Page 1 of 2 12 LastLast
Results 1 to 15 of 28
  1. #1
    Join Date
    Jul 2006
    Location
    Mooroolbark
    Posts
    520

    Default CBN, Tormek or both

    I see a lot of woodturners sharpening their gouges and other turning tools on CBN wheels and pondered whether this or a Tormek gave the best edge.... Or does one use a CBN wheel to reshape or remove dings from the cutting edge and then go to the Tormek for a final sharpen?

    Maybe that would be an overkill but I'm interested in peoples thoughts on one, the other or using both.

    Thanks Peter

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Posts
    Many





     
  3. #2
    Join Date
    Jun 2005
    Location
    Helensburgh
    Posts
    7,696

    Default

    If you don't want to fall asleep when sharpening then avoid the Tormek and use a CBN wheel on a bench grinder which will do the same job in about the tenth of the time. The Tormek does a very good job but oh so slow.
    CHRIS

  4. #3
    Join Date
    Oct 2019
    Location
    Brisbane, Australia
    Age
    43
    Posts
    519

    Default

    G'day woodtryer

    There is a lot of literature around on the subject.

    I doubt too many rely go from a CBN wheel to a Tormek. Both are too coarse for honing, as opposed to establishing profiles/bevels before honing an edge.

    And more importantly to go from a CBN wheel to Tormek you would need to have your sharpening jig or holder identical for both setups so that you are hitting the same geometry on successive wheels.

    That is a huge pain.

  5. #4
    Join Date
    Feb 2016
    Location
    Perth WA Australia
    Posts
    828

    Default

    Hi Woodtryer,

    I have a CBN and a whetstone grinder (not tormek). Both have their pros and cons.

    CBN is without doubt faster, but the biggest drawback is the lack of dust suppression. A con of it being fast is it's also easy to take too much off.

    Whetstone grinders are slow, but that is also the beauty of it. It allows grinds cooler, has perfect dust suppression and allows the user to have full control of the grind.

    I use the CBN to initially sharpen the tool or when I want to reshape the tool. Once i get the profile I'm after I only use the whetstone grinder. Which means the CBN wheel isn't used a whole lot these days.

    Do you need both? Definitely not, if I were to choose one, im going to disagree with others and go with the whetstone. Yes takes longer, but that's only an issue when you don't sharpen regularly or when you have a new chisel.

  6. #5
    Join Date
    Apr 2001
    Location
    Perth
    Posts
    10,810

    Default

    Hi Peter

    I recently sold my Tormek. It had been unused for about 5 years. The Tormek is not a sharpening system; it is a 220 grit grinder. As a grinder it is bloody slow. Definitely a method for the masochist or the timid. Adding a CBN wheel to the Tormek misses the point - it is not going to grind faster. What I do like about the Tormek is the blade guide. It offers repeatability and precision in an easy package.

    The CBN wheels are amazing. They are either made of steel or aluminium, and act like a heat sink. The end result is a cool grind. The other advantage over all other wheel types is that they do not wear out. This means that the surface never needs truing or settings need adjusting. Set once and you are done.

    I have been using mainly a 180 grit CBN on a half-speed 8" grinder. I have a 80 grit on the other side for serious grinding/blade restoration work. The 180 is all one needs.

    Dust is not an issue. Yes, there is some dust, but it comes off the steel and not off the wheel. It is heavy and does not float in the air. It falls down. Vacuum it up.

    Use the grinder with the Tormek BGM-100 tool rests. Best of both worlds.

    I began using the CBN wheels with plane blades and bench chisels before anyone else, and I was so excited at this find (which many turners had discovered many years before this!), that I began telling the world. It just took off. Thousands cannot be wrong.

    My original review: http://www.inthewoodshop.com/Woodwor...ningSetUp.html

    Regards from Perth

    Derek
    Visit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.

