12" working railroad

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

Moderators: Glenn Brooks, Harold_V

Forum rules
Topics may include: antique park gauge train restoration, preservation, and history; building new grand scale equipment from scratch; large scale miniature railway construction, maintenance, and safe operation; fallen flags; track, gauge, and equipment standards; grand scale vendor offerings; and, compiling an on-line motive power roster.
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

The lighting in the garage is very poor, so I took a flashlight out to have a look. The original flaking isn't as prominent as it is on yours but it is indeed still there. I also went through the toolbox of stuff that came with it, and I have 11 extra change gears plus what is on the lathe. Thinking I might have the whole set "as from the factory", but I'll need to look at the #'s tomorrow in better light.
Glenn Brooks
Posts: 2929
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: 12" working railroad

Post by Glenn Brooks »

You might have have a nearly new machine! Congrats. 11 gears sounds about right!
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

That's great to know! I was concerned some of the gears were missing and they are pretty proud of them on Ebay.
I engaged the power feed and turned the spindle 1 revolution with a dial indicator on the saddle. The current gear setup is close to .010" per revolution, which I think is a little rough? That said, I'll only be using the power feed for roughing and have to manually feed the compound to finish cut the tapers so it might work fine.
Glenn Brooks
Posts: 2929
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: 12" working railroad

Post by Glenn Brooks »

Ten thou is a little course, but probably a good comprise when hogging off material in a timely manner. I’ve used up to .030” sometimes on my SB Fourteen, just to reduce diameter quickly. Then usually couple of passes at .003 -.005 for finish work. I’ve found with my Dalton (7” swing) the power feed is essential for good finish work. To much surface variability when I try to manually turn more than a couple of inches of round stock. Of course most of my cross cutting is under an inch, so doesn’t matter as much, say as a long shaft or bearing surface.

One thing you might do- post over on the Lathe page, or go to south bend@ groups.io or Practical Machinist, and see if you can find a gear chart for your SB model that shows the feeds and TPI for each gear. Might be a handy reference.
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

The lathe actually has the threading chart in TPI and .001" per revolution on the gear cover, it's stamped pretty small though so I'll need better light to be able to see it. I'm going to do some cleanup and replace some of the light bulbs in the ceiling and try to remedy the light situation so I can actually see what I'm doing.
I'm using a wheel profile of a 5/16" wide flange-then cut with a 10 degree angle on both sides, and finally a 3 degree angle on the "tire" surface. With the surfaces not being very long cuts, I'm hoping I can hand feed those for a decent finish.
Glenn Brooks
Posts: 2929
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: 12" working railroad

Post by Glenn Brooks »

Yep, sounds about right on the wheel dims. Somewhere on line, maybe even earlier on this page there are some proposed 12” ga wheel standards. Can’t remember about flange width- 5/16 might be just fine... Derived from Eric Thompson’s early work building the Redwood Valley RR, down in Tilden Park, SF Bay Area. I’ve done all my wheel profiling and clean up by hand. Now, grinding a special form tool for the radius at the base of the flange might be a good idea... the radius actually helps the truck self steer down the rail, regarding hunting back and forth.

I salvaged an old hi intensity desk lamp out of the house to sit right behind my small lathe. Good lighting helps a lot!
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

I forgot my new lathe bits at work, so had to settle for an old brazed carbide that was less than perfect but worked ok. I think I can get a better finish yet. It seems to like a heavier feed or it chattered a little. I sort of wadded up my mill head tramming tool to center up one of my axle hubs in my 4 jaw and got the runout to about .0007”, and started cutting my first tapers. The wheel set has a "drive dog bolt" in it so I can lock the carriage down and slip each end of each wheel set into the hub in somewhat of a production line method.
57C0D1E2-545F-4A53-8784-2FEE2191732A.jpeg
BAB4EE70-1903-4543-9859-FEC4DD851D3B.jpeg
41B6036D-226C-460D-9074-F48B0D175013.jpeg
FB271F48-9FE7-4044-859F-66ACC415E93C.jpeg
Last edited by rkcarguy on Tue May 12, 2020 12:56 am, edited 1 time in total.
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

Glenn, yes those were the tools I forgot at work, I ground some with a nice radius for that flange root. The cutting I did tonight I had to cut short so I have meat left to cut that radius.
Because the gage essentially becomes a measuring point in space, I’m cutting the 3 degree angle first and facing the flanges (still square) to 12.000” apart. Then I will apply some poor mans dykem (black sharpie) and cut the 10* taper into that “root”. These are my riding car wheel sets, so I have a little room for error and will have this all figured out come time to turn the wheel sets for the locomotive.
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

Got the new bits home and played with grinding some profiles to get a nice finish, and loaded all 3 tool holders to cut each side of the flange and wheel taper. After fiddling around a bit with the setup I got one wheel set all done. I ended up doing an 8* angle on the flange which brought the "point" down to .190" wide before rolling the edges with a file. It doesn't show very well but that is a 3/32 radius in the root of that flange.
Do you think I need to turn more of a radius on those flange corners or is rolling them over with the file adequate?
Just rolling the wheelset down a section of my track it seems to center well and actually rides just inward of center of the flat bar "groovy track" rail, instead of making contact on that inner corner. I think I nailed the profile for the most part.
D4ACA52C-0B93-4F4F-9834-6BA900109C20.jpeg
3D9076A7-C2F7-4EC3-BD35-7E835E8DA86A.jpeg
A35BDBF6-9F0C-4B04-AE13-F8F7459F17D7.jpeg
Glenn Brooks
Posts: 2929
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: 12" working railroad

Post by Glenn Brooks »

Ryan, ideally, the rail profile should match your flange profile. E.g. same radius. groovy track bar has a pretty tight radius, so the smaller the radius probably the better. 3/32” is probably good to go. The theory for the flange radius is the radii forces when the truck wheels start to hunt off to edge of track, the radii forces the wheels to slide sideways back to center. Hence the truck stays centered between the edges of track.

Of course this also assumes your track and wheel gauge are tight and consistent as possible.

The big trade off with groovy track is of course you don’t get the benefit of the matching up to larger radius for ASME designed 12# rail- should you wish to run on another track at some point. Probably not a deal killer for something like my backyard RR. But you might have some future issue - possibly - running theough switches and frogs with your smaller radius. Bit that’s likely a long way in the future... given the paucity of 12” tracks in our neighborhood...

Overall you should be good to go!

Cheers.
Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
rkcarguy
Posts: 1730
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy »

Glenn, it matches the rounded edge of the flat bar I have for my rails. If I was to visit your track for example, with 12# rail and a larger radius I might find I'll hunt a little but I don't think any harm would be done otherwise.
The other radius I was referring to was the outside corners of the flanges. The IBLS wheel profile drawing shows this rounded almost completely with a .125 radius, while I have only rolled the edges to probably ~.050" radius with a file. I don't see this making any difference in the way the wheels would navigate a frog or curve. Even if I turn the wheel set significantly sideways and push it down my track it stays in place and doesn't make any contact with this outer radiused area on the flanges.
Glenn Brooks
Posts: 2929
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: 12" working railroad

Post by Glenn Brooks »

Ryan, I missed that part about the outside edge. Don’t know why the IBLS is .125. Unless they anticipate some outside edge contact with guard rails or frogs, etc. I’d probably increase the radius a bit more just for GP, and ease of handling on the fingers etc, when man handling the wheels and cars during operation. Prototype wheels are pretty heavily radiused as I recall...
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Post Reply