Taskboard TT Scale Tie Strips

Re: Taskboard TT Scale Tie Strips

Postby areibel » Tue Jun 03, 2014 2:39 pm

Like Bernd said, steam wheels are a whole different ball of wax!
Several guys have been experimenting with different centers, of plastic, white metal or brass. They can be cast up easily enough, but the machining necessary is a bugger. The center needs turned to the correct diameter for a press fit into the tire with the insulating material. The tire itself needs to be turned to the correct flange and taper, and the right ID to fit the center. Then you have to have the axle bores all correct, plus the centerlines of the crank pins need to be drilled the same diameter from the center and tapped. If you're using a resin center it's suggested to cast a brass block into it to accept the crank pin hole, once it's tapped there's no worry about the crank pins.
There's a Brass Loco Builder's group on Yahoo, there's some good info there. Several guys have made their own drivers, even spoke by spoke, but they're usually in O or S scale. And they're making wheels for one loco, so turning out a product to sell any numbers of (even in TT!) would be time consuming.
But if you do decide to do 63" spoked drivers, I'll be the first customer! Worsley Works in the UK offer a couple different etched chassis kits, there was a neat article in Model Railroad Hobbyist about scratchbuilding a boiler out of styrene and there are a few steam detail parts available.. I might be able to get an Erie Pacific yet!
areibel
 
Posts: 1700
Images: 7
Joined: Fri Jun 12, 2009 10:12 am
Location: Cambridge Springs PA

Re: Taskboard TT Scale Tie Strips

Postby areibel » Tue Jun 03, 2014 7:47 pm

Oops! Typo on my part, 69" is what I meant. 79" would work as well, there were classes with them as well, but I think the available chassis would work better with the smaller ones. There's a chart at the bottom of the page here-
http://rr-fallenflags.org/el/loco/erie-jk.html
areibel
 
Posts: 1700
Images: 7
Joined: Fri Jun 12, 2009 10:12 am
Location: Cambridge Springs PA

Re: Taskboard TT Scale Tie Strips

Postby ConnRiver » Thu Jun 05, 2014 8:12 am

Rats! Tough week at work, long days. I've started replies to posts here to share what I've learned but can't finish till Saturday. Just a note to say I haven't bailed on the discussion here. Exciting to read what everyone has to say about track and wheels topics.

-Brian

Brian Chapman / Cedar Rapids, Iowa
Brian Chapman
Cedar Rapids, Iowa / USA
ConnRiver
 
Posts: 428
Joined: Tue Sep 15, 2009 10:51 am
Location: Cedar Rapids, Iowa / USA

Re: Taskboard TT Scale Tie Strips

Postby ConducTTor » Thu Jun 05, 2014 9:29 pm

Bernd wrote:I got down to 5 pieces left to machine for the coupler height gauge and I discovered I had measure wrong and made the 28 pieces to thin.


Sadly I think we've ALL done that at some point :lol:
What people think: "liberals/conservatives are ruining my country"
What the powerful know: divide and conquer
User avatar
ConducTTor
Site Admin
 
Posts: 8293
Images: 13
Joined: Sat May 23, 2009 4:52 pm
Location: Atlanta GA USA

Re: Taskboard TT Scale Tie Strips

Postby railtwister » Sun Jun 08, 2014 8:47 am

Bernd wrote:
Some sad news to report too. I got down to 5 pieces left to machine for the coupler height gauge and I discovered I had measure wrong and made the 28 pieces to thin. Oh well, not the first time I scrap a bunch of pieces. I'll just have to start over.

Bernd



Shim?
railtwister
 
Posts: 699
Images: 4
Joined: Sun Oct 04, 2009 8:39 am
Location: Oakland Park (Ft. Lauderdale), FL, USA

Re: Taskboard TT Scale Tie Strips

Postby Marquette » Sun Jun 08, 2014 10:03 am

Bernd wrote:Ok, sounds good to me. I did an HO wheel to Proto87 once and I couldn't believe how small the tire width was when done.

Bernd


So, here are the P:120 numbers... not sure which of these are directly relevant to the wheel:

Track gauge (min): 12 mm (0.472")
Gauge widening (max): 0.14 mm (0.006")
Check gauge (min): 11.57 mm (0.456")
Crossing flangeway (max): 0.43 mm (0.017")
Crossing flangeway (min): 0.41 mm (0.016")
Between checks (max): 11.13 mm (0.438")
Effective flange (max): 0.25 mm (0.010")
Effective flange (min): 0.22 mm (0.009")
Wheel back-to-back (max): 11.31 mm (0.445")
Wheel back-to-back (min): 11.26 mm (0.443")
Tyre width (max): 1.27 mm (0.050")
Tyre width (min): 1.18 mm (0.046")

And a comment from my friend:

Note the rounding errors/typos when you go to mount them up. The flange depth is around .010". The fillet needs to be bigger than the railhead radius but other than that a look at the examples given on the P4 site should suffice


The above numbers are taken from the site he cites.

