T4 CBN vs DWC 200mm

[jackjohnsonuk]

About 3 years ago I brought a Tormek T4 as I started Turning, I've learnt a lot about using it effectively, mainly but using it wrong in the beginning. I do like my Tormek and use it often for both Turning tools and other sharpening duties, having said that I do wish at the time I had waited till I had enough funds to buy a T8, but nevermind.

After a hard life, my SG200 wheel is starting to get down to 6(ish) inches so I think I need to consider replacing it shortly.  With my turning gouges causing dips in the wheel, which requires it to be re-dressed when moving back to sharpening flat blades, I do like the idea of a CBN or Diamond wheel just for my turning tools, and keeping my ageing SG200 until it finally dies for knives etc.

After some research on this site, I've found out the T2's wheels can fit on a T4 which was great news, however, I can't seem to find them for sale over here in England, I do however have easy access to CBN wheels, and reducer bushings.

Please, can someone give me the pros and cons of importing a DWC-200 vs using a readily available CBN wheel?

Thanks for your help

Jack

[Ken S]

Welcome to the forum, Jack.

You probably found my posts about using the DWF and DWC-200 diamond wheels with the T4. (Incidentally, they also work with the larger size Tormeks.) I am puzzled as to why Tormek has not promoted them for use with the T4; they are interchangeable. In fact, excluding the zinc tops and the T2 knife jig, the machines themselves are identical.

I have both Tormek 200mm diamond wheels, and really like them. Before they were available, I also purchased a D-Way 180 grit CBN wheel for my T4, which I also like. Between them, my first choice would be whichever was available.

I should add a few more details. CBN wheels have changed since I purchased mine. The D-Way steel still works fine. My preference with all wheels used on the Tormek is to use them wet. The steel reducing bushing and balancing holes of the D-Way will quickly rust if you don'y use an antioxidant. Honerite Gold works fine. I have not used Tormek ACC with my CBN wheels, however, I see no reason why it would not work.

I was originally told that the aluminum CBN wheels should not be used wet. I have since learned from a most reliable source that the problem was caused by careless use. CBN wheels should be used with an antioxidant and carefully dried after use. Tormek recommends that the DWF and DWC-200 diamond wheels only be used dry. I don't know if this is based on actual testing or second hand information. I think it is the latter, however, that is just a gut feeling.

CBN wheels are now available in more grits. I have both 80 and 180 in the 250mm size. I chose 180 as a balanced approach for my T4. If you do a lot of reshaping, the Norton 3X eight inch wheels work well with the T4. For my tests, I purchased both the 80 and 46 grit wheels. Either makes a good coarse wheel, although, my first choice would be the 46 grit wheel. I found it cuts about 20% faster than the 80 grit. Both cut faster than CBN or diamond. A 3X 46 grit wheel makes the T4 like the original Mini Cooper S! As Alan Holtham might say, the 3X wheels are a bit "fiddly" to fit on a Tormek. At $50 US, they have a lot of firepower for a small amount of money.

Go with whatever wheel is available and please post your thoughts.

Ken

PS The thirty minute rest period nonsense goes back to when the all plastic T3 housing retained heat. The redesigned zinc housing of the T4 acts like a radiator. You will need a rest long before your T4 does.

[jackjohnsonuk]

Ken,

Thank you for your very concise response, I feel much more comfortable now with moving over to a CBN wheel, despite all the naysayers on the woodturning facebook group chiming about "buying a proper grinder to run a CBN". 

After my post, I found I can source the DWC-200 direct from Tormek, although this option is a little hidden away in their webstore, and at £20 difference between a CBN and the DWC-200 price is negligible.

Currently, I am leaning towards an 8" CBN wheel, simply for the reason of if I decide I need to go back to an SG full time on the Tormek for my flat tools then I can just move the CBN wheel over to a dedicated machine; I have a feeling the DWC-200 would not fair well being used at the faster speed of a grinder.

Also thanks for your note on the thirty minute rest period, I also assumed that would be a red herring.  My problem with the T4 as a machine, and my note about wishing I'd brought the T-8, is it seems to be viewed by Tormek as the "poor cousin", and as such, they seem to be purposefully holding back on some top-tier products/wheels i.e. the SB and diamond stones.  In reality, it's a clever marking ploy, however, in my view it just makes me feel a little dismissed.  I love there jigs and am extremely happy with my machine, but I'm disappointed that the T4 seems to get very little love.

Thanks for your advice

Jack

[jackjohnsonuk]

Ken,

I did indeed take the plunge, albeit after having the owner of the shop I brought the wheel from doing everything in his power to not let me buy it, as "it simply won't work, and is a stupid idea" according to him.

I am now the proud owner of a 360 grit CBN wheel.  The bushings I brought previously when I was toying with this idea were too long for the wheel I got, which despite being 40mm wide was only 30mm at the bore, so I had to make some extra bushings out of old chopping board (HDPE) which works extremely well to take up the slack space.

All is working well and after an initial test on two or three Bowl Gouges, I'm extremely impressed.  They are cutting fast, as expected when straight out of the pack, and I haven't tried them wet yet, but so far I'm very happy indeed!  The finish on the tool felt perfectly sharp, more so than my SG-200, even when dressed, and cut beautifully.  The scratch marks were very visible, but that's not something that comes into my mind as a concern when woodturning tools, and I imagine this will lessen both with the wheel wearing in, and trialling water on the wheel.

I have some Honerite Gold to try them wet with, do you also have to wipe the wheel down after use it, or do you just drop the trough? 

Something else that's been on my mind is I have some of my grandfather's tools which would be carbon steel based on their age, I have read this can clog or ruin a CBN wheel, is this a real thing I need to be aware of?

Many Thanks

JAck

[Ken S]

Jack,

I grind high carbon Irwin Blue Chip chisels for tests with no negative consequences. I recommend the videos of D-Way tools. Whether or not you use their wheels, the videos have good information.


I have found that most tool people think in terms of high speed (including half speed) dry grinding. They mean well, however, it is a different working environment. Tormek stands out as the only company which really understands slow speed wet grinding.

I remove and wipe down my diamond wheels after use, although it msy not be all that important. One evening I was not feeling well and just lowered the tray, planning to return the next day. I spent most of the next  week in hospital and did not return  to my shop for two or three weeks. The wheel was fine. The water with ACC had evaporated. A good wipe with a paper towel and a quick wash with Dawn dishwashing detergent restored the status quo.

Sadly, I agree that the T4 is seen as the poor cousin. We are still thinking in 1960 terms, when the Ford Falcon was a "compact car", the poor cousins of the day. The Falcon is probably larger than today's Lincolns and Mercedes. I remember early T4 posts where the customers thought of the T4 as a starter Tormek, and planned  to move up to a T7. I don't recall any posts where anyone actually switched. Tormek's two diamond wheels allegedly for only the T2 work very well with the T4. The eight inch diameter Norton 3X wheels (46 and 80 grit), the most effective coarse grinding wheels I am aware of, work very well with the T4. So do felt wheels. The flexibility is there; sometimes you just have to go beyond Tormek wheels.

Do keep us posted with your progress.

Ken