It's also true that stepping on the accelerator pedal on a Toyota Camry won't make a little old lady stop sooner. But a Dodge 3500 with a mechanics box will.
This is why we are in process of building our very own Lathe from scratch, rather make something as to go buy a cheap, inferior something!! Great video sir, just makes us want to get ours built even sooner!!
The original brake shaft has if you look a tapered square. I think Keith has overlooked this. The taper automaticly takes care fo wear in the handle etc. Thanks I don't mean to be too critical. I like the vids and watch every one.
It looks like having the rotation limit on the casting could put a lot of load on the spring pin and shaft if the engineer pushes the handle to the stop. Maybe warn the engineer to use a gentle touch....pushing to a hard stop doesn't improve the flat face valve operation. Just another one of those undocumented secrets to learn when running a steam loco. Thanks Keith.... I am the one with the machine shop keeping our club's 1913 Case steam traction engine running here.
“Warning: Pulling harder on this handle will not stop the train sooner.” Although, sadly, that same warning has never worked while I’m playing video games...
@@janvisser2223 I suspect the valve stem was all originally cast in one piece in bronze. The new 5/8" brass stem and spring pin are probably a later fix when the stem was twisted off above the 0.9" shoulder.
@@chuckinwyoming8526 You are correct, and Keith is the one who modified it with the roll pin! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-DAobpHBSSww.html
Chuck in Wyoming: Agree.. Keith has probably selected the material that he had on hand. I personally would have spent time to make a one piece part out of bronze. But hey, who is interested in my opinion😊 Put ten technicians in one room and you will end up with ten different solutions for the same problem. The design of this old brake system seems also unsafe as it is not fail-safe. As a rupture in the steam line to the brakes will produce al lot if steam blowing off to the atmosphere instead of slowing down the engine
I've been a fan of steam engines since I saw my first one up close in 1957 when I was 3 years old. It may have been the last one to leave New York City where I was born in 1954 when we left for Cleveland, Ohio. I'm glad to see you take the time and your experience to keep some running. The best restoration I've seen is the Union Pacific 'Big Boy' #4014 brought back to life. I do have a Rivarossi HO scale 'Big Boy' #4001.
Appreciate seeing where this part came from. It's the missing context from a lot of repairs. It should be a requirement of all youtube repairs that photos of the original machine/where it came from be included with the part! :)
31:54 shop boss signing off! A flat on the shaft with a mating flat machined in the end piece would be good for transmitting the torque, then you could use a very small diameter pin to hold the valve stem in but loose fitting in the end piece so there is no torque thru the pin. That would make it much stronger. PS:Need to tighten your chuck on that center drill. lol
@@cyrilhudak4568 With a little end mill. :-) Of course in my shop I would have to use 1/4" then file out the corners to get a good fit but with those less afraid of the small stuff an 1/8" would probably be the trick. lol
Being a Diabetic like Keith can be a scary time right now! My wife also works in a Nursing Home which makes me double scared, she has a habit of bringing home things that should remain at work! Last time I was in the hospital for 7 days because of a stomach bug that made it difficult to manage my insulin and the EMT's gave me a little too much sugar causing my sugar to reach 1580, 70-110 is normal. 1580 put me in a coma and then cause other issues. May God Keep us all Safe !
That's good info. Guy I work with hates metric bolts because they are fine thread and fine threads are easier to cross thread. Well, never in the history of threaded fasteners has a fastener cross threaded itself. There has always been someone turning it. *Every* cross threaded fasten was caused by the person installing it. He is just trying to justify his ineptitude by blaming something "foreign".
Fine thread bolts tend to be used on high strength bolts because the finer thread leaves a bigger root diameter. Any bolt table will tell you they accept more axial force. They may have been needed here because those four bolts hold the (fairly large diameter) top on that valve against full steam pressure. If they fail, the top blows off, there's a deafening noise from the escaping steam, the driver gets a bad burn as well as a sprained wrist, and the locomotive has no brakes. The fine threads and the bolt spec are potentially very important.
Good job. I liked the way you used the collet and the vice to mill the square. The old part looked like the square was tapered though, but it didn't matter.
