A better edge

A good number of spinners turn their own wooden spindles with wood turning tools.  And in wood turning, very sharp tools are essential.

A group such spinners on Raverly were advocating "grinding and burnishing" as a way of getting a good cut with tools made of high speed steel. I did research on the topic, concluded that grinding, sharpening, and honing produced a much superior edge.

I reported my research, and was promptly bashed by big bunch of the spinners.  I gave peer reviewed citations that they did not bother to check.  I cited names of engineers /spokesmen at the tool making companies that other spinners did not bother to contact.  The spinners just talked to each other and bashed me.  I find this a typical MO for spinners.

In the old days, wood turning chisels were made of carbon steel (CS), which has good ductility and a fine grain size. Think of CS as having a grain the size of peas.  Modern wood turning tools are made of high speed steel (HSS). If CS has a grain the size of a pea, then HSS has a grain the size of tennis balls.  HSS has been used for industrial purposes since 1910, and is very well understood.  It came to the retail market as the hones needed to sharpen HSS became available in the 1970s.

A fine edge on CS does not last long when used for wood turning, so a common practice was to grind an edge, and  burnish it over resulting in an edge the thickness of a pea with a known cutting depth.  This can produce a good quality cut.   HSS that is ground and burnished results in a cutting edge the thickness of a tennis ball, but which is brittle and tends to shatter, resulting in a (microscopically) rough edge  that produces a poor quality cut. However, even such a poor quality cut is much better than "dull" HSS  that has not been recently ground or sharpened.  Grinding and burnishing is better than nothing.  And this seems to be where the myth of the spindle makers come from.

However, when HSS is ground to shape, properly sharpened, and honed, the grains are cleaved resulting in a strong, uniform edge that is only a fraction of a pea in thickness, and which produces a superior cut compared to CS.  I often make temporary tools from inexpensive HSS.  Ground, sharpened, and honed,  these very cheap tools can produce excellent quality cuts.

When I use a freshly sharpened and honed a wood chisel for a final cut, mostly, I do not even bother to sand.  Sand paper coarser than 600 grit will just roughen the wood.  Mostly I use sand paper when I am  fitting a tenon or snug box cover.

I grew up sharpening tools on bench grinders. I have an industrial tool grinder. However, I grind and sharpen my wood turning chisels on a Sorby Pro-Edge. Then, they are honed with a diamond hone. Yes, it is expensive, but it saves my chisels, it saves the cost sand paper, and not sanding reduces dust in the shop.  Special tools are ground to shape on the industrial grinder, but they are sharpened on the Sorby.  Then, they are honed by hand.

I also have CS scrapers that I grind on the industrial grinder and burnish. It is technique that I understand and use -- just not on HSS.

Five of the 10 best spinners that I know are also expert wood turners.  These 5, all hone their HSS wood turning chisels.

So why did that thread on Raverly  need to bash me?   Yes, I challenged them, but they should have done their homework and gotten their facts correct before I got there.  They were telling me that they had 20 years of expedience, and that I had less, so I should defer to their expertise. Twenty years is plenty of time to do one's homework.  Experts do their homework.

I know a limited number of  spinners, and most of them are so talented, and so competent, and so nice, that I do not understand how there could be a bunch of readers on a spinning thread at Ravelry without somebody saying, "Hey guys, honing HSS works!" or somebody backing me up on where twist is inserted in a flyer/bobbin assembly.

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Beginners or Experts?

Who should I make tools for?

I have always made the tools that I like. Some of my first needles were polished like jewels. They were slippery and I found them unpleasant to use. So early on I found that annular striations around the tip facilitated a gansey needle pulling a loop of yarn through a stitch. This made it easy for me to learn to use gansey needles with a knitting sheath.

Over the last few years I have become a better knitter. I can now use gansey needles with highly polished tips.

Last night, I picked up a set of the old gansey needles with the annular striations around the tip. I happily used those needles to knit a gansey in 9 days a few years ago, but now I find that I can knit faster without the   annular striations. This morning, those needle tips are smooth and polished. A beginner would find them hard or impossible to use. If I had been presented with those polished needle tips when I was beginning, I would have given up in despair  However, now I want something faster.

