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antekboodzik
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[*] posted on 8-14-2013 at 04:38 PM
Grinding tools and resawing


Hi everyone,

last days me and my friend we are trying to finish a lute using one of my old, build for rehealsal purposes, sapelli bowl. With doing that, few issues come back to my head and don't let me sleep. Please, help me to better understand them.

First of all, there is tools grinding and sharpening... Until now, e.g. for sharpening my plane iron, I use few crazy techniques, including grinding on a jar with sandpaper glued to it :) Then I "reverse" the blade in the plane, which makes a simple honing guide, and continue sharpening on wet micromesh papers laid on flat surface. Almost the same procedure I use for preparing chisels. It is not bad, but far from being perfect, and rarely I get razor sharp edge of a tool that can shave hairs with ease.

As I am quite scare and aware of using power tools, I haven't got any power grinder. So I think the only one solution to improve this task would be having a grinder with geared handwheel. But now there are only quite old ones available, almost allways in poor condition. Also, I found a grinding device that was intended to be used with an ordinary electric hand drill. I am planning to set it with the lowest speed of a drill, and also use another, velvet-made buffing wheel with polishing compound for final honing - but I didn't test it yet.

So my questions are:
- what is the best way to grind tools?
- (maybe the most unclear issue) how should the grinding stone rotate? To you (like a lathe) or backwards? Logic would suggest that backward motion is better, but all available power grinders don't rotate that way,
- have You used any kind of buffing wheels for sharpening? Any suggestions are welcome,
- tools can be honed on a leather strap - but how?
- how about honing guides? Do they are necessary?
- is it possible in gereral to sharpen tools at home with cheap and peacefull methods?

Also, some about resawing:
- how were instrument tops resawed with no electricity?
- is it possible to saw lute ribs for the back by hand? which tools?
- also, I can't imagine how hard woods, such beech or ebony, were resawed years ago. I found that sawing just small bars for a pegbox from beechwood is a hard workout, so sawing planks from log has had to be terryfing job in the past... Or maybe I am wrong?

By the time, my lute is alive, and serves me well :) Here's one newly made video with me playing (and friend's little daughters messing around :) ). But actually it shows strings have to be changed immediately.

http://www.youtube.com/watch?v=nm4fBY3hERY
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SamirCanada
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[*] posted on 8-14-2013 at 05:10 PM


Nice sounding instrument.

I use the norton stones for my sharpening. 1000 to set the bevels. 4000 for knife sharp, 8000 to shave status. As long as you keep them flat by lapping them on a piece of glass with a sheet of sandpaper. They are nice to use and clean since they work with water. I also have an electric sharpening system called worksharp. It's also good but the sanding disks and bands are expensive in the long run.

People knew how to use a saw before. Also, they had bandsaws that were man powered.

I use a simple honing guide from lee valley. Costs $20




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jdowning
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[*] posted on 8-15-2013 at 04:33 AM


This is too big a topic to cover here in detail but briefly. Properly sharpened hand edge tools and saws are essential to perform accurate work with minimum of effort. At one time it is said that the Japanese apprentices would have to spend the first year learning tool sharpening before being allowed to learn to use a tool. How sharp? The Japanese philosophy was that a plane blade should be so sharp that if the plane is placed on an inclined piece of wood it will slide down under its own weight planing the surface as it goes! I am happy enough with making blades sharp enough to shave the hairs on the back of my arm!

I have used the Krenov method of edge tool sharpening for years - using a slow speed hand grinder to form a concave (hollow ground) edge that is then sharpened on oil stones and finished to razor sharpness on a leather strop (strip of leather glued to a flat block of wood dressed with fine abrasive compound). Here is a bit more information about the set up. No need for honing guides with this method - just 'feel' the blade lock into position on the surface of the stone. Also watch for oil being squeezed from the front edge of the blade indicating correct contact of the blade edge with the stone surface.

http://www.mikeouds.com/messageboard/viewthread.php?tid=8565#pid568...

If you cannot find a hand grinder a slow speed grinder with soft white wheel (specifically designed for carbon steel blade sharpening) can be used. Avoid using a standard high speed power grinder as you can easily overheat the steel of the blade and soften it.

The wheel rotation should be towards you so that it holds the blade onto the blade guide rather than tending to lift it off. The reverse direction is necessary if using soft leather or cloth buffing wheels for obvious reason.

Instrument tops were not sawn but were split from a log section in billets and then planed to thickness. Splitting ensures a top has minimal grain run out (due to spiral growth) and is cut perfectly on the quarter. Splitting wood is also far faster and more efficient than sawing.
Sawn tops can be (and often are) less than perfect containing run out and off quarter grain among other faults.

In the 19th C all veneers were cut by hand with a saw - a skilled job requiring a properly sharpened saw.
If planks needed to be cut from a log a two man 'pit saw' was used - the log set over a pit - the lead sawyer standing on the log to guide it and the helper in the pit below. Again a highly skilled job requiring properly sharpened saws.
To my knowledge pit saws were still being used in some small woodyards in Britain just after WW2 up until about 1950.
The Japanese did the same work with a single sawyer standing on an inclined log using a large coarse bladed saw that cuts on the pull stroke.

