Constructing The Josslin NYC Hudson Lead Truck

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Sat May 25, 2019 11:39 pm

Completing stage two of the wheel turning.

With two of the wheels cut from a hot rolled steel bar, I used a backing ring in the 3 jaw chuck when stage two turning. This was done to keep the outside jaws on the turned stage one wheel OD to keep everything as concentric as possible as the OD of the hot rolled bar was very rough and irregular. Of course the backing ring has to be as parallel as possible and in this case quite thin but having a surface grinder it was easy to accomplish. See the first photo.

The last photo is of the through the lathe spindle tapered stub arbor which will be used to hold and turn stage three of the lead truck wheels. I made it when I first started building live steam locomotives. It was made for the original Hoffman Hudson and it can be used over and over again on any NYC Hudson.
Attachments
582 Employing a Backing Ring When Turning a Wheel.jpg
583 Stage Two of Wheel Turning Complete.jpg
584 Stage Three Wheel Turning Through Spindle Stub Arbor.jpg

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Wed May 29, 2019 5:20 pm

Stage three wheel machining.

In the end I decided to go with Kozo's turned in place wheel stub arbor and not use the previous through the lathe spindle bore tapered stub arbor which I made.

Although you can only use it only once (for all of the remaining wheel turning operations), the Kozo turned in place stub arbor is the most accurate of all the stub arbor methods and it is not difficult to make. I did lathe cut the threaded portion of the stub arbor to maintain complete stub arbor concentricity but this is not necessary. See the first photo.

A stage two wheel blank was mounted on the stub arbor and then the rear rim face of the wheel was turned so that the center hub was left 1/16" proud of the rim as shown on the Josslin drawings. With these wheels, there is definitely both a front and back face so one has to mount the stage two turned wheel the correct way round on the stub arbor. At the same setting, the finished wheel flange diameter of 2-7/16" was turned. See the second photo.

After facing down the rear face rim and turning the wheel flange diameter, the wheel was reversed on the stub arbor and the basic wheel tread diameter of 2-1/4" was turned as well as the basic 3/32" flange thickness all at the same setting. One has to approach both these dimensions at the same time so measure often and don't be in a hurry when taking the finishing cuts. A special wheel flange, root turning, sharp tool bit having a 3/64" tip radius was made (as per Kozo) for this operation. I got away without experiencing any tool bit chatter but if this happens, one may have to reduce the lathe speeds and feeds or turn the lathe spindle by hand when forming the root radius. See the third photo.
Attachments
584 Machined in Place Wheel Stub Arbor.jpg
585 Facing Down Back of Wheel Rim Only.jpg
587 The End of Stage Three Wheel Machining.jpg

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Fri May 31, 2019 7:27 pm

The third stage of wheel machining completed.

Now nearing the end. There is a fourth and final stage yet to do.
Attachments
589 Completed Third Stage of Wheel Machining.jpg

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Sun Jun 02, 2019 2:28 pm

The wheel finishing operations.

The first finishing operation was to cone the wheel treads to just a shade under 3 degrees.

I particularly liked what Kozo had to say here; that is, use a black sharpie marking pen to highlight the wheel flange root radius when undertaking the coning operation. This can be seen in the first photo. It allows one to seamlessly blend the tapered wheel tread and the flange root radius.

After the wheel treads had been coned, the next operation was to machine the 10 degree taper on each side of the wheel flange. To accomplish this on the inside wheel flange face, one needs very good lighting and an eye loupe to exactly set the 3/64" radius tool to the inside wheel flange root radius. See the second photo. Then reverse the wheel on the stub arbor and proceed to machine the outer flange 10 degree taper. The stop on the graduated scale seen in the third photo was set to 3/32" to allow one to measure the 10 degree taper width as machining proceeded.

Following after the above operations, the wheel flange (both sides) and the wheel tread (front edge) were then all chamfered slightly at approx. 45 degrees. This was followed by filing to a half circle the wheel flange and then polishing it.

This completes all of the machining operations on the lead truck wheels.

After this, more wheel painting.
Attachments
590 Coning A Wheel Tread.jpg
591 Turning the Front Side of a Wheel Flange Taper.jpg
593 Turning the Back Side of a Wheel Flange Taper.jpg
594 Chamfering a Wheel Flange.jpg
595 Finish Filing a Wheel Flange.jpg
596 The Finish Machined Wheels.jpg

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Mon Jun 17, 2019 11:10 am

The finish painted wheels.
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598 After Painting.jpg

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Mon Jun 24, 2019 11:15 am

Finally, a rolling chassis.
Attachments
600 Pressing on a Wheel.jpg
601 A Rolling Chassis at Last.jpg

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Tue Jul 02, 2019 7:39 pm

Starting work on the lead truck four heart shaped links.

Since I often do things the most difficult way, here is another example of that. Those having digital equipment would do a job like this in 5 minutes but...

There are three central holes around which the heart shaped links are constructed. The first job then is to locate (layout) these 1/8" dia. holes as per the Josslin print on a link blank and then drill and ream them. Initially, I machined each blank to have two straight edges at right angles to each other as reference surfaces.

