Re-Facing and Lapping a Steam Locomotive Throttle Valve

[@wilsonlaidlaw]

When I was being taught lapping using a lathe, we were told to change the lathe rotation direction every time we lifted off the work piece. Otherwise we were told you could get spiral grooves on the seats. For smaller valves, we had a compressed air tool that had an oscillating rotational output shaft, with various end fittings from a chuck to a rubber sucker. A spring would be put under the rotated seat, so that every time pressure was released, the two seats would separate. The carborundum paste we used, was mixed with fish oil, that had a particularly nasty smell.

[@dannymorgan6053]

I would think that is more about speed of cutting in the lap. Once it is installed it will do final seat from the force of contact between the 2 parts. Lapping is really just doing final angle matching of the 2 surfaces. It would be different if using lapping compound that is massively strong.

[@marlobreding7402]

How I remember those days. Then I worked for a good shop with new Sioux valve Pacer and hard seat grinder. Then a good friend taught me how to really use it to my advantage. He also taught me to not laugh he taught me that you could grind a seat perfect where it seals the first time without using grit. Stop using that stuff in the late seventies.

[@kaydog2008]

In the Navy and ship yards we used valve seat bluing to show where your highs and lows are.👈🤓😉👍

[@Frank-Thoresen]

That is obvious a great practice only when someone knows about this trick. Thank you for sharing it. I can use this method when lapping motorcycle and car engine valves.

[@darrellshuman7751]

We called it Prussian Blue

[@dcrahn]

Back in the early 70's during my time in the Navy we used that lapping compound many times to lap in the seats on steam and fuel valves down in the Fireroom.

[@PlanetMojo]

My very first videos on this channel were train stuff - but I stayed for the machining videos as well. Great work Keith!

[@williamdodd8660]

Me too!

[@JohnMoore-xt3hz]

During World War I a vast system of 2 foot gauge (60 cm) railroads served millions of servicemen in the wartime trenches, all across France and the Battlefront.

[@royreynolds108]

The 60 cm or 600 mm = 23 5/8 inch gauge is close enough to operate with no problems on 24 inch gauge.

[@KG-yn9qi]

The reason for two size seats/ valve is for balance! So the two sizes work together, the larger holds valve closed. But not with the full pressure of the steam the small valve is trying to open the valve so the reduced the pressure holding closed! Now it is easier to open the valve! (You do not have to overcome the full steam pressure when opening and pop it open ) you now can throttle it easier with minimal force ! It is a balanced valve thats also why it is drilled through center and the valve itself floats on the pin and can self a-line to seat ! And if needed the operator can add force to hold valve closed, but can slowly remove the added force, and then easily to start to open the valve why it is a throttle!!!!!

[@johnspathonis1078]

Thank you. That is an excellent explanation. Well done!!

[@D989501L]

Nearly understood it ?

[@BenRichards227]

The idea is the pressure is the same on both sides, but the area is different. Pressure x Area = Force. Different area, different force. Based on my very rough estimates (derived by literally holding a rule up to the screen) the area of the large valve face is about 5 square inches, and boilers of that size run ~100psi. If the valve had only a single large seat, the pressure holding it closed would be 100psi X 5 square inches = 500 pounds! Even a 20:1 reduction provided by the throttle lever arm would require 25 pounds force to open it. Now I estimate the smaller seat has an area of about 3 square inches, which is 300 pounds force in the opposite direction. Now our 20:1 lever arm only requires 25-15, or 10 pounds force to open the valve. Much more palatable. (These numbers are nowhere near accurate, but they demonstrate the principle.)

[@KG-yn9qi]

@@BenRichards227 Yes!!! I did not go into the actual numbers it is having a smaller and larger vale it is not a true 100% balanced valve . If it was it would require a locking system to keep valve closed to keep from opening on its own so they left a small amount of pressure hold it closed. For safety and the leverage of any linkage would allow the operator easy to open the valve.

