Frame Milling

[Conrail Quality]

For a kitbashing project I'm working on, I'm probably going to need to mill the frame of the "donor" mechanism to fit the kitbashed shell. Does anyone have any recommendations, tips, etc, about how to go about doing this? Internet searches haven't yielded much fruit, suprisingly.  If it helps, the mechanism in question is an N-scale Life-Like E8, which I believe is made out of the same zinc alloy that most manufacturers seem to use.

Thanks,
Timothy

[richG]

I have read articles in the past where modelers used files to shave down the outside. If you have not done this before, consider it O.J.T. On the Job Training. Learning by doing.

Use different grade files. Fine for finishing up.
Maybe Dremel also. There are a wide variety of bits available for milling.
Buy a milling machine from Micro Mark.
Use a vise with rubber jaws.
Maybe a drill press vise with rubber jaws and bits in a drill press.
Micro Mark has a wide variety of tools which will work.

Rich

[Jim Banner]

It all depends on the shape of the material that you want to remove and what tools you have available to remove it with.  Many installations only require a corner to be cut off or notched out.  This can usually be sawed out, either with a band saw or a hacksaw and cleaned up with a file.

In other cases, you need a groove of some width, in which case a milling machine is the easiest way to go but you can also do multiple cuts with a band saw or a hacksaw and clean up with a file.  If you have the proper blade for a table saw and spend the time making a jig to hold the locomotive frame, then multiple passes on a table saw is a good way too.

For a pocket cut, a vertical mill is ideal, particularly if you use slot drills to drill out most of the material before milling to final shape.  Alternately, use a drill press to drill a series of small holes around the periphery of the pocket and some larger holes to remove the bulk of the material, followed by clean up with a Dremel tool if it is a blind pocket hole or a file if it is a through hole.

Another approach for pocket holes is to drill one big over sized hole and back fill it with lead.  You can make a tapered wooden plug the size of the finished pocket and pour the lead around that.  Just be carefull drilling large holes in small, delicate objects or you are likely to damage them.  Greasing the frame lightly and setting it in a wooden box, then filling the box with plaster of Paris and letting it set for a day or two, can greatly reduce the risk of damage while drilling.

Bottom line, if you are doing one or two frames, use what you have available, even if you have to spend quite a bit of time.  If you are going into business, buy a milling machine and do the job properly (that is why it is called "frame milling." 

[Yampa Bob]

Hi Timothy
I have used cutters like these for many years on non-ferrous metals, hardwoods, plastic, even hard Elk and Deer antlers for my custom canes and walking sticks. Since they cut on the end and sides, they work well in a drill press, with the work piece securely clamped, ideal for pocket cuts,  or used freehand in a dremel power tool for surface cuts.  Use requires a firm and steady hand, but with a light touch as they do cut fast. Suggest practicing on scrap castings to determine the correct speed.

http://www.widgetsupply.com/page/WS/PROD/dremel-burr-cutter/BCU61

For metals use a lubricant such as this.

http://www.widgetsupply.com/page/WS/PROD/dremel-hss-wheel-4/BET04

[Jim Banner]

Bob, those are exactly the type of tool I use for cleanup after drilling out the bulk of the material.  With that middle one, you can make square corners in a pocket cut, something even a milling machine cannot do.  Get two sets - one for metal and wood, the other for plastics.

[Yampa Bob]

I have one cutter that is only 1 millimeter diameter. My favorite method is to hold the workpiece in one hand, Dremel flex shaft in the other like a pencil, brace my elbows on the bench and use the cutter like a router.  Oh yeah, I use full formed eye protection and Optivisor.

I recommend the flex shaft keyless adapter chuck, that adjusts from 0 to 1/8".  I got tired of changing collets all the time.

[Conrail Quality]

Thanks to everyone for the replies. Bob, your suggestion sounds exactly like what I need.

If anyone is curious, what I'm contemplating is taking Bachmann's ancient (and poorly-running) E60CP and, after some shell work, mount it on the more modern Life-Like mechanism. Based on the dimensions I found it should be a good fit, except for the frame height, hence the milling.

Timothy