# What size bore..1:20.3?



## Cap'nBill (Dec 27, 2008)

Using my Bachmann Climax as a model, decided to give building one a try. At this time, I've bored the cylinders to 3/8th's. Would this be large enough?
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## Kovacjr (Jan 2, 2008)

The Aster Climax is about 3/8" and it has no torque. If you want to run at slow speeds a larger bore is needed. Id go for 1/2" if you could. Also you may want to pick up Kozo's Climax book, lots of good information in there. 

Do you know what the gearing is on the Bachmann trucks???


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## Cap'nBill (Dec 27, 2008)

I'm using 3/4" stock, so I can go to 1/2"....I think. Should be plenty of stock left.


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## Totalwrecker (Feb 26, 2009)

I think 5/8" should be doable too, that still leaves a 1/16" wall which is pretty thick for brass. 
But wait for those who know best. 

John


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## Cap'nBill (Dec 27, 2008)

Well, a couple minutes in the shop and I took them to 15/32. That leaves the tapped 0-80 end piece holes midway between bore and outside. I think I'll leave it there. I don't think I'd feel comfortable trying to drill and tap into 1/16th's...going to 5/8th's. But, that's interesting, I wouldn't have guessed one could go that thin......learn something everyday! Thanks, guys! Bill


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## HMeinhold (Jan 2, 2008)

I am a little late but anyway: My Betsy had originally the Ruby 3/8" cylinders. I then build 1/2" ones. The transformation was amazing: Much slower running (probably due to less condensation - volume to surface ratio better) and ample torque. The boiler has no problems supplying enough steam. So 1/2" is the way to go! 
Regards


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## Cap'nBill (Dec 27, 2008)

While I have some help and guidance here, what length of stroke should I be striving for with a 1/2"bore? I guess, too, we can only scale a steam molecule down so far. Bill


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## xo18thfa (Jan 2, 2008)

Stroke is generally a bit longer then bore. 5/8" or 11/16" will do


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## seadawg (Jan 2, 2008)

Hey Cap'n, don't forget to keep us all posted on your progress... Looking good so far.


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## Cap'nBill (Dec 27, 2008)

A little update for today's progress. I bored out a 1" x 1" square from which I'll cut out the steam ports portion. I'll mill out the passages, drill the cylinders, and silver solder them together. Don't have the patience to 'carve' out the cylinder ala Kozo! Saw that in one of Henner's references. For the end caps, etc., I use my Dremel mounted in a drill press stand, and the Kaydee drills and tap sets. I use a jeweler's pin vise to hold the wee taps. Turns easy as butter! Nice thing is: if it bottoms out, the vise just slips. With the Dremel, I just make very shallow, plunging cuts so as not to overheat these tiny bits.
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## Kovacjr (Jan 2, 2008)

Looking real good! How about some overall frame shots?


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## xo18thfa (Jan 2, 2008)

Bill: Cylinders coming along nice. That's going to be a sweet machine. Got pics of the frame??

I would suggest investing in a regular tap holder. You can make or buy them. Something like this, I made this one:











Use it in the drill press:










Or in the lathe:










This method keeps the tap in perfect alignment all the time. Feed in by hand about 1/3 turn and back out 1/2 turn to clear chips. Use oil, even on brass

CDCO Machinery has them for $9 (the small one)

CDCO Machinery

P.S. In 30 years, my tap handle has never broken a tap. Never, ever. Any size, any metal. 0 x 80 into stainless, no problem.


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## Dave Sykes (Jan 3, 2008)

Yo Bob, 
My tap handle has never broken a tap either. 
On the other hand, I personally have broken a couple !!!!!!!!!


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## xo18thfa (Jan 2, 2008)

Posted By Dave Sykes on 24 Jun 2010 09:46 PM 
Yo Bob, 
My tap handle has never broken a tap either. 
On the other hand, I personally have broken a couple !!!!!!!!! 

'Yer right Dave. I revise and extend: "I have never broken a tap while using my tap handle"


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## Cap'nBill (Dec 27, 2008)

I must admit, Bob, watching your Nina build is what gave me the encouragement to even try this. Generally, when I chuck something in the lathe, it's almost as easy to turn two of something as it is one. As for tapping, I usually hold larger taps in my MT drill chuck, and turn the headstock by hand..twisting back and forth. I seem to get the 'feel' if I'm forcing the tap. In brass, 0-90, 0-80, 2-56, I use the pin vise. As for the frame, I wanted to use the more scale 'channel'. Not finding a source, I happened upon 1/2" square steel tube in Lowe's. I clamped a guide on my band saw and ripped it in two, silver brazing only 2 bolsters in place at this point. I just copied the dimensions off my Bachmann. My goal here is to complete the engine with the main gear box such that I can run it on air. I need to order some more 1/4" bar stock to build the gear box. I thought I might visit the LHS and look for gears...such as used in cars...so as to at least get the gear box built.


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## xo18thfa (Jan 2, 2008)

Sounds good. Rip 1/2" square tube to make channel huh? That's another one for the shop notebook.