[@D989501L]

Hello Keith, it makes a nice change to have the part explained as to what it does and we're it is on the machine. It was nice to see the Locamotive as well and have it all explained as to where it goes. Always nice to watch your video's. Regards to all Richard 🇬🇧

[@craigcorrell3424]

Well done. Timesaver also works brilliantly on babbitt bearings. The yellow powder will get full or near full contact between bearing surfaces with a couple of thousandths space. You can check it with plastigauge as you go. And the grit breaks down rapidly as you explained. I've used it on all my antique engines.

[@thisolesignguy2733]

This was so cool, I love old locomotives. It brings back that mesmerized 10yr old that got a chance to ride the French Lick locomotive for the very first time. I'll never forget that, the conductor let us ride in the caboose before they stopped using it, we were the last ones to ride in it. Man, what a wonderful memory! When I was 18, The engineer gave me a tour of the locomotive and showed me the controls and the engine, and they even let me help with the greasing and maintenance before starting it. I wanted to be a train engineer growing up, but getting into the school was just out of my reach.

[@joebledsoe257]

Way back ago in High School Machine Shop class, I learned how to thread due to a feed rate error. I knew what the threading project was so I did it early. I built a crude cannon that would fire 410 shogun shells during what would have been shop time for the threading project and turned in the threading project a day early to boot. Ive got the cannon somewhere in the attic w/ my Boy Scout stuff.

[@alandaters8547]

Thank you for all the details about the lapping compound and the actual lapping process. Using the lathe was a great idea, I am sure its stability improved the accuracy of the job. Once again I enjoyed learning a lot.

[@patrickcolahan7499]

Very cool project. Thanks for sharing the pictures of the train. I have always loved the old steam locomotives.

[@allenbourassa1579]

Excellent video,being from Central Maine,this reconstruction,and rebuilding fascinates me Thank you!

[@billmorris2613]

Good morning to all from SE Louisiana 4 Dec 21.

[@bitsnpieces11]

Sears and Roebucks used to have a valve seating tool that was like one of the early hand drills where you turned a handle and it drove through a 90 angle to turn the drill bit. But it has a cup for the valve instead of a bit, it would turn 1/2 turn clockwise then 1/4 turn counterclockwise then clockwise and kept repeating until you stopped. If you had one of those with an electric drive it would be great to seat the valve.

[@jamespechie8436]

But it went back and forth

[@aussienebula8331]

Thanx for the wide variety on machinery you work on and show us. It keeps me hungry for the next vid. Cheers

[@Samalyzer45]

You're certainly right about the time that lapping takes. I don't know how many hours I've spent lapping slides into automatic pistol frames,

[@skol56]

Guns exist to hurt people....

[@Joe___R]

I am surprised you didn't check the the fit with transfer dye, that is the easiest way I know to check how well a valve is seating.

[@richardcavalloro8355]

Hey Keith. I belong to the WW&F railway museum in Maine and thought they knew the location of all the Maine 2 footers. This is pretty interesting

[@davidmontgomery1016]

Thanks. I've been wondering how a steam engine's speed was controlled. I'm not a machinist but I have used some of the techniques/tips/tricks that show to help improve my woodworking. It's also kind of mesmerizing to watch a rough piece of steel or cast iron clean up on the lathe.

[@russkepler]

There's really 2 speed controls. The primary one is the throttle, the secondary is the Johnson bar. The steam valve determines the amount of steam, the second changes the cylinder valve timing on both sides of a dead center - so one side is forward and the other is reverse and moving to center cuts off steam earlier. Cutting off steam earlier reduces usage of steam enough that the earlier cutoffs were nicknamed the "company notch" for the savings.

[@bobhazzard7747]

@@russkepler Most training manuals for RR engineers circa 1900 suggest running w/ the throttle wide open or close to and adjusting the speed w/ the Johnson bar but i think that might depend on long runs and gradual changes in terrain.

[@billmorris2613]

FYI: The pipe that the steam travels through from the throttle valve to the two engines is called the “dry pipe.”

