Need to mill 6 fine tiny V grooves in aluminum

Hello, my name is Ted, I am new here, and this is my first post. I am strictly an amateur machinist and only have knowledge from advanced high school shop class and what I’ve learned by working with my own equipment. I do have a friend who owns a machine shop who lets me borrow tooling and attachments I don’t have (if he has it of course). I have a small Logan lathe and an Alliant variable speed mill with digital readout. I restore antique cars for a hobby and have made a few molds out of aluminum to cast rubber parts that are not available. I am currently trying to make a mold for some floor mat area pieces. While I have most of the design figured out along with my friend, I have one thing that is a sticking point.
What I’m trying to duplicate is a ribbed section of floor mat that has .020 high ribs,.3125 wide, that run along side .375 wide flat grooves. Centered in these grooves are 6 fine v ribs that are equivalent to a 26 pitch. Of course making the mold in reverse the .375 grooves become ribs and the 6 fine v ribs become fine v grooves. These six grooves are about .005 deep and are basically about 1/4” wide total.
I’m curious if there thin slitting saws that are sharpened to a pointed edge that could be put on an arbor as a stack, then using a 90 degree adapter on my mill, used to mill those grooves. The picture I included shows the square panel around the shifter with the grooved, ribbed, 6 fine lines I’m trying to duplicate in a mold.
Any help or ideas todo this would be highly appreciated. Thanks, Ted

Not a mill or saw.
Push or drag a single point tool.

Essentially a shaper operation, but nobody has a shaper anymore.

Which is why mold building/repair is a niche market.

That mat is a sheet good, most likely formed by rollers.

Which is most likely why that exact material is unobtainable.

Stupid design.... does that nation of origin even MAKE stuff anymore?

If you use a saw or an endmill, you're better off either tilting the head (if a bridgeport) or the work (if a typical CNC mill) rather than worrying about a shaped cutter.

Shaped cutters only make sense if you need thousands of these.

I have done it with a cnc and engraver sharpened to a fine V to make aluminum V blocks to hold .004" glass fibers. Just locked the spindle and fed to cut the V. .001-.002" chipload will be fine. In my case the V was open on both ends so I didn't have to worry about what to do with the chip at the end of the cut.

Your Vs are big enough that a 45 degree sharp tip chamfer mill may work well.

Since these are straight grooves and very shallow, could he cut them with a conical engraving cutter? He didn’t say anything about the included angle. If it’s 60 degrees, maybe this would work for this application. 6deg Incl Angle, 1/8" Shank Diam, 1-1/2" 84 - MSC

Thanks for the fast replies. The ribs are so small I’m not sure if their angle could be determined but at the same time, it probably doesn’t matter. I did have an idea of making a tool holder than tightly straddled the rib. The body would be drilled across to accommodate a 3/8 x 24 tap (24 vs 26 pitch on the floor would be hard to tell the difference and would still be acceptable if centered on the mold rib). I would grind off threads on one flute except for the six I need then hold the flute in its optimal cutting position by angled set screws on the frame sides against the upper flutes. The tool holder would mountin my miller head and I would use the cross table to feed the material through the tool holder. The tap would work much like a file or gunsmithing checking tool. Come to think of it, I believe a two or three row checking head is available and probably in 24. My friend didn’t think the tap would work because the tap is not designed to cut straight. I’m still thinking of trying it because the grooves are so shallow.

Cut the shape you want in the end of a old end mill. Hold the work on your mill table. Use your non-powered mill like a manual shaper.

Chistech said:

I’m curious if there thin slitting saws that are sharpened to a pointed edge that could be put on an arbor as a stack, then using a 90 degree adapter on my mill, used to mill those grooves.

Click to expand...

Yes. This will work.

Another way to do it is to have a place that makes thread mills make you a one-off cutter. Or possibly they have something with 26 tpi already in stock ...

Ask your buddy is he has a top notch grooving tool and a 60* threading insert for it. Find a way to mount it onto or in you mill and use it like a shaper. This also works pretty well on a lathe for slotting screws before part-off.

I ended up buying two-three row, 24tpi, gunstock checking cutters. I made a holder out of aluminum and using the supplied tiny roll pins, pinned the cutters in place. The two sides of the tool were milled out of a hard nylon and one side was milled to the exact thickness of the 5/16” grooves. Two aluminum blocks finish up theends and keep all aligned. Two Allen head 8-32 machine screws hold the cutter holder at a set depth. The checking cutters are designed to cut from either direction and the tool works like a file in either direction. By keeping as much of the sides in the groove while pushing the tol along the grooves keep it al aligned as the cutters cut the lines. In the pictures you can see my test piece of grooves and ribs with the six fine grooves cut. The cutter will be lowered again to get a little more depth to all the grooves.

Or use an old thread chaser.