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Skew chisel grinding.....was a grind!

Started by Rob, May 24, 2013, 09:27:20 PM

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Jeff Farris

Just a couple notes on quenching.

If the tool is high speed steel, don't quench, even if you turn it cherry red. Quenching makes HSS brittle and you'll get micro-fractures in the steel.  It won't actually "crack", but its edge durability will be damaged.

In normal tool steels, if you quench after the tool turns blue, you've probably lost the temper of the tool edge already. Quench to prevent the tool from heating up in the first place, not after the damage is done.
Jeff Farris

Rob

Thanks for that Jeff. I didn't know that about HSS so good advice.  The trick seems to be very light pressure and then break, light pressure.  Its very different to the process with the Tormek.  Interestingly different in fact.  I've used an old beat up grinder for years for mower blades, axes etc but never anything refined before.  Shaping is a whole new thing on fast grinders for me.

Is there any reason you can think of that would preclude me from using the planar knife jig on the bgm-100....ie sharpen planar knives on a dry stone (to get the dings out) then switch to the T7 for final honing and ultra sharpening?
Best.    Rob.

Jeff Farris

I've never tried it. It doesn't seem like it would adapt to the horizontal base very well.
Jeff Farris

Rob

I guess the svh-320 is helped by gravity in the T7 upright position isn't it.  I'll check it out when all the kit arrives and see how it goes.  I'm expecting the delivery today (of the bgm-100 that is).

Thanks for the help.

Cheers
Best.    Rob.

Ken S

Rob,

While my grandchildren were at a gymnastics class this morning, I enjoyed a book I have had for several years.  The book, The Lathe Book, by Ernie Conover (revised edition) has a good section on sharpening skew chisels.  I have known Ernie for twenty years.  He is an excellent teacher, turner, and woodworker.  He and his father designed and manufactured the Conover lathe.  (That's a lathe!!!!)

The book should be available at a much mower price than the Ashley Iles book.

Ken

ps I would not be surprised to see the Ashley Iles book reprinted by Lost Art Press sometime in the future.

RobinW

The Lathe Book on which Ken comments above is available new from Amazon and a second hand one on Abebooks for a couple of pounds. Abebooks also list several other books by Ernie Conover  - most from outlets in the USA - all going for pennies or a couple of pounds. The shipping costs more than the book price. Like some tools, I have picked up good condition second hand books at times. Well worth keeping your eyes open.

Rob

My BGM-100 arrived today.  I'll have that little sucker on in no time then put those dry wheels through their paces.  It's funny but even using them freehand as I have extensively already.....the refinement of the Tormek is a pleasure to get back to.  It's the difference between a Rolls Royce and a Skoda!!

Best.    Rob.

Ken S

I found this venerable topic during a google search. Like the Biblical book of Proverbs, It is an old topic, but still rings true. I remember when this topic was first posted.

The glazing frustration referred to by Rob has also been a problem for me. A number of people whose sharpening experience I respect regularly use the SB-250 routinely enough to wear it out and then purchase new SBs. In my case, my SB just collects dust; I have never gotten it to work well. I admit to one valuable side benefit from my SB; when I was reshaping a skew, I had to use the TT-50 truing tool so much that I became very fluent with it. That fluency still benefits me.

That experience also explains why I am so pleased with the way the new Tormek diamond wheels cut. They definitely do not cut as fast as something like a 46 grit Norton 3X on a high speed grinder, however they do cut AND they continue to cut. While the reshaping journey was slow, I always felt I was making progress and did not doubt a successful conclusion.

Yes, as Jeff mentioned, a coarse wheel is a one trick pony. However, when you need that one trick pony, it is marvelous. This topic inspired me to try using the Norton 3X wheels when I got my T4. (The 3X wheels come in only six and eight inch diameters. Too bad; they would be marvelous in ten inches with the SuperGrind size Tormeks. They really would be a Super Grind!) I found the 46 grit 3X wheel (ideally matched with the T4, but usable with the larger Tormeks) the fastest steel remover with the Tormek.

The diamond wheels are not as fast as the one trick pony, however, they are very versatile. I have reshaped a skew with my DC-250 coarse diamond wheel. The process time improved considerably when I figured out how to do it better. Part of that realization was grinding away the old bevel and reshaping with the grinding angle set at ninety degrees. Completely separating reshaping and sharpening made the entire process go faster.

I have not done it, however, I am convinced that the diamond wheels can make it practical to sharpen planer blades with the Tormek.

Torgny Jansson did an outstanding job of explaining the SuperGrind SG-250 grinding wheel in the handbook. Almost ten years after being introduced, the SB and SJ wheels share only a paragraph or two in the handbook and only the most minimal video coverage. It appears that the new diamond wheels and Multi Base will get the same minimal coverage. That is unfortunate; they really are outstanding developments.

I am glad that Herman is still active with us. Unfortunately, Jeff and Tormek parted company several years ago, a major loss. I hope Rob will be able to schedule time to become active again. I miss him. He and I still correspond.

The new diamond wheels will make many long time limitations fade away. I am excited that Tormek continues to be the premier wet grinding innovator.

Ken

Rob

#53
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 :-)
Best.    Rob.

Ken S

Hi, Rob. I'm glad you're back; we missed you. We have this old guy who finally has his lathe running. He may have some questions for you........

Ken

Rob

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

Ken S

It certainly has stories fo remember for me, stories of my grandfather and father long ago and the tables and chairs they lovingly made. Happy memories of my childhood.

Ken

Rob

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.
Best.    Rob.

Ken S

Rob,

Your sage advice is spot on. Learning the skew reminds me of learning how to use my wooden 4x5 camera almost forty years ago. It was a generous gift from my favorite aunt and long anticipated. I was quite discouraged when I could not see through it to view or focus. I persevered. Finally my eyes learned how to work with the camera's groundglass. It was like viewing through the back of an ipad, but better. The precision and flexibility of a view camera made 35mm and digital cameras seem like glorified box cameras. Looking back the struggle was one of the most worthwhile photographic things I have ever done. I look forward in the same way to learning the skew.

My self imposed challenge of learning a way to sharpen the Lacer grind gives me a big head start. I know how to keep the skew quite sharp and can keep a Tormek "at the ready" all preset for my skew. With pre set, there is essentially no set up time.

There is a wealth of quite good instructional material available online, most of it at no charge. An excellent starting point is to google Alan Lacer, Dallas. This is an hour long video of a lecture he gave as a symposium in Dallas. Like my favorite Tormek related videos, I have viewed it several times, each time learning more. Although Alan Lacer sharpens with a dry grinder, much of his experience can be translated into Tormekese. I did the reshaping of my skew entirely with my Tormek and the new diamond wheels. While the process went slowly, I did not experience the frustration I did with the SB or SG. The coarse diamond wheel kept on cutting. I learned enough grinding technique from this that my next reshaping will go faster.

Lacer recommends practicing with short lengths of 2x4 lumber sawed in half. It is available, inexpensive, and easy turning. One of my practice exercises will be turning several diameter variations of parts of these billets (turning wood) to get a feel for what size I want for my first upcoming project. I have a very nice unhandled detail gouge made by Doug Thompson of powdered metal from a design by the late King Heiple. I met King at one of Ernie Conover's classes. King was an outstanding orthopedic surgeon, a fine turner and teacher, an a likeable person. This handled King Heiple detail gouge will be another tool with happy memories for me.

Rob, I am most pleased to have you as friend and turning mentor.

Ken

Rob

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