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In looking at Harris' book on 'Boilermaking', I notice drawings for various valves-such as safety valves. I have a small lathe, drill press and various other tools. While drawings are interesting they're not very descriptive in the 'How to' department. One of things that puzzles me is how to cut a good, or proper shoulder, or 'seat'. Are there any tutorials out there dealing with the subject. I'd like to be able to make a whistle, too. You start buying this stuff, and the price adds up quickly!
 

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Posted By Cap'nBill on 02/27/2009 3:01 PM
In looking at Harris' book on 'Boilermaking', I notice drawings for various valves-such as safety valves. I have a small lathe, drill press and various other tools. While drawings are interesting they're not very descriptive in the 'How to' department. One of things that puzzles me is how to cut a good, or proper shoulder, or 'seat'. Are there any tutorials out there dealing with the subject. [edited]






Cap:

If you have the dwgs, you have the info to build the item in question. If, OTOH, all you have are undimensioned line dwgs ... you have a bit of a problem. Are you a machinist? If not, get a copy of Machinery's Handbook, or the Machinist's Handbook. They are often available used, you sure don't want to pay new price for one.

To answer your question about seats/shoulders: so long as the mating surfaces are the same angle and all that, that's basically what you need. The ugly term 'standardization' rears up about here. If you're handbuilding 'one-offs', that is, one for your own use, I think you can neglect standards--just make 'em so they work and suit you.

I know nothing of 'standard practices' as applied to steam locomotives. Someone else will have to chime in. Be aware that, in the case of most valves, you'll need to 'lap' those seats and shoulders for a good mechanical seal.

Don't feel lonesome: I've been paging thru line dwgs of early steam locos, and I swear, the artist/draftsman who drew them didn't know what he was looking at. I can read blueprints. Problem is, very little in the books are dimensioned. If you're lucky, you can find a mention in the text of wheel diameter, then go from there. For your projects, I have to assume there're a lot of blueprints out there on specific items.

You should ask of someone who knows regarding safety valves, because they may have specs--after all, at a meet, you don't want someone's loco blowing up just as it reaches your adult beverage.
That would be awful.

I read where the boilers must be pressure-tested, but nothing is ever said about the valving, including safety valves. I'm really not the one to answer more than the machining issue.

Les
 

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CapnBill,

I have learned to make locomotives from scratch from the books of Kozo Hiraoka. I make all of my own valves and the safeties except the butane fill valve. You do have to invest in time and tools. Kozo's books will give you the tutelage you need in techniques. I would suggest his book The Pennsylvania A3 Switcher - The First Project for the Beginner. Even though it describes building a 3/4" scale locomotive, the techniques apply for Ga 1.




Ed
 

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Bill,

If you're really into machining and metal work and have the desire, take a machine shop course if you can. Maybe a night school course is available in your community. An alternative is a few trips to the library and spending some serious study time on how things are machined. Look for both Machinery's Handbook and a basic machining text.

A machinist can look at a drawing and determine how to make the item with what is at hand. Having the machines is a small part of the equation with the majority being knowledge. Your shoulder can be made in a variety of ways. End mill, boring bar, D-bit, etc.

There have been books published about building steam locos including G1 locos but they assume at least a rudimentary knowledge of basic machining. Machining isn't difficult but takes some study and experience. A little math ability and aptitude in spacial relativity doesn't hurt. You need to practice and make some scrap before you'll be making good parts.

Don't be mislead into thinking that making stuff is always cheaper. I have a shop that would probably cost $30,000 to replace and I'm still buying and replacing tools. If you ENJOY making things then now is a great time to start to learn about machining and metal work. If you just want to have the part cheap do some shopping!

I have done machining as both a hobby and a vocation and to me it is interesting and rewarding. I also do patternmaking, metal casting, woodworking, etc. When I stop learning and making things I'm probably dead.

My three cents...

