Dull bits

This forum is for general discussion regarding VCarve Pro
Post Reply
PJHandyman1
Posts: 6
Joined: Sun Aug 16, 2015 12:26 pm
Model of CNC Machine: CNC Digital Wood Carver

Dull bits

Post by PJHandyman1 »

Hey Guy's


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


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

Robert L
Vectric Craftsman
Posts: 100
Joined: Sun Dec 21, 2014 7:32 pm
Model of CNC Machine: Multicam

Re: Dull bits

Post by 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
Vectric Craftsman
Posts: 177
Joined: Wed Oct 27, 2010 11:35 pm

Re: Dull bits

Post by 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

User avatar
Leo
Vectric Wizard
Posts: 3072
Joined: Sat Jul 14, 2007 3:02 am
Model of CNC Machine: 1300 x 1300 x 254 Chinese Made
Location: East Freetown, Ma.
Contact:

Re: Dull bits

Post by 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.
Imagine the Possibilities of a Creative mind

www.leosworkshop.com

User avatar
ChrisInEstes
Vectric Wizard
Posts: 835
Joined: Fri Jul 17, 2009 8:00 pm
Model of CNC Machine: Vytek 4' X 8' - Perske Spindle - Mach3
Location: Estes Park, Colorado, USA

Re: Dull bits

Post by 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
Aspire 9.5 - FlexiEXPERT 11 - Vytek Rebel 4' x 8' - 5HP Perske Spindle

User avatar
RoutnAbout
Vectric Wizard
Posts: 2078
Joined: Mon Sep 19, 2005 11:09 pm
Model of CNC Machine: Old Bot with a Rope Pull Start Spindle
Location: North Manchester, Indiana

Re: Dull bits

Post by 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.
Roll of Honor <-- Never Forget
________
Don

User avatar
Leo
Vectric Wizard
Posts: 3072
Joined: Sat Jul 14, 2007 3:02 am
Model of CNC Machine: 1300 x 1300 x 254 Chinese Made
Location: East Freetown, Ma.
Contact:

Re: Dull bits

Post by Leo »

Don,

Cutter Grinders are becoming a dying breed.

You are worth your weight in gold.
Imagine the Possibilities of a Creative mind

www.leosworkshop.com

User avatar
RoutnAbout
Vectric Wizard
Posts: 2078
Joined: Mon Sep 19, 2005 11:09 pm
Model of CNC Machine: Old Bot with a Rope Pull Start Spindle
Location: North Manchester, Indiana

Re: Dull bits

Post by 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)
Roll of Honor <-- Never Forget
________
Don

Post Reply