Tag Archives: staybolts

Early-May 2019 Boiler Progress

Mid-Continent Railway Museum Posted on by

Since we have a new month and new Monday we also have a new update! Tom G. from Continental Fabricators writes:

Here is the latest update..
All but 22 backhead stays are installed, most of them have the root pass in and  working on completing the welding.

The side sheet stays are also moving along.
Throat sheet flexible stay installation to start this week…

Included with the update was two photos.

Late-April 2019 Boiler Progress

Mid-Continent Railway Museum Posted on by

Continental Fabricators’ Tom G. supplied Mid-Continent Railway Museum with another new photo and a brief progress update on April 29th. Continental Fabricators is the shop hired to construct a brand new welded boiler for Mid-Continent’s Chicago & North Western #1385 steam locomotive.

“Most of the backhead stays are fit as of this morning and they are beginning to weld. Stays in the sidesheets will be fit this week. The barrel is 60% welded.”

View of 1385 boiler backhead with most stays installed and ready for welding. The backhead is the portion of the boiler that extends into the locomotive cab. The large round hole in the center is where coal is shoveled into the firebox. Photo courtesy Continental Fabricators.

Flexible Staybolt Design and a Boiler Factory Tour

Mid-Continent Railway Museum Posted on by

Photos and text by Pete Deets

Staybolt Update

No, this is not a fleet of UFO’s lined up at SPEC Machine. These are the caps for the latest batch of flexible staybolts being made for the 1385.

 

The caps and sleeves shown (above) and the staybolt itself is completed when a ball end (below left) is threaded onto the bolt and the bolt is placed into the sleeve (below right).

Below is a comparison of the two types.

You may wonder why we need 2 types of flexi’s. That is because we have to allow for support of curved as well as flat surfaces. This illustration from the 1938 Flannery Staybolt Catalog shows how the first batch of staybolts will be applied. This is the UW style and is designed to be used where the staybolt will be going through the supported sheet at close to a right angle and the inside and outside sheets are very close to parallel. The flexible staybolts on the throat sheet at the front corners of the firebox will utilize the UW style.

The latest batch is the WR style which is designed to be applied where the inside and outside sheets curve at different rates and do not run parallel. This is the situation near the top of the wrapper sheet and firebox. Because the top of the firebox (the crownsheet) is rolled in a tighter radius than the wrapper sheet and the rigid end of the staybolt needs to be square to the sheet it is attached to the flexible end goes through its’ sheet at some angle.

All these parts are coming together and will be forming a boiler very soon.

A Look Inside the Continental Fabricators Factory

I took a quick trip with Steve & Tyler Roudebush of SPEC Machine to deliver a palette of parts to Continental Fabricating in St. Louis as well as inspect the progress on the new boiler for 1385. More photos and details about the boiler will be posted later but I wanted to share a few shots of Continental’s shop. I hope this will give folks a feel for the size of operation building our vessel.

 

Preparing for Backhead Stay Installation

Mid-Continent Railway Museum Posted on by

During the last week of January Continental Fabricators began installation of the 1385’s backhead diagonal braces. The backhead is the end of the boiler located within the cab and is a large, flat plate or sheet of steel that has been flanged and then welded to the wrapper sheet.  Flanging is the process of very carefully curling the edges of a sheet to meet the next piece it will be mated to.  The flanging process has been covered in previous update posts.

Much of the boiler is round, a naturally strong shape.  With areas that are flat or nearly flat the forces of nature (including steam pressure) are constantly trying to force them round and thus they require support or “staying”. Staybolts, or “stays” and braces are thus used to reinforce the area and prevent the backhead as well as the other flat areas from bowing outward when the boiler is under pressure.

firebox diagram

While installing these braces, crews at Continental Fabricators flipped the wrapper sheet/backhead assembly upside-down to facilitate easier working conditions. The first photo below shows the assembly as of the last week of January 2019 as the braces are being fitted and tack welded in place.  The tack welds are just enough to hold the braces in place so this assembly can be righted and lowered onto the firebox/mud ring assembly to check for proper clearance between the braces and the firebox.  Once Continental is satisfied with the fit-up between the pieces the wrapper assembly will once again be pulled off the firebox, inverted and the braces will receive the final welds.

upside-down wrapper sheet and backhead

Much of the backhead will be supported via staybolts connected between it and the firebox door sheet. The pictured diagonal braces are used to support the part of the backhead that does not line up with the door sheet and is instead connected to the wrapper sheet for support. This picture was taken during the last week of Jan. 2019. Photo courtesy Continental Fabricators.

A few days later during this the first full week of February, Continental’s crews had flipped the backhead/wrapper sheet assembly right-side-up again and placed it over top the firebox/mud ring assembly. The purpose of doing this is to test fit for any contact between the backhead braces and the firebox crown sheet before final welding of the braces and before the wrapper sheet/backhead assembly is welded to the firebox/mud ring assembly.  Once the two assemblies become one the installation of the staybolts can begin.

Lots and Lots of Staybolts

Mid-Continent Railway Museum Posted on by

A brief update to yesterday’s discussion on staybolts:

SPEC has received the stock to be used for C&NW No. 1385’s rigid staybolts and is cutting it to the length, engraving the heat number and drilling the tell-tale holes per Continental Fabricator’s specifications. There will be over 1000 new rigid staybolts created in all, cut to five different lengths as required by 1385’s boiler.