[@geckoproductions4128]

I use lapping compound to lap bolt lugs for equal engagement on rifles.....all by hand..... doesn't take an hour. Compound available at usual gunsmith sources

[@aaronmcclain1279]

Brownells has some really good compound. I done the same when I went to gunsmith school in 08 .

[@jerryshelton1481]

I would believe they had a setup to cut both surfaces on the valve at the same time same with the seats

[@johnquinn3899]

Practical info on “how to”. Thanks Keith

[@petert3355]

There were a bunch of 2-foot narrow gauge railways in Australia too. It's funny how the need for a railway was everywhere and yet the idea of standards were not at the top of the list of priorities for most railways that were created. Case in point, just in Australia. en.wikipedia.org/wiki/2_ft_gauge_railways_in_Australia

[@williamdodd8660]

2-foot gauge was done intentionally to save money.

[@bsdubois]

Standard Gauge is 4 feet 8 1/2 inches. Allowance of 4’ 8” to 4’ 9 1/2”.

[@Farm_fab]

This was also the gauge for Roman chariot wheels, incidentally.

[@audimaster5000]

@@Farm_fab wow I had to look into that. I had no clue it was based on something like that. My mind is thoroughly boggled. Thanks y’all! Found this: “Very early on, the British Monarchy insisted on a 4 foot 8.5 wheel spacing because they wanted to promote and ensure maximum trade and commerce throughout the kingdom. They decreed that every wagon and ox carts had to have a wheel spacing of 4 feet, 8.5 inches. They needed this width to match the spacing of the ruts in English roads. They knew that if any wagon or cart had wheel spacing different then 4 feet 8.5 inches its axles would get caught up in the ruts and break and the wagon would be destroyed. Many Americans are unaware that the standard railroad gauge in our country (the distance between the two metal rails) is set by federal law at 4 feet, 8.5 inches. Why the heck did our country’s government officials settle on such an odd size when they built our first rail line? Well, when our government and business leaders decided to pursue our first rail system they relied mainly on British expatriates to design and construct the railroad. These English expatriates were the same craftsmen who designed and built the British railways so they built what they knew. Wait a minute! Where did all those ruts in English roads come from? They were created by the Imperial Roman Army when the Romans invaded England. The Romans had brought with them their War Chariots and all their Imperial War Chariots were drawn by two horses by order of Caesar. Caesar insisted every war chariot be pulled by two horses to intimidate the enemy. To comply with Caesar’s proclamation Roman engineers calculated 4 feet, 8.5 inches as the minimum needed wheel distance on a chariot if pulled by two horses. Therefore if the British Monarchs wanted to continue to use the great roads built by the Romans they had to adopt a standard wheel spacing of 4 feet, 8.5 inches. When England decided to build its first railroads it relied on the trained craftsman who for years built the wagons and carts for the British highways and tram systems. Those craftsmen unfortunately only had tools and jigs to construct axle designs based on a 4 ft, 8.5 inch wheel spacing. Though it might be hard to believe - it’s true; the standard U.S. railroad gauge of 4 ft, 8.5 inches is actually based on an ancient Roman Emperor Law ordering all war chariots to be drawn by two horses.”

[@lwilton]

@@audimaster5000 Just so you know: that is a very well-known deductive reasoning chain. But if you really start digging into it rather than just saying "wow, that's cool!", you start finding a few flies in the ointment that start making you wonder if it is really all true, or someone just made up a whopping good story and everyone liked it so much they signed up to it. The first US locomotives were indeed imported from England, and they were in British standard gauge, which is 4' 8.5". That much is true. The British also used 4' gauge, 5' gauge, and a bunch of others, depending on which company was building the railroad. There was a period of time known as "the gauge wars" where freight and passenger interchange between various railroads was very difficult since the same cars couldn't pass thru; all the freight had to be manually unloaded and loaded onto new cars. The same thing happened in the US in places. So one has to wonder how "standard" "standard gauge" was, if there were a bunch of gauges in use. If you find someone that has a museum with Roman war chariots, you will find, I believe, that the wheel spacing is NOT 4' 8.5". I think it was a supply wagon that came closest to that. Commerce wagons were also much more common on roads than war chariots. All of which is to say, it is a rocking good story, until you start looking into the details.

