Pressure when sharpening

[Darryl J]

Since purchasing my T7 system in November of last year I have sharpened about 100 items, mainly knives but some scissors.  I have had to "true" the wheel several times.  My concern is that last Nov. my 250 mm wheel has shrunk down to 230 mm.  I suspect that I am putting too much pressure on the jigs when sharpening so... my question is how much pressure is too much and how do I tell what the correct pressure is.  Is it just a matter of practice?
Thanks

[Rhino]

I have no input regarding pressure.

I would respectfully suggest you are doing OK.  At the rate you are going, you need a new stone every 3.5 years before you go down to 7 inches.

If you are like me, a lot of initial grinding was to get the initial bevel right and grinding nicks off of tools.  That is a more metal removal.  Now that you have sharpened everything in the house/shop, you won't be removing so much metal anymore.  In view of that, your stone wear will likely slow down. 

Also, time is money and sharp tools save time so you make it up in other places.

[Jeff Farris]

Rhino is on the right track with the idea that the first few months you have the Tormek, you'll wear the stone more than you will in the next few years.

I doubt you're using too much pressure. I find far more people who don't use enough! The trick is to learn how to reposition the tool frequently so that the wear is fairly uniform. Another tip is to true the wheel when the job requires it and not otherwise. That is to say, if I am sharpening gouges with the SVS-50 or SVS=32, I have little concern for the shape of the stone. For the most part, I approach knives the same way...meaning I don't really care if the stone slopes to one side or the other a little bit. But, if doing a skew, fingernail gouge, bench chisel, plane iron or planer blade, you can bet I use the truing tool before I start.

[Herman Trivilino]

With more practice you'll learn how to wear the stone more evenly, so you have to use the truing tool less often.  Especially, like Jeff said, when sharpening things like knives where a true stone is not that critical.  Truing removes a lot more material than does sharpening.

When my machine was new I had the same concern about the stone wearing too fast.  After several years I rusted the mainshaft and broke the stone trying to free it, long before it wore out.  I'm on my second stone now, had it about a year I guess, and have never even trued it once.  Although, it is in need as the last time I used it I noticed it was a tad out of round.