Help for decision

[Ken S]

Jeff,

You make a very good point about the real carrying issue being awkwardness. I don't think the problem is really a design fault. I just think the Tormek, like so many machines, was designed to be primarily stationary. It would be interesting to examine one of the original Tormeks, the model powered by an electric drill. At some point, the Tormek engineers must have decided that there were two markets for the Tormek. The European model was smaller, lighter, and more generally used for sharpening knives and scissors. The North American model was larger, heavier, and more marketed toward woodworkers. These two models cross functioned, but with different design parameters. In my opinion, the T4 is the first model to combine the best features of both.

At half the weight of the T7, the t4 is definitely easier to carry. However, like the T7, it is awkward to carry. The awkwardness is due to the weight of the grinding wheel. With the wheel removed, the T4 is a joy to carry. Without the wheel, it weighs almost nothing. More importantly, it has much better balance.

My solution for this would be a carrying case shaped like a bowling bag. The grinding wheel would be stored in a separate compartment directly below the Tormek. The Tormek and wheel would be securly stowed and the case would be balanced.

I would keep the case small. it could also hold the water trough, USB, a few essential jigs/accessiries and extention cord/LED light. My preference would be to carry these in a separate case. Carrying one case in each hand would balance the load. An arrangement with wheels and a handle might be nice.

My basic point is that leaving the grinding wheel mounted is what makes the Tormek awkward to carry. The new EZYlock shaft is a big help in carrying the Tormek.

Jan, your math skills are formidable. I have never used an electrical invertor, and have no idea of their wattage limits. For a really mobile operation, if the 120 watt T4 would work with an invertor, that could be a game changer. I enjoy your mathematical musings; they make me think.

Ken

[Jan]

Thank you Ken, for your kind words. 
You know, when you're able to describe something with mathematical formula, though very simple (+, -, x, /), you become master of the situation; you can discover something about the world around us.

I enjoy many of your aptly expressions; they expand my vocabulary.
For example mathematical "musings". I have found following explanation:



Jan

[jeffs55]

Ken,
The term design fault is incorrect as you maintain. It just was not designed to be moved around much like an anvil is not a mobile fixture.
Jan,
Thank you Jan for your input but I had a thought. You have determined that the T4 is more economical to run. In your thoughts did you take into consideration that the T4 will always have to run longer to do the same job as the T7? Based on C=πD the T7 wheel is 31.4 inches in D and the T4 is 26.69 inches in D. Based on the T7 being 10 inches and the T4 being 8.5 inches. The difference is 4.71 inches. The T4 wheel then is about 15% smaller in circumference than the T7.
You would therefore have to run the T4 15% longer to do the same job and so use 15% more electricity and take 15% more of your time. You are the math wizard so see if I am right. thanx

[Jan]

Yes Jeff, you are thinking logically correct! 

You have made only minor numerical mistake, assuming the diameter of T4 stone is 8.5". In fact it is only 8" and therefore the T4 wheel is even 20% smaller in circumference than the T7.

So, your numerically corrected conclusion may read "You would therefore have to run the T4 20% longer to do the same job and so use 20% more electricity and take 20% more of your time."

This would be true provided that the circumferential speeds of both stones are identical. But in fact T7 has 90 RPM while T4 has 120 RPM. For this reason the circumferential speed of a new T4 stone is by some 7% higher than the speed of a new T7 stone. [(120 RPM x ¶ x 8") / (90 RPM x ¶ x 10")]

For simplicity, I have ignored both issues mentioned above, in my previous calculations.

So, the corrected price of electricity consumed by T4 could be (60 + 20 - 7)% of the price for T7:

(0.60 + 0.20 - 0.07) x $8.7 = $6.35

My previous conclusion, that T4 is slightly more economical than T7, what concerns electricity consumption, remains valid.

Jan

[Ken S]

Mr Euclid of Alexandria might point out that the grinding wheel of the T7 revolves at 90 RPM and the grinding wheel of the T4 revolves at 120 RPM.......

Ken

[Ken S]

I do not want to confuse any of the readers. Jeff, like many on this forum, is quite experienced with his two vintage Tormeks. i happen to be more of a late comer to the Tormek, and have a more recent T7 and a T4. I am no stranger to older tools. I am happy as a clam with my grandfather's well tuned 1891 vintage Stanley jack plane. I would probably snap up a vintage Tormek at a very low price (in a heart beat) rationalizing that I would use it with the SJ or SB grinding wheel.

I happen to think a new Tormek user who is also inexperienced in sharpening is best served with a new machine. The learning curve is hard enough without having to contend with possible problems from an older machine. I believe the only bad choice in purchasing a Tormek is paying a lot for an older machine in need of a lot or repair. The newer shafts are stainless steel, even before the EZYlock shafts. The older, non stainless shafts were prone to rusting and freezing with the grinding wheels. Repairs are easily done by the user, however, a new grinding wheel and EZYlock shaft will cost around $250 USD. I have found most used Tormeks are overpriced when the cost of repair is added, compared to getting a new machine.

I happen to like the T4 because of its size and weight. I also have no criticisms of my T7, especially if I do not have to move it much. Personally, I would forget cost and go with whichever Tormek suits your work environment. Do not agonize over which one is the right choice. There is no wrong choice; either will work fine.

This forum would not be as enjoyable if everyone was thinking in lockstep.

Ken

[OnealWoodworking]

I happen to think a new Tormek user who is also inexperienced in sharpening is best served with a new machine. The learning curve is hard enough without having to contend with possible problems from an older machine.

Agree.

Would like to add that the newer kits also come with darn near everything that one would 'need' for regular and accurate stone maintenance and angle setting.

The Taiwanese versions do NOT include these sort of items last time I checked.