[@Kelly-ip8nn]

@@lwilton Yes, but of course the width of the chariots were bases on the clearance for two horses. As such the width is based on two horses arses,. Mind you the booster on the space shuttle had to fit the loading gauge, which is determined by the track gauge. Therefore the most advance piece of technology booster rockets is limited by two horses arses. Come a long way haven't we

[@outbackladas]

Horses arses……. Good one 👍😂😂😂😂

[@steamdaysstoker]

I know size can be deceiving in videos. The seats looked really wide. Wide seats take longer to lap and are harder to keep steam tight. Narrow seats are much easier to make and keep steam tight. I have always used the oscillating method to lap valves, the only method I was taught. The quick method of checking the the tightness I was taught was to use a pencil across the face all the way round. The valve and seat were put back together and given the lapping motion. On withdrawal if all the pencil lines were cut the valve was steam tight. Yes I have also used bearing blue. I also came across some safety valves whose instructions gave a1 degree difference between the faces of the valve and seat. I have used this 1 degree differential other steam valves, I found them easier to lap, seemed keep steam tight longer, and the seats narrower for longer.

[@kimber1958]

Nice job Keith

[@nobuckle40]

Very interesting! I learned a great deal. Thanks Keith.

[@tropifiori]

I ( a neophyte) would not have done it that way- and I would have screwed up the job. A great video. Thanks Frank

[@CraigLYoung]

Thanks for sharing 👍

[@tomwestbrook1266]

Keith, thanks for the video and your time to do the work.....

[@clydecessna737]

Yes you did a video on the Vulcan throttle.

[@dannyl2598]

Thanks

[@MrItsthething]

I think there are two valve seats to reduce the force it takes to open the valve - notice that the flow goes one way through one poppet and the other way through the other one.

[@alexsam1175]

I work in a shop. Large one. That is made upbof 75% of the stuff keith works on. Every video is a mismatch of. We have that. I used one of them tdy. O thats how the saw drive works. Thats what that thing in the tool crib does. Its really exciting

[@billmorris2613]

Standard gauge railroad tracks in North America, US, Canada, and Mexico are 4 feet 8.5 inches.

[@Stefan_Boerjesson]

Nice work. I hope the guy checks the pipe between this valve and out through the boiler. Leaks there makes the loco keen on running... Saw such not long ago. It was a difficult but necedsary work to plug that leak.

[@alansvanes8479]

Always interesting thanks

[@kentuckytrapper780]

Great video Keith, keep'um coming..

[@infoanorexic]

4' 8-1/2" Rumor has it that it was based on the standard width of wagon wheels at the time. Rumor has it that wagon wheels were spaced to run in the same tracks as a Roman chariot. Rumor has it that the Roman chariot wheels were spaced to accommodate the horses that pulled them. So if all of that is true ... todays standard gauge railroads were designed by a horse's ass ... don't that give you a nice warm feeling of confidence?

[@williamdodd8660]

It's not the best engineer

[@evertwenderpirt6328]

good content well delivered, as always

[@dvddale111]

In the motor trade, those valves surfaces are 'pocketed', look out for 'tram' lines!

[@RPMechanics]

That was a great video.

[@jobkneppers]

Difficult job Keith. I was wondering how to approach the job and thought out exactly the same procedure as you showed. And then it turns out the top valve is more worn than the bottom one... That sucks big time when you notice it. Is there still enough metal to make it work or am I over the ridge already? Because of your careful approach you still managed to keep a window of success as you did. Hats of sir especially because you recorded the whole sequence and ended all well. These are tedious jobs which I want to do alone or no-one is watching. Close call but you made it! Thank you Keith! Best regards, Job

[@elsdp-4560]

Thank you for sharing. Watched and enjoyed.

[@millomweb]

I've cut a thread or two myself but never turned on a mandrel before !

