GE 23 ton boxcab in 7.5" gauge / 1.5" scale

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fresnojay
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by fresnojay » Thu Oct 22, 2015 8:12 pm

Jawn, Thank you sir. But only construction kuddo's can be credited to me. Its actually one of Chris Brew's prototypes built with my own twists here and there. Its my first build to date and have been very happy with it.

As for scale I believe Chris designed them at 1.6" vs 1.5". He can chime in more on that aspect. The chassis comes out to 15.5" wide x 25.5" long. The group 27's have maybe an inch or so air gap around them on the sides and front/rear of the cab.

The build thread had been buried deep in the ride on scale section since my wife came up with health problems last year. Since then I had been pretty inactive not working on or doing much, save for posting on facebook since it was by phone which was always with me. However now that things have returned to some semblance of normal again I will be on here more often and posting more updates on work being done to the loco. Am glad to help in any way I can.

Jason

chooch
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by chooch » Thu Oct 22, 2015 8:38 pm

Jawn,
I think it might be helpful if you mentioned what you plan to build your loco with--metal or wood--and if you have the type tools etc. to work with. A hand or drill press, saws, cutting tools for metal, welding equipment.
That could make a difference in the way of construction. For example, Plum Cove chassis are Steel "Bolted" together. They could be welded but, "Bolted" are easy to take apart if needed for any reason. I modified my P C chassis for smaller batteries and an industrial switcher body. The battery frames are welded but, Bolted to the chassis for the reason said above.

chooch

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cbrew
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by cbrew » Thu Oct 22, 2015 9:48 pm

good Evening jawn,
Thanks for the shout out Jason!,
this locomotive is based on one i grew up running built be my late father.
Dad has to up scale it in order to fit the 5hp honda engine and Eaton #6 hydrostat transmission.
it scales out closer to 2 inch scale of the little 23 ton GE.
dad started calling it a 25 ton because of its size.

I ended up measuring around and creating a 3D model in solidwork.
after that, I ended up having 5 kits laser cut,
one went to Jason,
two are here locally being used in cattle hauling service (featured in the you tube video below)
one of the chassis's went back east to PA.
I still have #5 in the basement. I need to machine up wheels and axles for it.

25119_427314478184_2047502_n.jpg
Boxcab12.JPG
Chassis.JPG
If it is not live steam. its not worth it.

[url=http://chris.brewfamily.info][color=red][u][b]Visit my website here.[/b][/u][/color][/url]

Jawn
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Jawn » Fri Oct 23, 2015 1:23 am

chooch wrote:Jawn,
I think it might be helpful if you mentioned what you plan to build your loco with--metal or wood--and if you have the type tools etc. to work with. A hand or drill press, saws, cutting tools for metal, welding equipment.
That could make a difference in the way of construction. For example, Plum Cove chassis are Steel "Bolted" together. They could be welded but, "Bolted" are easy to take apart if needed for any reason. I modified my P C chassis for smaller batteries and an industrial switcher body. The battery frames are welded but, Bolted to the chassis for the reason said above.

chooch
I had intended to build it out of plate steel very similar to how cbrew/fresnojay built theirs. I plan to buy pieces cut near to size, then square 'em up / trim edges as needed with whatever seems appropriate. Likely to weld the chassis together.

cbrew, thanks for posting that info. Hope you don't mind if I scale that drawing back down to help work out some of the dimensions of mine.

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cbrew
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by cbrew » Fri Oct 23, 2015 6:41 am

Jawn wrote:cbrew, thanks for posting that info. Hope you don't mind if I scale that drawing back down to help work out some of the dimensions of mine.
have at it, nothing top secret here :wink:
If it is not live steam. its not worth it.

[url=http://chris.brewfamily.info][color=red][u][b]Visit my website here.[/b][/u][/color][/url]

Jawn
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Jawn » Tue Mar 22, 2016 8:51 pm

Ok, it's been a while... busy times lately but getting back into it.

Today while sitting on my butt recovering from oral surgery I went a little crazy on Amazon and an online metal supplier. Ordered sprockets, chain, and some 1/2 and 1/4 inch steel plate to build the chassis. It's getting underway!

Jawn
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Jawn » Fri Jul 21, 2017 3:32 am

Sometimes I make good progress on a project, sometimes not.

A while back I did some work on the controller. It's about 80-90% there at this point. I have motor and direction control, function control, and control of a servo (to be incorporated into a brake system). Still to be worked out is interlocks and safety features... stuff like not allowing the direction switch to change while at speed, automatic stop in case of loss of signal, etc.

The handheld controller, without the brake buttons installed at the time of this pic:
https://drive.google.com/file/d/0B-IxKq ... GZpLW5aQ1U

The unit that goes in the locomotive:
https://drive.google.com/file/d/0B-IxKq ... jJOYWdxZXM
DB25 will be for misc connections such as lighting, brake control, sensors, and any other functions to be managed by the microcontroller.

