Help cutting narrower traction tires

[mmagliaro]

I ordered some Norprene (it's a neoprene type) tubing.  One only has so many choices for inside diameter with this stuff.
You can only get it in 1/16" increments.  I got some 1/4" and some 5/16"  (0.25" and .3125")
The wheels *grooves* are .306", so I'm betting the 5/16" isn't going to work (too loose).  The 1/4" may be too
tight (stretch/break).  But I'll give it a go turning some rings off on the mill.

[narrowminded]

I'll bet the 1/4" will work and may in fact be near ideal.  Is it the reinforced or straight rubber?  If the rubber, you may get it on to the finished arbor size.  If not, rough some off on a 1/4" arbor, enough to get through the fibers, and then go to finish size.  I'd still leave as much wall as I could while still getting it to stretch on to that finish arbor with the idea being that it will help the tubing to settle uniformly, not bunching or distorting.  Have you ever used air pressure to install or remove hand grips on a bicycle or motorcycle?  Some of those principles might be useful if you have any trouble getting the hose on and settled nicely in place.  Then make a few diameters, every few thousandths so you can dial in the perfect size by test on the finished loco.  This project is really cool and will be quite an accomplishment.

[rrjim1]

If you have a mill why not make a mold and cast you own tires out of the harder red silicone. If I ran a lot of steam that's what I would do. I made 2 piece molds out of engineering plastic for HO slot car tires and cast thousands of them, it's pretty easy to do. 

[mmagliaro]

If you have a mill why not make a mold and cast you own tires out of the harder red silicone. If I ran a lot of steam that's what I would do. I made 2 piece molds out of engineering plastic for HO slot car tires and cast thousands of them, it's pretty easy to do.

Because I don't have a rotary table.  Maybe the proceeds of a future magazine article can pay for that.

Also, I really didn't want this to turn into a whole side project of itself.  I was just looking for a simple way to
slice down Mikado tires, and it has expanded into this idea of slicing my own off a piece of tubing, which I
am certainly willing to try.

[rrjim1]

Well you sure don't need a rotary table to make a simple two piece mold. Slicing down a tire is really simple on a lathe, just make an arbor to hold the tire and use a thin cutter, you can make one out of a hobby knife.

[mmagliaro]

Well you sure don't need a rotary table to make a simple two piece mold. Slicing down a tire is really simple on a lathe, just make an arbor to hold the tire and use a thin cutter, you can make one out of a hobby knife.

How would I make a perfectly round recess into a metal plate?  That's how I envision such a mold.
I would cut a circle into metal plate, and it would have to be the correct depth, width, and diameter for the tire I want.

I am going to try slicing the tires off a rubber hose with an arbor and a thin cutter first.

[Mike C]

  I'm betting a couple layers of Scotch double sided tape would fill the tire grove . Without the trouble of cutting tires .

[narrowminded]

How would I make a perfectly round recess into a metal plate?  That's how I envision such a mold.
I would cut a circle into metal plate, and it would have to be the correct depth, width, and diameter for the tire I want.

Two piece. Bored with a button or pin in the center.  And quite a few multiples so you don't waste your mixed materials.  Materials that may not be best suited.   It's easy in theory but in reality when you have a specific size that you're after and may need adjustment after testing, you could spend a lot of time and tool dollars getting there.  Now, if you need a few thousand and have the dimensions all dialed in, I know a guy.   And in vulcanized resilient of the compound and durometer of your choice.  But slicing off from a good vulcanized material is probably the best and easiest over the long haul.  Plus, being around this as you are the little tools you make for this one  could be used making who knows what sizes of tires in the future.  One offs, just about any size, and relatively easily.  He who chose the hose, knows the hose, and knows he chose best.

[phil55]

Not to change the subject but I have an Atlas 4-4-0 that threw a traction tire. It runs much better without it but won't pull anything! Are there any tutorials out there on how to replace a traction tire on this model?

[mmagliaro]

Not to change the subject but I have an Atlas 4-4-0 that threw a traction tire. It runs much better without it but won't pull anything! Are there any tutorials out there on how to replace a traction tire on this model?

First, you'll have to find some that fit.  Atlas has no parts listed for that engine on their website, but hopefully
you can call them and get some.  Failing that, judging by the size of the drivers, I guess I'd try some Kato GS4 tires.
As for replacing them, although I've never actually done it, I've seen that engine and it looks like you'll have to do
the usual way: pull the crankpin, get the rod out of the way, and then ease the tire around the rim. I usually get it into
the groove in one spot, hold it there with my thumb, and then slip a toothpick inside the tire and run around the rim,
tipping the tire into the groove.  Don't use anything even the least bit sharp, like a jewelers screwdriver.  They make
little nicks and tears in the rubber that sometimes you can't even see, and eventually, that will make
the tire break prematurely.

[SkipGear]

Heat shrink tubing, good rubbery stuff, not the hard plastic found at Harbor Freight or Radio Shack (do they still exist?).  It may take two layers but it works well and shrinks tight to fit what ever rim size you need. Very easy to cut to width.

[Lemosteam]

Oooh, that is a great idea Tony!  the shrink wrap that I used on my Polar Express roof is like that!  Great tip!

[peteski]

From my experience with heat-shrink (in its as-intended application in electronics) I noticed that it can shrink unevenly (depending on how the heat is applied and whether what is inside acts as a heat-sink).  So, you might end up with a traction tire with uneven thickness. Also, when shrunk the material thickens up - this needs to be accounted for.