[@johndonlan5956]

FYI - standard track gauge today is 4' 8 1/2"

[@NathanOkun]

If the bottom originally matched the top in depth when both were seated and the large valve body was not worm too much, then the fact that the bottom seal was loose when the top seal had so much ground off of it (85 thousandths) implies that the lower seal actually was much more worn than was shown by the obvious surface distortion it had. Both should have worn in a similar manner, as they were locked together and the depth of one could not change very much from the depth of the other as they wore if they both were touching their matching valve-body seats at the same time. Obvious wear is thus not a good measure as to what is really happening to valves like these!

[@skol56]

I agree totally....

[@alanl.simmons9726]

Bravo.

[@theundergroundesd]

good job

[@erneststorch9844]

I don't know if you have ever used a small wire brush to clean out the threads before you test your nut while threading. I have a wire brush I keep on the lathe just for that. I think I would have used some high spot blue to check the seats Very nice job. You saved him a lot .

[@jamessimmons1888]

Standard Railway gauge is 4ft 8.5 inches, 56..5 inches

[@samvoelkel2046]

Very interesting.

[@WilliamTMusil]

Hiya Keith

[@Xlaxsauce]

could you spray weld or regular weld up a layer and remachine it?

[@catfishgray3696]

GREAT VIDEO, GREAT JOB, DON'T FORGET TO PET THE CATS AND DOGS, TELL EVERYBODY HELLO...

[@TrPrecisionMachining]

good video keith

[@vimeel4420]

Nothing is impossible!

[@marlobreding7402]

I don't like spinning when lapping, there's a tool from the ancient days of auto repair it has a crank handle when turned causes the head of the lapping tool to oscillate right and left advancing a ¼ turn at a time. Spinning can lead to a false impression because a single high point in the seat will register 360° of the valve face. Rebuilding cylinder heads I was confident in my technique that I would just check my work by marker on the valve face slap the valves to the seat transferring the true valve fitment 100%.

[@millomweb]

31:00 I'd have done the lapping in the lathe using the mandrel !

[@johnparker7874]

Standard gauge is 56.5” or 4’81/2”

[@sdangelo6]

Good stuff!

[@organbuilder272]

4' 8-1/2" is standard guage.

[@dannymorgan6053]

Just curious, is there a reason why the lapping compound is applied to the housing? It seems to me that its easier to apply to other part, and theoretically by my thoughts, achieve the same end result. Short answer would be understood...

[@wdhewson]

That's a lot of speed and power if the lather powered lap stops sliding and bites !!

[@lwilton]

Basically impossible with that seat taper angle.

[@wdhewson]

@@lwilton I wouldn't bet both arms on it.

[@NEAFarmKid4010]

I believe that standard gauge is 4' 8-1/2"

[@donreed5439]

Keith you really should cover you ways when you use lapping compound

[@RobertFay]

*- Did you send you friend the spindle so he could use a lath so any lapping he does doesn't wobble?*

[@miguelangelsimonfernandez5498]

just like internal combustion engine valve lapping. Surely a purist would make some objections to your system, but good enough. Nice video

[@DS75921]

4'-8 1/2" for standard gauge track

[@minigpracing3068]

Could those seats be spray welded if they needed to be built up?

[@royreynolds108]

Probably, but brazing would be easier.

[@williamdodd8660]

I don't see why not

[@gautamdamodaran]

Why no blue matching?

[@dlfabrications]

Is there an interference angle between the valve and body? The more you take off the valves, the contact point is higher up the valve face?

[@crossbowhunter9118]

What lathe insert tooling do you use? What inserts do you use?

[@azlandpilotcar4450]

Great video. Curious as to whether the valve bearing surface angle was still 30 degrees after the lap?

[@Mishn0]

Maybe, maybe not, but as long as the angle of the valve matches the angle of the seat, it's all good.

[@MrChevelle83]

Good job on the valve repair but, I did have to cringe a bit when you were using the chuck and pressing that piece together. That seems like a really unsafe technique on a lathe, Aint no way id use a lathe like that after the injury videos I've seen. I think id chucked the valve in the carlton radial drill to make that task much safer. Thanks for the great vids Keith.