Jack
 

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Jack,

I cannot disagree with a word you've posted. Howsumever, reading blueprints is a different breed of cat than machining, if one is going to go to a school. (I never did.) Cannily, trade schools tend to separate those two subjects. ($$). I know a guy who spent a year learning to weld. And weld good, he could. Read a blueprint? Um...

Les
 

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Valves aren't rocket science, and if you have a drawing so much the better, you just read the drawings and do what it tells you to do. However the problem comes if you've not made valves before or if you've not done any machining from a print before as each part will have its own demands and as with any machining job there is a learning curve. More times than I can remember, when I have an unfamiliar (interms of maching) part to make I have done a practice piece or two to atempt to crawl up that learning curve before attempting the final piece. My scrap bin is full of "learning" pieces, but then I wouldn;t have it any other way.

Valves will probably be the same way, you might make a couple of failures before you get the hang of it and start turning out good ones, especially if you are relatively new to machining. If you plan to make valves for future projects those practice valves are probablty time and material well spent, but if this is going to be a one-off project then buying might be more cost effective. Every once in a while there is a fellow on eBay who sells valve "kits" containing a nice print, 4 bronze body castings, and all bar stock sufficient to build four 1/4" valves. I think that's about as easy as anyone can make it, short of providing the finished valve. For your boiler a 1/4" valve would be fine but for most Ga1 locos that's a bit too large.

Safety valves are similar in that there is a learning curve. As most of the posters here know, there are "pop" valves and then there are dribblers. The difference is in the internal geometry. To achieve a true pop action the seat and internal cavity need to be made to very definite proportions relative to the size of the ball, if indeed a ball is used. Finding a reliable design and then getting this geometry right can be a challenge as a couple of thousanths of an inch can make the difference between a popper and a dribbler. On the other had if a dribble valve is acceptable, and they do the job after all, then the job is much easier for the inexperienced and almost any published safety valve design will do.
 

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You could read "shop, shed and road" by LBSC. It not only give drawings and sketches of several types of gear for engines but also the "words and music" of how to do it.
 

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Cap'n,

I made an acceptable steam regulator valve for a pot-boiler loco from one of those small brass valves found in the plumbing section of the hardware store and sold for applications using copper tubing. The valve spindles and valve seats are very well machined. I disassembled the valve and centered the valve body it in the lathe 4-jaw chuck to turn the threaded inlet and outlet ends down to smaller diameter for appearance. The square body was filed down on its flat sides to make it smaller. 1/8th inch bore bushes can be made to press into the valve inlet and outlet to which to solder 1/8th inch steam lines. (Be careful not to get solder inside the valve body.)
To make the valve action more gradual I used the lathe to bore a hole down the center of the valve spindle busness end (carefully not to damage the valve seat area), pressed in a short length of brass rod, and turned the short length of rod to a gradual taper.


Steve
 

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Posted By Cap'nBill on 02/27/2009 3:01 PM
In looking at Harris' book on 'Boilermaking', I notice drawings for various valves-such as safety valves. I have a small lathe, drill press and various other tools. While drawings are interesting they're not very descriptive in the 'How to' department. One of things that puzzles me is how to cut a good, or proper shoulder, or 'seat'. Are there any tutorials out there dealing with the subject. I'd like to be able to make a whistle, too. You start buying this stuff, and the price adds up quickly!

I think what your looking for is not what books to read but just a simple question answered, so grind a lathe D bit tool to a point and it will cut a shape like an inverted volcano then tap a stainless steel ball onto the seat to make a seal.
 

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Discussion Starter #10
Precisely! Often times, it's not a question of not knowing the what......but the how! I was trying to find the descriptive word to describe a 'volcano' seat! Now, no doubt the books long term will be of help. Like books, have tons of 'em, and will check on those mentioned. Now, all I have to do is find a lathe D bit, that's a new one on me. Bill
 

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simple, if you have no D bits just shape a lathe tool on a grinding wheel to firstly fit into the valve then small enough to only cut one side inside the valve. I have been doing just what your wanting to do today I am making a crosshead pump for my 5" 'Torquey Manor' it has an inlet side and outlet side for the water flow so both valves need seats for the 3/16" stainless balls.
 

