T-4 vs T-8 BESS sharpness?

[Antz]

Good morning everyone,
I thought this might be an interesting topic maybe for people who are deciding between T-4 and T-8. Has anyone ever sharpened two identical knives, one on T-4 and one on T-8 and compared BESS sharpness scores? I'm just wondering if there is a significant difference between scores. I don't have a sharpness tester so maybe someone out there has either done this test or has some insight into the topic.

Thanks,
Antz

[RichColvin]

I can't imagine how there would be a difference.

[Ken S]

Antz,

You ask an interesting question. My opinion of the real differences between the T4 and the T8 should be well known by now. For me, the actual work and working conditions are the deciding factors. Minor differences in cost and potential small differences in BESS numbers don't factor in with me.

The improvements in edge longevity, which I consider more important than fleeting initial sharpness, are derived from careful deburring, not grinding. For me, the key factor in BESS is the skill and dedication of the sharpener, not the diameter of the grinding wheel.

Ken

[John_B]

In addition to what Ken said I think adherence to a procedure that is known to produce exceptionally sharp knives is key. Being able to always repeat this process and achieve the same results is the true demonstration of your skill. While there may be small differences in the concavity of the grind due to wheel size I doubt that it is much of a factor in final sharpness.

[Antz]

In addition to what Ken said I think adherence to a procedure that is known to produce exceptionally sharp knives is key. Being able to always repeat this process and achieve the same results is the true demonstration of your skill. While there may be small differences in the concavity of the grind due to wheel size I doubt that it is much of a factor in final sharpness.

John, that's exactly what I wasn't getting at, I know there would be a small difference in concavity but I think you and Ken are correct that in that the initial sharpness would be the same if you follow a strict deburring process and properly apex the edge.

I just think it's interesting that if you primarily sharpen knives you could use either machine and get the same results, and one is half the price as the other. Only draw backs would be the t-4 is only rated for 30 mins continuous use, which wouldn't work for me. I usually do 5+ knives at a time on my t-8 and run it longer than 30mins. Most I did consecutively was 17 knives straight without stopping (about 3 hours continuous use) but for home use where only knives are concerned I think a t-4 would be the more economical choice. Thanks for your responses.

Antz

[Ken S]

I agree with John about the importance of carefully following good procedure. Watch the videos by Sharpco and KnifeGrinders. There is no "rock n' roll". There is solid, well crafted technique.
Which Tormek will produce the best BESS numbers? Answer: Whichever Wootz or Sharpco happens to be using.

I wish someone would finally end the 30 minute myth with the T4. The thirty minute limit was a hangeron from the all plastic housing of the T3. The design of the all plastic T3 housing retained motor heat. As a result, there could be a problem with the housing melting. This caused shaft alignment problems. This problem was corrected with the machined zinc top of the T4. The zinc top increased the machine's precision and acts like a radiator to disperse the heat. END OF PROBLEM!

Ken

[Antz]

Good to know Ken. I never heard that before. I thought it states on the tormek website itself that the t-4 was only rated for 30 minutes. But if it can be run continuous then shoot I might have to pick me up one. I'm planning on starting to do some farmers markets and maybe the t-4 would be a better portable option along with 8 inch paper wheels.

Thanks,
Antz

[Ken S]

You are correct, Antz; the handbook does state that. Normally I regard the handbook highly. In this case, I am skeptical.

I would do considerably more sharpening before comtemplating purchasing a second machine.

Ken

[Elden]

I fully understand what you are saying Ken. I have read the post about Steve Bottorff running his T-4 continually for a few hours and you monitoring the heat level. I know you probably have extensively used yours beyond the 30 minute rule.

However, here a couple of quotes straight from Tormek's website in their T-4 section. The first is from the general information, the second is from the specifications. They are copied from Tormek's web page and pasted below.

"The motor is rated for 30-minutes continuous use at a time. That is usually more than enough for the house need, but if you sharpen more we advise you to take a look at one of the larger Tormek machine models which can run continuously."


"Motor: Industrial single phase, 120 W (input)
230 V, 50 Hz or 115 V, 60 Hz. Duty 30 min/hour, Maintenance free.
Silent running, 54 dB. 10,000 hour life
Warranty: 7 years*

*When used for commercial, industrial or educational purpose the T-4 warranty is 2 years."


From these quotes, I feel one should realize that the warranty is not the same as the T-8.

The T-8 specifications state the following quote. This again is copied and pasted from the Tormek website.

"Motor: Industrial single phase, 200 W (input)
230 V, 50 Hz or 115 V, 60 Hz. Continuous duty, Maintenance free.
Silent running, 54 dB. 25,000 hour life
Warranty: 7 years*

* Including professional use."


I am not contending with Ken. But be aware that warranty for the T-4 is only good for 2 years if used beyond "house need". The expected "hour life", also is substantially different. Personally, I would never begin to approach to the 10,000 hour expected life of the T-4.

Has anyone contacted Tormek support with this this ongoing debate?


P.S. : This was being typed before Ken made the post immediately above this one. 😊

[Ken S]

Elden,
You have correctly quoted the handbook. If we follow this to its logical conclusion, the "best" Tormek would certainly be the T7, which came with a ten year warranty (seven years plus three years) Does that make the T7 almost 50% "better" than the T8? Not in my book . I own and like both. My favorite is whichever one is ready to go.
Frankly, I don't think the numbers really mean anything to most of us. Elden, I assume you are still using your SuperGrind. Steve Bottorff was using his SuperGrind week in and week out. The T4 was introduced in 2014. How many members have posted complaints about wearing out their T4s? I do not remember any.
There are situations where a larger Tormek seems the logical choice. Anyone regularly sharpening planer blades full time should certainly have a larger Tormek. Anyone regularly sharpening more than a hundred knives every week, is a very active turner, or will wear out a grinding wheel every year would be better suited with a larger Tormek. I do not see any advantage in having a larger Tormek for the average user who sharpens chisels, hand planes, and knives.
I leave your choice to you all.

