Wheel Lathe

Tom,

I was going to suggest the EBT, but saw at the end of your message that you had already found that info. I've toured their shops a couple of years ago and saw that lathe in person. Quite impressive. I've also been buying the EBT shop building kits put out by Broad Top Mountain Models. 

http://broadtopmountainmodels.com/east-broad-top-machine-shop.html

I'll be following along on your progress of designing the lathe.

Bernd

EBT

Bernd - That's definitely a trip I need to take, EBT.  I was under the impression that they had closed their doors but if you were there a few years ago then I should look into it again.  Thanks for the link too.

- Tom

EBT

EBT had closed for a while, it was bought by a non profit group in 2019 resumed operations in 2020 for the 60th anniversary, details here:  https://eastbroadtop.com/nonprofitbuysebt/

As for a wheel lathe don't know how big it is, but pretty sure the Baltimore Steetcar museum has one, but since street car wheels are much smaller than drivers might not be helpful.

about 4 years ago I found a

about 4 years ago I found a wheel lathe on shapeways in HO. It was sized more for Diesel or freight car wheels and it was definitely designed for that early 20th century look. I bought 2 of them and took them apart and rebuilt it into a more modern looking unit to put in the club layout roundhouse. 

What I really wanted was a big 100" lathe like California State Railroad Museum has in their backshop. But apparently the interest level for that is low. 

What a Trip

OK guys.  I'm gonna take a trip to see the East Broad Top in Rockhill, PA.  I Googled it and found it's only two hours from my sister's house outside York.  Of course it's a 15 hour drive to my sister's house but it's a good excuse to get up there.  Seeing the lathe (plus the rest of the shop) in person should give me the detail I need to do a proper model.  Cool!

- Tom

Crank Pin Pocket

I've only seen one wheel lathe in person, more modern than the one you are modeling, Tom. That said, it included a feature I don't see in your assets - a pocket for the driver crank pin. It stands to reason that it would exist on older wheel lathes since it would be a real hassle to press out the pin just to freshen up the wheel tread. 

Pocket

Good thought Matt.  I went back to the drawing above and it looks like there's a pocket straight up from center.  I'll hafta add that.

- Tom

Progress

Got some more work done on the design.  The wheels are 48" narrow gauge (On30)

Re the labelling on the drawing about shaft "D"

I suspect it is to assist with quartering the drivers.  Curious that their drawing shows the drivers not quartered.

Cool project. Are you printing with filament or resin?

3D Print

Mike - This is my second project on my new Anycubic Photon resin printer.  I had been using an Ender 3 filament printer in the past.  Once I got past the glitches and bad behavior I found the resin printer to be waaaaaayyyyyyy better.

Tom

Looks good so far.FYI

Looks good so far.

FYI someone used to make one in HO.  One of my buddies had one.  It was (I believe) a white metal kit.  But I think it is long out of production.  Simone used to sell a lot of shop equipment decades ago,  I used to drool over them and dream of building a big roundhouse with a huge machine shop with overhead drive.  That stuff is just fascinating.  To bad it is all so dangerous…

BTW don’t forget to offset the crank pin holes to accept the quartering on the wheels.  As those look to be geared so you probably can’t rotate one by itself to align them.
 

-Doug M

Wheel Lathe

That picture of the wheel lathe Matt Goodman posted looks like it's at the Age of Steam in Ohio.

Note the difference of the face plate of the one in Matt's picture and the one that Tom has on the drawing. The drawing one has a longer center point. The one in Matt's picture has a much shorter center point. That's probably why there is no hole for a crank pin in Tom's drawing. Notice in Tom's drawing how far out the centers protrude to hold the wheel from the face plate.

Here's a lathe with only one face plate and a center.

http://sanfranciscotrains.org/pics/wheel-on-lathe.jpg

1913 Wheel Lathe.

https://www.practicalmachinist.com/vb/attachments/f19/1544d1202346547-1913-wheel-lathe-work-img_2339small.jpg

Here's one from the U.K. I believe. Note that the wheels are not touching the face plate on either side.

https://www.dhtcollections.com/images/products/large/1337189446uploadTextilesPhotographsDUNIH2009.31DUNIH2009.31.59.jpg

That concludes our lesson on steam locomotive wheel lathes.

BTW Tom I'm a member of the EBT. Joined this year and plan on a trip to the EBT next year.

Bernd

(No subject)

Thanks Tom

I was so enthralled with your fabulous CAD work, that I completely missed the resin printer indication in your opening post.  Can’t wait to see your printed output, and perhaps some “part way printed” photos.

@Bernd

That photo looks like a superior approach with one faceplate and a center.  The design of the lathe in Tom’s reference photo obviously worked, but imagine if those gears got out of synch in the slightest. Instant torsion on the axles, a twist of a few thou, aggravated a few feet away at the tire surface …

Either makes a great model though.

Lathe Gears

I'm sure the gear on one side would have been take out of contact or disengaged and would be free wheeling. There's no need to drive both sides. Even if there was, the lathe would not get out of sync. Take it from a guy that's been around large machinery during his working career.

Bernd 

That photo looks like a

Given the THOUSANDS of horsepower those wheels and axles transfer when in use, I really can't see a mere lathe exerting enough force to distort the wheels and axle significantly. And given the diameter of the wheel, you don't need a high rotation rate to get the proper surface speed for tooling.

Long Centers

Bernd, you're right on the location guess (Age of Steam). 