  7. #6
    Join Date
    Sep 2010
    Location
    Port Sorell, Tasmania
    Posts
    592

    Default

    G'day Peter
    I have both and use both, the Tormek I got about 20 years ago long before I started turning and a half speed grinder with CBN wheels (80&180grit) (as per Derek's photo above) that I got about 3 years ago. As others have said they both have their place. With gouges I grind a primary bevel with the half speed grinder then use the Tormek to sharpen a secondary bevel. I can get quite a few quick resharpens on the Tormek before having to go back to the half speed. I put a 1200 grit CBN wheel on the Tormek several years ago when the stone wheel needed replacing and anything other than touching up secondary bevels is exceedingly slow. It takes a quick pass to sharpen the secondary bevel in the order of 15 seconds.
    You definitely dont need both and if I was starting out I would get a double end grinder, regular speed, with 80 and probably 320 or 600 grit CBN wheels.
    Which ever way you go Tormek have an excellent range of jigs that would be worth considering.
    You can't use up creativity. The more you use, the more you have. ~Oscar Wilde

  8. #7
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,757

    Default

    This chart is from https://graffdiamond.com/files/commo...tes-013522.pdf

    Once it get you head around it chart you will see it shows that the most efficient removal of stock using a Dry CBN wheel on an 8" grinder is between 1450 and 2850 rpm. the lower speed will produce slower grinding but with more control and VV.

    If you go below this range the grinding rate becomes relatively inefficient - a potential problem is then that the slow rate of grind may lead to operators pushing harder which may damage the wheel.

    If wet grinding is used even higher speed are recommended.
    CBN.jpg

    FWIW I have my two 8" CBN wheels on a variable speed (up to 3600 rpm) grinder but run these wheels at ~2850 rpm.

    The older (6 years old) 180g CBN wheel is nowhere near as efficient as when I first got it, probably because I have also used it to grind hard Crobalt bits for my MW lathe.

    The older wheel still works but now behaves more like a higher (240-320) grit wheel which is why I bought another 180g wheel.

  9. #8
    Join Date
    Apr 2001
    Location
    Perth
    Posts
    10,810

    Default

    I need to qualify my earlier post and add that my choice if grit is for a hand plane blades and bench chisels, not lathe chisels. Tony’s selection is a better selection for the latter. My turning is largely limited to spindles, and my experience here over the years reinforces the preference of a bench grinder over a Tormek.

    Regards from Perth

    Derek
    Visit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.

  10. #9
    Join Date
    Jul 2006
    Location
    Mooroolbark
    Posts
    520

    Default

    I've just been reading all your very informative relpies. I guess something I was not thinking about was the issue of matching the two setups perfectly if i thought that going from CBN to Tormek was an option. This however doesn't seem to be of any advantage unless as Tonzeyd said you are using the Tormek for a more controlled resharpen.

    My knowledge on CBN is obviously well out of date as i believed that 240grt was about as good as they got but tony_A is running a 1200grt, well above what i thought was the finest available.

    Derek, one question i have is that you said the Tormek is only 220grt but tbey say you can "condition" the stone to 1000grt ??? Is that not correct?

    Everyone has given me plenty to think about and i am curious to hear about this so called "conditioning" of the Tormek stone.

    Thanks for all your feedback.

    Peter

  11. #10
    Join Date
    Apr 2001
    Location
    Perth
    Posts
    10,810

    Default

    Derek, one question i have is that you said the Tormek is only 220grt but tbey say you can "condition" the stone to 1000grt ??? Is that not correct?
    Peter, that is "correct". Take it with a pinch of salt.

    What I mean is that 220 grit grinds a blade, but 1000 grit does not do a whole lot more than this. When I use waterstones to sharpen a blade, I start with 1000 grit - it is at the low end of the ladder.

    Frankly, I think that one should call a spade as spade - the Tormek is a grinder and, as such, I would rather grind at 220 grit than 1000 grit ... what is the point of the latter? It's a bit of this and a bit of that, and not much of anything.

    Regards from Perth

    Derek
    Visit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.

  12. #11
    Join Date
    Feb 2015
    Location
    Hobart
    Age
    77
    Posts
    647

    Default

    Thank you all for this very informative discussion!

    I raised the question of grinder speed selection in another thread a few months ago and I am still unsure about what to do. I have a full speed grinder and I read that a 180 grit CBN will be quite aggressive at 2850 RPM then, when the wheel settles, it will be less so. And, knowing this, to be more "careful" when grinding with a new wheel.

    I would consider the purchase of a half-speed machine but, if it is not essential, could use the funds towards the cost of CBN wheels.

    I feel like I am sitting on the proverbial fence, unable (unwilling?) to make the decision!!

    All opinions, suggestions and/or advice will be gratefully received!!!

