Update on RGS #20 at http://ngdiscussion.net/phorum/read.php?1,243450

I like seeing a CNC mill utilized for grinding links! I have long advocated the idea despite being told it will not work. Huh, sure looks to me like it works pretty well!

Cheers, Jason

Linn,
Your work on RGS #20 is beautiful, thank you for your work and for sharing.

Not to wander too far off topic, but I might add that I was interested as Jason was in the machine doing the grinding - and the comment. I worked in a tool cutter grinder shop as a teen - from the ol' timers mouth, "you never do grinding on a machine tool, and you never do machine work on a grinder." Now we did precision sharpening on Norton, Brown & Sharp, Winston, Oliver, Bridgeport and Cinncinnati equipment built between 1930-1960 (still working in 1998 to better than .003!). Their reasoning for this was a couple pretty good arguements; 1)grinding dust will damage some machine tool's ways, beds, Vs and balls precision 2) the motors/bearings for machine tools are not made for the speeds/forces present with high speed precision grinding 3) the motors/bearings of grinders are not made for the torque/forces of lateral machining.
Now I happened to beleive them and agree at the time - so that may be a stigma lingering in the machine shops still - or it may be wrong or true?
...but, I believe that was most applicable to that era of machines - I see now many manufacturers offer machines that are capable of both - to me it seems obvious that all 3 of the reasons above could easily be solved at the product engineering phase.
Anyhow - it's an awesome link set and I look forward to seeing more!

Jason, et al:
Hummmm, Valley RR (and others) have been doing links and link blocks on CNC machines since at least C.1992...
However, this raises a good point: how many innovative solutions to real time problems have been solved and then LOST again?
Doing a "search" on rypn, could save someone a lot of bother and "reinventing the wheel"...
(your results WILL vary),
J.David

Thank you for the reply J. David! Hope all is well in the B-E-A-UTIFUL northeast!

Cheers

J. David,

Are you cutting links or grinding links in your CNC machine?

For what its worth, when doing Southern 401's hardened links, we used a local shop who had a heavy duty CNC mill. Our links were cut using a 3/4" solid carbide end mill at some VERY high rpm. (don't remember what speed it was turning) The resulting finish was very good, but we did a final polish by hand anyway with a die grinder and 2" wide flap wheels.

We were initially looking for someone to grind them, but the shop owner assured us his milled finish would be nearly as good, and he was right. We've been happy with how they came out, and with how they are holding up in service.

Kent

That's a very good point. Besides techniques such as this, I wouldn't be surprised to find that there are steam operators looking for tools, parts, supplies, services or equipment that are out there, they just don't know where to find them. I created a steam repair links directory on my website several years ago (http://www.trainweb.org/tusp/r_links.html), and I try to update it regularly, but I have no idea if it's actually used very often.

Thanks for what should be termed a quality post. The prose and photgraphs certainly do tell a story. Appreciate your time.

Using a conversational mill as a grinder can be done if used properly. The biggest item as I'm sure Mr. Moedinger knows is matching the tooling to the capability of the machine and the setup. Removing small amounts of material in a handful of passes would be optimal especially with a longer tool. Surface finish will follow as such (I imagine in the neighborhood of >2 Ra) which is plenty fine for a link's application. The only gripe I would have is the grindings you get from performing an operation like that on a mill. They will get everywhere you don't want them to be, especially in between way covers and in ball screws...just my personal observation if it were a more regular operation. For as little as this type of operation would arise, I wouldn't sweat it.

We had Stephenson links done as 1 piece, using CNC wire feed EDM in the early 1980s for NP 328.

-Hudson