Allen models Fitchburg Northern build by first timer

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mcjustis
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Re: Allen models Fitchburg Northern build by first timer

Post by mcjustis » Fri Apr 23, 2021 7:14 am

I've done a little more work. I figured I'd start on the front end as I felt I could do most of the parts fairly quickly and have something that actually looks like I'm making progress. Anyway, I have the bolster, center pin, center guide pin, cap, clevis, and rod all finished. I'll try and start on the bearings, wheels, and axle next week. I also threw in a picture of my recently finished vise. That was a blast to make and as usual, put a smile on my face.

Another dumb question...Anyone know the size of spring that goes between the center pin and the cap? The plans are quite vague in that regard, just says 3/4" od spring. I bought some from Mcmaster and it is WAY to strong. I couldn't compress it without a vise. Also the springs that go on the suspension of the front end are just marked on the print as "3/8 od from a hardware store".

I did cheat a little on the clevis pins. I got to looking and saw there were 40ish clevis pins. i thought I'd check Mcmaster. I ended up buying all the clevis pins I need for just under $1 each. I figured my time is worth way more than that, so the clevis pins are finished too! There is one clevis pin that is called out to be case hardened. I just bought a hardened pin for die work and I'll have the ram EDM guy at work burn the cotter pin hole in it.

Anyway, still having fun.

Martin
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front end 2.jpg
front end parts.jpg

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NP317
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Re: Allen models Fitchburg Northern build by first timer

Post by NP317 » Fri Apr 23, 2021 10:20 am

Good looking parts! Their finish looks excellent. And I like your little vise. 'Satisfying projects to make.

I also purchased clevises and pins from McMaster-C for the brake systems on my two locomotives. And many more parts too.
No reason to reinvent those. Our time IS valuable. The locomotive is the goal for me, not having to make every single piece myself.
Keep up your good work and please continue sharing your results/progress with us.
RussN

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Bill Shields
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Re: Allen models Fitchburg Northern build by first timer

Post by Bill Shields » Fri Apr 23, 2021 12:26 pm

I have about 20# downforce on my Allen front wheels.

I calculated the spring based on 3/16" of travel creating 20# downforce -> figuring that would be the maximum the front end would travel independent of the other wheels (WAG at the time)..without the coils binding up

Using the LEE SPRINGS calculator (was in a handbook at the time, is on line now), found a spring of the appropriate size...and preloaded a little bit once assembled since nothing sits exactly where you expect it to sit.

since it was 20+ years ago that I did this, i don't remember what the size is (sorry...)
Too many things going on to bother listing them.

mcjustis
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Re: Allen models Fitchburg Northern build by first timer

Post by mcjustis » Fri Apr 23, 2021 1:26 pm

Thanks for the spring help Bill. That should give me some place to start at least.

Thanks,
Martin

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Bill Shields
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Re: Allen models Fitchburg Northern build by first timer

Post by Bill Shields » Fri Apr 23, 2021 9:03 pm

All of loco building is a starting point. Very few ever go together like a watch
Too many things going on to bother listing them.

mcjustis
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Re: Allen models Fitchburg Northern build by first timer

Post by mcjustis » Tue Apr 27, 2021 5:41 am

I got some brake part castings in the mail the other day and I just had to see how they cut. Just like all the other castings I've cut from Allen Models, they cut very well. This is the brake cylinder. Still have to flip it and face the other side to length. Then it'll be off to the mill for the mounting lug and some top/bottom plate bolt holes.

Thanks,
Martin
Attachments
brakecylinder2.jpg
bakecylinder.jpg

mcjustis
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Re: Allen models Fitchburg Northern build by first timer

Post by mcjustis » Tue May 04, 2021 5:54 am

I got a little more done this morning on the front end bolster. I finished the cast swing links and got the bolster put in the frame just to see how it looked. I still need to deburr the castings and file off some mold flashing, but they are dimensionally correct.

This is the fixture I made to hold the swing links to machine them to the correct height. The first step was to flatten out one side on the belt sander, then I clamped them on a flat plate to put in the hole on one side and make the face flat. Then, they went into this fixture to do the other 1/4" hole and face that side to height. I then flipped them again on the dowel pin and machined the other two sides to the correct thickness.
IMG_7150.jpg

And here is the front end bolster put together. I need to get some proper pins for the shaft holes. I just cut some paper clips to put in there to hold it together.
IMG_7153.jpg
Next part should be the spring holders and the spring alignment pins. Then I can get the bearings and axle shaft knocked out.


Still having fun,

Martin

mcjustis
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Re: Allen models Fitchburg Northern build by first timer

Post by mcjustis » Tue May 04, 2021 6:04 am

Question time:
Is there a reason that the journal box for the front end only has one flange on it? Wouldn't you want this to be like the driver journal boxes with a captive flange on both sides? I'm just curious. I know it can't really go anywhere as it's stuck in place by the wheels. Maybe I'm just over thinking it and should just do what is called out for in the prints?

Thanks,
Martin
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IMG_7155_LI.jpg

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Bill Shields
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Re: Allen models Fitchburg Northern build by first timer

Post by Bill Shields » Tue May 04, 2021 7:50 am

Sure. The wheel keeps it in place in the other direction
Too many things going on to bother listing them.

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NP317
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Re: Allen models Fitchburg Northern build by first timer

Post by NP317 » Tue May 04, 2021 10:30 am

Single flange works fine, all the time. You generally want plenty of motion in steam locomotives mechanisms.
Too tight and they derail. BTDT.

Nice looking progress.
RussN

mcjustis
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Re: Allen models Fitchburg Northern build by first timer

Post by mcjustis » Thu May 06, 2021 1:25 pm

Got the back sides of the front end bearings done this morning. I made a small fixture to hold them. It was nothing more than a 1" piece of aluminum turned to .750", then drilled and tapped 1/4 NPt. Slot on bandsaw and deburr. Install back in lathe with bearing on it. Put in a 1/4 NPT plug to hold bearing on shaft. Cut the backside to length. Also spent some time de-burring the 4 swing links. I did get to use my newly completed vise to hold them and clean them up.

Martin
Attachments
IMG_7160.jpg
IMG_7159.jpg
IMG_7163.jpg

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Bill Shields
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Re: Allen models Fitchburg Northern build by first timer

Post by Bill Shields » Thu May 06, 2021 7:27 pm

careful you don't warp the links with that monster vise :shock:
Too many things going on to bother listing them.

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