Author Topic: Kozo A3 Steam Tee - something does not add up  (Read 1110 times)

Offline matthew-s

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Kozo A3 Steam Tee - something does not add up
« on: March 28, 2021, 11:03:52 PM »
Having succeeding with my silver soldering challenge, I am deeper into machining this part. However, something does not add up.

The flanges on the Tee are 13/16" tall (measurement 1). The intake and exhaust holes are drilled through the "arms" of the Tee in the faces of the flanges.

You'd expect these holes to be at the vertical center line of this part =  13/32" from the bottom of the flange. However the drawing shows 11/32 from the bottom of the flange (measurement 2) - 1/16 off center. 
Hmmm ....

This is a critical dimension - the cylinders bolt up here and need to clear the frame itself, etc.

If you add up all the vertical dimensions (11/32 +1 7/32 + 1/2) = 2 1/16 is the Tee height.

A separate figure 14-30 implies the height of this part should actually be 2 1/8" (but that is the raw build up, and includes machining allowance for the width - - so it's not 100% definitive.

However, if you use the 2 1/8 dimension, and step off the top (1/2" + 1 7/32") you DO end up with a steam passage centerline in the center of the flange - 13/32 from the bottom of the part, rather than 11/32.

I'm thinking the 11/32 dimension is wrong ... but I would would feel a lot better hearing from someone that has been down this road and successfully assembled these parts!


Offline EricB

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Re: Kozo A3 Steam Tee - something does not add up
« Reply #1 on: March 29, 2021, 03:39:05 AM »
I think the bottom center section at "2" where the 11/32" dimension is shown is 1/16" shorter than the flange end "1" where the 13/32" is shown. There appears to be a line showing the difference on the diagram. I've connected the points below.

Eric
« Last Edit: March 29, 2021, 03:44:50 AM by EricB »

Online Kim

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Re: Kozo A3 Steam Tee - something does not add up
« Reply #2 on: March 29, 2021, 05:28:30 AM »
Wow... An interesting and complex part, Matthew. You're a bit ahead of me so I haven't gotten to where I've seriously investigated this piece.  It's coming up for me though!

Eric's answer looks right to me.  I've found a place or two where I thought Kozo had left out a dimension or made a mistake somewhere, but most all of them have been me missing something.  I wouldn't go so far as to say there are no mistakes in the book, but I've found it to be really quite good on that front.

Best of luck and do let us know if you find an issue!
Kim

Offline matthew-s

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Re: Kozo A3 Steam Tee - something does not add up
« Reply #3 on: March 29, 2021, 01:21:23 PM »
I think Eric found it!

That hidden line he found confused me too - I should have put it together!

The photo-image of the part helps - it's pretty clear the center is relieved.

Kim - don't get too excited. I've been skipping around - I only finished my tender up to the frame rails. I was intimidated by all of the sheet metal forming of the tank, especially as it's workmanship will be highly visible - so I set that aside.

Oh, and I've been chipping away for over 3 years now!




Offline matthew-s

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Re: Kozo A3 Steam Tee - something does not add up
« Reply #4 on: March 29, 2021, 05:36:57 PM »
Shoot. Yet another image, figure 14-34 for those with the book, makes this additional machining operation crystal clear.  We can mark this solved. Thanks for the extra set of eyes.

Offline crueby

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Re: Kozo A3 Steam Tee - something does not add up
« Reply #5 on: March 29, 2021, 05:41:29 PM »
Shoot. Yet another image, figure 14-34 for those with the book, makes this additional machining operation crystal clear.  We can mark this solved. Thanks for the extra set of eyes.

Fun with directions in a book, where they have to make things fit. Spend days on this page, think its figured out, and on the next page it says 'but first, do this other thing'....    :wallbang:

Offline matthew-s

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Re: Kozo A3 Steam Tee - something does not add up
« Reply #6 on: March 29, 2021, 06:15:22 PM »
Ha - the tender water pump is like that - they have the finished drawings, and if I recall correctly, a little further on, step by step instructions.

The first step shown includes making the pump body quite a bit longer than final dimensions so you can grab it in your lathe chuck.

Somewhere along the line I missed that, made the part initially to final length, did 1/2 of the machining, and then realized I was unable to hold the part for subsequent operations!  That cost time and $. I think I took a break for a while after making that mistake.  :'(

Both Kozo and others tell you to read ahead. Even if you do , you can still miss something. I'm glad I paused here when unsure, as this is also a serious chunk of brass that I have a fair bit of time into it already!.

 

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