I once worked at a living history museum as a carpenter where we constructed copies of historic frame buildings starting with logs and using only the tools of a 19th C carpenter - broadaxes, chisels, two man cross cut saws etc. - more efficient and cost effective than other methods - providing, of course, that the tools were maintained razor sharp at all times!


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antekboodzik
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[*] posted on 8-16-2013 at 01:09 PM


Thank you for your answer. Here are my very first trials with "grinder".

First of all, what a slow speed grinder means? I found and managed to get to work quite nice, undamaged grinder designed to be propelled with a drill. I set up it and put the drill to the lowest speed, it was about 500-700 rpm I guess:

[file]27585[/file]

The support for tool was a variety of what I could find around at that moment, and could be made better. Anyway, I realized that grinding a tool or blade isn't so easy, as it seems to be. But after a bit of practice I have prepared an iron for my plane and a few chisels quite nice. Only small, short iron for Stanley's No64 spokeshave was problematic, but for that I found a solution of temporairly make it longer with two small pieces of metal sheets:

[file]27587[/file] [file]27589[/file]

Next step was honing using 1000 and 2500 grit wet sandpapers on a piece of glass. Not so perfect, but I managed to sharpen the plane iron pretty well. It rather cut hair 1-2mm above skin (teared out?) than shave, but it was good enough. Chisels went better or worse, but usable, the hardest part was spokeshave iron:

[file]27593[/file] [file]27595[/file] [file]27597[/file]

At the end I realised I own one, decent hand plane I got in supermarket for less than 3 US $. I also grinded and honed its iron, and there was a big surprise, because it occured to be way much sharp than other tools, shaving hair nicely (soft steel???). It would probably become dull quite fast, but for small work it is good enough plane, and has an advantage of very low weight itself.

[file]27599[/file]

So here are my tools prepared to make another lute :) Wow, at least I am not convinced at the moment, did I say that? :)

[file]27601[/file]

Well, a few things still bother me. What can I improve? Sharpening stones do significant improvement? And this is sad, that hand grinders are not produced anymore, as they could be cheap all-you-need alternative for small jobs. Also, there are a calico wheel do be tested and an old belt for use it with green extra fine polishing compound - but both of them are "soft", wouldn't it "round" the cutting edge?
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jdowning
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[*] posted on 8-18-2013 at 02:49 PM


A speed of 500 -700 rpm is slow speed (with a 6" dia grinding wheel). If you are careful with a soft (white) grinding wheel you should be able to avoid 'burning' the steel of your carbon steel tool blades.

There are plenty of used hand cranked grinders being offered for sale on EBay.

If you are serious about wanting to hand cut oud ribs, this might be the best saw for the job - a traditional Japanese Ryoba saw - available from Lee Valley Ottawa. The saw works on the pull stroke and has no 'set' like a Western saw - instead the blade is ground to a taper both cross wise and longitudinally. The width of cut (kerf) is therefore less with less wastage of wood.
The rip teeth on one side are designed to cut efficiently along the grain (sharpened like a chisel blade). The wide blade would help guide the saw to make a straight, smooth cut.

The traditional Japanese saw for cutting planks from a log was just a bigger version of this saw (but without the cross cut teeth on one side).

My Western style saws that I now occasionally use are all sharpened for rip cutting - but still work pretty well for cutting cross grain.

[file]27611[/file]
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antekboodzik
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[*] posted on 8-20-2013 at 06:01 AM


So it seems that ancient woodworkers had an army of co-workers just for sharpening saws :)

Here is a flickr gallery of one maker:
http://www.flickr.com/photos/20810645@N06/
he posted some photos of sawing ribs by hand using a kind of frame saw. Of course, I realize he is very fine craftsman and has very sharp saws. But I don't see the trick - is it the weight of whole wooden frame that helps to cut?

And how is called such a saw?
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jdowning
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[*] posted on 8-20-2013 at 08:40 AM


That's right - the army of co-workers were known as apprentices, children bound under contract to their trade masters for periods of 10 years or so to learn the trade in exchange for their labour.

That saw is called a frame saw - one of two types used for cutting veneer (or planks from logs in the larger sizes). The frame kept the thin narrow blade taut under tension so that it would cut straight. The other type is wide bladed that is supposed to be easier to use - the wide blade acting as a guide to straight cutting. Both use rip toothed blades. Some Western woodworkers cut their veneers using a standard wide bladed panel rip saw.

Here is how the ancient Japanese used to cut logs into planks using a very wide bladed saw that cuts on the pull stroke - the ryoba style saw is the same in principle - just smaller in size making it suitable for cutting narrow veneers for ribs. In the Japanese woodcut print you can see an apprentice (?) working away sharpening the teeth of a spare saw.
Another way to keep physically fit!

http://lumberjocks.com/reviews/2094

Give me a bandsaw any day!
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jdowning
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[*] posted on 8-20-2013 at 02:29 PM


I have just noticed in the Japanese woodcut print in the previous link posted that there is a second sawyer - continuing the sawcut of the upper sawyer - underneath the log where accessible. Now that is teamwork!
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