Ken

[Antz]

So I decided to get a t-4 in addition to my t8. I wanted a more portable option for going mobile as the t8 is deceptively heavy, especially with the wheel saturated with water.

I received it yesterday and set it up. I ordered it from amazon and when I opened the box I realized they had packed the tormek t4 UPSIDE DOWN the whole time during shipping (Tormek Box was upside down in amazon box and shipped). I was worried something would be wrong but after setting it up it ran just fine to my relief. Only issue was the SG200 wheel was severely out of round. I had to true off about 3mm to get it flat and true.

First thing I noticed was the considerable weight difference, it's so much lighter than a t8 and I love  the compact size. Also with the smaller wheel I don't end up wetting my shirt leaning over the machine. It had plenty of power to do knives (primarily what I do) doesn't bog down at all. I sharpened 3 knives on it, one being a super thick SOG survival knife that needed to be completely rebeveled. It worked like a champ. I had no problems on the skinnier t4 grinding wheel. It performed and did the job just as fast as my t8 would have.

My honest opinion now that I own both a t8 and a t4 is you can't go wrong with either one. I literally  LOVE my new t4. It's just such a more convenient size and perfect for knife sharpening. I ran it for about an hour continuously and it never felt any hotter than my t8 runs (so much for the 30min duty time). Honestly I can actually see myself using the t4 more often than the t8. I am VERY pleased with the t4. If anyone is just focused on sharpening knives of a reasonable volume (15 or so a day) I would definitely recommend saving some money and buying a t4. There is no way you will be disappointed. Now if you have higher volume of knives or lots of turning tools and planer blades I would definitely get the t8.

Hope this post will be helpful advice to anyone deciding between the two.

Antz

[Ken S]

Antz,

You are now a multiple Tormek owner, a growing group. I believe you will find yourself gravitating toward whichever Tormek seems best suited for your immediate task at hand.

Fifteen knives a day? I do not disagree in general with the preference for the larger Tormek for higher volume, more industrial applications. However, when Steve Bottorff, a longtime SuperGrind professional, hiked into his set up location at a Boy Scout Jamboree packing his T4, I cannot imagine him stopping at fifteen knives!

I totally agree that you can't go wrong with either model, although, in some cases, one or the other may seem better suited.

Someone on the forum posted the idea of bringing his Tormek with him when dining at friends' homes. The idea was to sharpen the cook's knives as a thank you present. Great idea; I wish I had thought of it! It inspired me to look for an inexpensive, practical way to carry a T4. My solution is a single ball size bowling ball bag. I purchased mine at a local sporting goods shop for $32 US. It easily holds my T4 and everything I might need. It has both a hand grip and a shoulder strap. It is quite comfortable to carry, even for an old guy like me.

I remove the SG-200 and place it in its original box. (Do not forget the spacer to prevent the shaft from sliding. The boxed grinding wheel sits on the bottom of the bag and provides a stable base for transporting the T4. Store the grinding wheel in a gallon size plastic storage bag or plastic wrap to keep the cardboard box from getting wet. A cardboard or plastic box will protect the plastic water trough, stone grader, black marker, and honing compound. Pack the necessary knife jigs, scissors jig, TT-50, and homemade small platform. I would include at least one kenjig and an anglemaster. Bring at least one towel to protect the T4 in transit and the table while sharpening as well as a piece of plastic to keep the work surface dry. Don't forget an extension cord and some paper towels.

If carefully wrapped, there is plenty of room for a bottle of wine.

You may soon have plenty of dinner invitations.

Don't forget to continue posting.

Ken

PS My bowling ball bag is black with a Brunswick logo. I have suggested that Tormek have some made up in blue and gold, with the Tormek logo. (Blue and gold are the Swedish national colors going back to King Magnus III in 1325, as well as the Tormek logo.)

[Ken S]

Antz,

I have reservations about sharing this information with you, for fear that you will purchase more stuff. However, relying on your good character to refrain from reaching for your wallet, I will share this:

With the water trough from the T4, a ten inch diameter felt or paper wheel will work with the T4. This means that it is possible to sharpen a knife with the ten inch (250mm) diameter grinding wheel of the T8, and then use a felt or paper wheel of the same diameter mounted on the T4 for deburring. (Caveat, I have not tried this yet. It is on my already too long list of Tormek projects.)

As I stated, file this with "future possible" for your future reference.

Ken

[Antz]

Ken,

Very interesting about possibly using a 10 inch paper or felt wheel on the t4. Did you mean "without" the water trough? I will most definitely file that under my future projects list as well (it'll probably be a while as my wife is on my case for purchasing the tormeks...). But I've been doing pretty well business wise considering it's just a part time venture. I've almost made half my money back towards the cost of the equipment. About the 15 knives a day, I'm sure the t4 is more than capable of exceeding that number by a lot. I can't really describe how satisfied I am with it, it's such a great portable machine.

Antz

[dusmif]

One of the many reasons I bought the T8 and not the T4 was the 30 min restriction on continues use, reasoning that if the factory pointed this out, it must be important, secondly the difference in price was so minimal that I thought I buy the bigger one, it must have more advantage's  than the T4 for sure. That is what I thought and I do not regret that I did because I found out that I have to reshaping all my chisels and plane blade from scratch, because they are so in bad state that it is taking me hours to bring them in shape again, but I am enjoying myself.