If these are doable for you I have a spare MTB wheelset I could send you to see if you could cut that down? If that is a success I could then send you the wheelsets out of my SW? But aside from that until I'm ready to build my next locomotive I'll mostly need 33" wheels for freight cars...
http://espeett.blogspot.com - The SP in 1:120 - my attempt at a blog
#include <std/disclaimer.h>
User avatar
Marquette
 
Posts: 2061
Joined: Wed Dec 23, 2009 8:16 pm

Re: Taskboard TT Scale Tie Strips

Postby Marquette » Sun Jun 08, 2014 12:39 pm

Okay! Thanks! :)
http://espeett.blogspot.com - The SP in 1:120 - my attempt at a blog
#include <std/disclaimer.h>
User avatar
Marquette
 
Posts: 2061
Joined: Wed Dec 23, 2009 8:16 pm

Re: Taskboard TT Scale Tie Strips

Postby ConnRiver » Mon Jun 09, 2014 8:39 am

> I was going to get into the track work after I get the first production of track gauge's made. I'm working on these at present. Since I'm further ahead than you I'd say hold of till I get the first track section out of the mold, so to speak. It's an experiment at present. I think you can use resin to make track section cheaper than getting a mold made for injection molding. -Bernd <

Three things about resin: An Alumilite person said she does not believe resin will be pliable in a way that flex track must be. But, I don't believe she well understood the application we have in mind. And, there are thousands of resins out there, I have read, so there might be some that would fit our mission. Second, resin is of such low viscosity, I'm concerned about controlling/limiting its flow within a mold. Thirdly, cycle times would be long, considering time-in-mold for curing.

This is the key book for me: "Understanding Thermoforming" by James Throne:
http://www.amazon.com/Understanding-The ... 1569904286

The first edition (what I have) is out there for $15 or so. For example, a 1" x 36" strip of .080" thick polystyrene (cost about 32 cents from a 4' x 8' sheet) is heated to a certain temperature, placed over a negative flex track mold (aluminum) containing rails, and a top platen presses down onto the mold. The hot polysty forms around the rail flanges and fills the tie plate and tie areas, excess plastic is vented to the sides via tiny channels. Much more detail involved, but this is the basic approach. Cycle times would be seconds to tens of seconds, according to the book, which is a professional book but easy for the newcomer to understand.

(Foreword excerpts: The thermoforming industry is growing much more rapidly than the plastics industry as a whole. . . . This growth has also attracted the interest of plastic products manufacturers who consider the thermoforming process as competition for their current plastics processes, such as injection molding. . . .)

(Chapter 1 excerpt: Thermoforming is a generic term for a group of processes including vacuum forming, drape forming, billow or free bubble forming, mechanical bending, matched-mold forming, and the newer processes of pressure forming. . . .)

Pressure forming is what most interests me right now. It is what I imagine can be used to attempt to manufacture track.

One consideration for making a flex track mold would be to glue wood tie strips to a base, affix plastic tie plates atop the ties in gauge, and pour Devcon (a metal/epoxy product) into the mold form holding the flex track pattern. Devcon is able to withstand injection molding pressures and produce many thousands of replicated parts.

This is kind of a hodge-podge of what I've been thinking about. Anyway. . . .

Brian / Brian Chapman, Cedar Rapids, Iowa
Brian Chapman
Cedar Rapids, Iowa / USA
ConnRiver
 
Posts: 428
Joined: Tue Sep 15, 2009 10:51 am
Location: Cedar Rapids, Iowa / USA

Re: Taskboard TT Scale Tie Strips

Postby ConnRiver » Mon Jun 09, 2014 8:59 am

>> . . . I would move on to tackling metal wheel production based on the Sherline owner who set up his CNC lathe as a sort of screw lathe production center. (Have you seen his video?) . . . -Brian <<

> That's another product needed, wheels and axles for both rolling stock and engine's. . . . No, I haven't seen the video. I'd be interested in seeing though. -Bernd <

The YouTube video of David Clark's creative approach to wheel cutting on a Sherline lathe has been removed. I'm going to ask him if I can have a copy of the video to study.

Some here have mentioned steam loco drivers, perhaps I'm not the only one to have collected several articles about creating them? (Now, if I can find them . . . house moving is such a chore in so many ways. Man. . . .) I think I have many, if not all, of the British books about loco production, too (found 'em just last night!), and lots of good stuff within. Perhaps the tough resin Elmer used to cast truck frames would find a use in creating centers and spokes?

I'm thinking Code 72 wheels for TT scale. Would they be considered a semi-proto wheel? (A scale 1:120 wheel would be Code 46, iirc. Right?) Created the 3D artwork below some time ago. I've got to look at all the discussion we've had in the past about wheels to re-familiarize myself with the subject. IIRC, a Code 72 wheel seemed a consensus choice in that it can run on track out there now while presenting a semi-prototypical appearance . . . IIRC.

(I think I also drew a 3D Code 46 wheel at the time, if I remember to do it, I'll post it here with the Code 72 wheel, for comparison, if anyone wishes to see it.)

-Brian

Brian Chapman / Cedar Rapids, Iowa

0 - Cad Drawing with Dimensions - rp-25 wheel.jpg
2 - Qtr Front - 33-inch wheel - rp-25.jpg
3 - Side-Tread - 33-inch wheel - rp-25.jpg
Brian Chapman
Cedar Rapids, Iowa / USA
ConnRiver
 
Posts: 428
Joined: Tue Sep 15, 2009 10:51 am
Location: Cedar Rapids, Iowa / USA

Re: Taskboard TT Scale Tie Strips

Postby gerhard_k » Mon Jun 09, 2014 12:13 pm

Bernd wrote:I'll do a 28" dia. HO wheel which is close to a 33" (33.6") wheel in TT scale.
Bernd

And then 4 posts later, you say "I'm going to give the 20" HO wheel a try."

Is this just a spate of typo's? I thought you were talking about a TT 33" wheel, which is 24" in HO.
Or did I just completely miss what's going on?
Sometimes you win... sometimes you learn.
gerhard_k
 
Posts: 166
Joined: Sat Dec 21, 2013 9:27 pm
Location: Annapolis MD USA

PreviousNext

Return to General Discussion

Who is online

Users browsing this forum: No registered users and 0 guests