Northern 4-8-4 Build 3/4”

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Bill Shields
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Re: Northern 4-8-4 Build 3/4”

Post by Bill Shields »

I would put some locating pin holes in scrap areas of the link, then XY drill a fixture that locates on center of the table and locates the links on dowel pins.

XY drill the links for the locating pins and the corners of the sector.

Once located radially..then clamp down and rotary mill away.
Too many things going on to bother listing them.
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Dick_Morris
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Re: Northern 4-8-4 Build 3/4”

Post by Dick_Morris »

What Bill said. I did this a couple of months ago. This is 1-1/2 scale. I had to hang the fixture plate off of the edge of the rotary table and had it resting on a piece of stock in the vice to keep it from jumping around. A thicker fixture place would have been nice, but I used what I had.

While drilling and reaming the dowel pin holes in the blank I also drilled (and reamed where appropriate) all the permanent holes, the holes at the ends of the slots, and a couple of places that would be radii after the extra material was cut away.

I twisted the rotary table and clamped it so the zero was in line with the X axis so I had one less thing to screw up on. Zero zero on the X and Y axes was the pin in the middle of the rotary table.

Plan ahead so you can cut the radius on the link blocks and the links in the same set up.
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20220619_214351[1] recuded.jpg
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bushav
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Re: Northern 4-8-4 Build 3/4”

Post by bushav »

Wow! That is a cantilevered set up! I plan on setting up so the arched cuts are made by using the rotary table functions. Plotting x and y coordinates this week for drilled holes with x/y zero at center of table. Thanks for advice guys.
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Building 3/4” 4-8-4 Northern &
1” 4-6-2 Pacific
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Bill Shields
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Re: Northern 4-8-4 Build 3/4”

Post by Bill Shields »

Or give the job to your brother in law with a WEDM and wait for a package in the mail.

Nice having a hardened and ground part that is within any measurable desired tolerance.

There are times when I gratefully embrace technology
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Harold_V
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Re: Northern 4-8-4 Build 3/4”

Post by Harold_V »

Bill Shields wrote: Fri Nov 04, 2022 7:08 am Or give the job to your brother in law with a WEDM and wait for a package in the mail.

Nice having a hardened and ground part that is within any measurable desired tolerance.

There are times when I gratefully embrace technology
Yep! The real advantage being that pieces that should be hardened can be created with a high degree of precision, all done AFTER heat treatment, so the parts don't distort as they would when heat treated after they were created.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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bushav
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Re: Northern 4-8-4 Build 3/4”

Post by bushav »

Machining Morse Taper
Machining Morse Taper
Plug for creating radius rod ends
Plug for creating radius rod ends
I know you guys want to see loco parts. However every time I study the plans I’m reminded of another tool or jig I need before I start. Today I disassembled the rotary table. It was still slipping. The eccentric worm gear needed cleaning up and polishing so it could rotate fully. It was time well spent as I now know how the table works.

I was excited to use my taper attachment on the lathe to create a Morse Taper 3. Everything worked out just right and I am now prepared to mill radius ends on my rods. I promise to start making more parts soon!
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Yay!
Yay!
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Building 3/4” 4-8-4 Northern &
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Greg_Lewis
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Re: Northern 4-8-4 Build 3/4”

Post by Greg_Lewis »

bushav wrote: Tue Nov 08, 2022 7:30 pm I know you guys want to see loco parts. However every time I study the plans I’m reminded of another tool or jig I need before I start.....

It often seems that way. In order to make the part, you need a fixture. But in order to make the fixture, you need a special tool, which you can make. But in order to make the special tool, you need a fixture.......... :arrow: :arrow: :arrow: :arrow:
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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Bill Shields
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Re: Northern 4-8-4 Build 3/4”

Post by Bill Shields »

they all go in a box, labelled so that you can find them in future decades....
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Greg_Lewis
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Re: Northern 4-8-4 Build 3/4”

Post by Greg_Lewis »

Bill Shields wrote: Tue Nov 08, 2022 7:50 pm they all go in a box, labelled so that you can find them in future decades....

I've got them all in a box. But being un-labeled, I have no idea what they were for. :roll:
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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Bill Shields
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Re: Northern 4-8-4 Build 3/4”

Post by Bill Shields »

Pictures...I take pictures
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bushav
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Re: Northern 4-8-4 Build 3/4”

Post by bushav »

Plotting coordinates
Plotting coordinates
Verifying coordinates
Verifying coordinates
Fun time today setting up the expansion link production. I’ll be gone 10 days but I can’t wait to get back and make some chips.
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Building 3/4” 4-8-4 Northern &
1” 4-6-2 Pacific
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Dick_Morris
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Re: Northern 4-8-4 Build 3/4”

Post by Dick_Morris »

I've been putting my fixtures into a box. It's going to make is easier for my kids to throw them out when the time comes. :-(
However every time I study the plans I’m reminded of another tool or jig I need before I start.
I feel your pain. My shop time for the last couple of months has been spent rebuilding a kiln to use for burnout for my investment casting and upgrading a sand blast with dust extraction and gravity feed for the media.
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