CBN discs for Worksharp

[fredhargis]

Anyone buy these? I see Woodturner's Wonders has them...a set of 3 (double sided) for $150. If you have any how well do they work, and have you given up the sandpaper yet?

[Timberwolf]

Anyone buy these? I see Woodturner's Wonders has them...a set of 3 (double sided) for $150. If you have any how well do they work, and have you given up the sandpaper yet?

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I think this is what would stop me from buying them...you don't have this problem with sandpaper... I do have several diamond laps that I bought from Amazon that work extremely well when used correctly..., and at a very attractive price...less than 15 bucks...I also have a WTW CBN wheel on a bench grinder that I bought from them and it works well on steel that is very hard..

From the website:

A WORD ABOUT WORKSHARP CBN DISCS
1.) Try to avoid softer steel used in older tools. If Softer steels are used we suggest using the Wonder Slick Stick to avoid loading and used for cleaning.
2.) Softer metals will start to load up the discs which means particles of softer steel will begin to embed in between the pores of the CBN grit and start to glaze the disc over. Sometimes this will happen over a wide area gradually or it could start a single narrow ring if a tool is held a certain way. This is more likely to happen on the higher grit discs because the pores are smaller and closer together.
3.) The grain on these discs is half embedded in nickel alloy and half sticking up. The grain is especially small on the higher grit discs and is susceptible to being "gouged" if a very sharp pointed object is pushed into it. Make sure any tool you insert from below or above is square to the disc with bevel presentation first otherwise you risk SCORING the disc. This is especially true with the 800/1200 disc. This is NOT covered under the lifetime warranty of the grit not coming off as it is rather a misuse of the disc.

[fredhargis]

Yeah, I saw that...it's why I asked. Although I don't really have any tools I consider soft steel. But I also have a couple of the diiamond discs, and they do work well....they just don't replace all the sandpaper grits.

[Timberwolf]

Yeah, I saw that...it's why I asked. Although I don't really have any tools I consider soft steel. But I also have a couple of the diiamond discs, and they do work well....they just don't replace all the sandpaper grits.

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I consider any steel I can scratch with a file to be soft, so that eliminates some knives that test out to be 55/ 58Rc or so...That's what I kinda go by...When the steel embeds, its like paving a gravel road with asphalt.

[cputnam]

Not directly responsive .....

I bought a WS3000 and table quite a few years ago and also bought enough sandpaper to last me a lifetime. Using the wide blade table and a rubber cleaner, I can get many tools worth out of a single disc of sandpaper. My unit, although it grinds square, gets the bevel slightly tilted compared to the stones. I've also gone down the road with a circular grinder with a buffing wheel. That might be a better investment.

[John Mihich]

Not directly responsive .....

I bought a WS3000 and table quite a few years ago and also bought enough sandpaper to last me a lifetime.  Using the wide blade table and a rubber cleaner, I can get many tools worth out of a single disc of sandpaper.  My unit, although it grinds square, gets the bevel slightly tilted compared to the stones. I've also gone down the road with a circular grinder with a buffing wheel.  That might be a better investment.

Me too.  I think mine is 10+ years old.  I do touch ups with the leather disk so I don't have use the SP often.  I did just have to change the highest grit this past month - my fault - I pushed it too hard on an 1/8" chisel.

[tablesawtom]

A couple of things,

I did a Rockwell test a file and it came in at 63 Rockwell  and a file has teeth meant to cut metal so it will cut or scratch anything softer than Rock C63. That test is usually preformed on a piece of steel just out of heat treat so it is a very dark color and the scratch shows up nicely but unreliable because one will get different results with a dull file. In my trade, which was die making, steel is usually hardened and then drawn ( tempered) back to 58-60 on a Rockwell C scale.  Usually one will take a file and hit a corner of the block with a file and 63 cuts 60. Sharpness of file amount of pressure in the cut and  usually .005 is allowed to get through the decarb so if not decarbed you get a false reading. that is why a Rockwell test is always preformed on a spot that has been ground.

In other wards a file test is not to reliable. That is why they make Rockwell testers in the first place. If you have been around hardened steel for a while a file will give you the feed back you are looking for as Timberwolf stated but he has been or still in the trade. To most who are not in  the trade you will get differing results and It is like gossip and you came not be sure what to believe.

And the term (usually) is my disclaimer. 

Tom

[tablesawtom]

Now that I have the file test out of the way, I would like to address the CBN issue.

Some or all or the disclaimers that Woodturners Wonders puts out is like seeing advertisements for medicine ( certain drugs) on TV. They claim they can help but they also have to mention the side effect so the term is, ask your doctor.

Woodturners Wonders also posts a video on there web page about grinding coper ( which is a no no for any grinding wheel) and how to prevent the wheel to getting loaded up and how to clean it if it does. They also sell a product called Slick- Stick, which whelps prevent the wheel loading up. The slick-Stick is around $7 and it works.


I have a 80 grit CBN and a 350 Grit CBN wheel on my grinder and  I have reshaped a lot of older plane blades and  sharpened a lot of chisels and have not seen any of the problems listed. But I can see if a person is heavy handed ( which isn't necessary ) it could. I even use the side of the 350 wheel to help flatten the backs of chisels. I am considering buying a gear reducing motor and a disk for a Work Sharp to make a motorized lapping plate for the back of chisels. 

I suspect the disclaimers are to protect the life time quarantine form people who think the know all there is about everything because they read it somewhere but really don't have a clue.

Personally, If I had a work sharp I would, for sure, try one, you can always buy more.

Tom

[MVWoodworks]

Anyone buy these? I see Woodturner's Wonders has them...a set of 3 (double sided) for $150. If you have any how well do they work, and have you given up the sandpaper yet?

I have the WS3000 with the add-on to sharpen from the top. Also bought the disks. The problem I have is they are a bit too thin. When installed in the WS, their surface is about 3/64" below the glass/sandpaper disks. This causes a problem when I go to higher grits. Haven't gotten around to finding a 3/64" washer to see how it works.

[fredhargis]

Thank you, that's useful to know. That platform can't be easily be put any lower.