Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 27632 times)

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #345 on: June 17, 2019, 06:56:28 AM »
Thanks Bill and Rich!
Kim

Offline 90LX_Notch

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #346 on: June 17, 2019, 11:10:23 PM »
I'm still following along Kim.  Very nice work.  I admire the soldering.  I've never done it.

-Bob
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Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #347 on: June 18, 2019, 05:23:36 AM »
Thanks Bob!
Please don't admire the soldering job too closely or you'll see how truly rudimentary my soldering is!  But I am getting better! :)

I actually enjoy the silver soldering process.  It's kind-of magical to see it in action. 
Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #348 on: June 30, 2019, 03:44:48 PM »
Chapter 4.9 – Center Pins and Drawbar Pin

The final parts of the Tender Frame are the Center Pins and the Drawbar Pin.  These are simple turnings and shouldn’t have taken too long.  But being as talented as I am, I was able to make them take my full shop time today!  Pretty impressive, eh?

OK, I did some other puttering around – sharpened some of the yard tools that my wife had asked me to and fixed the electric hedger.  But after that, I started on my project!

I got all set up on the lathe and then remembered I’d left the change gears in a non-standard state.  That was back when I did the springs for the truck - I needed a really course horizontal travel for the spring which required a gear change.  So, I thought, “I’ve got plenty of time, why don’t I change them back now?”

So, I did.  It just took longer than it should have.  But in the end, I got it done.  With the added bonus of breaking the gear change banjo (or Change Gear Pivot Bracket, as they call it in the Grizzly manual).  This picture shows the change gears on my lathe. The three gears in a row there are all connected to the banjo – the bottom one is where it pivots and the next two up are mounted to the banjo.


It’s held in place by the nut you can see just below the middle gear (to the left of the lowest gear). And by a clamping screw that clamps it to the pivot point at the bottom.

And that’s where it broke.  I was tightening the clamp at the pivot and suddenly, the screw turned way too easily. Apparently, I’d over tightened the screw and broke the casting?  I didn’t know I could do that.  I didn’t think I was exerting that much force, but clearly, I did.


After fretting about it for a bit, I decided to go ahead and use the lathe for today.  The clamp around the pivot isn’t what provides the rigidity anyway – it’s the other nut that really clamps it into place.  I’m thinking as long as there’s enough material to hold the banjo in place at the pivot point, I shouldn’t miss that clamping force from the pivot too much?  Thoughts from anyone on this?  Am I foolish for continuing to use the late with the banjo broken as such?

Regardless, I’m going to contact Grizzly and find out what it will cost to get a replacement banjo.

Anyway, after that exciting little mishap, the rest of the work went without hitch.

I started with the Drawbar Pin.   This was made from 1/4" 12L14 rod.  Using a 1/4" collet to hold it, I cut about 3/4” down to diameter (5/32”) then chamfered the end at 30o using the cross slide.


I then slid the bar out another inch or so and brought the required length down to diameter.


And parted it off the rod.  I also took this opportunity to chamfer the top of the pin with a file.


Now for the Center Pins.  These were also made from the same 1/4" 12L14 rod.  Kozo specifies these to be 0.245” to provide an easy sliding fit in a 1/4" reamed hole.  So I skimmed off a few thou from the 1/4" bar and chamfered the end.  Then I cut a 1/32” groove for an e-clip.


Next, I used a parting tool to cut a 1/8” groove in the pin for a set screw.


And parted it off.
And did it again.

Here’s the three parts I made today:


Showing the Darwbar Pin in place:


And the center pins.  You can almost see one of the e-clips on the bottom of the rear center pin if you use your imagination! :)


Thanks for stopping by and taking a look.
Kim

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #349 on: June 30, 2019, 05:17:55 PM »
Drawbar and pin looks great!  :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Don't worry about the broken banjo casting. Seen lots of broken ones on machines from China. The castings are pretty iffy it seems. Just use the old one as a patterm and cut / mill out a new one from mild steel. Breakage worries overwith. Outline could also be laser or waterjet cut if you have CAD capability and friend with those machines. Good luck with the repair!

