Can you just dremel the sprue nub?

I see a lot of people using hand files to file down what’s left of the cut sprue (is there a technical term for that?). Could it just be dremeled carefully? Or is the hand file technique the best?

The biggest reason why I ask is because I want to sprue my ring on the insides so as not to mess up the outside detail. I won’t be able to get a hand file inside to clean up where the sprues were.

What do you suggest? A dremel is the only thing I could think of. I have needle files but I don’t know what grit they are.

A half round file that will fit the inside curve of the ring, then whatever you use on your flex shaft to quickly remove material and clean up the surface. I use rubber abrasive wheels. Then various grit papers on a split mandrel or wooden cone and finally polish. You would likely have to do this regardless of where you sprue. This is a lot of work and why I don’t make many rings. Good luck…Rob


You just need to get the unwanted metal “gone”. Files, sanding, burrs, what ever. Burrs are fast but you have to be careful not to go too far!!! Files are slower but pretty good. Different coarseness files gets are not that expensive and you should have differing tools at hand if you are getting into this in any sort of way. (Seems that one NEVER has enough different tools……). Files should work fine, no matter the grit but if you are having problems of the them loading up (more a problem if working on waxes) “pre load” the file with chalk, by filing on a piece of chalk, then nothing will easily stick/fill up the file. Reload with chalk as needed. This is really great for wax work more than metal but for soft metals it does come in handy.

Use whatever you have and what you can get into the area safely and relatively easily. Good Luck.



I have a rotary file that grinds away a great deal of metal inside a ring shank, quickly.
I follow this up by using a split mandrel holding a strip of 320 grit abraisive paper to level everything, switching to 1000 grit.
I used to use a course half round file, but the technique I now use is far quicker.


I use something similar to this. I bought mine in person, so I’m not sure of an exact equivalent, but it’s definitely a wider cylinder that I use for inside ring sprues. It takes away a lot of metal, FAST, but it will also take away a lot of skin if you aren’t careful! I tend to grind down the worst of sprues with these, then switch to half round files as I find I have more control matching the surrounding curve. Then I go down to split mandrels with various grades of sandpaper, as others have said, as well as rubber and silicon bits. I like to have a lot of options… You just start to learn when you want to use which tool based on how the metal is behaving.


Thank you everyone for your input!

A fine tooth carbide rotary file makes short work of sprues, but it can be very aggressive and takes some multiple grits of silicone abrasives to get all the scratches out.

1 Like