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## Cap'nBill (Dec 27, 2008)

Projects like this seem to run full speed ahead and then slow way down for a while. I must now turn a steel drilling jig for the holes in the rear cylinder, rear cap, and crosshead guide to line up. A lot of machining left to get the guides where I want them...my Bachmann has 'rings' left at the rear of the guides. Most model pics seem to have open 'U' shaped rear ends. With piston installed, 4-40 threads on 1/8th SS rod, I have almost a perfect 5/8" stroke. I must select gears before drilling anymore.
Gear box started, awaiting more 1/4" stock.
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## Cap'nBill (Dec 27, 2008)

Sometimes you just gotta think about what your doing! I decided to try turning the crosshead guides out of steel, thinking they would be stronger. My little lathe required untold passes to turn them down, then the problem how to accurately drill the 0-80 size holes through the rim, rear cylinder head and into the cylinder. After all that, mill, grind, and/or saw half of it away. Found some 3/8th's steel tube in my junk and brass washers.....Eureka! I'll drill the washers cylinder head and body, then silver solder the washer onto the tube. I plan to make a piece for the rear to fit into the engine mount, and part of another washer. I like the Bachmann double ringed guide. But, this was after screwing up several hours work on the steam port housing. I had hoped to get two pieces out of the bored 1 x 1 brass, but my little homemade milling attachment managed to 'jump', wobble, wiggle, or twitch just enough to screw up the job. I decided before boring, the second block, I'd try starting the steam ports by chucking my 1/16th end mill in the drill press and just starting the holes......so far so good! I did get one cylinder soldered up and rushed to my compressor to blow some air and see that the piston was working.........YES!
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## Cap'nBill (Dec 27, 2008)

Waiting on a set of helical gears to get into the gearbox. I see the standoff required to line up the crosshead guide with the flywheel. I'll bore a 1/2" hole through a piece of square stock, and cut in half
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## Cap'nBill (Dec 27, 2008)

Some progress, like most projects, we seldom have what's needed on hand! I decided I should start the steam chest with 00-90 bolts, of course, I had one bolt and no tap, so......I awaitith the Postman. The adustment nut is 2-56, the rod's end 6-32.
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## xo18thfa (Jan 2, 2008)

Looking nice Bill. Maybe you mentioned it and I did not see it, but what's the plan for gears on the trucks? Kozo had 2 reversions of his Climax, one used stock bevel gears


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## Cap'nBill (Dec 27, 2008)

Thanks Bob. I am using Kozo's alternative standard bevel gear method. I looked at several 'on-line' sources for gears and noted some of these places want $30 a piece for gears in small amounts. I went to the LHS that has bunches of RC car parts and bought several sets at $7, or so, a set. I will start with these: Team Losi auto gears. They, and the bevel gears, measure about 3/4" diameter. I'm not sure of the ratio, but I'll give these a try. What's milling another gear holder........the reject parts pile is growing already!
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## Cap'nBill (Dec 27, 2008)

No. 2 cylinder is about ready for hard silver soldering. Once soldered, I'll drill the exhaust passage starting with small bits. To clamp the assembly together and line up passages, I stick drill bits through from the cylinder passages which have been drilled at 45 degrees.
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## Cap'nBill (Dec 27, 2008)

A pic of cylinder no. 2 soldered up. Strangely, or perhaps not so, I had trouble getting the silver to run. The result was the bore actually distorted perhaps a .001 or so, such that the rear cap wanted to bind. I used only a small 'C' clamp to hold the pieces together. So, I wound up reboring both cylinders to 1/2". The boring tool leaves a great finish. I'm using leather as a ring, but may look for 'O' rings.
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## xo18thfa (Jan 2, 2008)

How much gap did you have between the cylinder and the portface block? Silver solder needs a little gap tp flow. If you pop the sufaces lightly with a center punch, that gives enough stand off. Usually those kind of parts will distort a little. Next time, cut the final bore after soldering it together.

Coming along nice. That's going to be a sweet machine.

Bob


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## Cap'nBill (Dec 27, 2008)

Thanks, Bob. I left no gap, the bored- through 1 x 1 brass block gives a pretty snug fit, just clamped under some pressure. I assume the solder will wick where it needs to go. I merely 'recessed' the exhaust port and then drilled through from the side. At this stage, with no gaskets installed, I ran air from my compressor blow gun over the ports. The pistons work well down to about 20lbs psi, but, by working them under water they leak heavily with no gaskets. Now, I'm a bit unsure as to what size tubing I need to use for the steam supply lines. The next steps are to build the smoke box saddle which will cover the manifolds, and work on the Walshaert gear.......if there's a clear 'next'! These are a thousand mini projects!


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## Garry Paine (Jan 2, 2008)

Hi, 

Whose bevel gears? The Losi set I found, ASC25674, looks different in the catalog picture. 

