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Author Topic: TOOL SHARPENING  (Read 5672 times)

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Offline RICH

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« on: May 12, 2016, 08:54:55 AM »
Not much CNC work as this was a build as you go kind of project.

I have a Darex end mill sharpener and it works great and also use A Foley saw sharpenener as a bench grinder, but,
never used the Foley much because the grinding dust went everywhere.
Shop space is rather limited.

As the used / chipped / broken carbide end mills and lathe tools start to pile up wanted something to prep them for finish grinding.

So started looking at all that "stuff" one collects over time to see what could be used to  make some general use carbide grinding fixtures.

Some thoughts on the matter included:
1. Cheap / "this is not going to cost much" ( hobbiest creed!)
2. Use the "stuff" you have
3. Must be easy to setup, rather accurate to minimise use of expensive diamond
   wheels for rough sharpening.
4. Be able to sharpen carbide lathe tools including inserts and end preparation  
   of broken / chipped / end mills.
5. Keep it small, is movable, and can be easily stored away.
So the attached file shows some of the things made.

Note: When you make a fixture the mounting needs to be accurately done as that provides for easy and accurate setup. Keep things symetrical about drilling, based plates
square etc.

Pay attention to recomended and max rpm of wheels. Don't believe the cheap stuffs claim that it's good to 30K RPM. Test anything you make for runout and vibration. I put a rated 35K small wheel in a bench mounted die grinder and it went into vibration at about 15K bending the tool steel arbor ...almost jumped off the bench ( it was rigidly clamped down). Be carefull!  

« Reply #1 on: May 13, 2016, 09:22:33 AM »
Awesome post Rich!  I'm always in a panic trying to fix a chipped or broken tool on a weekend doing emergency work for a neighbor's company and I really need to build some of the grinding attachments you've shown.

Thanks very much for taking the time to put that together! ;D
Milton from Tennessee ya'll.

Offline Chaoticone

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« Reply #2 on: May 13, 2016, 04:38:40 PM »
Nice Rich, thanks for sharing!  :)
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!

Offline RICH

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« Reply #3 on: May 13, 2016, 10:26:28 PM »

Hopefully gave you some ideas for a cheap system that can be home built.
About $30 if you don't include the digital angle finder ( Harbor Freight and it's magnetic to .1 deg about $25).

Offline rcaffin

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« Reply #4 on: April 20, 2017, 07:51:09 AM »
Hi Rich

Your PDF mentions  that you should use diamond on carbide but CBN on cobalt. I feel this may be incorrect.

Use diamond on carbide for sure. It goes really well. I typically use resin-bonded diamond wheels.
You can use diamond on cobalt - in fact many bits of carbide contain cobalt as the matrix. There is no real restriction here.
CBN is used for steel (HSS) as the carbon in the steel can interact with the carbon in the diamond and erode the diiamonds away. Well - if it gets hot enough. For casual touch-ups at cool temps you can use diamond on HSS, and I do so sometimes.

I have just spent the morning regrinding a number of carbide and HSS end mills which I had damaged. One end mill had seriously damaged corners, so rather than take several mm off the end I turned the square-ended cutter into a rounded corner cutter. That went quite well, and the rounded corners are a lot more rugged.