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 Post subject: Drive Rod-Crosshead Wrist Pin
PostPosted: Fri Mar 26, 2021 11:53 am 

Joined: Wed Dec 02, 2015 10:38 am
Posts: 88
I have been working on drawings of Climax CN 1551 as some of you may have noticed based on some of my prior posts here. I am now trying to develop drawings of the Wrist Pin and Bearings at the Crosshead. I hope to be able to visit Cass late next Fall to get some measurements and ideas from CN 1551. However, 1551 is now assembled and I will only be able to see and measure the visible surfaces of the wrist pin etc.

I do have a Climax drawing of the Crosshead itself and measurements I made of the Drive Rod and some dimensions from a Climax drawing of the Drive Rod Assembly with a few notes.

Does anyone have any good drawings of typical Crosshead Wrist Pin configurations on the period 1900 - 1915 (when CN 1551 was designed) so that if and when I again obtain access to 1551 I will have an educated understanding of what I am seeing and measuring. The Climax cast Engine Frames have a Round Hole for access to the inside of the Wrist Pin.

Attachment:
F405R Engine Frame.JPG
F405R Engine Frame.JPG [ 119.11 KiB | Viewed 1916 times ]


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Fri Mar 26, 2021 12:37 pm 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 2000
Location: Strasburg, PA
Attachment:
BLW crosshead & knuckle pins 02.jpg
BLW crosshead & knuckle pins 02.jpg [ 340.13 KiB | Viewed 1883 times ]

This is a top view of a typical wrist pin.

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"It was not easy to convince Allnutt. All his shop training had given him a profound prejudice against inexact work, experimental work, hit-or-miss work."
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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Fri Mar 26, 2021 12:45 pm 

Joined: Wed Dec 02, 2015 10:38 am
Posts: 88
Thanks! That is exactly what I was looking for.


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Fri Mar 26, 2021 4:06 pm 

Joined: Wed Dec 02, 2015 10:38 am
Posts: 88
No indication of Taper in the Climax F188 Crosshead Drawing. Now to determine good "Engineering Practice". Preliminary Draft of Wrist Pin based upon Climax Crosshead Drawing solely.

I do not know if this is "correct" but the 2.696" Dimension is from a Climax Drawing which states the diameter of the Bronze Bearing. Please note that the same dimension of the Split Bronze Bearing for the Crank Pin was a few thousandths SMALLER than the specified dimension of the Crank Pin. Maybe someone can clarify this practice for me on Split Bearings.

Attachment:
F188 Crosshead Assembly Section.jpg
F188 Crosshead Assembly Section.jpg [ 174.29 KiB | Viewed 1740 times ]


Attachments:
F188 Crosshead Assembly Section.pdf [110.57 KiB]
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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Sat Mar 27, 2021 7:24 am 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5985
Location: southeastern USA
Looks like Corry decided to come up against a shoulder rather that draw in to a taper. There are two ways to fit up a split bearing - packed together tightly - with or without shims - or left with some looseness clearance for lubricants (and dirt in the case of Shay crankshafts). Don't know if I'd want to make the ID of the bearing smaller than the OD of the pin in any case though...... seems like asking for a high temp breaking in if not failure.

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Corollary: "He who does is doomed to watch those who don't repeat it anyway."


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Sat Mar 27, 2021 9:10 am 

Joined: Thu Feb 27, 2014 10:08 am
Posts: 559
WESIII wrote:
No indication of Taper in the Climax F188 Crosshead Drawing.

If you are looking for consensus, here is ALCO Practice from early 20s:


Attachments:
ALCO Crossheads.jpg
ALCO Crossheads.jpg [ 201.67 KiB | Viewed 1479 times ]
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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Mon Mar 29, 2021 10:49 am 

Joined: Fri Dec 17, 2010 2:41 pm
Posts: 144
Kelly Anderson wrote:
Attachment:
BLW crosshead & knuckle pins 02.jpg

This is a top view of a typical wrist pin.


Do you have the referenced sheet 5-9A that has the dimensions associated with each letter available to share?

DC


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Mon Mar 29, 2021 4:05 pm 

Joined: Sun Aug 22, 2004 7:37 pm
Posts: 248
Just a shameless plug: Many of you often see pages of the BLW Standard Practice sheets posted here by Kelly Anderson. Original sets of The Baldwin Locomotive Works Standard Practice Book (1927-1948) may be found in series #427m.54 in Manuscript Group 427 BALDWIN-HAMILTON COLLECTION, at the Pennsylvania State Archives, Harrisburg, PA. It is also microfilmed; digital copies of the microfilm may be ordered from us for a fee.

K.R. Bell
Railroad Archivist
Pennsylvania State Archives (PHMC)


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Mon Mar 29, 2021 4:40 pm 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 2000
Location: Strasburg, PA
Donald Cormack wrote:

Do you have the referenced sheet 5-9A that has the dimensions associated with each letter available to share?

