Dull bits

[PJHandyman1]

Hey Guy's


Does anyone have a tool/idea for sharpening dull bits or do you just buy new?


Thx ...................... PJ

[Robert L]

It depends on how accurate your parts need to be. If you plan on sharpening it would be best to send them out to a pro.

I know over the years of woodworking that sharpened bits almost always change their diameter.

It also depends on the type of bits you are using as the cost of sharpening is not that far from a new bit cost.

Robert

[bluridg]

did a post on 3/15/14 re sharpening. check bamcarbide.com. very happy with their sharpening of my bits and extremely reasonable. ted

[Leo]

In the metal cutting industry we send out cutters that are over ~ er about 1/4 inch or so. Depends on the original cost. The resharpening is done on CNC cutter grinders - same machines the cutters are made on. The resharpening companies generally charge about 2/3 of the original cost.

My tapered ball nose cutters cost about $35 so the resharpening would be about $23. Plus shipping.

Maybe that is not a bad deal. Maybe it's not worth the trouble.

If the cutters are resharpened on "conventional" non-CNC, they will not be as good. The flute clearance will also be smaller with conventional grinding, (unless they reflute), tending to clog and burn faster.

Cutters at 1/4 of smaller are just not worth it. I can get solid 1/4 carbide straight flute end mills or a good brand name for $18-$20

Then you also want to regrind the end cutting, so you can still plunge.

For me ---- I just use new, unless it is a big expensive ($50-$100) cutter.

[ChrisInEstes]

I get most of my bits sharpened. There's a really good sharp shop a couple of towns away, and I take them there. Their work is precise, and I've never had bit come back from them that didn't cut as good as new. So, if you can find a shop that's set up for that kind of thing, you'd likely be ahead.

If the diameter of a bit has changed after sharpening, I just enter it as a new bit with the new diameter.

Chris

[RoutnAbout]

One of the benefits I have allows me to of take mine to work and regrind them.
I always make sure the final diameter is not on an odd size like 0.247.
I'll make sure its either 0.245 or 0.240.
I also throw them on a optical comparator to make sure their is no taper.
I also use the comarator with the Vbits, there is no guess work on the angle.

The way our grinder is setup it will grind inside the flutes, then swings around to gash the end, then swings back around to do the diameter then finishes with the end geometry.
A 1/2" 4 flute carbide with a cut length of 1" takes approx 5-7 minutes with a regrind cost of approx $10-$12.00
A 1/4" 2 flute carbide with a cut length of 1" takes approx 4-5 minutes with a regrind cost of approx $6-$8.00

The best thing is when last bit is dull or broke and midnite, I don't have to wait.
On a normal day I'll grind about 50-70 tools.

If you find grinders in your area, take them a sign or trinket, they may give you a deal (maybe) first time around and if it don't cut right when their done, tell them they'll work with you and make sure your getting the cuts and finish you need.

[Leo]

Don,

Cutter Grinders are becoming a dying breed.

You are worth your weight in gold.

[RoutnAbout]

Thanks Leo,
I agree, but there are a few still around.
Now with the cnc grinders, they can do really intricate tooling.
But just like with these cnc routers, It matters where you place the decimal point. (don't ask - it just happens)