3/4" Scale J1e

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Steamchris
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Re: 3/4" Scale J1e

Post by Steamchris » Wed Feb 06, 2019 2:12 am

Hey Jack,

no worry about it, every model engineer makes mistakes from time to time...we're no machines. That makes us human beeing. To help and to find out of this situation is the art...and you did it. By the way , like always very beautyful work.

All the best,
Chris
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Pontiacguy1
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Re: 3/4" Scale J1e

Post by Pontiacguy1 » Wed Feb 06, 2019 8:29 am

They say good machinists make very few mistakes, but the best machinists know how to cover and/or correct their mistakes without scrapping the part!

Harold_V
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Re: 3/4" Scale J1e

Post by Harold_V » Wed Feb 06, 2019 5:20 pm

Without delving in to the concept that one is "very good", I can attest that it is unusual for a seasoned machinist to make mistakes. When I was at the height of my working career, I had 26 years of experience behind me and could almost guarantee that a job would be accomplished without error.

Here's a picture of a part, an electronics chassis, with numerous features, all done on a manual mill, no DRO. Five thou tolerance on locations, with features within features.
chassis top.jpg
chassis bottom.jpg
These parts were made in quantities (long before reliable CNC's were the norm). The part shown was a spare, made in case one in the lot was scrapped.

It took years to achieve that level of competence, keeping in mind that machines were operated for hours on end, daily. It would be unusual for the home shop type to be able to duplicate that level of performance, and that includes me, as, having been away from machining for years, the skill has faded. It's hard to achieve, and is gone quickly if not exercised daily.

Edit: As a matter of perspective, the chassis, made from ¼" aluminum plate, is displayed standing on a pair of sweat 1¼" copper pipe couplers.

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

Asteamhead
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Re: 3/4" Scale J1e

Post by Asteamhead » Wed Feb 06, 2019 6:59 pm

Harold,
We (hobby) modelers can hardly match with such precision industrial products made by very scilled mechanics! :oops:
The way I found (and which I recommend to other modellers) was to make simple tools :idea: before starting production! Means a little patience ...
And to use a turntable whenever possible to achieve precision drills!
Please see some examples (photos taken during making of my A - now CNC at all!)
Just my two cents.
Asteamhead
Attachments
A axle boxes, drilling precise fits for the ball bearings, red.jpg
A axle boxes, drilling precise fits for the ball bearings
A crosshead, turning precise fits for ball bearings, red.jpg
A crosshead half, turning precise fits for ball bearings
A how to drill precise cross bores, red.jpg
A how to drill precise cross bores into bolts
A sawing the excentric lever by means of a tool, red.jpg
A sawing the excentric crank by means of a tool
A leave springs packed and welded by means of a tool, red.jpg
A leave springs packed and welded by means of a tool
A baker connection rod, milling a radius, red.jpg
A baker connection rod, milling a radius on the turntable

Harold_V
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Re: 3/4" Scale J1e

Post by Harold_V » Thu Feb 07, 2019 2:27 am

Asteamhead,
I have often been overly impressed by the creativity and exceptional results that are achieved by novice machinists. They have an advantage in that they often aren't concerned with the speed in which a part is machined, so they are afforded the luxury of taking as much time as might be needed to complete an operation. As you alluded, building fixtures is very much a part of that, too.

It makes sense to make shop aid fixtures, even for a one-off item, assuming it is troublesome without doing so. That was common practice for me, even when building tooling. How a part is held, and how operations are sequenced are often critical to success. It's really disconcerting to take a cut, then realize that you just removed the material that would have been useful for an operation. Armed with that thought, wise machinists make a part mentally before moving any metal. That helps avoid doing stupid things (which we are all prone to do, including seasoned machinists).

As usual, your work never ceases to amaze me. Beautiful stuff! I really enjoy seeing the work of a person with pride in craftsmanship.
H
Wise people talk because they have something to say. Fools talk because they have to say something.