Thanks Keith. Wonderful explanation on the brake valve. You do make it look easy. Had you made a couple of spares, you would have ensured the stem would NEVER break again! Regards, R
If you do have to revisit this repair consider tapering from the 7/16ths to the 5/8ths diameter where the packing rides. It would remove the stress riser from the hard transition.
I wonder if the issue it's with radial forces from someone being too heavy handed with the handle and stress cracks forming. It took me a long time to teach my kids to shift a manual transmission using their finger tips instead if grabbing it and forcing it into gear.
@@robertoswalt319 I think the steam pressure pushing down on the valve disk makes the lever hard to move otherwise we would see a ball on the end instead of the large handle. He had to machine the valve surfaces before and the spring inside is not super strong so that wear force came form somewhere else... steam pressure.
So by your explanation, that’s technically a sort of pressure vessel. That’s why you have fine thread bolts because they are stronger in tension than a coarse thread.
Hi Keith, just watched the valve lapping vid from 2 years ago, where you installed this brass shaft that just broke. For such a light load that's not a very long life. In that vid you also remachined and installed a guide bush as well as removed the original shaft. During these operations I saw several places where missalignments could have crept in. This could have resulted in a slight bending force at the region of the spring pin. After a few thousand operations this could easily have broken the shaft. If this new shaft breaks again in a couple of years, check the alignment.
Keith, if Lady Luck is unkind and that stem fails again, changing from brass to something stronger, say manganese bronze, might be wise. With strength comparable to steel and highly corrosion resistant, manganese bronze seems a "winner".
Keith does not read the comments. People have been telling him to use bronze for parts exposed to steam for a long time but he just wanders along in a fog using brass because that's what he has.
@@MrJohnnaz Stainless is the best, all machinery used in autoclaves in modern times uses 304, or 306 stainless steel. Most autoclaves us 125lb incoming steam pressure, so there is really no reason not to use it on locomotives.
25:25 Looks very much like the square on the original stem has a taper, similar to a square taper bicycle bottom bracket. When this one breaks because it's brass and you make a fresh new one from bronze, you can take out the handle slop by making a square taper on the new one :)
Love watching and learning from every video you post. I would love if you made a video on lathe tooling and why you choose which cutter and how they are used.
Keith, As I see it the problem is the stopper is down on the bottom casting, and any pressure applied by the operator in rotating the brake handle, to the full off or full on position, applies a lot of load on that pin and reduced section on the bottom of the shaft. you might be able to find a suitable bell shaped pipe reducer or make something up, but you need have it so it can slide down over the main housing with a suitable slot in it for where the steam inlet pipe is, the steam inlet pipe will act as a stopper to stop this sleeve from rotating around the housing, the reduce needs to be big enough to fit over the packing nut on the small end of the reducer, then at the top weld a flat piece in that is just above the packing nut with a hole for the shaft, and another piece a smaller tube welded to that plate that is 270° so it acts as a stopper on the brake handle.
Brass should not be used where it is continually exposed to steam or hot water. The zinc will leach out, making the part weak. A bronze, which is copper alloyed predominantly with tin, will retain its strength much better. As to the size of the spring pin, would the locomotive have had spring pins originally? I’m thinking it was originally a small tapered pin. At some point in time, when a repair was made, brass was substituted for bronze, and a larger spring pin was substituted for a tapered pin. These two changes would make the shaft susceptible to fracture.
I don't know how deep the center drill went but it might have been a good idea to make the turned down section that goes into the valve driver to a little longer. It might have been deep enough to weaken the cross pin. Making it longer would allow for the center drilled section to be cut off. Could have also done the handle side first. Going 7/16 will definitely help. Maybe use a bronze instead of brass as a different material? Polish the shaft at the gland nut?
I think I speak for many people when I suggest that Mr Rucker should self isolate himself in the machine shop for the next few months and produce thousands of hours of videos to help us get through this difficult time!
My observation: The brake valve is about as easy to operate as a light switch. Like a switch, it has two positions, on and off (ok, some shades in between for slowing). It doesn’t matter whether you’re stopping gently at the station to swap passengers or doing a panic stop cause Buster’s car is on the tracks again, there is no need to torque on the brake handle. The room doesn’t get dark any faster if you slam your light switch and train won’t (can’t) stop any faster even if you’ve got a 36” pipe wrench on the stem. My rambling point is, if used as intended, your your brake valve stem should last you several lifetimes. 😎👍
You are absolutely correct. The train travels 5 to 10 mph and is stopped by closing the throttle and using the reverse lever. The brakes are used to keep the loco from rolling.
