VIntage 1923 Structural Channel Section

[Peckett]

Hi,

I am restoring a 1923 Climax steam locomotive in New Zealand. The frame/chassis is made up of a pair of channels (one each side of the loco), each fitted with a doubling plate.

The chassis is pretty corroded, and we are looking at replacing it.

The channel has a standard section, except the web thickness is much greater than today's sections.

The details are:

Tapered flange channels

Height 203mm (8”)
Width ~67mm (2 ½”)
Web thickness ~15mm (most likely 9/16”)

I would prefer to replace the channels with like for like, but have not found any channel of this section available on the market.

Does anyone know where we can buy this section?
If we have to use a thinner section channel, we were intending to increase the thickness of the doubling plate to make the total web + doubling plate thickness the same. Any ideas on how this may act on a loco with vibrations, oscillating loads etc.

Any help appreciated.


Cheers,


Chris

 

[Teguci]

C8x18.7
F = 2 1/2" x 0.39 avg with 2/12 taper
W = 1/2"

For vibration loading I'd suggest welding the plate and channel together. If you insist on bolts, you will need to provide a slip critical connection to prevent loosening over time.

 

[msquared48]

Have you tried to contact the people who restored this one?

http://www.australiansteam.com/Climax 1653.htm

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[Peckett]

Tequci,

Thanks for this. Weldign the plate to the channel is a possibility. The current doubler is bolted. Teh current bolted design is probably a slip critical connection, but I haven't checked this.

I wonder if welding will give the same characteristics as a bolted connection. With the welded connection, the connection is only at the flanges (where the weld is), and the channel may flex between the welded connection.

Mike,

Thnaks for your comment. We haven't been in touch with these guys, but thanks for the link. There are several Climax's in restoration around the world at the moment, and we are in contact with 2 of them. The 3rd one in the US has a good website showing what they have done. This includes extensive weld repairs to their channel frames, where they have replaced large sections of the flanges.

Appreciate your help with this.

Chris

 

[paddingtongreen]

Motor channels have heavier webs and are available in the USA:

http://www.tmtco.com/products/channels.html

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[ToadJones]

never heard these called "motor" channels...

 

[paddingtongreen]

That's because you're not old enough.

They call them miscellaneous channels now, but they were odd sizes used for auto frames back when they had frames.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[ToadJones]

Oh, I thought you may have been referring to Car channels ...but they dont look like regular channels.

 

[paddingtongreen]

Now there's a conundrum, I don't remember if I came across them after I came to the USA, it could have been British terminology. They had started morphing from the special shapes intended only for the auto industry.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[Teguci]

MC = Car building and shipbuilding channels, never heard them referred to as Motor Channels though. Seen them on drawings as SC.

Peckett - Love it if you shared photos of your work from time to time. As for the welding vs bolting, I'd leave the bolts for decoration, but rely on the weld for the connection.

 

[msquared48]

Never knew that...

We always referred to MC channels as "Miscellaneous Channels".

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[ToadJones]

Car Channels and Z's are not MC's...look nothing like a MC

 

[dhengr]

Peckett:
Determine what combined section existed. Determine that combined section’s section properties and use something as husky or slightly stiffer. Look for an C8x18.75 which is very close to what you measured and a slightly huskier (thicker) doubler plate. Almost any steel you buy today will give you a higher yield strength than what was used in 1923. Alternatively, you must determine the Fy of the existing material and purchase something stronger.

If I understand correctly your doubler plate is a second web plate, standing vertically and bolted to the web of the channel. I would use two continuous fillet welds to attach the doubler plate to the new channel, at/near each channel flange. This weld and detail has very good resistance to vibration and fatigue. They did not have high strength bolts back then, so forget slip critical joints, actually rivets would have been better at really connecting the two pieces because they filled the holes. However, you will still undoubtedly have drilled web holes and bolts for attaching these built-up channel sills to the cross framing and other mechanical components. Some of this cross framing and some of the equipment brackets might also be welded, thus making an entire sub-frame. Then add a few bolts and nuts only where authenticity and aesthetics dictate, but they won’t actually be load carrying or a significant part of the connection.

Misc. channels, MC channels are probably not a good choice, their flanges are wider. This might lead to interference (clearance problems) with running gear, cylinders, piping or other mechanical components. Try to match the existing channel size fairly closely. A slightly thicker doubler plate will probably give you fewer fit-up and clearance problems. Staying within or near the same sub-frame envelope and clearance around it will likely be your biggest problem with all that goes on under those locomotives. Study this well as you disassembly and rebuild. I’ve never heard the motor channel terminology either, although their most common use used to be in railcar and ship building.

 

[Teguci]

Pretty sure these car building channels match up with whats in AISC (seeing as thats where this is from).

 

[Peckett]

Thanks for all your messages. An interesting problem! dhengr, thanks for your practical comments. Your interpretation of the doubler is correct - it is bolted to the web of the channel. It appears to be fitted to the profile of the channel, producing a snug fit.

So it seems that finding a channel of the same section as original is unilkely. Redesigning the combined channel/doubling plate looks like th eway to go.

I'll post some photos of the loco.

Cheers,


Chris

 

[dhengr]

Peckett:
I think you have a match in the C8x18.75 that Teguci suggesting in the very first post back to you. That’s why I mentioned it too. And, it is still a commonly available std. channel section, I believe, in a number of different grades. Many of these channel shapes changed slightly over the years, a 16th here and there, due to rolling practices or demand, etc. With your ~15mm web, be sure you are not measuring on a few spots of rust, then consider rolling tolerances too. And, if in doubt on the web thickness make this up with a 2mm increase in the doubler pl. thickness. Is your doubler pl. 9" or 7.25" wide (high), to make for a good weld connection detail, and this may incline you to add another mm in its thickness for total section properties. They may have used an 8" double pl. because they were matching heights and bolting, but you don’t want to have to prep. two grooves on the doubler pl. to make the welds to the C8. So, make the pl. .75-1" wider (higher) or narrower than your channel is heigh, then you can just use two fillet welds.

The MC channels changed even more over the years, due to demand, or lack thereof. In the railcar business we wanted the added beef in the flanges for section properties and we wanted the added width for easier bolting through the flange. These were primarily side sill, center sill and end sill shapes. If you post further on your rebuilding project you might consider posting on forum #671, “Railroad equipment engineering,” there are a few people there who understand railcars and locomotives, some of them frequent this forum too, but it should be interesting in either forum. I’ll watch and comment, either place.

 

[Peckett]

Dhengr,

Thanks for this. Teguci's (struggling with the spelling on all these non-de-plumes!) channel did have a smaller web thickness, but was otherwise the same.

One of my colleagues has found an early 20th century standard that has this channel with a 9/16th web thickness. So in an ideal world, someone would know a steel company that still makes this section. I thought this was unilkely but possible.

I have uploaded one photo. Not sure how to upload multiple photos on this message format, but have a number of further photos that may be of interest.


Chris