My N&W class A 1239 (gauge 5", 1 in 10 scale)

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Bill Shields
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Re: My N&W class A 1239 (gauge 5", 1 in 10 scale)

Post by Bill Shields » Sat Apr 30, 2022 6:34 am

:mrgreen: That's a hot water faucet...
Too many things going on to bother listing them.

Asteamhead
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Re: My N&W class A 1239 (gauge 5", 1 in 10 scale)

Post by Asteamhead » Thu May 05, 2022 3:57 pm

Hello friends of the N&W,
Today was fine to me for I could assamble all the parts to built a complete tender truck for the first time :D . Just the right wheel sets are still missing. Will be built soon, too.
The cross bars are bolted rather than welded in favour of better access (for adding in the brake rigging!).
The equilisation will allow the axles to move about a generous + / - 5 mm (1/5 of an "). Springs will ad about 2 mm at full load then.
The trucks are intended to turn around the outer cross bar (the big bore) rather than the center :idea: . Thus the wide lateral travel of the long tender ends in curves will be reduced for better connection to locomotive and train. Vertical load will be transferred by means of a central cross bar and sliding plates as common, yet.
Best regards
Asteamhead
Attachments
A T 95 trucks with parts made of stainless steel or bronze_3646red.JPG
A T 95 tender trucks, all parts made of stainless steel or bronze
A T 95 truck frames_3643red.JPG
A T 95 truck frames
A T 95 truck with wheels_3669red.JPG
A T 95 tender truck with wheels (not finished yet)
A T 95 equilisation in position middle up_3663red.JPG
A T 95 maximum equilisation in position middle up
A T 95 truck frame from below_3666red.JPG
A t 95 truck frame from below. No welds, just bolts

Andy R
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N&W class A 1239 tender trucks

Post by Andy R » Thu May 05, 2022 6:06 pm

Very, very nice.
I like the offset support too.
The equalization will be interesting when in service because of the eccentric vertical load on the truck.
It may behave more like a 4-wheel truck with an idler axle. Time and experience on the track will tell.

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Dick_Morris
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Re: My N&W class A 1239 (gauge 5", 1 in 10 scale)

Post by Dick_Morris » Fri May 06, 2022 4:08 am

Nice!

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JBodenmann
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Re: My N&W class A 1239 (gauge 5", 1 in 10 scale)

Post by JBodenmann » Fri May 06, 2022 4:36 pm

Hello My Friends
Very nice and ultra cool Asteamhead.
Jack

Asteamhead
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Re: My N&W class A 1239 (gauge 5", 1 in 10 scale)

Post by Asteamhead » Sun May 08, 2022 8:40 am

Andy, Dick and Jack,
Thank you all!
Andy, you are right, the equilization will be supportet by just 4 points to the truck frame. The total load will be distributed to all 6 wheels equaliy, yet.
The people from Roanoke found this construction superior to the standard Commonwealth design at higher speeds. Hope they were right :)
The center axle-boxes will get a bit more lateral play to improve running around sharp curves (of about 30 feet radius).
In the meantime I started milling the 12 axle boxes, more to come soon.

Best regards by
Asteamhead

Asteamhead
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Re: My N&W class A 1239 (gauge 5", 1 in 10 scale)

Post by Asteamhead » Fri May 13, 2022 4:28 pm

Hello friends,
Time to show some progress. First, all the 12 axle boxes were turned, milled and tested by use of some tools in several steps from raw rings of bronze. Starting with the fit for the ball bearings of 32 mm diameter and the front surface :idea: , they were turned and centered again. Thus the rear (inside) fit for the sealing was turned as was the rear side.
Next I milled the two sliding plates in two steps, related to the finished bore and front surface :idea: . The final precision cuts were milled after some testing and adjusting the position of the parts in the vice. Thus the gap between the truck insides and the axle boxes could be achieved precisely at 2 x 0.1 mm (1 / 256 ") to insure for a slight glide without sticking. (The prototype drawing asked for 2 x 1 / 16 ").
The fits for the pair of ball bearings to be pressed onto the axles are intended as very slight press fits :!: to insure easy assembly.
The next steps will be milling the bottom first and then the top head finally. For all other surfaces are finished and rectangular that will be a more easy job :) . A lot of chips could be saved by means of a shovel :)
Not to damage the finished surfaces by the vice, very thin plates of aluminium (taken from Märklin metall) :idea: worked best.
More to come soon.
Asteamhead
Attachments
A T 95 axle box, turning the fit for the ball bearings_3684.JPG
A T 95 axle box, turning the fit for the ball bearings
A T 95 axle box, turning the fit for the backside sealing_3685.JPG
A T 95 axle box, turning the fit for the backside sealing
A t 95  axle box, testing the fit for the ball bearings_3681.JPG
A T 95 axle box, testing the fit for the ball bearings
A T 95 axle box at raw milling_3691.JPG
A T 95 axle box at raw milling
A T 95 axle box, precise milling by one final cut_3697.JPG
A T 95 axle box, precision milling by one final cut
A T 95 axle boxes before final milling_3698.JPG
A T 95 axle box, before final milling

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