Steam brakes😮.I didn't think there would be any locomotives of that era still running them .A westinghouse brake set up would be nice upgrade,if a little expensive.
That spring pin hole is a serious stress riser at a critical point. Making it bigger will help a bunch. Maybe consider silver soldering it in if there is a next time.
Keith, this was another very interesting video -- I enjoy seeing the locomotive repair you do (along with everything else). I agree that the spring pin seemed too large for the size of shaft it went through, but could the wrong material have been used previously? I think I've read that many brasses don't do well in steam service. Anyway, your fix ought to last a long time. Take care.
*i am so pleased with myself, Keith. Before you got started on the fixin' part i had instinctively chose to bore the hole bigger by 1/16 inch. That "small" increase in the diameter adds a lot of brass to resist torquing forces, increasing significant robustness against breakage in the future from brittleness being introduced over time. I wonder what a mechanical/metallurgical engineer would be able to calculate is the increase in strength? Maybe someone here knows the calculations to run on that. (i hope) [i hate to say it, but i would be getting ready to core a new brass rod and insert a stainless rod within to take the drilling. I know my strength (like yours) would introduce too much Hammering the Break Handle to the ON position and thereupon introduce a Lot (too much) of a sudden torquing (and thence brittleness) to the too small brass stem given the size of the pin needed for strength.]*
yup its time for a design modification keith ! if it was me and i had your tools i would drill out the socket for the shaft remake the shaft with a longer threaded section extending through the socket and secured with a nut and possibly a key the pin as you point out is the weakness here but is also what locks rotation of the handle to the valve which is the issue here it needs to be locked in rotation for the valve to operate but any pin through the shaft that size weakens it to a point where it will fail in time right there over and over ,, so i believe my method will be a superior repair but hey you know what is said about opinions and how there as numerous as certain orifices and just as welcome to public exposure ;D
Two things strike me, firstly why do you just run the bit back along the workpiece without pulling it away? It leaves an unsightly helix. Secondly you use the blade ends of the Vernier caliper, which risks error due to inaccurate alignment along a parallel cylinder. Could you not eliminate that error by measuring using the flats and allowing them to be snug on the work?
Keith I would have been very tempted to broach the round hole in the casting to square or maybe hex and as Single70s suggested below, replace the brass shaft with a high cobalt content stainless steel such as EP0250690A1, which is used in hydraulic valves and has good wear properties and corrosion resistance. However maybe that is overkill for a low speed locomotive, where you always have the reverser for emergency braking.
@@paulatkins894 any shop that makes repairs mainly auto has to have liability insurance for just such a thing. When i was an A.S.E. tech though i can tell you 98% of failures after a car left where not directly related to the recent repair. Eventhough its very hard to explain that to customers
Is brass the right material for a component that experiences such high temperatures in operation? Brass tends to weaken over time in live steam environments. Surely a bronze would be a better choice.
I think a solution to not breaking this arm in the future would be to have a disconnected shaft with a spring latch. You can pull it to your position, it does its job, but if the engineer pulls harder, instead of breaking, the handle skips a turn. It would mean that the handle isn't aligned with the setting, but that's a small price to pay vs not having brakes in a possible dangerous situation.
Maybe you could just machine the shaft and the casting it is pinned to out of a single piece of brass? Maybe I missed something, but it seemed to me that everything would still go back together the same way. I appreciate the videos. Thank you.
I really like the little bench anvil you have. Thinking of making one for myself. Are there any suggestions on making it better? I was thinking different size V slots on either side.
Do you have a video about how the threading is synchronized so that you keep going in the grove as you increase depth on the thread. The man who taught me Woodworking also did metal work on his lathe but I was never there so missed out on the details. You kept calling out numbers before the next pass to increase the depth. Thanks.
Why not square-broach it, make a handle to fit then drill and tap a set screw that engages a dimple in one of the flats? Much stronger since there would not be any through-hole.