Both parts of the control system are Atmega328p based and utilize the Arduino IDE for programming them. Wireless modules are NRF24L01+ 2.4ghz modules. The motor control portion uses a BTS7960 based 43 amp H-bridge module.



Tonight I got back to messing with the wheels. Printed out a document from the IBLS website for reference. Faced both sides, drilled/reamed center bore, made a fixture to hold it by the center bore between centers so I can work on the wheel profile. Turned the tread up to near the base of the fillet. Turned outer diameter of flange and flange width at outer edge. Started removing a little more material at the fillet, but need to make a tool to cut the radius of the fillet as well as the outside radius of the flange itself, and cut the necessary tapers on either side of the flange.

https://drive.google.com/file/d/0B-IxKq ... XRfUU5DSXc

Jawn
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Jawn » Fri Jul 21, 2017 7:34 am

I went back to the basement to work on that wheel some more. I tried to use a radius HSS bit for the tread to flange fillet but it didn't work well, I guess a griz 10" lathe is far too light to use that. I think a shallow (but tall) radius turning attachment would work better, smaller cut per rev... may have to build something suitable.

Harold_V
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Harold_V » Fri Jul 21, 2017 3:19 pm

The setup you're using is an open invitation to trouble. You'd be far better served if you could grip the wheel (assuming you can use soft jaws) than to run between centers. Also, if you must run that way, you'd be best served if you could keep the diameters as large as you can, for the sake of rigidity. The slender end you have now will encourage chatter. Keep the mandrel as short as you can, too. Anything to increase rigidity.

I am NOT a fan of turning between centers unless you can use a live center in the tailstock. Even then, I avoid center work, the exception in this case being unless the item is ground. Center pressure, for grinding, is established by spring pressure, and is not a problem like it is when turning.

Turning between centers is almost always a slower process than gripping by other means. There are exceptions.

Form tools tend to be troublesome unless one has a VERY robust lathe. You most likely will experience chatter when generating the corner radius of the wheel, but by careful manipulation of a form tool, you can limit the amount of area that is in contact with the wheel, limiting, or even eliminating, chatter. Couple this concept with the one of making a far more rigid arbor and you may enjoy success, even with a light duty machine. Increase feed rate and reduce spindle speed when chatter is an issue.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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Gary Armitstead
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Gary Armitstead » Fri Jul 21, 2017 5:11 pm

Image

This is how I turn wheels on my 12 inch Craftsman Commercial lathe. These wheels are 4.125 inch diameter at the tread and the material is cast iron. The mandrel was made from 1 inch diameter tool steel and has an axle diameter of .625 and threaded with 5/8-16 and a nut & washers. Tight against a shoulder. I can place the mandrel anywhere into the 3-jaw to get as much "rigidity" as possible. I always put the mandrel into the 3-jaw with the same area of the mandrel at the #1 jaw........the same set-up as I used to turn the mandrel. Note the lack of chatter and note the simple radius tool to cut the flange fillet. 1/2 inch square tool with "soldered" carbide tip. Also note how close my live center is to the wheel I.m turning. Keep everything as close together as possible. The more rigid the setup, the less chance of chatter.
Gary Armitstead
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Member LALS since 1980
Member Goleta Valley Railroad Club 1980-1993

Jawn
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Jawn » Fri Jul 21, 2017 10:46 pm

The mandrel shown in my previous post was a first hack at it using what I had on hand... I may try making a beefier one tonight since I will have a lot more wheels to turn. I picked up a larger nut that will allow me to keep the "stub" on that end to a larger diameter, and I have some beefier steel to try a second attempt at making it. I like the idea of turning between centers so it's easier to swap wheels when doing multiples. I could try putting the headstock end on something besides a center... just slower to swap, and I assume less precise?

Harold_V
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Re: GE 23 ton boxcab in 7.5" gauge / 1.5" scale

Post by Harold_V » Sat Jul 22, 2017 1:19 am

Jawn wrote: I could try putting the headstock end on something besides a center... just slower to swap, and I assume less precise?
Not necessarily. One of the options open to you is to use tailstock pressure to drive the wheel. That requires a live center, but you can turn a spud in place, on which the wheels simply slide on. A pressure plate is then used between the wheel and live center, which drives the part. The spud would require a shoulder on the side that is gripped in the chuck, so cutting or tailstock pressure wouldn't cause movement of the spud in the chuck. Once machined, you can remove and/or replace a wheel by simply backing off the tailstock. The one negative aspect of this type of setup is that you may have trouble with slipping, depending on the depth of cut and amount of material to be removed. It's great for finish cuts, not so good for roughing, and works best on robust lathes.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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