Tightening the stone on a T-7

[Timberwright]

I purchased a used T-7 at a good price a couple of years ago.  As the T-7 came out of its box without a stone attached, I tried tightening the grey stone, to no avail (it would simply slip when any meaningful pressure was applied).  I keep pretty busy, so I chalked it up to a bad used tool purchase ... and while the Tormek has been collecting dust, our sharpening guy has been smiling.

After doing a search on this forum, I've come to find out that my assessment of the T-7 may have been erroneous and that, in fact, there may be a way for me to tighten the stone properly. 

Before I man-handle and break anything, however, I thought I'd ask the forum for the definitive T-7 stone tightening method. 

- Are you supposed to hold onto the stone while you tighten the nut? 

- Is there a torque specified for tightening the nut? 

Any and all constructive posts will be much appreciated.

Thanks very much for your time ...     

[Herman Trivilino]

The newer models have a self-tightening "nut". If you have the older model with a hex nut you will need to use a wrench to tighten it. I don't know the torque specs, but just use my judgement to get it tight enough so that it doesn't slip.

Alternatively, you could upgrade the main shaft so that you have the features of the newer models:

http://tormek.com/international/en/spare-parts/shafts/msk-250-stainless-steel-shaft/

[Ken S]

Welcome to the forum, Roy.

There should be a thick washer between the grinding wheel and the shoulder of the shaft. If that is missing, you will not be able to tighten the wheel until you replace it.

You will need to determine if your shaft is the regular shaft or the newer EZYLock shaft. My 2009 vintage T7 had a (stainless steel) regular shaft) with a hex nut and right hand thread. My present 2012 vintage T7 has the EZYLock shaft with left hand thread and a round nut. You don't have to tighten it. You can pull the grinding wheel toward you with the grinding wheel on the right side of the frame if you wish. The rotation of the motor keeps it tight.

Be sure to watch Alan Hotham's review video of the EZYlock shaft on the tormek.com website.

My other question for you is: Does the grinding wheel slip on the shaft or does the motor appear to slip? If the drive itself is slipping, there is an easy fix. Unscrew the plastic knob which holds the leather honing wheel in place. Remove the honing wheel. Remove the drive wheel which is located just beneath the leather honing wheel.There is a smaller rubber shaft which rubs against the drive wheel. Rough up the surface just a bit to give the drive wheel better traction. This is routine maintenance.

Did you get a bill of sale when you purchased your Tormek? If so, you should register your unit with TormekAB in Sweden. There are at least three good reasons to do this:
1) to keep the warranty active. This is very rarely a problem

2) to download the latest version of the handbook, which will change frequently

3) (This happened to me.) Should your tormek be stolen and you do not know the serial number, you can email Tormek in Sweden. They will promptly email you your serial number. I needed this for the police report. Someone now has a T7 with no jigs and no water trough......It is a terrible dry grinder!

If you are still having problems, by all means, post again. If this solves your problem, post, also. Another available resource is support.tormek.se  That's the support email address in Sweden. They are good at answering promptly.

best of luck,

Ken

[Jan]

- Is there a torque specified for tightening the nut? 

For T7 with 250 mm (10") grindstone, the recommended torque is 14.7 Nm.
Be careful when your torque wrench is calibrated in Imperial units.
1 newton metre ≈ 0.738 pound-feet.

Jan

[Ken S]

Jan, I'm impressed. We are not so precise in the US. We normally just give the wrench a tap with a hammer.

Ken

[Jan]

It is interesting, Ken, that for the smaller grindstone 200×40 mm (8"×1 5/8") the recommended torque drops to 8.4 Nm. So please tap your T4 more gently, if necessary at all. 

Jan

[Ken S]

Jan,

I can not locate anything about mounting torque in the handbook. The pamphlet on mounting the stones shows a picture of hitting the wrench with a hammer for "Older machines with conventional locking". All T4 machines and the newer version of the R7 have the EZYLock shaft.

I think using torque is a far better method than using the hammer. It would appear that both methods work. In my opinion, the EZYLock is a more efficient method, especially if one takes the time to learn which way to unthread the left hand thread.

Ken

ps Having an index in the handbook would simplify things.........

[Herman Trivilino]

I would recommend the hammer only for getting it loose. As for tightening, I just do what feels right.

[Jan]

Jan,

I can not locate anything about mounting torque in the handbook. The pamphlet on mounting the stones shows a picture of hitting the wrench with a hammer for "Older machines with conventional locking". All T4 machines and the newer version of the R7 have the EZYLock shaft.

I think using torque is a far better method than using the hammer. It would appear that both methods work. In my opinion, the EZYLock is a more efficient method, especially if one takes the time to learn which way to unthread the left hand thread.

Ken

ps Having an index in the handbook would simplify things.........

Ken,
In the part Maintenance and Tips of the Manual ver.10 you will find:
"Put the grindstone onto the shaft and turn the EzyLock anticlockwise by hand. When sharpening, the grindstone will automatically tighten to the right torque. You need no tools."

The torque values I have mentioned are at Tormek web sites
http://tormek.com/international/en/machine-models/tormek-t-7/
http://tormek.com/international/en/machine-models/tormek-t-4/

Jan

[Jan]

I would recommend the hammer only for getting it loose. As for tightening, I just do what feels right.

Ken, I agree with Herman.

I am not against the use of hammer when releasing a nut. But for tightening the stone I would be afraid to use the hammer. Mr. Newton told me, that the hammer tap corresponds to the impulse of force while torque is application of moment of force, and significantly raised an eyebrow.

Jan

[Ken S]

Jan and Herman,

I agree with you; tightening the nut which holds the grinding wheel to the stone with a hammer does seem a bit barbaric. However, the instruction sheet enclosed with the T4 states (Mount the Grindstone) "Use a 19mm (3/4") wrench. Untighten the right-hand threaded nut by hitting the wrench with a hammer. After mounting a new wheel, tighten the nut by hitting the wrench a few times with a hammer."

In my opinion, the left hand thread EZYLock shaft is a major improvement. I bought the upgrade for my first shaft. I believe it was well worth the cost. I am pleased to see that it is now standard equipment.

Yes, Jan, you are completely correct about the directions included for tightening and loosening the new shaft. I have just found that having a label with arrows pointing the correct direction to push/pull to loosen the shaft is a great memory aid. Just the act of creating the label may actually be adequate for the memory. You may think it is a crutch. I think it is a useful crutch.

Ken

[Elden]

"Use a 19mm (3/4") wrench. Untighten the right-hand threaded nut by hitting the wrench with a hammer. After mounting a new wheel, tighten the nut by hitting the wrench a few times with a hammer."

Aren't you supposed to hit the wrench with the hammer after you lay it down on the bench? That sounds safe to me. 

[SharpenADullWitt]

I have been off the net for a few days.  You did remove the sleeve that gets shipped on the machine to put the stone on?
Do you still have the DVD that should have been with the machine?  I looked for the video's from the older 2000 model but I don't find them online (really wish they would post the setup video's for the machines).  That should go into using a wrench/spanner with the stone.
Grabbing the stone to loosen or tighten it, only happened to be recommended, AFTER they introduced the left hand thread/EZ lock nut.

The new shaft they talk about with the EZ lock nut:
https://www.youtube.com/watch?v=IX96a9WoAJE

[Ken S]

What we need at this point is a followup from timberwright.

Ken

[Rob]

yes....its almost like the same voices keep coming back isn't it...is there an echo in here!!!!