Suggestions needed - flutes in nylon rod.

[challenger]

I need to cut 12 flutes down 2 pieces of nylon rod so they mesh loosely together. I did the same thing with a pair of hard rubber rollers but it took forever and I'd like to be more efficient with this set.
I've already laid out, and scored, the twelve divisions in the rod shown and started grooving it using the carriage as a shaper. There must be better ways.
I have a mill but I'm concerned about using it for this because I don't have any indexing tooling.
Thanks

[Toolguy]

Get a Phase II Spindex with a matching tailstock. Index every 30 degrees. Need 5C collets or 5c lathe chuck.

https://www.ebay.com/itm/5C-Spin-Index-and-Tailstock-Set/172055892147?epid=2094235170&hash=item280f5490b3:g:oW4AAOSwa-dWnOh8

[Dan Dubeau]

I'd make a toolpost mount for a router, or trim router and use the lathe to index. If you don't need super fine meshing a straight sided bit would work, but you you could always use that to remove the bulk and come back with a "d bit" (easy to grind) to cut a better tooth form.

[challenger]

I'd make a toolpost mount for a router, or trim router and use the lathe to index. If you don't need super fine meshing a straight sided bit would work, but you you could always use that to remove the bulk and come back with a "d bit" (easy to grind) to cut a better tooth form.

I thought about this and explored the idea while looking at three different routers I have. One is a Bosch 1/4 “, another is a rotozip and the last one is a dremel. The dremel doesn't have a 1/4 " collet so that's out. The other two are possible candidates.
Fabricating a mounting system for any of them is a lot of time/work so I put it on my mill table and," indexed " it using a really sharp center punch. I ran a ball end mill down one flute and am satisfied but not totally convinced it will prove out.
Waiting for more advice won't hurt.

Btw, even though the indexer is cheap it ain't in "the budget" right now.
Thanks

[Arcane]

Why don't you make yourself a simple indexer?

[754]

Yeah , bolt anything divisible by 12 to it with a spacer and detent, and have at it.

[Lew Hartswick]

Yeah , bolt anything divisible by 12 to it with a spacer and detent, and have at it.

Yea a 12 point socket . :-)
...lew...

[Dan Dubeau]

A simple quick and dirty dividing method is to do some math (or cad work) and figure out where the feature you just cut will end up when you rotate whatever division you need, then drill a hole there for a locking pin. You could simply make a dividing plate with the pivot hole, and another pin to lock in the groove you just cut. Each groove indexes on the last. It's not the most accurate, but it's quick and cheap......

[Corbettprime]

Yeah , bolt anything divisible by 12 to it with a spacer and detent, and have at it.

Try a sprocket off a 12_speed bike that has multiples of 12 teeth, for a cheapie indexer!

[754]

Exactly or a gear.. just make sure the detent holds it without slop, then clamp it to cut..

[gellfex]

I've made improvised indexers using gears from my lathe! Problem with any process on nylon or a low melting pt plastic is keeping it cool so you don't end up with a gummy mess. I hadn't worked with acrylic in ages and cut a cat door opening out of a piece of 1/4" with a jigsaw, what a PITA mess!

[tom_d]

I thought about this and explored the idea while looking at three different routers I have. One is a Bosch 1/4 “, another is a rotozip and the last one is a dremel. The dremel doesn't have a 1/4 " collet so that's out. The other two are possible candidates.
Fabricating a mounting system for any of them is a lot of time/work so I put it on my mill table and," indexed " it using a really sharp center punch. I ran a ball end mill down one flute and am satisfied but not totally convinced it will prove out.
Waiting for more advice won't hurt.

Btw, even though the indexer is cheap it ain't in "the budget" right now.
Thanks

It's a challenge not knowing exactly what you have available when making recommendations. You have a mill, so I would exploit that. Is there enough stock to mount a temporary plate on the end that has twelve holes, slots, teeth, or other reference features? A twelve hole bolt circle is not impossible to make. Even if you're rusty with the trig there are reference tables available for the coordinate dimensions. Machinery's Handbook is a good source. Or just give a shout out with the basic dimensions and one of us here on the forum can provide the numbers needed.

[darryl]

You have two needs as I see it- index and hold the piece for grooving, and doing the actual material removal. A router can do a nice job as it can move along the track it's cutting fairly quickly, meaning it's moving away from the heat affected zone quickly enough that it isn't affected by it. Multiple passes required probably, depending on the final size and shape of the groove.

On the other hand a shaper can remove material without heating it so much. It would need many more passes though.

Working with a router you typically have to plunge in and move along right away- no loitering at the plunge point. If you're coming in from an end, you enter and keep moving, you don't stop in the cut. If your X axis is long enough, you could set up the router as a high speed spindle by adapting it to your mill spindle. Be prepared to move your table at woodworking speeds.

[dian]

what is the shape of the flutes and how acurate does the spacing have to be? have you considered a horizontal cutter (even if its vertical)?

[challenger]

I am satisfied with using my mill. The ball end mill has to go only about 1/4" deep. I'll make a 12 position index tool of some sort using one of the suggestions here.
FWIW these two cylinders don't come in contact with each other. There will be at least one hundred thousandths separating the two.
Thanks for all the suggestions.