    Cheers Yvan

  13. #12
    Join Date
    Sep 2010
    Location
    Port Sorell, Tasmania
    Posts
    592

    Default

    As the OP's initial question was framed in the context of sharpening bowl gouges and other wood turning tools you need to be clear on what you want to achieve. For a bowl gouge I like a primary bevel at about 35 degrees then a secondary of 45deg. This allows the gouge to transition around the inside of a bowl while still riding on the bevel at the cutting edge of the tool. With just a primary bevel the gouge starts to ride on its heel on sharper concave curves. Some professional turners advocate removing even more of the heel on a gouge with what is effectively a tertiary bevel.
    With a secondary bevel on by gouge which may only be 1mm wide the 1200 grit Tormek is perfect for sharpening it. It only requires a light touch to sharpen, not much more than a hone. Having a fine wheel for this leaves a better edge than a coarse wheel and gives much more control over the rate of steel removal on a fine secondary bevel. Having said that I couldn't justify buying a Tormek just for this but as I already have one Ill keep sharpening this way.
    Sharpening regular woodworking tools is a different proposition and I rarely use the Tormek for that.
    You can't use up creativity. The more you use, the more you have. ~Oscar Wilde

  14. #13
    Join Date
    Feb 2016
    Location
    Perth WA Australia
    Posts
    828

    Default

    Replicating the setups on both grinders is easy, especially if you go with the tormek jigs. The BGM-100 bench grinder kit is all you need plus is a good idea anyway as the stock tool rest on most grinders isn't very useful. If you then get the gouge jig (SVD-185) it comes with a tool rest setting jig which you physically can't make it simpler to setup. The jig accounts for differences in wheel sizes so automatically adjusts as your whetstone grinder wheel decreases in size. Yes this adds up, but imo worth it. I'm sure if you're a professional turner who sharpens everything by hand you'll disagree, but im not. So id rather enjoy turning rather then focus on sharpening.

    I'm the same as Tony_A, couldn't justify the Tormek, just for gouges so i went for the cheaper route and ended up with the Scheppach. Compared to the Tormek, its rough as guts. Came close to junking it, as no matter what i did to it, couldn't get the wheel to run true. However it takes the Tormek jigs, and for turning tools the slight elliptical wheel rotation doesn't seem to cause any dramas. Wouldn't touch a bench chisel/plane blade with it though, unless you want a slight skew in your tools.

    To justify the Tormek, you really need to be invested into the model, ie buying the jigs, sharpening loads of different tools. As the Tormek grinder is a do it all solution, and like most things that are one size fits all, it'll do some things well and other things ok. If thats what you're after or if money is no concern, getting the tormek will be a good buy.

    To answer your question yvan, i have 180grit wheel on a full speed bench grinder, yep aggresive as when its brand new, but once you sharpen a few tools it settles down and its a very nice wheel to grind on, fairly quiet, cuts cool and leaves a fairly nice finish. Your tools are sharp after coming off the wheel, but you'll want to take it further as when you experience a chisel/gouge that is truely sharp you'll never go back, its a game changer.

  15. #14
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,757

    Default

    Quote Originally Posted by yvan View Post
    Thank you all for this very informative discussion!

    I raised the question of grinder speed selection in another thread a few months ago and I am still unsure about what to do. I have a full speed grinder and I read that a 180 grit CBN will be quite aggressive at 2850 RPM then, when the wheel settles, it will be less so. And, knowing this, to be more "careful" when grinding with a new wheel.

    I would consider the purchase of a half-speed machine but, if it is not essential, could use the funds towards the cost of CBN wheels.
    I don't think its essential. Even though I could run my grinder at slower speeds I rarely use the CBNs at these speeds and nearly always use 2850 rpm. It takes a little getting used when the wheel is new but it's no big deal.

  16. #15
    Join Date
    Nov 2012
    Location
    SE Melb
    Age
    64
    Posts
    1,277

    Default

    Quote Originally Posted by woodtryer View Post
    I've just been reading all your very informative relpies. I guess something I was not thinking about was the issue of matching the two setups perfectly if i thought that going from CBN to Tormek was an option. This however doesn't seem to be of any advantage unless as Tonzeyd said you are using the Tormek for a more controlled resharpen.
    My own setup consists of both half-speed grinder and tormek. In fact, I like Tormek so much that I bought my 2nd one recently. I use 220 grit on the half speed to reshape my tools, and then I move to the Tormek fitted with a 1200 wheel to hone the bevel to an edge accurately. I then move the 2nd Tormek to give the edge a good polish.

