couldn't figure out how it had been made, and I
wanted to know. It's marked "Trimo" and was made by the Trimont
Manufacturing Co. of Roxbury, Massachusetts. Someone here might have the
same wrench.

Anyway, the wrench has an approximately rectangular hollow channel in
which the movable jaw slides. The channel has closed sides, i.e., it
isn't a T-slot. The wrench appears to be forged. The movable jaw is
marked "Drop Forged", although the fixed jaw isn't.

There is a line around the whole of the wrench, which appears to have
been made at the junction between the forging dies. The line also goes
down the back wall of the hollow channel.

I'm puzzled because the channel has sharp corners. If the corners were
radiused, I could imagine that the body of the wrench was a solid
forging, which later had the channel cut using an end mill or small
grinding wheel. But the corners are sharp.

There are no visible machining or grinding marks inside the channel.

I can only think that perhaps:
(i) The channel was punched out in a secondary forging operation.
(ii) The channel was created in a complex forging (possibly forge
welding) operation designed to make hollow parts.
(iii) The body of the wrench is actually a sand casting.

I'm inclined to favour option (i). I'd be interested to hear what other
people think.

I even checked the patent listed on the wrench, but it says nothing
about how the body is made.

Here are some pictures:
http://www.mythic-beasts.com/~cdt22/trimo1.jpg
http://www.mythic-beasts.com/~cdt22/trimo2.jpg
http://www.mythic-beasts.com/~cdt22/trimo3.jpg

Best wishes,

Chris

Martin H. Eastburn wrote:
That isn't a monkey wrench. It is the tool before a Crescent.

It says "10 inch M.W." on it.

Chris

Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

Christopher Tidy wrote:

Ed Huntress wrote:


"Christopher Tidy" wrote in message
...


Ed Huntress wrote:

snip

The channel was broached.



Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.


Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.



Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file --
some as long as twenty feet or so -- with each successive tooth cutting
a thousanth or three more than the last one, typically cutting on all
sides at once (or not, depending on the job -- some cut on only one side
at a time). They come in two general types: pull-broaches and
push-broaches. They were made from a single piece of tool steel but
recent ones have replaceable inserts.

The broaching likely was done cold. The rough-punched body would be held
and supported in a fixture. Designing a feature for support is an
important part of designing the forging.


Thanks, Ed. That's interesting. Does anyone have a picture of one of
those broaches?

I think I found one:
http://www.ohiobroach.com/index/broaching2

Chris


Yeah, that's it. I've seen them as big around as your thigh, and nearly 20
feet long. That one machined the internal teeth on the ring of a planetary
gearset in one pull -- maybe five to ten seconds.

That sounds awesome if you need to cut internal gear teeth of a
particular size. I'd certainly love to see a machine like that in action!

Best wishes,

Chris

Christopher Tidy wrote:
Martin H. Eastburn wrote:

That isn't a monkey wrench. It is the tool before a Crescent.


It says "10 inch M.W." on it.

Chris

Stick ta ya guns, Chris. or go he

http://www.metalworking.com/dropbox/wrenches.jpg

Of course ya owe me a pint now. :-)

Tom

Fine - it has the pipe wrench design but flats.
The monkey wrenches I am used to had pipe jaws.
These might be a variant that tried to take Crescent on.
I think I have a variant in another direction.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Life; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


Christopher Tidy wrote:
Martin H. Eastburn wrote:
That isn't a monkey wrench. It is the tool before a Crescent.

It says "10 inch M.W." on it.

Chris

Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.


Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file -- some
as long as twenty feet or so -- with each successive tooth cutting a
thousanth or three more than the last one, typically cutting on all sides at
once (or not, depending on the job -- some cut on only one side at a time).
They come in two general types: pull-broaches and push-broaches. They were
made from a single piece of tool steel but recent ones have replaceable
inserts.

Another thing I've been wondering about: is the broach inserted into an
oversize hole and firmly held by guide rails, or is the broach
self-centring in a tight pilot hole? In other words, what determines the
precise location of the broached hole?

Best wishes,

Chris

"Christopher Tidy" wrote in message
...
Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

Ed Huntress wrote:

snip

The channel was broached.


Probably after being hot-punched in a secondary forging operation. The
whole body could be forged and punched in two hits.

Thanks for the thoughts. That was my own best guess.

I'm a little surprised that it's possible to broach a deep channel with
such thin walls (only about 3/32" thick) without everything getting
mangled. Guess the key must be getting it hot enough.


Production broaching is not much like the kind we do in hobby work. The
broach itself looks more like a long, extremely coarse tapered file --
some as long as twenty feet or so -- with each successive tooth cutting a
thousanth or three more than the last one, typically cutting on all sides
at once (or not, depending on the job -- some cut on only one side at a
time). They come in two general types: pull-broaches and push-broaches.
They were made from a single piece of tool steel but recent ones have
replaceable inserts.

Another thing I've been wondering about: is the broach inserted into an
oversize hole and firmly held by guide rails, or is the broach
self-centring in a tight pilot hole? In other words, what determines the
precise location of the broached hole?

Push broaches are usually located with their own guides, but they can be
free-floating in jobs for which precise location is not important. In the
case of a an old wrench, it could be free-floating. The punched hole was
close enough.

The hole is undersize, not oversize. The leading end of the broach is
undersize, and then the teeth progressively cut the hole to size.

--
Ed Huntress

Ed Huntress wrote:

Push broaches are usually located with their own guides, but they can be
free-floating in jobs for which precise location is not important. In the
case of a an old wrench, it could be free-floating. The punched hole was
close enough.

Thanks. It's interesting to know that you can get both kinds. Looking at
the wrench, the hole appears to be quite precisely located, so I imagine
there was some kind of guide.

The hole is undersize, not oversize. The leading end of the broach is
undersize, and then the teeth progressively cut the hole to size.

I meant oversize relative to the small end of the broach, not the
finished hole.

Best wishes,

Chris