Mill turn or mill?

Gents, I have no experience turning anything, and I rather ask before I get myself into some trouble with the S3. I was thinking how to get a D6 x 30mm Al rod into a D5.5 x 30 rod with two tiny grooves on the side of the cylinder.
Option one is to mill it to the required diameter and than mill the grooves with a T-slot cutter. Option two is mill turning the whole thing but I am concerned about the high RPM of the Makita router and also my lack of experience.

I would appreciate any suggestion on both option concerning that I have to make 100 of these tiny parts without a lathe. I can grind a HSS form tool or I can invest in the appropriate T-slot cutter.

Are you sure you can’t get 5.5mm diameter rod? I’d start there if at all possible.

I suppose you could have a pair of fixtures — first holds the rod vertical and allows one top half to diameter, then put in the top groove, second holds the machined end and allows a repeat of the operation.

Sorry for not being clear enough. I ment grooves around the side not along - not like a keyway. Paralel to the top/bottom of the cylinder.

Yes, I caught that — I meant to add that you’d need to use a ball or theadmilling endmill or other endmill capable of the undercut.

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You want to put flats on the side? Sorry, trying to follow what you’re describing, do you have a model or picture? Making 5.5mm x 30mm rod from 6mm round stock isn’t going to be easy without a lathe, but there’s one person on here that might know if/how it can be done @RichCournoyer is who I would ask. Or try to buy 5.5mm round stock as @WillAdams suggests.


I am no pro and I am Nomad user not a S3 user. Think that gets all the warnings out of the way.

If it is truly round you need, the mill probably wont get you there easily. What I have done in the past for long(ish) round pieces is machine it out of square stock using a double sided job. Its pretty hard to make perfectly round however, so a bit a fussing and multiple tries usually required.

However it sounds you are attached to this particular stock - so if you have no choice you could put it in a collet block and do a similar two sided job. Again - if perfectly round is what you need this may not be for you.

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Hi boys and girls…did I hear my name?

I also don’t have a lathe and do LOTS of round things either on or off the Shapeoko…

Based upon the length, I’d recommend that you chuck it in a drill chuck and then turn (file) the diameter to size…use good files and a file card to keep the file clean. I do this (drill chuck turning a LOT (as well as OD Grinding of carbide and HSS cutters using this same method) and with a little patience and practice this can be done fast and with precision. (I often hit +/- 0.025mm with ease)

PS because of the length, I’d do half, then turn it around and then do the other half…

Then pop it into the mill to do your keyways…

EDIT: I put my drill into my bench vise (to hold it still during the above turning/filing process). As AvE recommends, place the drill into the vise, tighten until you hear a crack, then back off 1/4 turn. PS Don’t block the vent (cooling) holes.



I abaondaned the idea of using a drill chuck for many reasons. Mostly because it can leave some marks on the surface. I have ER collets also but would be to difficult to fit into the S3.

My best idea was to make a pallet with a bunch of 6mm and 5.5mm holes to accommodate a lot of these than mill it to the desired OD, chamfer and undercut. Than flip it to the 5.5mm hole and mil the OD and chamfer.

Any concerns?

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I have to be honest. I would have rather machined the whole thing but I gave it a shot fallowing your recommendations and come out really nice. Furthermore it works as it planned. Fits the reamed 5,75 airtight. I’ll test it under pressure ASAP.
Thanks again for the help!


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