DC
I looked, and our copy doesn't have that page.

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"It was not easy to convince Allnutt. All his shop training had given him a profound prejudice against inexact work, experimental work, hit-or-miss work."
C. S. Forester

Strasburg Rail Road Mechanical Department


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Mon Mar 29, 2021 6:11 pm 

Joined: Sun Aug 22, 2004 11:06 am
Posts: 512
Location: NE PA
Attachment:
BALDWIN STD PRAC 9-5A.TIF
BALDWIN STD PRAC 9-5A.TIF [ 69.33 KiB | Viewed 1027 times ]
BLW 9-5A


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Tue Mar 30, 2021 12:41 am 

Joined: Wed Dec 02, 2015 10:38 am
Posts: 88
I have been advised by Grady Smith who was in charge of the CN 1551 restoration for more than 14 years that the Wrist Pin on CN 1551 was tapered. Pending measurements I have used the indicated max dimension on the Inside from the F188 Crosshead Drawing and Tapered the Wrist Pin 1.790° which is a known from several other Climax drawings which do have a taper indicated. See revised drawing. Fifty years of doing historical research has taught me to Never assume I know the answer. Always ask the question(s).

Attachment:
F188 Crosshead Assembly Section Revised.jpg
F188 Crosshead Assembly Section Revised.jpg [ 117.6 KiB | Viewed 882 times ]


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Tue Mar 30, 2021 9:30 am 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 2000
Location: Strasburg, PA
That looks more like it. Note that the keyway in the crosshead will be pointing toward the piston rod, so it isn't affecting the strength of the crosshead casting.

Regarding the journal diameter, it is very odd that Climax would specify anything other than a fractional size for that. Are you certain that the dimension you are referencing isn't smudged or otherwise made illegible?

In any case, the bore of the brass would be whatever the pin size is, plus .005+/-, or in the logging camp, snug but free. Whether the two halves of the brass would be tight together at running clearance, or cut back to rely on the wedge to hold running clearance would be up to the shop foreman.

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"It was not easy to convince Allnutt. All his shop training had given him a profound prejudice against inexact work, experimental work, hit-or-miss work."
C. S. Forester

Strasburg Rail Road Mechanical Department


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Tue Mar 30, 2021 11:26 am 

Joined: Wed Dec 02, 2015 10:38 am
Posts: 88
I have again revised the Wrist Pin to follow Baldwin and Climax practice. All Baldwin except for Pin to act as Key and slightly domed end of Wrist Pin which is in accord with other Climax tapered pins.

I have asked Grady Smith if this is what he remembers/knows?

As to your comment on the Pin diameter, I have been aware of that issue and am in agreement with you and will re-check all the Climax info I have. The Crosshead drawing itself referred to another Climax drawing for details which probably contained the taper and dimension(s) which are missing/uncertain.

Attachment:
Wrist Pin Baldwin-Climax3.jpg
Wrist Pin Baldwin-Climax3.jpg [ 14.13 KiB | Viewed 610 times ]


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Thu Apr 01, 2021 2:27 pm 

Joined: Wed Dec 02, 2015 10:38 am
Posts: 88
This is a undimensioned profile of a Wrist Pin for Climax A-313 (1902).

Whether Climax changed its method by 1919 for C-1551 yet unknown.

Attachment:
A-313 Wrist Pin (2).JPG
A-313 Wrist Pin (2).JPG [ 59.41 KiB | Viewed 509 times ]


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 Post subject: Re: Drive Rod-Crosshead Wrist Pin
PostPosted: Fri Apr 02, 2021 8:42 am 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 2000
Location: Strasburg, PA
WESIII wrote:
This is a undimensioned profile of a Wrist Pin for Climax A-313 (1902).

Whether Climax changed its method by 1919 for C-1551 yet unknown.
Note that your drawing shows a pin nearing the end of its life in that the journal diameter is turned down to where it is nearly impinging on the smaller taper. Our practice is to make a new pin with the journal as large as will fit through the small end of the large tapered hole to give it the most life possible to wear and be turned down until the journal starts to impinge on the small taper where it locks into the crosshead.

The exception to that would be when making the journal as large as possible would cause the brass bushing to be too thin for safety. In that case, perhaps it is time to consider welding down and reboring the tapered holes in the crosshead.

There would be no reason to change between 313, and 1551. What you have was the industry standard until near the end of steam when wrist pins that were installed from the outside (what a concept!) began to be used (and they still used the tapered seats as shown).

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"It was not easy to convince Allnutt. All his shop training had given him a profound prejudice against inexact work, experimental work, hit-or-miss work."
C. S. Forester

Strasburg Rail Road Mechanical Department


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