Cutting shallow narrow slots on lathe 0.01" or less

[Aaron_W]

I'm looking at making a series of narrow slots, probably 0.01" wide and a 0.005" depth and 0.01" spacing.
I've tried doing this with a standard angle LH or RH cutter, but the grooves are not distinct enough, mostly just being a texture, rather than distinct grooves. I'm trying to replicate the slots around the circumference of the disk on a mechanical siren in 1/25 scale. On a 1-1 siren these slots are typically 3/16-1/4" wide, and perhaps 1/8" deep.

Example
https://www.fedsig.com/product/q-siren

At a larger size the cut off tool does this job well, so I'm thinking a much narrower blade like tool would do the job, but I'm guessing at such a thin blade wouldn't be stiff enough. I'm sure there is a tool that would work, I just need to know what tool I'm looking for, assuming it will be a bit I will need to shape with a little nub at the end to do the cutting.

 

[4GSR]

Look at Thinbit tooling. I have a few grooving tools that will cut a .010" wide groove and as deep as you need it.

 

[Dan_S]

For something like that you are going to need to custom grind a high speed steel tool bit.

 

[brino]

On the lathe, my first choice would be a specially ground HSS bit.
Use a dial indicator mounted on the ways to space the carriage over the gap+cutter width.

What about using a slitting saw on a mill?
They leave very well defined grooves and are available in different thicknesses.
The work would need to be mounted on a rotary table though......

-brino

 

[RJSakowski]

I have made HSS tools of similar proportions from broken taps. A .01" cutter would be fairly delicate but since your groove is only .005" deep, you should have sufficient strength. I also keep a supply of 1/8" tool bits to make those small tools. A parting tool could be ground down to make the groove as well.

Probably the hardest part will be grinding the tool. Get it close and perhaps finish by honing with a stone or diamond plate. Measure frequently during the process so you don't over cut.

 

[Zathros]

Perhaps you Will find it in the metric system, that is fairly small. I use to make electronic print in the past with à small dremel like tool in the sizes you give there.



Verzonden vanaf mijn iPhone met Tapatalk Pro

 

[darkzero]

I'm invested & have been using Nikcole Mini Systems for a while. Great tool but if you don't have it already it'll be expensive to buy & use just for this op. However .019" is the smallest grooving insert they make. You could always grind it thinner though.

 

[Aaron_W]

Ok so a variety of options. I imagine if I cut a custom bit for it, it should resemble a V with a little squared off nipple at the tip?

I'm in the process of buying a mill, so the slitting saw idea might be an option. I have a rotary table already.

 

[francist]

And the material is..... steel, aluminum, brass, plastic?

Ten thou wide cutter is doable enough, but I'd be prepared to have to take a few runs at getting it. That's pretty skinny when it comes down to the grinding aspect. Really you just want a sharp spur sticking out, otherwise you stand a good chance of snapping it off either during the grinding or the actual cutting.

One thing I will throw out for consideration is scaling that particular feature up a bit -- maybe twenty thou grooves and spaces. Yes it may not be faithfully correct to the life-size part, but sometimes there comes a tipping point whereby the eye still recognizes the feature for its intent rather than its faithful dimension. Especially true of small features and details which would be meaningless unless viewed under a microscope. I wonder if this may already be occurring when you say your initial attempts are more of a texture than a defined pattern. Just a thought, throw it by the wayside if you don't want to go there.

-frank

 

[Aaron_W]

Aluminum or brass. I haven't done enough with brass yet to determine if it may have better characteristics for this part. Aluminum preferred as it can be left as is, not need to paint or chrome the parts.

I understand that the groves will just be an approximation. I'm half happy as it is in that I'm finding the straight side of the tool cuts a much crisper grove while the angled side is softer and much less distinct. I'd be quite happy if I was able to get both sides to have that nice crisp edge.

I'm still learning what the different tools are called, but maybe a center cut type tool (V shaped tip) cut with a much sharper angle than my LH/RH tools would provide an adequate groove.