Are the T8's front and top USB binding sleeves positioned identically?

[Nico]

Apologies if this is a naive or obvious question. I don't have accurate enough tools to measure this for myself to find the answer.

The T8 has 2 attachment bases or sleeves for the USB. One allows a vertical attachment, the other a horizontal attachment towards the front of the machine.

My query is, suppose you have a blade clamped in a jig, and you have set the appropriate angle using your favourite method, and have locked the USB into let's say the top binding sleeves. If you then remove the USB from those sleeves - and carefully - so the adjustment nut does not move, re-insert the USB into the other binding sleves, and lock it - and change nothing else - will the angle of the blade against the same wheel be exactly the same as before? Or you cannot assume this.

[cbwx34]

Apologies if this is a naive or obvious question. I don't have accurate enough tools to measure this for myself to find the answer.

The T8 has 2 attachment bases or sleeves for the USB. One allows a vertical attachment, the other a horizontal attachment towards the front of the machine.

My query is, suppose you have a blade clamped in a jig, and you have set the appropriate angle using your favourite method, and have locked the USB into let's say the top binding sleeves. If you then remove the USB from those sleeves - and carefully - so the adjustment nut does not move, re-insert the USB into the other binding sleves, and lock it - and change nothing else - will the angle of the blade against the same wheel be exactly the same as before? Or you cannot assume this.

It doesn't look like it.  I set the USB on the vertical side so that it was just touching the wheel, when I moved it to the horizontal side there's a few mm gap.

[Ken S]

Interesting question, Nico. I do not have the engineering background to offer a solid answer. Whether of not the setting varies between the vertical and horizontal sleeves, I would wonder if that variation would remain constant. For example, if the variation proved to be X millimeters, the correction could be dialed in using the microadjust on the universal support bar.

If you are wanting to switch from vertical grinding to horizontal honing or using the SJ wheel, I would first try using the TTS-100. Use whichever hole (A or B) works best for you. The two small wheels are Tormek's patented way of wheel diameter correction.

Please keep us posted.

Ken

[Nico]

Thanks everyone, I will keep the forum posted as I learn more, for example, the exact difference.

My typical use case for this is switching from grinding into the blade with the SG-250, then switching sleeves to polish away from the blade with the Japanese waterstone SJ-250. I know the purists will (correctly) comment that most likely the diameters of the two wheels won't be identical anyway, and I acknowledge that, but I was curious to know whether (if they were), we can consistently adjust whatever difference there was by using the micro-adjust or turning the adjustment nut on the USB by a precise amount (as Ken mentioned).

[tgbto]

If the image in TormekCalc is homothetic to the actual T-8, then there is a 18% difference in the distance between the axis of the sleeves and the wheel axis in the horizontal and vertical USB position.

So there won't be a fixed amount to correct by, whatever the position of the front of horizontal sleeves relative to the top of the vertical sleeves.

[Ken S]

I think we should distinguish between an actual small difference and a problem difference. We routinely switch directions between the grinding wheel and the leather or composite honing wheels. Whether we use a consistent projection program or the black marker, this switch does not seem like a problem, especially if a second universal support bar is used.

Using the SJ seems more applicable to lower volume sharpening where time is not so much of the essence. Grouping similarly sized knives and using a second support bar and a black marker should minimize the extra time needed to switch wheels and direction.

Ken