Thanks, Garrett


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## Cap'nBill (Dec 27, 2008)

The better choice, I think, and what I'm going to use are HPI Racing 86032. They're thicker than the Losi LOSA3102 I also bought. There may be better choices if you have place to look at the selection. Bill


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## Cap'nBill (Dec 27, 2008)

The question about gears got me to thinking how the trucks will go together, what additional stock is needed, and wheels. I found a bag of worn metal wheels I had intended to machine for future use and thought I'd give this a try. The HPI gears(these main gears have a recess such that a roll pin thru the axle is a possibility) are a sliding fit, almost guessing loktite might hold, or even CA. Or, probably, soldering on a collar. I'm going to try milling out the sketched shape(s)...Kozo's concept. But I'm going to attempt 'building up' 1/4" brass with bearing blocks, rather than trying drilling/milling 3/8th's, or better stock.
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## Cap'nBill (Dec 27, 2008)

I wanted to see where I was at getting the engine parts to work. The engine/crosshead guide have only one bolt( little 0-80) holding it on the mount. I have not made the standoff piece as such..just a small block of brass to hold the assembly off the mount. Two things seem obvious: 1. the whole assembly needs to be moved back toward the flywheel about 1/8", I had to remove the crosshead link to the valves to get it back this far. 2. I must add a few more threads to the crsshead end of the piston rod, and/or, shorten the rod a bit. I think this needs to be pretty well perfect before starting any of the various linkage pieces. The guide is pretty close, I could grind a bit away forward, the rear pretty well at its limits...and still retain the rear 'ring'.
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## xo18thfa (Jan 2, 2008)

You may want to leave that 1/8" in there. You need to get inside later to tighten a packing gland nut on for the piston rod. You may also decide to put a jam nut on the piston rod against the crosshead too. A little room never hurts.

Anything binding between the cylinder and crosshead guide? 

Looking good


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## Cap'nBill (Dec 27, 2008)

You're right, Bob. I left that little 'tit' on the front of the crosshead so I'd have plenty of threads for the rod. I had tapped the end cap for a gland...but haven't made it, so that's got to be accounted for. Indeed, there needs to be a jam nut, I mave to find some really small hex rod to make something scale like. Appreciate the comments, nice to have the help! Bill


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## Cap'nBill (Dec 27, 2008)

I made a paper cutout to use in making the smokebox support. While I'm not real happy with the amount of distance/standoff of the engine to the mount, it may be necessary to accomadate the boiler. I've ordered 2 1/2" copper pipe for the rear and need 4" of 1/34" diameter for the front and smoke box. 
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## xo18thfa (Jan 2, 2008)

Bill: You should use a jeweler's apron. It's an apron that connects to the edge of the binch to catch the parts you drop before they get to the floor.

McMaster Carr (page 133) and Online Metals have 1 3/4" dia copper pipe.

Online Metals Copper Pipe

McM-C, page 133


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## Cap'nBill (Dec 27, 2008)

Thanks for the leads, Bob. I think Online will be the cheaper, since I only need a 4" piece. The apron is a good idea, crawling around looking for a 00-90 nut...brass at that, ain't easy. You have to consider the micro-sized parts when you scale down!


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## Cap'nBill (Dec 27, 2008)

Steam chest for no. 2 cylinder roughed out, I'll finish it up on my 'milling attachment'. I've only drilled and tapped one corner 00-90 bolt. Hard otherwise to hold the pieces in line, one slip with this tiny stuff ......and it's the junk pile. 2 1/4" copper for rear portion of boiler, 1 3/4" x 4" copper on order from Online Metals. Thought I'd better start working on the valve gear. Rear brackets and rod is for the reversing pivot. Return crank is roughed out/mounted....I'll probably have to this several times to get the timing correct.
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## Cap'nBill (Dec 27, 2008)

Pics to show start of making the Walshaert valve gear.The mockup is from 3/32 rod threaded for 00-90 bolts.....test your patience, if not one's ability! The object now is to get the right lengths, etc. Rods have been attached and the drive rotates pretty well, the helical gears are sticky in one place. Electric drill and lapping compound will fix that. The crosshead guides will have to be cut out forward to allow the linkage to move forward a bit. 
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## Cap'nBill (Dec 27, 2008)

Pics of the expansion link/trunnion assembly. Each of the 3 pieces cut from 22ga steel with jewler's saw, the slot drilled and opened up via diamond bit in my Dremel. Held together for now by 00-90 bolts, with 2 -00 washers each side of the expansion link. I have to clean up the slot a bit, will put a pivot/pin through the assembly, solder and grind off inside. The' pins'..trunnions will allow the assembly to swivel inside the bracket. I should have made the link assembly first! The bracket is 1/8" too narrow and a few thou's to short.
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## xo18thfa (Jan 2, 2008)

Looking great dude, just keep plugging along. Building a live steamer is like eating an elephant, do it one bite at a time.


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## Cap'nBill (Dec 27, 2008)

Thanks, Bob! I guess my only regret is the scale. The parts can get so small, each one becomes a challenge. I have to hand it to the commercial manufacturers that can make parts so precise and tiny.


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