The central hole layout was easy using a vernier height gauge but then one of the layout lines in each link needed to be centre punched as a home position. With more exacting work, I often use an optical centre punch as seen in the first photo. With great care one can get to within 0.001" - 0.002" of the intersection of the layout lines but this method is not for everyone - see the second photo. If one does not have a very steady hand and good eyesight, this optical centre punch method is not for you.

After centre punching, a wiggler held in the spindle of the mill is used to pick up the centre punch mark. A lot of work for...
Attachments
602 Center Punching a Heart Shaped Link Blank with an Optical Center Punch.jpg
603 The Center Punch Mark on the Blank.jpg
604 The Center Punch Mark with the Link Outline.jpg

Harold_V
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Harold_V » Wed Jul 03, 2019 1:34 am

I'm curious why you don't simply use an edge finder and a stop in your vise. Once you've clocked the dials (or DRO) with the datum points (the fixed jaw of the vise and the stop on the left hand side), you have no need for a wiggler, nor for a layout. Saves a huge amount of time, is far more precise, and you can install and remove parts at random, keeping registration. With care, a wiggler will locate within a half thou reliably.

H
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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Wed Jul 03, 2019 9:05 am

(bad) habits? I don't necessarily trust my micrometer dials as I think there is some variable wear in the mill's feed screws.

Richard keeps telling me to go digital but I can't afford it at the moment.

As to repeatability. the heart shaped link hanger pins in the truck cross frame members are not all at the same spacing (more manual errors - close, but not exactly the same) so I have to micrometer measure across two pins and slightly adjust the hole spacing in each of the link blanks.

But yes, I will try what you say on the last two link blanks. I also need to grind my vise jaws again to get at a true reference surface (for the edge finder) as the jaw surfaces are always getting beaten up with use.

Harold_V
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Harold_V » Wed Jul 03, 2019 4:02 pm

Carrdo wrote:
Wed Jul 03, 2019 9:05 am
(bad) habits? I don't necessarily trust my micrometer dials as I think there is some variable wear in the mill's feed screws.
Unless you work over large areas (long travel), wear isn't generally a problem. For short distances such as this project requires, I suspect it should be far more precise than using a punch mark. If you understand backlash, and work within the short distances of the part in question, you should be able to work to .001" without issue. Of course, you likely understand that drilling holes is often a cause for error, as drills wander, even when well started. By boring critical holes, location isn't a problem. Not suggesting that would be necessary in this instance, however.
Richard keeps telling me to go digital but I can't afford it at the moment.
Digital is nice, but hardly a requirement. I have never in my life used a DRO, and I used to do tight tolerance tooling routinely, trusting the screws of my machines.
As to repeatability. the heart shaped link hanger pins in the truck cross frame members are not all at the same spacing (more manual errors - close, but not exactly the same) so I have to micrometer measure across two pins and slightly adjust the hole spacing in each of the link blanks.
You'll still have to do that, but instead of marking the individual parts, you'd simply transfer the finding to the machine screw.
But yes, I will try what you say on the last two link blanks. I also need to grind my vise jaws again to get at a true reference surface (for the edge finder) as the jaw surfaces are always getting beaten up with use.
In order for your dial to read clockwise, you should not use the jaw itself for establishing the datum point. Instead, make your setup, then use the actual piece you intend to machine. That sets your dials so they read directly, in the proper direction. That's the reason one uses the upper left hand corner (left side of the part as you face the machine), and the fixed jaw surface using a common milling vise.

I hope you don't mind my interjecting this tidbit. It is a wonderful way to work, saving a lot of time, and making it dead easy to make multiple parts. Once you determine a location, using a grease pencil, you can mark the spot and record the dial setting. That avoids making errors.

If the grease pencil marking process escapes you, and you are interested, I'll explain that further, too. Just ask.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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Carrdo
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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Carrdo » Wed Jul 03, 2019 11:04 pm

OK Harold, I'm game if you care to explain further for all of us.

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Re: Constructing The Josslin NYC Hudson Lead Truck

Post by Harold_V » Thu Jul 04, 2019 1:59 am

What I'll try to describe is exactly how I worked when I ran my machines for gain. It lends itself extremely well to jobs where you have multiple parts, or to even one part, where you have multiple operations and must visit the same location more than once.

First, consider that both the saddle and table can be marked. A permanent mark is made with a grease pencil at the datum point, which I always number as 0, the setting on the dial. I create a pair of marks, one on the surface that does not move, and one directly in line with it on the surface that does (the table, for example). That mark allows you to return to the 0 position on both the X and Y features. You then move to the next location, both table and saddle, and make another mark directly in line with the permanent mark for each location. Above (or near) that mark you write the dial setting for that axis. Repeat for each location. All of the marks are made while actually machining the part----and after checking each move with a ruler. A ruler will disclose any errors you may make.

Now that you have all the locations marked, you can move to each one by stopping at the line, and setting the dial to the numbers marked above the line. This prevents making moves with an error of one turn, which is really easy to do if you aren't paying attention. Do note that you must have good work habits, always setting the dial with backlash in mind. By using the upper left hand corner of a part, that means you'll read your dials in the proper direction, and you'll make all your settings in the same direction. If you work like that routinely, it's automatic and you don't make mistakes.

Hope I described this adequately. Please let me know If I've glossed over something. That's easy to do when you try to explain something you do without thinking.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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