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Thread: CBN Wheels for chisels and plane blades questions

  1. #16
    Join Date
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    Quote Originally Posted by Sam Murdoch View Post
    John, sounds like you've got great things going on. Me? I am very much into the lessismore phase of life. Still lots of projects and in the biz too.
    Still - Je ne suis jamais seul avec ma solitude.

    Thanks for the heads up about the break in period with CBNs.

    sam
    I think of being alone not as loneliness but as quietness and peacefulness, with the fullness of introspection, contemplation, creative exploration, or simply being, all on the other end of the spectrum from things like the assault by sporting events or TV, of which I refuse to participate.

    My wife is interested in the less and suggests that 43 animals is enough. I agree and have already given away a high pedigreed llama before it is born (due in about a week). I do, however, very much enjoy experiencing certain frantic busyness, such as watching the beehives in action. The guineas are entertaining too.

    JKJ

  2. #17
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    Fun with grinding and sharpening

    I always hone/strop after grinding. Some detail follows. I can go with the "grinding" vs "sharpening" terminology.

    I might call using either the 600 or 1200 grit CBN wheel "finish grinding". I grind with coarser wheels on the bench grinder for rough shaping, sticking to the 80 grit these days. I go directly from the 80 grit to 600 or 1200 - don't think I've used my 220 grit CBN for a couple of years - I don't see the point of using a wheel too fine for shaping quickly and too coarse for honing/polishing quickly.

    I think that due to the violent nature of sticking a sharp tool into rapidly spinning wood in woodturning the sharpening can be different from hand tools - it's a waste of time to spend too much time with very fine stones since the microscopically perfect edge you might put on a dovetail chisel would probably be gone almost immediately when turning. Also, most tool edges have compound curves which is not easy to dress by hand with very fine, flat stones.

    For my lathe spindle gouges I grind on the 1200 grit CBN wheel on the Tormek. I use the honing compound on the Tormek 8" leather wheel for the spindle and other curved gouges. I use Tormek's leather profiled honing wheel for inside the flute. This gives removes the grinding burr and gives a polished edge in just a few seconds, perfect for detailed work on the lathe. When using the Tormek with water wheel I really liked dressing it with the fine side of the stone then polishing on the leather wheels.

    Note that grinding/sharpening spindle gouges with even a very fine Tormek wheel only takes a few seconds since very little metal is removed, an extra 30 seconds if I need to I set up the jig. (To save on setup time I keep six spindle gouges with identical grinds and only have to set up the jig once to do all six.)

    For my lathe skew chisels with straight edges I grind on a 600 grit CBN wheel on a bench grinder use a piece of MDF with honing/polishing stick/compound rubbed into a surface resawn expose a bit of roughness. I use this to touch up bench chisels too after sharpening with a series of ceramic stones. Skews with curved edges are done the same way but with a little coordinated arm waving. Note that my chisel sharpening and use is pretty crude compared to the neander norm. When a lathe skew chisel goes dull I first strop on the MDF surface a time or two then when that loses effectiveness I touch up the edge with the Eze-Lap diamond hones and MDF strop a few times before going back to the grinder.

    For the lathe negative rake scrapers and traditional lathe scrapers I grind with the 600 grit Tormek wheel then hone off the grinding burr with an extra fine Eze-Lap diamond hone (the blue handled one) before turning a cutting burr with a burnisher.

    For curved hand scrapers I grind the edge with the 600 grit Tormek wheel then continue as with the NRS.

    For plane irons I do the best I can with the Tormek and stones. Again, my standards are low compared to the community of plane lovers. But I rarely use planes except on doors and decks.

    Chip carving knives in good shape are sharpened differently (http://mychipcarving.com/product_inf...ening-kit-p-77) when needed then stropped on pigs leather glued to wood. This method works amazingly well when following the My Chip Carving instructions. Carving gouges are usually stropped.

    That's about the extent of my sharpening except for knives.

