Regauging a 7 1/4" Minnie Project

Where users can chronicle their builds. Start one thread and continue to add on to it.

Moderator: Harold_V

10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

I purchased a 7 1/4" gauge Minnie locomotive project a few years back that has been left dormant way too long. Upon inspection several things needed attention in the running gear, valve gear and boiler. I will elaborate in future post.

We recently bought winter property in Florida and upon inspection I have decided to tear it down and regauge it to 7 1/2".

Rob
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

First upon removal and inspection of the cylinders. The packing glands were using O-Rings which I dislike due to wear out and having to disassembled everything to replace. So I converted to packing glands for graphite packing material.

Second, there were no cylinder drain cocks and the drain ports were not machined in. I will note the cylinders are the same as used on my Allen Ten Wheeler, so I had prints and knew what was needed. So machined in the ports and made a set of automatic cylinder cocks.

Next I noticed the bores were machined very well, but had not been honed to smooth the tool mark ridges. So I honed them.

Next the cylinder heads were not machined to correct thickness, which means the cylinder to piston clearances were under size and the brass covers would not cover right. So machined them to proper dimensions. Then I made brass cylinder jackets and machined and mounted the cylinder cover blanks to fit.
Attachments
IMG_20171020_210947_856_640x360.jpg
IMG_20171023_175034_508_640x360.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Next up was removing the main driver axles and cleaning the hardened grease from the needle bearings, the project had bee stored for several years so that was expected. This is that laminated frame locomotive design so a lot screw removal to get at the bearings.

The axles fits to wheels were way to lose for Loctite and one had been knerled as well. The lube passage had not been cross drilled to get lube from the hole in the axle center to the bearings either.

New axles were made to be 1/4" longer and to fix poor fit issue. Still require locking compound due to the free construction not allowing wheels and axles to be preassembled. The derivers are keyed to the axles for alignment.

He a pic of the old axles.
Attachments
IMG_20171024_204955_314_640x360.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Painted the frame from the cab deck forward. It was now or never before driver and axle assembly.

A trial fit of the drivers and old side rods came out great. Drivers roll without any binding.

Also added the regauged pilot truck and trailing axle.

Shorting crank pins is next to be done to work with the regaging.
Attachments
IMG_20171108_154555_417_640x360.jpg
IMG_20171108_171546_153_640x360.jpg
IMG_20171108_172006_790_640x360.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Today's progress.

Crank pins shortened for the regauging.

Stevenson's valve gear eccentric strap rod lengths checked. The red dimension in the picture was off by 0.041 to 0.387 inches over size. Reworked and ready to put back on when the time comes.
Attachments
IMG_20171110_153729_234_640x360.jpg
User avatar
dnevil
Posts: 373
Joined: Fri Aug 03, 2012 10:19 am
Location: Springtown, Texas
Contact:

Re: Regauging a 7 1/4" Minnie Project

Post by dnevil »

About 18 months ago I contacted Bill Oberpriller and received permission to harvest and reproduce his website for the Minnie project. I hope it will be a help to you and other Minnie owners/builders.

http://ibls.org/mediawiki/index.php?tit ... 27s_Minnie

Happy steaming!
Daris
Daris Nevil
IBLS Secretary
North American Region
http://www.ibls.org
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Daris, that's great to hear. I only got a partial set of plans with the project. So additional information will be helpful.

Rob
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Here's a couple of Minnie completed pictures that were on the above posted link.

I have the ballon stack from the first pic and the metal cab from the second.
Attachments
Bret_Kuebar_Engine13_Minnie2_resized_640x341.jpg
BillOberpriller_and_MinnieII_640x479.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

While I am waiting for rod material to arrive. I got the blast pipe fittings made and the inlet fittings set up in the saddle.
Attachments
1113170741_Burst19_640x480.jpg
1113170743_640x480.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Rest of today was spent on correcting the defencies in the Steven's valve gear links. A lot of time consuming fiddly work.

Drilled and put in dowel pins on the rocker arms and lifting arms. They were just set screwed. Added oil holes to the swing links and rocker boxes. And did trial for to get position of the outside rocker arms on the shafts for drilling there pin holes.

Also measured and sketched out the valve rods and made the adjusting coupler nut. The builder had it set up for a single rod passing through a bar in the slide valve that also has a set screw to secure and adjust it. Using set screw attachments as primary fastening are failures waiting to happen.
Attachments
1113171715_HDR_640x480.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Today's progress, fished the valve rods, adjustor couplings, made stainless valve stems and T nuts for the valve
Attachments
1115171806_HDR_640x480.jpg
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Regauging a 7 1/4" Minnie Project

Post by 10 Wheeler Rob »

Got drivers a fixed to axles with Loctite retaining compound, mounted the cylinders and cut gaskets for cylinder heads and steam chest.

The close fit between front drivers and cylinders required trimming the cylinder covers so they can be installed over the valve head and clear the wheel flange. Trimed area does not show after assembly because its hidden behind the cylinder.
Attachments
1119172152_HDR_640x480.jpg
Post Reply