Sharpen countersink?

[bphaynes]

My Fuller countersinks are getting a little dull and burning up. I've cleaned them, but is there a way to sharpen them so I don't have to buy another set? I don't have a grinder, but I do have diamond stones if there is a way.

 

[Mike Davis]

Diamond stones will work.
Be sure to keep the same angle and hone all the tips equally or else only the highest one will do all the work and it will chatter.

 

[jfynyson]

Do you have any of these type diamond stones ? Good for small items like forstner bits and probably countersink bits...

https://www.amazon.com/DMT-D2K-Dia-Sharp-Diamond-Mini-Hone/dp/B000S5SD9M/ref=sr_1_5?crid=3EUWTD0K1WAUI&keywords=diamond+files+for+sharpening&qid=1636385938&qsid=141-7397927-5119613&sprefix=diamond+files%2Caps%2C360&sr=8-5&sres=B000S5SD9M%2CB000UVS62S%2CB001EPZ71C%2CB0951T4WM9%2CB0735X9Z9H%2CB00004WFTV%2CB0923GXHRY%2CB00ULPD5E2%2CB002RL83DQ%2CB00004WFTZ%2CB00004WFTD%2CB0797TCNWP%2CB004TBJGNI%2CB001910FOA%2CB000UVTDZC%2CB076C2478J%2CB08ZYCV8NN%2CB00004WFTW%2CB00U1T2ZVM%2CB01MT3EREP&srpt=KNIFE_SHARPENER

 

[bphaynes]

No I have the bigger DMT ones, but I will look into it. Thanks

 

[Mike Davis]

You can drill a hole in the end of a dowel to hold the countersink while you hone it on the large stone.

 

[bob vaughan]

My Fuller countersinks are getting a little dull and burning up. I've cleaned them, but is there a way to sharpen them so I don't have to buy another set? I don't have a grinder, but I do have diamond stones if there is a way.

I'm very interested in the outcome of this.
I picked up a new set a few months back at an estate sale. I've tried them a few times and felt those countersink cutting edges weren't very sharp to begin with.

 

[creasman]

Might be a crazy idea but what if you chucked the countersink in a drill and then ran it in reverse while holding a stone against it (lightly)? I don't have any of these so can't comment on whether the angle is right for doing this sort of thing.

 

[Mike Davis]

Might be a crazy idea but what if you chucked the countersink in a drill and then ran it in reverse while holding a stone against it (lightly)? I don't have any of these so can't comment on whether the angle is right for doing this sort of thing.

I would not do that. Think of running the blade out on a plane and dragging it backwards on a stone…

 

[Hmerkle]

I would not do that. Think of running the blade out on a plane and dragging it backwards on a stone…

I thought you sharpened the "faces" of the countersink (at least I always have)

I use my DMT mini-hone_ DMT Dia-Sharp Diamond Mini-Hone
(not sure if I got those at KWS of if I had to darken the doorstep of that other store...)

But I just touch-up the flat face of the countersink to get a sharp edge and then lightly strop away the burr sharpening creates on the O.D. of the countersink...

@Mike Davis do you agree?

 

[Mike Davis]

If you have a small stone sure that keeps the tips the same, I've done it both ways and either will work.
I think if you have it machine sharpened they will grind the bevels.