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Bill: The best books I've seen are by Kozo Hiraoka. Everything I know is from Kozo. Most of my fittings are fabricated from Kozo designs, to include springs. He not only shows plans, but actually shows you how to machine these kinds of parts. Ed Hume recommends the A4 Pennsy book. My vote is for the Climax book. Either one you can't go wrong.

All of Kozo's books are for 3.5" gauge engines, but the shop techniques work for anything. And if you divide Kozo's dimesion by 2, you have Gauge 1. The A4 Pennsy is inch dimensioned. The Climax book is metric. I use the metric plans with a scale of 1mm = 1/32". You end up with a perfect inch dimensioned plan, bar stock is widely available, taps and dies are standard, they work well for our size equipment and you know the dog-gone fitting will work.


LBSC has a lot of designs in Gauge 1 as well. He goes into fairly good detail on fabrication. He's kind of a fun read too.

One shop technique I have never seen written anywhere is how to use taps and dies on the lathe. If you make your own fittings, you will do a lot of that. To put a male thread on a rod, you will need a die holder. Here is a die holder from http://www.littlemachineshop.com




This thing slips into the tailstock on the lathe and holds the dies for a prefect thread every time. The handle end slides back and forth on a rod. Turn the lathe chuck by hand and use a little oil. I made my own so I don't have this particular model, but I suspect it's double ended for 1" and 13/16" dies.


To tap female threads there are 2 ways to go. The little guy is from McMaster-Carr:




The bottom part is pretty much an ordinary "T" type tap handle. It slides freely in the top part, which goes into the drill chuck on the tailstock. Makes for perfect alignment. The tap handle slides back and forth in the guide so its is always supported. Here's the tap handle I made from an old 3/8" drill chuck from Sears:




Here it is in action on the mill drill. It works the same way in the lathe tailstock:



I have never never never broken a tap with this tap handle in 25 years. To include 0-80 in stainless steel.

Another way to tap holes on the lathe is to use something like this from Littlemachineshop.com:




This goes in the tailstock of the lathe. The point is spring loaded. Use a regular "T" type tap handle like this to hold the tap:




The tap goes in the hole and the spring loaded point goes into the hole on the backend of the handle. The spring loaded point keeps alignment and support as the tap works its way in. Rotate the lathe chuck by hand and use a drop of oil.

There is only one tricky part to make when doing your own fittings. Look at Ed's photo above and you see a hex nut on the end of that part. Those hex nuts can be a challenge. But, there are 2 ways to handle them. More later.

Get one of Kozo's book. Just do it.


Bob
 

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Bob,

Thanks for the photos and descriptions of the various tap and die holders. I especially like your homemade tap handle. That's worth copying.

As you imply, cutting male threads with a hand-held die does not always produce perfect results. You've prompted me to rig up a proper die holder for the lathe.

Steve
 

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Capn - Here is another photo from the Set on flickr from building my Gauge 1 Climax. All of the fittings are shop made except the pressure gauge. The boiler was also made using techniques learned from Kozo. The whistle valve is taken from Kozo's new Shay book. The photo is linked into flickr. You can look around on flickr at my Sets for the Heisler and A3 builds too.




Ed
 

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Discussion Starter #18
Thanks guys for the pics, info, and recommendations. That is truly some beautiful work!Guess one of Kozo's books must be ordered! I've bought quite a bit of stuff from the Little Machine Shop for my 7 x 10. Bill
 

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Since I have a Bachmann Climax, I ordered Kozo's 'Shay' (my other favorite engine)......besides, got the best price on it! Hopefully this will answer many of my questions. Bill
 

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Capt'n Bill,
The boiler design system in Kozo's New Shay book was a bit simpler for me to use than the standard text as it is presented in graph form. This makes chosing sizes of pipe, stays, tubes ect a lot simpler than using a lot of math. Kozo also covers the amount of o-ring squeeze needeed for steam service tabled for both inch and metric o-rings.
John
 
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