[@lwilton]

With 30 degree valve seats the taper isn't able to lock, so it can't grab the part and spin it. With a very steep seat taper, or some other locking taper, it would be a seriously bad idea. But with slow speeds and a normal seat taper angle, all you have to watch out for is barking your knuckles on the chuck jaws. It really isn't particularly dangerous with even moderate care.

[@jwaterous224]

Narrow gauge trains are interesting for sure. Two foot track is the smallest I have heard of. I wonder if there was a specific industrial reason / use for that size? When you lapped on the lathe: I heard "the sound" meaning happy iron and cutting all the way around.

[@Stefan_Boerjesson]

Such narrow gauge costs a lot less in both track building as well as the rollung stock. Provided that the lower load capacity was enough.

[@jerryshelton1481]

They used them alot for mining and rough terrain so they wouldn't have to cut such a big swath for tracks

[@cyrilhudak4568]

Used back in the woods to harvest timber. No forwarders and skidders back them.

[@jwaterous224]

@@cyrilhudak4568 I wonder if they laid narrow gauge track then picked it up and moved it around constantly for various stands of timber?

[@cyrilhudak4568]

@@jwaterous224 Absolutely

[@jeremycable51]

What lathe are you on looks like the old pacemaker from the museum don’t get to see it much these days

[@pacificcoastpiper3949]

Hey Keith, what is your favourite material to machine?

[@ellieprice363]

I would bet either 360 free machining brass, 6061T6 Aluminum or 1212L leaded steel.

[@bigun447]

I thought when you mentioned double lapping you were talking about putting your granddaughter on both legs. Just kidding Grandpa. Great video.

[@websitesthatneedanem]

Stoker Engine! 😁 Stoker Engine! Stoker Engine! Stoker Engine! Stoker Engine! Stoker Engine! Stoker Engine! Stoker Engine!

[@southern207hobbies]

The owner might want to reach out to the ww&f

[@benjamindusseau4912]

Would or could this have been a place where the spray welding process could have been used to build up the valve prior to shaping?

[@pacificcoastpiper3949]

I had that thought myself, or some kind of hard facing

[@PeterWMeek]

Didn't you show us a big set of valve-seat reaming tools a few years ago? Could you refresh the seats in the main casting with some of the cutters from that set? (Questions like this are usually too-late, job-done, but still curious whether this might have worked.)

[@lwilton]

Theoretically yes. But in this case, having two seats that have to be an exact distance apart, it would be very difficult to get a good result. You also need both seats on exactly the same center, and this valve doesn't have any good pilot surface that can be used to center the shaft for the seat reamers. That makes it even harder to use traditional seat reamers. Originally the seats would have been cut using a duplex milling cutter with an exact spacing between the cutters that would have been verified with a master gage. Something like that could be duplicated if the exact seat spacing was known, but would be a lot of work and possibly expense if special-sized 30 degree cutters were required. Trying to duplicate that with just a valve with unknown wear as an example would be a debatable enterprise. You could make a bunch of measurements and just pick a set of numbers and cut the seats to match, then cut the valves to match. If the seats had to be cut, probably the best way would be to set the valve body on a face plate or in a 4 jaw chuck and cut the seats with a boring bar, if you have a big enough lathe.

[@PeterWMeek]

@@lwilton - I was think of doing minimal seat cutting on the two seats individually to prepare them for lapping, to be followed by adjusting the distance between then by cut'n'try with the spool as Keith did in the video. I didn't expect this method to preserve the spacing. The kit had mandrels and centering cones to keep the cutters straight on the seat. I do not recall if there were any 30º cutters in the kit Keith showed us years ago (and 15 minutes of searching didn't find it).

