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

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Jawn
Posts: 268
Joined: Wed Apr 09, 2014 12:39 pm
Location: Canton, GA

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

Post by Jawn » Sat Jul 22, 2017 3:32 am

That's an interesting idea, I never thought of doing it like that. As to the live center, the picture I posted may not show enough to show the live center but it's there. :) I bought one early on as I didn't much like the idea of using a dead center.

A club member suggested I finish out the fillet by getting it close with a normal turning/facing tool, then finish the profile with a round file. I then rounded the edge of the flange by cutting a couple 45's on the edges and smoothing with a flat file.

End result seems perfectly adequate, but I do want a better way to do more. I have started making a beefier mandrel to go in a collet chuck or 3/4 jaw, maybe I'll get better results with that. I want to have this down pat before it comes time to do steam drivers. Next loco project is already in the pipe (Allen Mogul).

"before and after" pic...
https://drive.google.com/file/d/0B-IxKq ... sp=sharing

Harold_V
Posts: 16671
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

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

Post by Harold_V » Sat Jul 22, 2017 4:51 am

I'm not a huge fan of using files to create radii, although they can do the job.
Here's something to consider. When you attempt an inside corner radius, starting with the correct radius tool, stop a little short of either dimension. Then, move to the proper location and feed the tool from the other direction. That way you don't machine the full radius at any time, decreasing the area of tool contact with the work. If you do it a few times it will make sense, and you'll know where to stop the tool for each cut. I generally take the longitudinal cut, at full depth, stopping short about a couple thou. I then withdraw the tool, move to final linear location and plunge the radius tool to the desired depth. You approach a full radius, but only momentarily. If you're running the proper speed and have a rigid enough setup, you should eliminate chatter, which is the chief issue with form tools.

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

Jawn
Posts: 268
Joined: Wed Apr 09, 2014 12:39 pm
Location: Canton, GA

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

Post by Jawn » Thu Jul 27, 2017 5:15 am

https://drive.google.com/file/d/0B-IxKq ... sp=sharing

Round two: shorter and thicker, held in a chuck instead of center and dog. Previous one was so thin because I didn't have a 5/8 nut on hand and improvised with a 1/2 nut... but while I was out and about in the following days, I picked up one in 5/8-18. Faced the next wheel casting both sides to appropriate thickness, drilled, reamed, and mounted it to the new mandrel ready to go tomorrow night. Baby is awake, so that's the end of my night in the shop. Won't be long til I have the required four wheels.

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