magnifiers for sharpening
Lyn J. Mangiameli
>I got an email asking for recommendations and sources for the hand held magnifiers I mentioned as an assist to sharpening. I though the answer might be of some general interest so here it is.
Lots of sources, often including your local drug store.
One convenient source is from ENCO
http://www.use-enco.com
whose catalog is well worth having as a shop resource for inexpensive drill rod, tool bits and the like.
I think the best for woodworkers are the illumated flashlight or square "card" magnifiers. I have some of both, but most often use a shirt pocket size illuminated card magnifier of 5 x power. Unfortunately, I haven't been able to find a current source of what I use most often. However, the flashlight size magnifers probably are even better but for size.
The light really helps reveal the scratch pattern under magnification and is a great help to older eyes.
I think 4-6 power is the best, just because it allows for more depth of field, has a wider focusing distance, and requires a less steady hand. 8-10 x are at the limits of what is convenient for hand held use (particularly when both tool and magnifier are hand held), but obviously give more magnification for fine inspection. I will occasionally resort to a 10x magnifier if something seems awry in what I see under lesser magnification and I want a closer look.
You can obtain almost all of these magnifiers for less than $25 dollars, often less than $20. Enco currently has on sale an Illuminated Coddington 10x magnifier for $19.49 that is excellent quality, but slightly more magnification than is optimal. They have a regularly priced 3.5 illuminated magnifier with a large lens for $24.95 (page 252 of current full range catalog).
There are other sources, and you may be able to find even cheaper prices from them. Places like LS&S
http://www.lssproducts.com
and Adaptive Technology
http://www.adaptivetech.net/products/low_vision_magnifiers_01.htm
and other places that sell to the visually impaired and are often excellent sources.
LS&S has a 3 x illuminated maginfier with an internal circle at the bottom that gives 5x for only $9.95.
Adaptive Technology has several Schweizer illuminated pocket magnifiers that will work well also, and they can be had for well under $20.
Jerry Glaser was the first to encourage me to use a hand held magnifier to examine the effectiveness of my sharpening, and it has transformed the quality of my edges. It is amazing and saddening to realize how often what one had assumed was a uniformly sharpened edge was far from so (this applys best to hand plane and chisel blades, but is also very pertinent to the woodturner's skew). It isn't that one needs to use a magnifier each time one sharpens (though I usually do with hand plane blades), but to help in the learning process of what is required to get the edge the way you want it to be, then you can duplicate this procedure without constant checking in the future. For example, some exotic allows just require more sharpening time than "lesser" alloys, and one learns the amount of time or pressure it takes to bring that edge to a truly sharp level. It can also be useful to learn what it takes to obtain a uniform burr on the edge of a scraper, and how much pressure is optimal to obtain a burr of optimal rise before beginning to fold over.
Hope this helps,
Lyn