Video - Cutting TT steel wheels

Video - Cutting TT steel wheels

Postby ConnRiver » Wed Jun 26, 2013 2:22 pm



A few weeks ago I began a thread on CNCSherline (yahoo group) by asking if a CNC Sherline lathe could be set up as an automatic screw machine, or set up to accomplish the same ends. ASMs are often used to cut scale model railroad wheels, I understand.

David Clark has posted a You Tube video link at the CNCSherline group that demonstrates his approach to cutting TT scale wheels. He isn't a model railroader, which likely explains the overly wide tread cut, but I thought perhaps a few TT'ers here might wish to watch the video (link at top of page). <<< edited by me - no longer a link. ConducTTor >>>

Here is a link to David's post at CNCSherline explaining what he did to develop this cutting operation:
http://groups.yahoo.com/group/SherlineCNC/message/18452

I thought it darn nice of David to pursue the Sherline as ASM concept. Kudos to David!

-Brian Chapman
Evansdale, Iowa
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Re: Video - Cutting TT steel wheels

Postby scaro » Wed Jun 26, 2013 7:12 pm

with the bit wobbling about like that, i would wonder how a wheel drilled that way would perform.they discuss this in the comments.
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Re: Video - Cutting TT steel wheels

Postby Rob M » Wed Jun 26, 2013 9:42 pm

That is awesome!!!

The wobble looks to be from an off center dimple (or bump) on the end of the bar. That should be easy to fix in a production type run.
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Re: Video - Cutting TT steel wheels

Postby ConnRiver » Thu Jun 27, 2013 12:59 pm

David replied that the tool holder rotated a bit during taping the video; he says he will re-shoot it. He had other ideas for improvements, too, as he mentioned in his "CNCSherline" list posts.

Can a, say, 1/16th inch drill bit cut an axle hole "true enough" for our purposes? Or, must a drill bit hole be followed with a boring tool?
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Re: Video - Cutting TT steel wheels

Postby Rob M » Thu Jun 27, 2013 2:18 pm

I would imagine once you have everything dialed in you should be able to just drill them.

If it were me I would go with an 1/8" hole (or there abouts) and a pressed in plastic bushing. That way the plastic can absorb any small differences you may end up with. Without the plastic you would need to achieve much closer tolerances.
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Re: Video - Cutting TT steel wheels

Postby ConnRiver » Thu Jun 27, 2013 3:36 pm

Rob M wrote:. . . I would go with an 1/8" hole (or there abouts) and a pressed in plastic bushing. That way the plastic can absorb any small differences you may end up with. Without the plastic you would need to achieve much closer tolerances.


Wonderful advice. Do you know if plastic (nylon the best, maybe?) bushings are readily available, or would someone need to cut their own?

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Re: Video - Cutting TT steel wheels

Postby Rob M » Thu Jun 27, 2013 3:57 pm

NWSL has a few different sizes. You can go to the link below and do a search for "Insulator" for more sizes. These are Delrin.

http://www.shop.osorail.com/product.sc?productId=2250&categoryId=-1
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Re: Video - Cutting TT steel wheels - V.2

Postby ConnRiver » Fri Jun 28, 2013 12:46 pm

David Clark has re-shot the video, it now contains more information and corrects the miscues within the first test cut. From David's post at the CNCSherline group:

----------
New video of Batch CNC demo
Hello Group, please see:
http://youtu.be/d2kFXjM9W64

Re-shoot is longer, shows more action, and got rid of the Wobblies. Note the nice, symmetric chip formation off the drill bit at about the 2:20 mark. In this one, I'm using a solid carbide #50 drill bit with an 1/8" shank, McMaster pn 2841A52

Best, David Clark in Southern Maryland, USA
----------

David tells me I'll have to write a program to accomplish on my CNC lathe what he demonstrates on his; software won't be able to accomplish such moves. So, more time consumption required. Sigh. . . .

Anyone here have a handle on machine code?

(ConduTTor, would you instruct how to place a video photo link as you did in my initial post?)

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Re: Video - Cutting TT steel wheels

Postby Rob M » Fri Jun 28, 2013 1:37 pm

That looks much better :thumbup:



For Youtube videos you just need to surround the file name with the youtube tags like below but without the spaces after the first brackets.
[ youtube]d2kFXjM9W64[ /youtube]
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Re: Video - Cutting TT steel wheels

Postby ConnRiver » Fri Jun 28, 2013 2:58 pm

Rob, thanks much for the you tube posting information.

David has posted code information on the SherlineCNC site (I've erroneously been labeling the site CNCSherline).

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