Monday, January 05, 2009

Saw Piercing


Anyone who knows me can tell you what I love best- Silversmithing! For some unexplainable reason I have not- until this point, felt the need to create a post about it. Probably because I'm usually at my bench working on some project!

Lately I have been enjoying my Jewelers coping saw- a tool that receives a lot of bad-mouthing from many silversmith students. Yes, I do understand that it is hard to saw without breaking saw blade when you start out. However, if you keep trying, you will improve with time. Soon you will be wearing out blades rather than breaking them.

Think about learning to ride a bike. Most people didn't hop on and tootle off down the street on the first try. Most of us ended up in a heap on the ground quite a few times. Scraped knees, elbows
and tears were part of the learning experience.
I remember my son at 3 1/2 years old... like anyone else he crashed and would end up shrieking that he hated his bike. Five minutes later he was back on again. By the end of the afternoon he was riding without crashing (much).
So if a pee-wee kid of 3 1/2 can ride a bike without training wheels then it stands to reason that an able bodied adult can learn to saw a thin piece of metal that pretty much stands still.

Here is a bit of collected wisdom from myself and the web:

When loading the jewelers saw frame with a blade, proper tension is a must!
With saw teeth pointing downward (toward the handle end), tighten one end of the blade in th upper knuckle of the saw. Place the frame open side up, against the table and push the handle of the saw toward the table edge- tighten the lower knuckle, securing the
blade. Test the tension as follows:
When you pluck the blade the sound should be a high & tight "ting".
If you hear a low, shaggy or flat tone you do not have proper tension. Loosen the frame-back nut, hold the frame-back end on the table top and press the cross-bar downward, re-tighten and test again. If your frame only has front edge adjustments ("C" frame), loosen a front knuckle and press harder to tension the blade, re-tighten etc.

Important Basic Sawing Practices:
These points are important for accuracy in cutting:
Keep the blade perpendicular to the sheet that you are sawing.
Sit with your head above the work piece & your elbows at chest height slightly below the pin.
Find a comfortable position that allows you to see where the blade is going- not where it has been.

Saw slightly outside of your design and file finish.

These things keep your blade from binding:
With your free hand, hold the sheet flat to the wooden pin, and don't let it wiggle around.
Keep all sawing activity close to the
edge of the wooden pin where the metal will be supported.
Lubricate your blade often- candle stubs are cheap and work well.

These things keep you from breaking blades:
Proper tension (see above).
At corners and tight curves- Turn the work piece s-l-o-w-l-y, while "sawing" the blade in place. Proceed slowly through all curves.
Never push the blade forward against the uncut metal. Let a gentle pressure on the saw advance the blade as it saws. The blade only cuts on downward strokes.

These things will make your work easier:

Choose a saw blade appropriate to the sheet gauge that you are cutting.
A saw blade that is too big will catch and chatter along the edge- You will go mad!
A blade that is too small will clog up from metal chips and stop cutting until the chips are cleaned out. This will slow the cutting job down unnecessarily- You will get bored!
When starting your first cut, use a file to make a notch on the sheet edge. This will keep the blade from wandering.
Use the full length of the blade on each pass. Avoid short strokes which will only engage the center teeth of the blade. This will help to advance your progress with less muscle fatigue & will distribute the wear to the blade which will prolong its use.

Buy good quality blades. Students often buy the cheapest tool because they don't think that expense is justified. With saw blades cheap is not the way to go! Quality German or Swiss blades will cut cleaner and last longer. Many have rounded backs for easier turning. I bought some cheap saw blades early-on, they would wander terribly and mess up my projects. They also broke like crazy!
I had a lot more filing to do with those cheap blades, and wasted silver too.

Thanks to PB Cohen's site http://www.pbcohen.com/index.php?itemid=53
for this link to
Contenti:
Sawblades.pdf

James Miller FIPG has posts regarding saw piercing on Ganoksin.org. Here is a link to one of his many informative posts:
James Miller on saw piercing

If you want to customize the saw handle for a more comfortable grip, Brian Meek has the plan:
frankensaw

Well that is about all I have to say on the subject. I will leave you with a photo (at the opening of this entry) of a piece I made in red brass and copper.
It was practice for a silver piece I want to make next.
Sorry for the blurry photo. My phone doesn't have a focus feature.
Happy sawing!

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1 Comments:

At 11:43 AM, Anonymous Jason said...

Great tips, could not agree more. I hate cheap saw blades!!

 

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