Machining v notch at end of a dop rod

These dops are for a gem faceting machine. I would like to make some similar to these. Wondering how to machine that groove at the one end that is nominally 60 degrees. I think original manufacture was 61 degrees.

This would be with Sherline/Bridgeport/Lathes. I am not up to speed on CNC yet.

If anyone has some pointers to videos or web material, or just useful info, I’d appreciate it.



Roughly what is the length/diameter of the round shaft?

EDIT: I could envision putting the square rod vertically into the Bridgeport vise, running a 60 degree chamfer mill through it edge to edge (in progressively deeper passes), flipping it to machine the channel through the other end, and then turn the shaft.

There are a few different ways you can approach it. Easiest would be to get a 60 degree mill/drill. You can get custom grinds if you wanted to for the angles. @delpn & myself were talking about some custom end mills a couple weeks ago.

Another way is you could machine the majority of the stock then create a broach to make that last bit of material removal. This would certainly be more time consuming.

I understand it can be done as one part, but is it feasible – and then if so, a good idea – to machine one of those in two parts, the round part and the squared-off end part. This would only make sense if the two parts could be threaded male and female to be assembled. If this makes sense, you only need to to the tube part once, then make the various screw-on parts as/when needed

Due to the application I think it requires it to be one part. Since this is for gem faceting I don’t know if the screw on approach would work. I have never seen one done that way.

Something like this?

This is what I was going for


One thing I still struggle with is the sequencing and holding this in the lathe to turn it.

I was thinking :

  1. put square rod (longer than required) in lathe to turn (but how to stablize to avoid end chatter)
    spinning center in the tailstock?
  2. finish round end flat
  3. extend and add support?
  4. turn round
  5. mount square end up in bridgeport
  6. finish face
  7. groove v
  8. flip, groove notch

Something like that…

You could use round stock, turn the part between centers, mill the end square, mill the v-groove. The bottom photo looks like it was made with round stock

That might be a good option, too. Thanks for the suggestion.

you can make the V with a double angle cutter on the mill.

the drill/mill works well but the tips don’t last longl leading to more of a U shape

For a jewelry dop stick, I’m not sure that precision in the slot is a necessary thing. It’s just got to be enough to hold your wax onto the “stick”.

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More on this topic… Do we have a rotary chuck that would mount on the mill so I could rotate the piece and cut the four sides without having to take it out of the vice for each movement? Saw someone making something similar using that technique. It would be like four-jaw chuck with a dial to control the rotation…

I know we have a dividing head. I last saw it in the locker, at the very bottom, in machine shop.

Not sure if this is what you have in mind -
Machine Shop has rotary tables for the Bridgeport mill.
They’re under the table behind the Tormach lathe - next to the Haas.

Also for making 4 sided stuff with a concentric round shaft, a 4 sided collet block can work quite well. Put the part in the collet, then put the block in the vise. After each operation, just open the vise, turn the block, and lock it back down. This makes 90 and 180 indexing really easy.

I’m not sure we have such a collet block, but I thought I read discussion about it here before.

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If you can stand taking it out of the vise - and if your part will fit into one of the 5C collets, you could use the square collet block and then just turn it 90 degrees.

EDIT: Didn’t type fast enough!

EDIT 2: You could use a vise stop so your collet block goes back into a repeatable position.

Having used the dividing head with much help from @wanderson (and messing up my count in one instance), IMO you will spend a lot less time just putting in the collet block and indexing it once than trying to figure out how to set up and use the dividing head.


For this job I agree collet block much easier and you’ll get more precise alignment which I would expect is important for what it is used for.

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We do. We also have a hex collet block.

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