Thread: How to engrave scales?

I haven't done any scale inlays, but I regularly use a rotary tool for my other hobby (scale models).

I found the choice of rotary tool has a big impact on what you can and can't do. I've gone through several models of tool, And pretty much found out that all of the mains powered ones have too much speed, not enough speed control, and far too much torque. I tried a battery one and found it was better but too heavy to be delicate with.

So I've ended up with a unit that uses a much lower voltage. 12-18V on a mains adapter plug. I think the model is Rotacraft rc18.

At low speed you can stop it with a finger, Or use a finger to feather the speed. It's good because it doesn't drag the tool off the line so much, And the other advantage is at low speed you can use the felt wheels for buffing plastics that burn almost on touch with a mains powered unit. It's also quiet, and much cooler in the hand for longer periods.

https://www.amazon.co.uk/Rotacraft-V.../dp/B000B8JNWC

Useful on the other or any universal/ brush type motor:
Router Speed Control:

Cheap anywhere but Harbor Freight here has them.
~Richard
For single speed motors not multi speed. ( Thanks Tom!)

I use an old Dremel 100 single-speed hanging with a flex-shaft. You can still find them on the bay. It has worked for 6 or 8 years. I firmly believe with it hanging and the shaft, it will last indefinitely.
A NOS sewing machine pedal lets me control speed nicely.
You cannot use the pedal with the multi-speed or the electronic ones. Will burn something out.

I use a foot pedal for speed control. I also like to clamp what I am working in the vice or engravers block.

Being a full time carver and on occasion depending on power carving I tend to lean in the opposite direction.
Working on models (plastics ?) you don’t want speed as burrs generate too much heat at high speed and simply melt ( and clog) the material . And not having grain and higher density to contend with then yes , slow speed and lower torque is needed.

But if you plan on inlaying, carving , engraving ( gunstocks , scales etc) then speed is needed as well as torque. At slow speeds burrs and cutters tend to “grab” and ruin cuts. Imagine trying to use a router for example at slow speeds or a circular saw at slow speed. Doesn’t work.
Actually there are some tools designed for etching, engraving form gunstocks to glass that spin at 400000 ( yes 400 thousand ) rpm’s.
And torque? Right you don’t need it for softer plastics. Want to cut horn, wood, bone , ivory as you’d find in scales? You need torque to power through these materials.

I do use a micro motor now as I had gone through 6 dremel in a year and a half and needed something more powerful and reliable. What I most appreciate about this tool is regardless of the speed ( 1,000 to 40,000 rpm’s) the torque remains constant and doesn’t slow down when loaded. Speed is constantly maintained. Not a necessary feature to have but nice.

And using a tool such as a paragraver ( 400000 rpms) you don’t really feel the bit touching the stock. It’s more like you’re just brushing away material. Weird sensation.

Agreed!
Another option for torque power and variable speed is a Flexible shaft machine. My background is Jewelry and prototype building in an industrial model-shop.

There are also flexible shaft machines with plenty of torque and variable speeds of up to 20K or more. I have a "Foredom" that has been in use since 1959 and I have only replaced the flex. I also have a few different hand pieces for it. #30 is the key chuck version. The Foredom line is pricey, there are some HF ones also.
A positive point is the foot speed control
Less joyful, is that the flex shaft is often stiff and the machine works best hanging behind and above the shoulder.
That means it is better to have a dedicated work area. Laying the machine on the table is a recipe for problems caused by the torque moving the motor.

A search for "Flexible Shaft Machines" should get you to videos and sales sites.
JMO, YMMV
~Richard

I also have the Foredom in addition to my 2 micromotors. It’s a workhorse for sure. Same one for nearly 30 yrs . I depend on that for bigger projects that aren’t as delicate or where you need maneuverability . I can chuck smaller bits in it but it’s , in my opinion , not as accommodating to use in tight situations.
Whereas the other tools I can handle much like a pencil.