Here's the rest of the story

This photo shows some of the loco weights I started with:

 From top-to-bottom: two red-box Atlas U30C sets of weights, an Athearn SD45T-2 set of weights and two Athearn SD40T-2 sets of weights. You can see Sharpie marks showing what I wanted taken off.

Here is an After photo of the same weights:

I disassembled about eight locos that will eventually get RAilPro receivers installed. Here's a group photo of them after being milled:

The long one in the back is a Proto 2000 SD60.

Next I'll post a photo & video of the CNC Mill.

Everyone needs (access to) one of these!

We were almost done milling all of the weights before I remembered to grab a couple of shots and videos.

Here's a shot of the small, gold-colored, front weight piece from an Athearn Cotton Belt Bicentennial SD40T-2 loco set up in the mill:

If you look closely in the lower left quadrant you can see the weight chucked up on the right side of the blue work-piece vise/clamp.

And here's a video of the mill doing what it does best! We turned the coolant flow off and turned down the feed-rate for the video so you could see the action.

I'm so very fortunate to have a connection with someone with this kind of machine tool who is only too happy to lend a helping hand.

What was Tim Allen's famous line from the TV sitcom "Tool Time"? More power!

Sort of like a "How It's Made" TV episode! Life certainly is good!

Wow

When you said "CNC mill" I had something quite different in my head! That looks like something you could CNC mill a 7" gauge live steamer or something like that! And that's with the power turned down, too!

Me too, almost

I've used angle grinders and drill press as milling machine to cut groves for wiring

Not pretty, but gets the job done.

Been there myself...

dennis461! That's essentially how I was doing it too until my friend said, "hey - I think I've got something that might make that job a tad easier."

oops

A friend of a friend ran a shop with a number of those of different breeds and generations. He was a sole-proprietor so mostly he bought used ones and ended up with no two the same. I visited one saturday when they were just farting around basically, he was making a part for his old car. Anyway, he was programming the thing in this ancient language called G-code and got a plus-minus sign backwards in a Z axis movement. Instead of lifting the drill bit up (to move it over) the thing suddenly tried to push the drill bit through the piece in one quick motion, making a huge thump, breaking the $250 drill bit, sending the piece and part of the drill bit flying inside the containment area and my friends-friend diving for the big red EPO button. It was all over before I could even be startled. 

So if a friend volunteers to route out a bit of your engine chassis, you might be advised to take a break from the chit-chat while he programs it, because an "oops" will probably result in a two-piece chassis.

Yup!

EW - my friend has a few of those "oops" pieces around for show & tell. They are incredibly instructive to see first-hand because trying to describe them with 1,000 words wouldn't even come close....

Ancient Language

Would you be surprised that today's table top 3D printers use that ancient language? I use it on my table top Sherline CNC mill.

Bernd

nope

not surprised, g-code is crufty, and I suspect error-prone, but it was built to the purpose of controlling CNC routers and became a standard. A newer language might be a little easier to deal with, but nobody wants to change without good reason.

Regardless of the machine ...

... and having milled many N Scale chassis out on my vertical knee mill, (as well as a lot of 1.5" Scale parts and 1:1 airplane parts) it seems to me that these kinds of jobs are easier done by hand/eye control, and very gently owing to the light alloy used in locomotive frames to begin with.

I can't imagine it being worth the risk/effort to program when you can put the job on a parallel(s), true it, clamp it, and remove the required depth in a couple of 10 thou passes.  Now maybe this machine can auto zero with a laser indicator and you can just tell it how many thou to shave without programming.   

Cool to watch for sure.  I watched one at a machine tool exhibition about 30 years ago digitize an ivory liquid soap bottle in 3D and then cut the mold in reverse in 3D.  Fascinating things. 

CNC maybe a little overkill for MRR

I bought a mini mill a few years ago and use it constantly now.  Mine is just a basic Harbor Freight version with some upgrades but no CNC or XY motor drive accessories.  Just hand cranking and eyeballing.  I use it to mill frames, weights and mainly body parts.  Here I'm milling out a C30-7 radiator housing for installation of KV Model's etched grills.  Got this during a sale for about $500 and maybe have $750 in it total with tools and upgrades.  Little Machine Shop is a go-to reference and supply point for either entire machines or parts and accessories.  Makes sound installations stress free! 

No mill

I have been cutting engine weights on my 12" band saw with a metal-cutting blade for the last several years with no issues.  Not 100% true like a mill but close.  I even have the cut off pieces to be used for weights in cars. 

The beauty of your set-up....

Robby is that it's in your basement (I assume) and that you can use it for anything/everything when it's convenient for you. For what we do, your set-up is all that one would need.

Great work on the C30-7 radiator housing!

The beauty of your set-up....

Sorry Paul, been away from the computer for a couple weeks.  Thanks, yes this is in my garage next to my paint booth.  No basements here in Texas so I stuck it out there to keep the mess out of the house.  Still easy to access anytime I need it.

If you are space and/or money challenged ...

For a small machine tool for your workbench, and don't have room for both a mini-lathe and a mini-mill, I’d recommend investing in a mini-lathe (first or only).  You can easily mill small things on a lathe with a milling vise, but you can’t easily turn things on a mill.  It can be done, but very far from ideal.  I made a set of wheels once as a kid with a drill press and a toolbit in an X-Y vice, but they were far harder than they’d have been on a lathe. This ultimately led me on my journey into finding a lathe I could afford.

Just make sure a milling vise (X-Y) is available for the lathe you choose.  They look like this and bolt on to the top slide where the compound rest goes.  You use the lathe bed and cross slide for X-Y movement and the milling vice for Z axis movement.  You can always mill a block to attach to a bigger vice and clamp it in one of these if you need a bigger gripping area.

No milling machine

I wish I had one but for the past 10+ years I have relied mostly on a fine toothed hack/hobby saw.  Slow and steady to get the clearance I need for speakers. My preference for a decoder is a plug and play board which is similar in vertical height to the factory mother board. On occasion, I use my Dremel with a toothed metal cutting blade.

We use what we got!

Duckdogger - that was my modus operandi (hack saw) as well until this opportunity presented itself. So, when the CNC mill opportunity presented itself, I got busy disassembling a batch of locos to get at the weights because I didn't know if I would get access to that CNC mill again going forward.

Poor man's mill

I sold my mill several years ago when we moved with the hopes of getting a better one (still waiting). So for now I have a poor man's mill using a drill press and x-y table.

Experts will say don't do this as drill press spindles aren't made to withstand lateral forces, but I only do this occasionally and with soft metals. Also, only when accuracy is not important (good to .005" +/- .060")...

Craig