Countersinking Bits

[Onoff]

Can these be re-sharpened or are they scrap?

 

[gaz1]

if you have a tool cutter grinder they can be resharpened

the same as most drills and milling tools can be done the same way

 

[dan.taylor.1]

I think the last ones I sent away were about 4 quid each for a 16mm ish one.

 

[roofman]

I had some cheap ones so nothing to lose i thought...rubbed them up against the bench grinder and a nice square stone and good as new regarding countersinking. Ok would not pass countersinking aircraft wings but certainly works in a jobber type capacity.

 

[Maker]

One of the toolmakers at work said he'll teach me to sharpen countersink bits, hasn't happened yet thought. In my experience, once they're blunt they've had it, I've never reliably reground one.

 

[500e]

Had a Canadian who worked for us he could sharpen drills size no problem & lathe tools free hand, the real down side was they kept their edge as well.

 

[Kram]

I have done a few of the 1-3 flute type by eye on grinder and they worked ok, I wont claim they were as good as new but good enough for general countersinking. Grinding a consistant but not excessive clearance, is the hard bit.

Reason is, I bought a set of 3 and they were all blunt from new so no choice but go back to shop or sharpen.

Then I did the reverse and made a pair of bar chamfering bits, which work great. You can buy them but most reviews are not so good.

Stuff you have made today

The better organisers - dewalt, Stanley, festool- are too heavy when they’re empty I have some of the Stanley boxes, & not overly fond of them for similar reasons. Fine for getting lugged about, used on site etc., but for home/workshop storage, just a tad bulky & clunky.

www.mig-welding.co.uk

The larger one was a great pain to get the clearance to work and to cut, while the little one was easy. I dont know if thats a size thing or just that I did the small one first...

 

[Pete.]

You sharpen countersinks by grinding this face. How much you grind depends on how far the cutting edge is rolled from using a blunt one. If it's badly worn you might have to grind a few mm, if it's only just blunt then it'll just need a lick.

The same applies to gear cutters, if you use a blunt one you'll quickly trash the entire cutter.

 

[maroon]

One of the best countersinking bits I have just has a hole in it with a sharpened edge. Really nice cut.

 

[500e]

Have found those good as well

 

[Morrisman]

You sharpen countersinks by grinding this face. How much you grind depends on how far the cutting edge is rolled from using a blunt one. If it's badly worn you might have to grind a few mm, if it's only just blunt then it'll just need a lick.

The same applies to gear cutters, if you use a blunt one you'll quickly trash the entire cutter.

View attachment 378117

I've sharpened them freehand using the edge of a thin cut off disc. Works okay if you're careful.

Sharpening twist drills was something I learned as an apprentice, from the shop a**ehole. Turns out he could be a decent chap occasionally and it was a skill I've used for years.

The second ever machine shop I ever worked in used to send their drills out for sharpening, until I arrived. I could hand grind up to a 2" drill with no problems. Either normal, or flat bottom. Maybe I should have subcontracted to do them for a price?