I thought this was curious as well, as that offset from the faceplate would seem to make driving the work more difficult and put more load into the center rather than the face plate. As you noted, it must have worked (and had a purpose).

< Edit> Thanks for the links above. The period vendor photos/artwork for Ulro (Bernd) and Sellers (Tom) are always a joy to look at.

Actually i expect that they

Actually i expect that they did drive both gears at once,  For two reasons.  One not much point in having two gears if you only ever drive one of them.  And two.  It is all two easy to spin a driver,  So much so that it was known to happen while on the locomotive if the engineer slipped his wheels.  I know that some railroads would put lines into the the wheel as witness marks so they could see if the wheel slipped.  So you probably have to be careful if you are putting all the power into spinning this through one tire while turning the other,  You have the tire 1 to wheel one that could theoretically slip as they were held on by pressure (heat the wheel to expand it then slip it on and cool it off it shrinks onto the wheel). That joint can slip and the C&O actually had an engine that had more then one tire come off once because of engineer screw up,  Then you have two Wheel to Axel joints (pretty solid so should be ok) then you have the wheel to Tire 2 joint that you are milling.

And remember when milling the wheel back to round you need to do it in relation to the wheel as the wheel may not be 100% round so you could end up with a thicker or thinner tire in one location to compensate so slupoing the tire while milling would suck.

There has to be a reason for both sides having gears…. or the gear wouldn't be on both sides,

-Doug M

@Matt re centers

The centers don't drive the job to spin.  They only support it axially, and provide a reference to true from the wheel’s original turning.  There will be a small center hole in the axle that was made originally when the axle was turned true and to size.  Everything flows from there as the wheel casting might be initially out of round, but is trued up to the axle or an identical mandrel and made round before the steel tire is shrunk on.

In Tom’s drawings, all those slots in the face plates would be for big lathe dogs and/or some kind of clamps that would grab a few spokes to “join” them to the face plate’s for turning.  Not much would be needed as once these were spinning, the rotational inertia would be huge, and light truing cuts don't impose that much load in comparison, and as pointed out above, too much cutter load could result in a tire spinning on the wheel proper, buggering everything.

Having turned many wheels up to a foot in diameter, it is fine work getting the flanges shaped just right, perfect fillets (the curve where the tire surface meets the flange), and the tires tapered perfectly.  Not a job to be rushed on castings that take a lot of time and effort to make, or $$$ to buy.  Even more critical on the prototype where the driver castings were likely made years in advance to allow for aging of the iron before machining.

The wheels on the prototype have a very slight taper (< 3 degrees) to keep the wheels running on the middle of their treads on track, versus having the flanges rubbing all the time.  Gravity is a very useful force!

For those who care, in addition to truing up the wheels, or doing the initial turning of new tires, here are all the details that are turned.  Drawing from IBLS by Bill Donovan of Realtrains.com: 

If anyone has close up photos of the cutter toolposts, and various cutters, shapers and gauges being used, they would be fascinating to see.

I have seen many full size steam locos, and the axles are normally keyed to the drive wheels, but as was pointed out by Doug M, enough torque can still spin a wheel, twisting the key.  as Doug points out, tires can be spun as well with enough torque.

This is not a great photo, but the key can be seen here.

Faceplate Info

In the drawing from EBT the two faceplates are connected by a shaft with gears on each end.  It runs along the bottom and shows just above the large arrow in the drawing.  There are also indexing pin slots 90 degrees out from each other on the faceplates.  One can be seen directly above the "center".

In the book about the EBT shops they mention that the faceplates can be disengaged from the shaft so they can be aligned to install the crane (wheel hoist).

- Tom

I found a guy to help me get

I found a guy to help me get a better perspective on the size of the lathe.  He's 5'10" and when he stood next to the 66" lathe I realized it looked kinda puny.  I really want this to be the main attraction in the shop so I resized the faceplates to 84" and raised the bases for the tool stands.  I think this looks much better and the tool height looks more reasonable for running the lathe.

Changing to 84" was a bigger deal than it sounds.  All the T slots had to be re-positioned and I kept the centers the same size to help push the "look".

I also added the indexing pin holes and slots for the wheel crane.

I think the faceplates are pretty much finished and I can go back to the tool stands.  I'm making faster progress than I expected.  It'll be interesting to see how much detail the printer can handle.

- Tom

Wheel lathe

Tom,

That's looking mighty fine. Excellent work. The 84" plate looks better.

Crossing my fingers in hopes you get a good print. 

Bernd

Test Print

I’m using an Anycubic Photon 3D resin printer to make my parts for this project.  This is only the second model I’ve built with it so I’m still working to get the bugs out for a quality print.  I’ve done two runs on the faceplate so far.  The first one had supports and was tilted 5 degrees in X and Y.  The supports were on the flat “work” surface and the results were pitting wherever a support came in contact.  The back side or “frame” side looked clean.  For my second try I printed the part flat with the “work” surface directly against the build plate, no supports, no angles.  It came out much better.  The photos below were taken after the part was cleaned in an ultrasonic cleaner using 70% alcohol.  It was cured for 45 minutes on each side under a UV lamp.  No additional cleanup of the part has been done yet.  The “frame” side shows slumping around some of the bolt down slots but the other side of them is pretty crisp.  I don’t think this will be an issue since that part of the slots will be inside the gear drive housing.  This part is 1.75” in diameter.  I think it’ll be a “go” for 3D printing this model.

- Tom