When one is making specialized tools, how does one compromise the needs of the beginner with the needs of the expert?

Makers of wood turning tools have a similar dilemma.  Wood is abrasive, and even the best wood turning tools have to be resharpened frequently.  Does one tell one's (new) customers how to get the best professional edge, or do you tell them they can do a "good enough" job of sharpening with a bench grinder?

Robert Sorby stands up and says, "This is how we recommend that our tools be sharpened."  It is an approach that requires a large capital investment, but results in a very high quality edge, saves tool material, and saves time.  Hamlet on the other hand, declines to make a definitive statement about how to sharpen Hamlet tools, and mumbles something about bench grinders being "good enough", fast, and inexpensive.  I feel sorry for owners of Hamlet tools that are not informed as to the best practice for sharpening HSS.

In wood turning, the burr raised by a bench grinder is ephemeral and will quickly be worn away by the wood it is cutting.

Any burr that can be raised  on a HSS scraper edge with a manual burnisher is ephemeral and will quickly be worn away by the wood it is cutting.  The cutting edge of a HSS scraper edge with a burr raised by a manual burnisher is not as sharp as a HSS scraper cutting edge honed with a diamond card.  This is a combination of tool engineering, metallurgy, and physics. I am amazed that people that would rather work with dull(er) tools than admit that I am correct.

Yes, it takes longer to sharpen a wood turning tool with a fine, slow speed, wet grinder, but the cutting edge lasts much longer than the cutting edge produced with a bench grinder.  So the slower sharpening system actually saves time in the course of a full day of high end wood turning. And since less tool material is removed, the very expensive turning tools last longer.  Thus, over all the system is less expensive.  The even more capital intensive Sorby system removes even less of the wood turning tool, and thus for somebody doing a lot of wood turning, the Sorby approach is even less expensive, because the big cost in wood turning is the cost of the wood turning tools that are ground away in sharpening.

Wood turning tools do not need to be hollow ground.  In fact, flat ground bevels are less likely to catch, and stronger. And, flat wood turning chisels with flat bevels last longer.

On the other hand, a bench grinder will very quickly produce a reasonable edge. And just as quickly, it will grind that expensive HSS into a pile of worthless gray powder.  Then, Hamlet can sell another set of  expensive HSS tools.

Diversity of knitting sheaths

A knitting sheath is as simple or complex as a hammer. Their essence is the same, they are tools that provide leverage.  My tool dealer (Grizzly industrial)  offers 157 different kinds of hammers, and that does not include antique hammers such as a cobbler or wheel wright might have.  Thus, it is reasonable to think that there might be a large number of different kinds of knitting sheaths - each used for a different kind of knitting. And there are.

If we look at the various knitting sheaths drawn by Peter Brears in The Knitting Sheath, published in Folk
Life vol 20 1981-82.  We see the following kinds of knitting sheaths:

     Fig 2


         
Fig 3

Fig 4


   Fig 5

Fig 6


 
   Fig 7
                                                                       


     Fig 8


I am struck by several factors.  One is that he does not distinguish between knitting sheaths used for swaving and those for use with long needles. he does not indicate the size of the needle that fits the sheath.  And, he does not distinguish between, professional tools, 'love tokens' intended to be functional, and love tokens intended to be purely decorative or sentimental.With only one exception, Brear does not indicate wear marks (or lack of wear marks).

In Fig. 3 Nos. 1 and 8 are clearly utilitarian tools. Nos. 2, 3, 7, 10, and 11 are functional tools with decorative carving that enhances their functionality.  While Nos, 4, 5, and 9 have carving that diminish their functionality, and  Nos, 6, 12, 13, 14, 15, and 16 were likely never intended for any use what so ever. No.6 is heavy. The woods that are soft enough to carve ball-in-cage are to soft to make good knitting sheaths.  The  ball-in-cage structures in nos. 12, 13, 14, 15, and 16 are not likely to be to survive the stress of knitting with long needles.  The  ball-in-cage in No. 4 is not required to transmit the full stress of the needles, but only survive handling.  It could survive handling in the context of careful knitting for the family, but is not likely to survive sustained professional / commercial use.  Thus, some knitting sheaths were made for use, and others were purely for sentimental and decorative purposes.  And some were made to show off whittling ability.