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JBodenmann
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Re: 3/4" Scale J1e

Post by JBodenmann » Thu Feb 07, 2019 10:56 pm

Hello My Friends
Pontiacguy is correct, a good builder, or the ones that actually finish things must be good at wiggling out of a tight spot. And to Harold, I admire you skill, to become a real machinist and not just a parts loader takes a lot of time and experience. And hopefully a knowledgable old cat looking over your shoulder and guiding you when you are starting out. Fortunately I had a few mentors that I could always tap on the shoulder and ask, how do you...or where do you...or why do you.... And to Asteamhead, thanks for the cool photos and all of your fine work that we can admire here on the board. Thanks for contributing everyone. Here is the beautiful little lead truck after a bit of clean up. Whoever built it did a very nice job. The brake cylinder is 5/8" bore and is too big. It won't fit under the driver brake cylinders so masters will be made and a smaller brake cylinder investment cast. Probably 1/2" bore. Then we have a couple shots of the pilot. This has been getting some attention. One of the drawings has a vague reference to the coupler support pin keeper, but no more. I looked and looked at photos but couldn't really find anything useful, although I could tell that there was something there. Why are most New York Cetral Hudson photos of the engineers side? So I shot off an E Mail to Tom Gerbracht asking if he had any info on this pin keeper thingie. He wrote that really cool book, Know Thy Hudsons, so I figured if anyone knew it would be him. Later that evening I was checking my E mails and guess what. There were three pages of drawings, pin keeper, general arrangement, and the chain arrangement. That is one of the wonderful aspects of our hobby, all the people that are willing to help one another and share information. I was able to accurately model something that hasn't existed for more that fifty years, how cool is that. Thanks Tom. The little wedge that holds the coupler support pin in place is .045" thick and .110" wide and .437" long overall. The tricky part was milling the slot in the pilot that it drops into. The tiny little bolt that holds the end of the chain is #00-90. Thats the smallest bolt commercially available. I may have to have a go at making some #000-120 bolts. I have that dap and die. These sizes used to seem really small but once you get used to them they are no problem. Too much fun!
Jack
Attachments
Lead Truck.jpg
Pilot1.jpg
Pilot2.jpg

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Greg_Lewis
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Re: 3/4" Scale J1e

Post by Greg_Lewis » Sun Feb 10, 2019 11:16 pm

I don't make mistakes. I just make lots of "practice parts" and do lots of "research and development". :wink:

JBodenmann wrote:
Thu Feb 07, 2019 10:56 pm
...
That is one of the wonderful aspects of our hobby, all the people that are willing to help one another and share information.
...
And I think part of that is that, at least here in America, there are no competitions or trophies involved. When I was in another hobby, as soon as prizes and trophies started to be awarded the whole atmosphere changed and folks were less interested in sharing their tricks and techniques.
Greg Lewis, Prop.
Eyeball Engineering — Home of non-interchangeable parts.
Our motto: "That looks about right."
Celebrating 30 years of turning perfectly good metal into bits of useless scrap.

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Bill Shields
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Re: 3/4" Scale J1e

Post by Bill Shields » Mon Feb 11, 2019 12:55 pm

Jack: I had the same problem with the pilot truck brake cylinder on my J1 -> no clearance.

When I got to looking about making it smaller, found that I needed additional clearance for curves, and ended up making a much smaller cylinder.

That was 35 years ago, and I don't remember exactly the size cylinder I ended up using as a silver soldered fabrication...but it took 2 tries before I got it right what with curve radius and spring motion being somewhat unknown until I took it 'out to the track'.

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JBodenmann
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Re: 3/4" Scale J1e

Post by JBodenmann » Tue Feb 12, 2019 10:59 am

Hello My Friends
Thanks for the info Bill. You are correct in that there isn't much room under there for the brake cylinder. I have a 5/8" bore cylinder and it won't fit. I am thinking of a 1/2" bore cylinder but will make a crude wood mock up and see if it will work. I have thought about modifying the lead truck casting to lower the cylinder but that is a last resort as it's a beautiful casting. Can you post some photos of your Hudson? Is it 3/4" scale? I'm sure everyone would like to see it.
Jack

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