(By the way welding and bronze welded repairs have not been successful on several broken ones I have run across, welds held but the iron just broke again 1/2" away. Others welded fine. These experiences are why I suggest new fab in  mild steel)

Offline Ye-Ole Steam Dude

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #350 on: June 30, 2019, 05:53:28 PM »
Hello Kim,

Still following along and enjoying your beautiful work.  :popcorn:

Have a great day,
Thomas

Offline b.lindsey

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #351 on: June 30, 2019, 07:41:30 PM »
Good looking pins. Sorry about the banjo, but agree a fabricated one and your worries will be over.

Bill

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #352 on: July 01, 2019, 05:19:31 AM »
Thanks Cnr, Thomas, and Bill!
Thanks for the suggestion on fabricating my own new banjo.  That makes a lot of sense to just make one.  I was hoping it would be easier to just get a replacement part from Grizzly.  But if its not that sturdy of a casting, maybe its not worth the money to replace.

I'll have to give fabricating more thought.  I'm still thinking the lathe is pretty usable even with that bit broken off the banjo, but it will inevitably break more, so I'll so something about it eventually...

Kim


Offline 90LX_Notch

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #353 on: July 01, 2019, 10:05:38 PM »
I'd say you nailed those pins.  Nice work..

-Bob
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My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #354 on: July 02, 2019, 05:38:28 AM »
Thanks Bob!
Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #355 on: July 02, 2019, 05:42:39 AM »
Well, all my deep thinking about fabricating a new banjo for my lathe just flew out the window today.

I called Grizzly and the part cost $34.38.  When I looked at the cost of a chunk of steel big enough for the bracket, it cost as much as the casting.  Plus I'd have to put a bunch of work into it. Sure, it'd be a stronger part, but this one lasted me 6 years.  If I spend $35 on a new casting and it last me as long, I won't be too unhappy.  And if it breaks again, I can always fab one then.

So, I've got a replacement banjo on its way to me.  3-5 business days, so they said.

Kim

Offline b.lindsey

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #356 on: July 02, 2019, 02:19:24 PM »
That seems a reasonable price Kim, Like you say, there is always the fabrication option down the road if needed.

Bill

Online crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #357 on: July 02, 2019, 03:14:22 PM »
That seems a reasonable price Kim, Like you say, there is always the fabrication option down the road if needed.

Bill
Before installing the new one, take measurements for any possible future making of a replacement replacement...

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #358 on: July 02, 2019, 04:26:21 PM »
Kim, with a new casting, there's also a chance the factory have improved the casting technology or the metallurgy of the part. Could be far better than the older banjo. The factories in China do sometimes make improvements if user's complaints make it back to them.

I did not realize replacement banjos were affordable now. I priced one a number of years ago to replace a broken one for a friend's China lathe and was quoted multiple hundreds of dollars and a 12 week wait by our local (not very honest or cost effective) dealer.

The ones I made from mild steel were cut from scrap on hand, so cost was just for the labour.

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #359 on: July 03, 2019, 05:21:35 AM »
Thanks for the support, guys!
Cnr, I hadn't even thought about them making it better :) That would certainly be a bonus!

Plus, I've learned a lesson - you don't have to reef down on the clamping screw - most of the holding power comes from the nut further up the banjo anyway!  I can just snug that screw up and call it good.  This should make the casting last twice as long - and any improvement will be a extra bonus :)

Taking measurements - good idea Chris.  Will I do it?  Maybe, but the problem would be that I'd never be able to find it n+1 years from now when I actually need it :)  So I may wait till necessity demands that work :)  (its not that  I'm lazy, exactly, I just don't mind avoiding work that doesn't need to be done, unless it seems like fun!  :LittleDevil:)

Kim