Trevithick

[Brian Rupnow]

Today is a "banner day", as I have completed the cross-head and cross-head guides, and my air cylinder and rotary valve are moving the cross-head thru it's travel. Everything is a bit herky-jerky right now, because everything is new and stiff. Once it has been operated a number of times, any "tight spots" will be smoothed down and the travel will be much smoother.

<a href="https://www.youtube.com/watch?v=-8n-77EDhEE" target="_blank">http://www.youtube.com/watch?v=-8n-77EDhEE</a>

[crueby]

Love it!   

[Brian Rupnow]

Here is a fun little video of "running in' the cross-head and cross-head guides to make them operate smoothly without binding.
<a href="https://www.youtube.com/watch?v=k98R9-F3M8I" target="_blank">http://www.youtube.com/watch?v=k98R9-F3M8I</a>

[Brian Rupnow]

I have now reached the point where I can't do much more until I mount the shaft which the flywheel mounts to.--And--the exact position of that shaft depends totally on the meshing of all the gears. I only have to actually cut 3 gears--the ones attached to the wheels will be made as one extra thick gear, then split with my parting tool to yield two identical gears. I have a tiny bit of cosmetic work to do on the "boiler", but that can wait, for now. I can make all of the smaller gears tomorrow if I have the material to make them.

[Brian Rupnow]

This morning I went searching about for material to make all of my gears. Okay--Good news is that I already have a 36 tooth gear left over from some project, that can be repurposed. It is the gear which sets up on the same shaft as the flywheel, and by all rights should be made of steel. Since this is only a demonstration engine that will see very few miles, I will use this gear anyways. I hunted up two bronze flywheels from the old Rupnow Hit and Miss engine, which has been scrapped and caniballized, but they aren't really of  size that I can use. I found a really big round piece of mild steel that was a cut-off from something else I built, which will do to get the 108 tooth gear from.--And---I have a big long piece of 2 1/2" diameter hot-rolled which will work fine for the 50 tooth gears that attach to the wheels.  In other news--Yesterday, on my "fat mans walk" I lost a pair of bifocal glasses. As soon as wife and I got home, I realized that I didn't have them, so we went back and walked the trail again looking for them, but no luck. I have put up a sign at each end of the trail explaining what I had lost and my phone number, in case someone else found them.--If not, I'm out $300. That would have bought me a lot of material for my hobby.

[Brian Rupnow]

Okay---Here we go---hang on. The 2 1/2" round hotrolled has been cut off, to a sufficient length to give me two or three gears and a handle to hold in my rotary table chuck.  The large outer diameter has been turned to what the actual outside diameter of the gear will be. The smaller diameter is turned to a diameter that is smaller than the root diameter of the gear teeth to be cut, and long enough so that I don't run the gear cutter into the hardened chuck jaws. That will immediately ruin a cutter. Don't ask how I know this. The center has been drilled and reamed to 1/4", which is the diameter of the axles on my Trevithick.

[Brian Rupnow]

I've just finished cutting the 50 tooth gears. A couple of things here worth mentioning. Any time I cut  gears, I try and make the gear blank a bit longer than necessary. That way I get the two gears I wanted, plus a "free-bee" that I can use on some future machine. I use the tailstock support, because the material is sticking out quite a long ways from the chuck. At the very front of the table, you will see two "table stops" that I set before I started cutting, so I can't run the cutter into the hardened chuck jaws nor into the tailstock support. Lastly, you can see that I used my cut-off tool in the lathe before I started cutting the gears. I cut just deep enough to be lower than the root diameter of the gear teeth. This avoids pulling burrs on all of the gear teeth, which happens if you wait until after the teeth are cut to part off the individual gears.

[Craig DeShong]

... so that I don't run the gear cutter into the hardened chuck jaws. That will immediately ruin a cutter. Don't ask how I know this.

I see that not only me, but Brian sometimes needs to learn the "hard way".  It's an expensive lesson to learn.

... Lastly, you can see that I used my cut-off tool in the lathe before I started cutting the gears. I cut just deep enough to be lower than the root diameter of the gear teeth. This avoids pulling burrs on all of the gear teeth, which happens if you wait until after the teeth are cut to part off the individual gears.

Ugh, why didn’t I think of that.   Thanks Brian.  Another great tip to “file away”.

[Brian Rupnow]

Thanks for saying "Hi" Craig---I'm following your very interesting project also. This is what I end up with. Two 50 tooth gears to go on the Trevithick, and one spare to be used on some future project. The centers will eventually be removed from these two gears and they will be attached to the wheels as shown on the 3D model, but for now they can stay mounted on the axles until I finish all the gears and see that they mesh properly.

[tghs]

this popped up in my saved searches page  https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO6-THE-TREVITHICK-BOILER-C1920-PHOTO-INDUSTRY-/363122432870?&_trksid=p2056016.l4276

[crueby]

this popped up in my saved searches page  https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO6-THE-TREVITHICK-BOILER-C1920-PHOTO-INDUSTRY-/363122432870?&_trksid=p2056016.l4276

That is very interesting!  I wonder if it is a photo of a patent model, judging from the sign below it?

[Brian Rupnow]

It could be the Trevithick, but 1920 is over a hundred years after the Trevithick was built in 1805, so it could be anything.

[crueby]

It could be the Trevithick, but 1920 is over a hundred years after the Trevithick was built in 1805, so it could be anything.

Good point!!

[ShopShoe]

Too bad "The History Detectives" is off the air. (U.S. Public Broadcasting show that was on a few years ago where a team of researchers followed clues back to determine what an artifact actually was.)

In this case they could have obtained the lantern slide and followed back what is known about it to find where the boiler was displayed and how it might have been labeled.

My guess is that someone found this boiler (dug it up, from the condition) and matched it to what was known about the original Trevithick and put it on display. Hence the quotation marks.

Then one of the many firms that went around documenting things to sell image collections to users of magic lanterns photographed this display. There were a lot of firms doing this for magic lanterns and for stereoscopes. There may have been a catalog of the images originally that may still be archived somewhere or in a private collection.

(Editorial comment follows)

What is a shame is that a lot of artifacts, or primary-source documents related to those artifacts, are actually saved somewhere and not properly tracked so anyone can find them. I also feel sad that the rush to "digitize" everything sometimes results in someone making spur-of-the-moment decisions to destroy or discard parts of the record so what the future searchers for information can find are only a bunch of "pretty pictures" that no longer have the provenance or the context necessary to understand the past..........

ShopShoe

[tghs]

if look on the seller's other items he posting a good selection from what must have been a set on steam power,, "each slide has a set number" https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO32-RICHARD-TREVITHICK-PORTRAIT-C1920-PHOTO/363122432897?hash=item548bc89b81:g:bTMAAOSwEOhfYKVY