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

"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

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:

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

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

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