Milling out a HO frame

[Anonymous]

Anyone have a suggestion or a way or what to use to cut out the hard metal frame (through the fuel tank) of locos like Athearn, Atlas, etc for installing a sound system speaker? [?]

[wp8thsub]

Have you considered taking the frame to a machine shop? If you don't already have the proper metalworking tools it may be a cost effective option.

I've modified a number of Athearn frames for can motor installation by grinding with various Dremel bits, as well as their fiber reinforced cutoff disks. The process is the "meatball surgery" of metal work, and may not be the optimal solution for removing a lot of material from the fuel tank.

[Anonymous]

Sounds like a job for a milling machine. Enough metal can be removed from the bottom of the tank to install a small speaker and retain enough metal for the motor mount.
I realize not everyone has access to a milling machine though.
You could drill holes clear through the bottom of the tank then use files to enlarge them to one large opening the speaker will fit into, then screw or epoxy a metal plate on the inside of the tank to mount the motor to.
Would see through grills and fans and an internal speaker box be another approach?

[sparkingbolt]

If you have a drill press, you can do as I did to correct a problem. I have an MDC RS3 that the motor was mounted too high in. So....

I used a Dremel milling- deburring tool bit which is 7/64th" across the head, straight sides, (not a Ball) it has 10 "teeth " on it. This bit does fine on white metal.

Mount the loco frame in a drill press vice, as it has a flat bottom and can be slid around on the drill press frame. This keeps hands well away from that carnivorous little cutting bit. Please, DO NOT TRY THIS TECHNIQUE WITHOUT THE VISE! Make sure the frame is level all around.

I am using a small drill press from Harbor freight, the one they put on sale for $39.95 every other month or so (Central Machinery 813B) I set it at it's highest speed; 3100 rpm. I think around 5000rpm would be better.

with SAFETY GOGGLES on, now you can set the fixed depth of the cut to about 1/16 to 1/8" deep and just guide the vise around on the table to mill out the metal. When the whole area being milled is done reset the depth again, if needed until the desired depth is reached. some locos will probably need only one cut depth. This is not the same as a mill, granted but it does give WAY better control than a hand Dremel. I especially liked the fact that the resulting job rendered a very uniform depth cut for a new smooth base to mount the motor on, in this case. You could even clamp steel rulers to the table of the drill press to give you definate clean lines, but i found that just eyeballing the operation and working slowly and carefully gave good results. This is going to produce a LOT of chips, take appropriate measures to contain them.

By the way this drill press, a chunky rigid little bench drill press with cast iron construction, at about the price of a cheap locomotive, is one of the best model building equipment purchaces you can make. It gives the obvious straight and true drilled holes, can mill as above, be used as an arbor press, and can be set to run slow enough to not melt styrene when drilling. I keep it on my model building bench in the house (my wife thinks it's cute) It's "regular price" is around $80 but it is on sale about half the time, as I mentioned earlier, at Harbor freight. Check it out! Dan

[Anonymous]

I bought a Dremel 7150 Diamond Point Set.
I started to buy a 196 which seems to be what you are using...but it states for 'soft metal.'
The 7150 has two bits: 7103 and 7144.( for hard metals, etc).
Also, the owner of Aztec gave me an address to mail in my frame, but I would like to do it locally. He is the owner of the track cleaning and does N-Scale frames.
THANKS FOR EVERYONE'S REPLY!!!

[sparkingbolt]

The white metal used in our locomotives is definitely a soft metal. Even softer than brass and copper which are soft metals too. Sure, it feels hard to our hands, and may even be brittle, but soft and hard are relative terms. These metals are soft, as opposed to steel, iron, stainless....hard metals.