    BTW, my honing/polishing of lathe tools might be a little different compared to what I read most people do. Most seem to use the tool directly from the grinder, not even removing the grinder burr. For one thing, those who turn bowls from green wood are happy with less since the wood cuts so easily compared to hard, dry woods. (Love ebony, lignum vitae, gidgee, dogwood, "iron wood", rock maple, etc) Another thing: a grinder burr is quickly knocked off on the lathe. (I disagree with working this way on principle. A clean cut with a polished edge on good wood needs very little sanding.) I like to turn a lot of smaller things with detail, using tools and techniques different than what's used for big bowls.

    acrylic_ornament_green_bell.jpg cedar_and_ebony2_IMG_7528.jpg Threaded_Ebony_Box3_comp_smaller.jpg

    BTW2, I don't really see the point of using CBN on the Tormek if diamond is available. But at high speeds CBN shines compared to diamond.

    JKJ

    Quote Originally Posted by Derek Cohen View Post
    John, do you do any honing after grinding, or is your grinding your final step? I imagine that you can get away with this on lathe chisels after a 1200 grit CBN wheel.

    As a predominantly hand tool user, I have always considered the Tormek as a grinder, and not a sharpener (Tormek view it as a sharpener because of the wheel strop). It is not advisable to end on 1200 grit. I finish on waterstones to 13000 or better. Consequently, when using the Tormek, I would keep the wheel at 220 grit and not re-dress it to 1000. What is the point of 1000 - it just grinds too slowly. 220 is slow as well on the Tormek.

    180 grit CBN at speed works quickly and leaves a better surface than the 220 grit Tormek. Even the 80 grit CBN off the bench grinder is pretty good. All will be honed on waterstones, so smoother is unnecessary.

    Regards from Perth

    Derek

  3. #18
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    In the "For what it's worth" department - this is the advice I received from WoddTurners Wonders on the subject -

    "Our advise is that if you have a means of rough shaping a tool, then buy a fine grit CBN like a 350 or 600. The finish on both will be far superior than you can ever get with a stone wheel. Later, you can augment with the 180 or even an 80 if you need to do a lot of material removal."

    Realizing that "grinding" is not my main objective here (though I did suggest the possibility in my 1st post) - I don't do rough shaping on tools but rather reconditioning edges that need more work than some bench stones can achieve. I do have chisels that get used in the field and get dinged by the odd hidden saboteur. These definitely could use some light grinding - otherwise I am looking to set up for edge maintenance on my edge tools. From the CBN to my bench stones and strop for sharp.

    If I were to buy just one wheel for now (and an 8" - 1/2 speed) - is the consensus that the 180 CBN is fine enough? 350 now with a 180 later, even better? I don't want to bother Ken with swapping out wheels that I regret buying. The price doesn't change with the higher grit so in this regards $$s is not a consideration - simply achieving the best results.

    Thanks again.

    Sam
    "... for when we become in heart completely poor, we at once are the treasurers & disbursers of enormous riches."
    WQJudge

  4. #19
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    Sam, John is discussing the CBN wheels he uses a turner, not as a flat woodworker. While his information is interesting and valuable, it serves to confuse the issues for a newby to CBN, such as yourself. If you are aiming for a single wheel, get the 180 grit. I use it 90% of the time, with a 80 grit the other 10%. At some stage I will get another grinder and add a 350 grit, but this will be for lathe chisels only. Most turners work from the grinder. Bench chisels and planes blades are finished on stones.

    Regards from Perth

    Derek

  5. #20
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    Quote Originally Posted by Derek Cohen View Post
    Sam, John is discussing the CBN wheels he uses a turner, not as a flat woodworker. While his information is interesting and valuable, it serves to confuse the issues for a newby to CBN, such as yourself. If you are aiming for a single wheel, get the 180 grit. I use it 90% of the time, with a 80 grit the other 10%. At some stage I will get another grinder and add a 350 grit, but this will be for lathe chisels only. Most turners work from the grinder. Bench chisels and planes blades are finished on stones.

    Regards from Perth

    Derek
    Thanks Derek - I admit to getting a bit of a burr on the matter.

    Sam
    "... for when we become in heart completely poor, we at once are the treasurers & disbursers of enormous riches."
    WQJudge

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