Life Expectancy of my Grindstone SG-250

[staysharp]

Thank you all for your replies in the topic Grindstone roughness & smoothness.
Now all that advice has been absorbed, I would like to know does anybody else keep a record of how long there Grindstone will last them. I have used up 6mm of the new stone sharpening 17 basic flat steel metal blades that includes Rough(fast) and Fine plus Stone Grading 34 times and just twice using the Diamond Dressing tool. The blades where 7 Hand Plane blades 60-40mm wide and 10 Chisels 30-3mm wide a total of 500mm steel blades, the time taken on average 4 minutes per blade including grading each time, total of 68 minutes.
So my conclusion would be, new Grindstone 250mm (10inches) to be replaced as advised at 175mm (7inches) 75mm of stone use. The work I do I would need to sharpen all 17 blades aprox 6 times a year using up 6mm of the grindstone each time total for one year 36mm two years 72mm, the wheel would only last two years maximum after sharpening aprox 6000mm (20 feet) of Steel and taken aprox six half hours. Why maximum is because as the grindstone wheel reduces its diameter there is less surface stone to sharpen on, I 'am not a mathematician to work that one out.

[Ken S]

I have no idea of the math involved.  However, I do wonder what condition your blades are in before you sharpen them.  I'm being curious, not critical.  If you sharpen your tools when they just begin to lose sharpness, you shouldn't need to remove much metal.  It should be more of a refresh operation than a major grinding.

I am also surprised that all of your blades need to be resharpened at the same time.  I am not a very active woodworker.  In my case, only a few chisels might need to be refreshed after cutting some dovetails.  Perhaps two or three planes might need the same refreshing.  Some of my rarely used chisels haven't needed to be sharpened in years.

Perhaps you might share some more of your sharpening situation.

Keep us posted.

Ken

[staysharp]

I should have explained that my work involves carpentry, joinery, and furniture making. On site work the larger chisels to get used a lot and renovation work soon takes the edges of the plane especially on old doors.

Admittedly I would never again sharpen up all the blades at the same time. The exercise was just to see how much of the grindstone was used up and then roughly work out how long the grindstone wheel could last, what made me curious about this was a sales person when asked how long would a stone last the answer was well how long is a piece of string.

I do hope the grindstone will last longer then my prediction of two years yes there is a lot of variables in the working out also the type of woodwork I will get to do in the future.
I do have a dry grindstone to take the worse nicks out of the blades first.

Sharpening has come a long way on since I first started 40years ago when we only had a two sided Indian stone or carborundum stone with a small oil can as an apprentice having to make a wooden box to house them in, then the Japanese flat wetstones, on to the diamond ones that personally I can never get a razor sharp edge on, but I am sure this method with the Tomrek wet sharpening results in the finest edge of all.

Michael

[Jeff Farris]

I truly doubt you'll use up the stone in two years, even in professional use. I've experienced much the same as you have time and time again. The first 6mm or so seems to wear away very quickly, but then you get every tool you own dialed in, your technique improves and I think there's something physically different about the rim of the stone.

[Ken SOS]

I use the Tormek T-7 professionally. I use it mainly for sharpening knives (everything from pocket to commercial restaurant) and an occasional tool. I absolutely love it. But I feel the SG-250 wheels wear out very quickly. I don't think I have had one last more then 6 months. I have been taking a hard look at the SB-250 and wondering if it will hold up better for my use.

[Herman Trivilino]

Welcome to the forum, Ken.  I haven't used the SB grindstone, but others here who have find it useful for harder steels.

I'm curious about your knife-sharpening techniques.  Do you use the knife jig for the larger knives and free hand the smaller ones?

[Ken S]

If you guys are concerned about wearing out the SG 250, consider switching to oilstones.  I have a couple of Norton combination India stones which belonged to my grandfathers.  These remarkable stones have outlasted two generation of my family, and will most probably out last me as well.  They don't cut very fast, but their staying power is remarkable!

On a more serious note, I would suggest actively watching for sales at Tormek dealers and buying ahead if the price is good.  Kudos for having built up such a thriving business!

Ken

[Ken SOS]

Thank you for the welcome Herman.

The main jig I use is the SVM-45 Knife Jig. If the knife is long and flimsy I go with the SVM-140 Large knife jig. The Short Knife Holder Jig SVM-00 I use rarely, its hard and time consuming getting the knife lined up perfectly balanced.

Going with a bench stone isn't realistic for me since time is always key. I do use whetstone and diamond bench stones. But mainly for re-profiling or to straighten cutting edges.

Ken W

ps There is a lot of Kens in this forum.

[grepper]

Ken SOS-

Just curious... How many knives a day do you sharpen?

What is your wheel like after 6 months?

[Ken SOS]

Hi Grepper,

Not sure how many knives I avg a day. At 6 months they are still usable but small.

-Ken W   

[grepper]

Hi Ken,

Wow!  You must use it a lot!  Or true the stone a lot. Or something.  I've got to agree with you insofar as that seems like you are going through stones more quickly than I would think is normal.  But then I've never used mine 8 hours a day or anything even close to that.

Maybe we could get Jeff to chime in on this.   Hey Jeff...  I'm curious... Does this seem normal?

Mark

[Herman Trivilino]

The main jig I use is the SVM-45 Knife Jig. If the knife is long and flimsy I go with the SVM-140 Large knife jig. The Short Knife Holder Jig SVM-00 I use rarely, its hard and time consuming getting the knife lined up perfectly balanced.

So, do you just freehand the blades that are too small for the SVM-45?

ps There is a lot of Kens in this forum.

Reminds me of a Monty Python skit.  Bruce?

[Jeff Farris]

Maybe we could get Jeff to chime in on this.   Hey Jeff...  I'm curious... Does this seem normal?

Mark

It seems really high to me, unless it is going 8 hours a day, 5 or 6 days a week....which it could if being used professionally. I had a commercial account (Goodyear) who used it on a daily basis and at least two shifts a day, and they bought a stone about every 9 months. Amazing that in the modern manufacture of tank treads, there's still work done with hand knives (trimming mold seams).

[staysharp]

Ken S & Jeff
The main reason I choose the T7 over other bands was that in the UK it came with a free lifetime stone certificate from the dealer up to a maximum of three.

I was just curious on how long other members grindstones had lasted them.

Staysharp and have a merry Christmas & a Happy New Year everyone.

[Jeff Farris]

"Free Grindstones for Life" was my idea. I pitched it to Tormek for the very reason that people worry about how long the stone will last, when the reality is few will go through a stone in their lifetime. I don't remember how many countries ran it, but I know that very few stones have been sent out as replacements. Heavy users got a great deal, average users got a big chunk of peace of mind.