[@lwilton]

@@PeterWMeek I'm having trouble remembering exactly what Keith showed in that kit, but all of them that I'm familiar with expect there to be a centered bore for an operating shaft, and this is what they use to center on the valve seat. This valve is a little unique in not having a central spindle, it just has the two seats, and all else is just rough casting. Without the central spindle bore to center on, I'm not sure how you could use a typical seat reamer without a lot of fixturing and jigging. I'm sure it could be done, it just seems to me that it would be a lot more work than for a normal valve with a central operating shaft bore.

[@donaldshires4143]

When are you going to do the stoker engine????

[@waynep343]

The stoker engine goes to a locomotive restoration underway by another group.

[@CabooseKid]

What is the condemning limit on that valve? That should tell you if you took too much, or even if you could have taken any to start with......

[@lwilton]

It might, if you could find that number. Or any specifications on the valve at all. Not necessarily easy on a valve of unknown manufacture that might be 150 years old.

[@skol56]

Always fighting the impulse to assume stuff, if the surfaces were, ie 4" apart, then cutting 85 thou from the upper would suggest taking that same amount from the lower? This would have maintained the distance between each valve.... That is how it would be in my world......I think...

[@LambertZero]

that thing is cast iron, right?

[@chrisstephens6673]

Good fix but just being curious were your 10 thou cuts radius or diameter, looked awfully fine for a full 10 thou cut.

[@johncoops6897]

He stated the cut depths were "across", so would already be finer on the taper. My guess is that he was winding in 10 thou, not saying 10 thou on the diameter... but that's a guess. Keith rarely responds to questions, unfortunately.

[@chrisstephens6673]

@@johncoops6897 yes I know, but was he watching the fro, usually in diameter, or lathe dials. What I am saying his total removal, if diam, doesn't sound as bad as it would if radius.

[@linuxaos]

Wait a second.... wait just a second. If we are taking off metal from both pieces, wouldn't the gap between them get bigger ? How could these 2 pieces ever line up and close the gap? What am I missing here ?

[@Henning_S.]

The cones of the valve just drop deeper in the mating cones until the gap is closed.

[@linuxaos]

@@Henning_S. Good answer. However if he keeps cutting the thing will just drop through.

[@terrycannon570]

I criinge seeing you do that with the lathe. It would much safer and accurate if done in the mill.

[@Mr_Meowingtons]

it don't seem like it would be that hard to make a 100% new one with some bar stock..

[@Th3Su8]

As I am watching this I started wondering at what point would it become necessary to just make a new valve? You were talking about taking material off the valve and how it was more than you had wanted to.

[@royreynolds108]

It would be easy enough to build up one or both valve faces with braze and then remachine the faces.

[@kerrygleeson4409]

🌲👀👍

[@davidstreeter9426]

Nothing like duplicatng 100+ y/o technology.

[@andrewsteed3048]

First in the UK ! Whoo !

[@johncoops6897]

Nobody cares, loser ! Whoo !

[@audimaster5000]

@@johncoops6897 I just learned we cared so much that our railways were built off British standards which came from Roman chariots pulled by two horses. 4 1/2 foot width. The ones who built our first railways in the US were in fact British who simply made them how they knew. That didn’t go how you thought it would

[@johncoops6897]

@@audimaster5000 - No, it didn't. I didn't want a history lesson, I was just poking fun at idiots who post "first" comments on KZbin videos, and adding absolutely nothing to the discussion.

[@brianevans1946]

I couldn't figure out what a bawler was then realized it's a boiler....

[@BretBerger]

Keith lubes his ways with awl.

[@deedeeindustrialsuperprecision]

That is the worst example of lapping ever!

[@emilgabor88]

Now that is a rubbish design for a valve…

[@stumccabe]

I don't think so! I assume it is designed so that the force (due to steam pressure) is approximately balanced between the bottom and the top thereby requiring less force to open and close it. So the opposite of rubbish design.

[@russkepler]

Yup - it's called a "balanced valve" and the double seat balances the pressures so the valve doesn't open or close under pressure. If you've ever worked with steam on an unbalanced valve you'll really appreciate the balanced valve.

[@Hoaxer51]

@@stumccabe, and it lasted over 100 years, that kinda proved it was a design.