    I have setup the half-speed grinder with the Tormek BGM-100 universal support, and I took the time to line up the universal suport bar to be exactly parallel to the circumferential surface of the grinding wheel. In this way, I only have to setup the jig once and they are used in both the half speed grinder and the Tormek. The bevel ground by the half speed can be matched easily by the 1st Tormek and then the 2nd Tormek.

    On the 1st Tormek I have a 1200 grit wheel, It only takes seconds to match the bevel ground by the half-speed grinder and another minute or so to hone the bevel to a fine edge. One can then use the honing paste and the leather wheel afte that to do the next step, which is to polish the bevel and the edge and establish a micro secondary bevel. You can hone the inside of the gouges on the profile leather wheel as well.

    I however added an extra step. I installed a 4000 g Japanese water stone on my 2nd Tormek and all I do is to move over to the 2nd Tormek after I finish with the 1200 g wheel, using the same jig and bar height and make a few passes on the water stone. I have a shiny bevel with a very keen and sharp edge on my gouges, in fact on all my tools.

    The half-speed grinder is excellent at removing material quickly at 220 grid but it leaves the edge jagged. The resultant edge is not very sharp and your gouges don't cut very well on the lathe and the finish from them quite rough. The advantages of using the Tormek are that:
    1. you can use the many available jigs to hone to the exact original profile of your turning tools.
    2. you can polish the inside of the gouges.
    3. No dusts or overheating issues.

    Without a Tormek, one would either have to hone and polish by hand with curve stones or something (is there any curved 4000g+ water stones?) or leave the edge with a rough finish.

    There are potentially CBN wheels that are 1000g plus. But in Australia they are only available for a 250mm grinder or a Tormek sharpening system. In the US, I understand you can buy 1000g CBN wheel for a 200 mm grinder, which will improve the edge finish with the half speed grinder.

    In my own experience, half-speed grinders and Tormek systems are complementary to each other, rather than a competition between each other. When one complains that a Tormek is slow, they are comparing apple with oranges. When one insists that Tormek is a grinder, not a sharpening system, they are not making full use of Tormek's capability. I initially listened to those argument and I used it as a grinder and felt disappointed. As a grinder, Tormek of course is very slow, turning at 90 rpm. In fact, the physics of a 250mm running at 90 rpm will have the same surface speed of a 200mm grinder running at 112.5 rpm. Comparing to half-speed grinder, a 90 rpm 250 grinder will be expected to be 10 times slower than a 200 mm grinder running at 1450 rpm. Physics tell us that.

    But people don't finish their sharpening after they stop at the half speed grinder. They usually go on to hone their tools by hand. It is the honing part of sharpening that a valid comparision can be made:
    1. When you don't count setting up the jig, honing on a Tormek at 90 rpm is definitely faster than honing by hand.
    2. Honing a gouge by hand to a genuinely sharp edge would be even slower and a nice profile would be hard to achieve.
    3. While setting up the jig consumes extra time, but they are still used by a lot of people using a half speed grinder because they allow better precision. If you are already using the BGM-100 for the half-speed, moving it to a Tormek would be so much faster than taking the jig off so that you can hone it by hand.
    4. I can get a razor sharp edge on a gouge with micro secondary bevel with my SJ-4000 water stone with minimal effort.


    My conclusion is that using Tormek merely as a grinder will lead to disappointment because physics should have told them not to do that. But Tormek is a excellent honing system, especially on turning tools. BTW I sharpen all my tools with Tormek - knives, secateurs, plane irons, chisels, turning tools (I am only a beginner at turning). It can grind at a stretch, but its not good at it. However it makes an excellent complement to a half speed grinder.

Page 1 of 2 12 LastLast

Similar Threads

  1. VICTORIA Tormek SVD 185
    By greyhound in forum WOODWORK - Tools & Machinery
    Replies: 3
    Last Post: 2nd December 2018, 10:26 AM
  2. CBN on a Tormek?
    By Phily in forum WOODTURNING - GENERAL
    Replies: 17
    Last Post: 2nd August 2016, 08:17 PM
  3. Which Tormek ?
    By woodtryer in forum SHARPENING
    Replies: 3
    Last Post: 1st February 2014, 09:14 PM
  4. CBN on a Tormek
    By Scott in forum WOODTURNING - GENERAL
    Replies: 0
    Last Post: 28th September 2013, 11:14 PM
  5. Tormek v jet
    By kmthor in forum SHARPENING
    Replies: 5
    Last Post: 20th May 2008, 05:08 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •