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Right....I've gone and bought another SB today.

I guess on balance I wasn't inclined to accept the risk of the diamond stone given it was nearly a hundred bucks more and as we're all agreed, scant detailed information about it's performance and longevity.  it seemed a bit too much of a shot in the dark.

So I've opted for known security and safety over blind innovative optimism :-)

Many thanks Ken.

I might have a gander at Glenn's BLOG actually.  Like you I really rate him so his input will be worth reading especially considering he was an official prototype tester for Tormek.  I might even drop him an e mail as I have an account with him.

But your recommendation of the finest of the three sounds reasonable too.  I appreciate your input, many thanks :-)

Best
Rob

Hi there and welcome to the forum.

The geometry of elliptically ground gouges is moderately complex.  But it boils down to the fact you need to know that 3 adjustments affect the geometry and by that I mean the bevel angle and the degree to which the wings are swept back.

They are:


- the distance the tool is protruding from the jig (P)
- the distance between the pivot point and the grinding media (hole A or B with Tormek's quick set jig) which is the distance the USB is from the grinding media
- the angle at which the bevel is presented ie the angle between the tool axis and the grinding medium axis. (knuckle setting in the elliptical grinding jig).  That's what the manual refers to as JS 2 or 3 or 4 etc

If the chart shows the same angle for any of these variables, then one or both of the other 2 variables must have been altered.

To add to that is also an operator component ie the time spent focusing grinding on different parts of the bevel.  This is classically demonstrated by spending too much time on the nose (goes flat and dips) or not enough (gets pointy and is very frisky during turning).  Or too much wing grinding can wear them out at the backs and not enough means they dont sweep right round and have no cutting edge at the back.  But the angles are managed by adjustment of those 3 variables.  That also holds true for every other jig based grinding system in the market.  one has control of these 3 factors.  Tormek just happens to do it very well because of the precision engineering and good design.

Morning Folks (well it is in England anyway).

Despite the title, this is a serious question.

My trusty black friend, the SB250 has finally run out of diameter and has reached the stage where I have to remove the honing wheel for anything long.  I've just had a frenzy of knife sharpening and that was the final nail in the proverbial coffin.  it's still OK for gouges for turning because they're largely ground from up above in the elliptical jig and dont foul on the honing wheel.  But as for anything else, particularly chefs knives, alas, too small.  I think it was down to about 190 from memory so really has served me well and I think I bought it in 2015 so its pushing 5 years.

So I've done a round robin to see whats new because I have been a little distracted of late and not been on the tools anywhere near as much as I would have liked.  All comes of that pesky distraction - having to work for a living.  Boo.  Hiss.

Whats popped out of my research is of course the advent of the "girls best friend" diamonds!  They weren't really a thing last time I looked, now it seems, they really are.

Now I dont take the replacement of my SB250 lightly because it's been a versatile friend, primarily to my wood turning which has become the dominant form of my woodworking but also to the outlying fray of other edge tools I have need to sharpen.  That includes all the usual suspects ie scissors, kitchen knives, plane irons and chisels and the odd set of secateurs (felco of course).  So the replacement has to be every bit as "game" as it's redundant original.

They're also, a fair sized investment for a consumable so the value must be there.

I could of course simply replace the SB with another but that would be to betray the opportunity that innovation brings and that doesn't sit well with me.

So, I dont have the knowledge to make this decision on my own.  I thought, who/where should I turn to for expert advice and guidance and of course, add to that, warmth, friendship and camaraderie.....and of course......I visited my local tool shop!   No....stop it.....I came here.  Didn't give it a seconds thought.  I knew you guys would know the answer.

What I haven't done is trawl through umpteen posts on here to "mine" the answer and for that I apologise.  But perhaps a good enough starting point to engage your very useful minds is to say that my current thinking is to opt for the 1200 grit very fine diamond wheel.  My understanding is it's never going to need dressing (so that's one in the eye for the SB....no more need to worry about gouges furrowing the stone, requiring endless redressing with the truing tool).  Allied to the last, it will never lose it's shape and therefore will remain geometrically accurate to the universal tool rest?

Those seem to me to be the fundamental differences between this medium and a friable one like the grey or black stones.  in short, it never changes shape through the action of grinding.  Is this absolutely 100% true for HSS turning gouges with, swept back wings and quite pointy tips like 3/8" bowl gouges?  I ask this because those suckers really really really do grind quite the trench in the SB over a relatively short space of time.  So not just the diamonds themselves (which I appreciate are about the hardest substance known to man) but the underlying wheel itself would have to phenomenally resistant to avoid this happening in the future.  Are we certain this is the case?  Do we have precedent from any wood turners that use HSS gouges in the elliptical grinding jig?  This is definitely my greatest concern because I guess once, it's dented in any way, it's more or less useless since you cant dress or true it.

The other can be packaged in the general versatility category i.e. I do need this to perform widely once we're beyond high speed steel turning tools.  So my next priority would be the global knives in my kitchen.  I'm a reasonably accomplished chef and not only cook for my family on a daily basis but have wont to throw the odd dinner party where I will prepare more esoteric dishes of the moment.  This is a chore if the knives are blunt and a joy if sharp.  So this application is also really important.  Add to that the usual cornucopia of other assorted tools including scissors and my needs are met.

The grit question is the next big one then.  9 times out of 10 I'll be coming to the Tormek with a known edge and therefore only require sharpening, not shaping.  Is my thinking correct on this........the friable stones, when graded with the fine side of the stone grader, end up at 1000 grit right?  The finest diamond stone is 1200 grit?  So by buying the 1200 grit, I'm more or less just polishing the existing bevel?

The fundamental question for me, with respect to grit size is......will the 1200 be just a bit too fine and leave me grinding for ages if I dont set the angle accurately enough?  is it forgiving enough to remove enough metal to still give an edge if I'm out by a degree or three? 

I'm not big on fiddling and messing so I dont want to waste my life having to be uber careful setting the jigs all the time.  On the other hand, I dont want a medium so course that the edge isn't fine enough.  it's this balance between setup time and edge quality that's got me agonising between the 600 and the 1200 grit diamond stone choices.  I'm pretty clear I dont want the course one though as that seems to be more in the "ding removal" camp.

So that's my dilemma folks, that's what I would humbly ask that you bring your excellent minds to bear on and help me make the decision.  it boils down to this I think:

Should I replace the SB 250 with an SB250 or the 600 or the 1200 grit diamond stone?  But more importantly, why?

Your input, as always, is appreciated.

All the best
Rob

If we BREXIT.....I'm coming to the US :-)

Excellent Ken :-)

Hi Folks

I've been using the Tormek to sharpen my bowl (and spindle) gouges for many years now and I use the silicon blackstone wheel for any hard metals.  In the case of the honing.  I dont do this every episode of sharpening but perhaps 1 out of 3.  I'll polish the inside of the flute with the little leather wheel and then sharpen with the SVD as normal.  I then finish with 1 light pass on the flute inside with the little wheel.

If I'm doing a finishing cut on a particularly brutal piece of stock (dry, with interlocking grain for example or something punky and spalted), I'll always use the above procedure.  Every time this allows a sheer cut, with the flute at 45 deg to the stock to make gossamer thin shavings and move yourself up the starting grit with the sanding.  Rarely need to start at less than 120 grit using this procedure.  But the old adage is true, sharpen little and often because that fabulous edge doesn't last very long.  Hopefully, it does last long enough to complete the finishing cut though and cut off any bruised or torn grain.

I'm a big fan of Glenn Lucas.  Some years ago I bought his platter DVD and it's really well thought through and presented which makes the task of turning one so much easier.  He's quite the gifted teacher is our Glenn and I've also just bought a pair of calipers he recommends in that DVD called the Martel calipers.  They all ow one to measure the base of a platter or hollow vessel, through the jaws of the chuck with the other leg inside the vessel.  They're a very odd shape to achieve that but really useful for avoiding the dreaded "turning through the bottom of the bowl" problem when hollowing the inside. 

Platters are particularly susceptible to this common problem because they've got to be thin to work....too easy to go through the base.

Happy new Year to all by the way.  Long time no post :-)

All the Best
Rob

Richard Raffan.....the master's master :-)

This is going to sound ever so slightly obtuse Ken.......but I would actually "turn" something....you know....now your tools are sharp :-)

There's a variation on that theme when grinding gouges that I wont go into now as I'm short of time.  It's known in our club as "the horseshoe" technique and its extremely useful when aiming to get a symmetrical grind on the swept back wings of a bowl or spindle gouge.  it's a virtually fool proof method of avoiding the common gotcha of grinding the wings unevenly and winding up with a tool that looks and feels unbalanced.

I'm pretty sure Jeff used to talk about some years ago too if I recall correctly.

When I get chance I'll ferret out a training class I gave on it and send you the document Ken.

I look forward to reports of your first experiences with the skew Ken :-)  And dont forget....we need pictures....or it didn't happen :-)

And that very provenance will help you turn better Ken. The respect and love that the very tool represents will get engineered into the work.

I think all you need now Ken is to put as much time on the tools as you possibly can. Let us know how you get on.  Don't get depressed if the skew doesn't deliver for you at the start. It's a bit frisky to say the least and will give you catch after catch at the start. Don't let that put you off. Perseverance is the name of the game with the skew.

I hear the lathe itself may have a few stories to tell :-)

Hi Ken

I'm in France.  Brittany to be precise, in an 1800 built Breton style stone farmhouse with metre thick walls. Family wedding yesterday and I thought it was high time I popped my head round the door to see how my old friends are doing :-)