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C.B.Fiddler

Calipers

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OK, yes, we've got those.

Which means I could get one.

Which implies a degree of fore-thought and planning which I don't possess.

I do have ten spare keys though - two in the house, one in the workshop in case I lock myself in (it's a slam-lock anti-burglar thing), two with my mother in a neighbouring suburb, one with my moher-in-law 1200 miles away, one with the local police, one with my sister, and one each with my two sisters-in-law.

But the one I lost is the MAIN one, with a fancy key-holder (but no Clapper). I'm devastated by its loss.

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In order to make you feel less stupid, I will share a story.

One time, about fifteen years ago, I was having dinner in a fancier restaurant than I was used to. I went to use the men's room to wash my hands. I was having great difficulty activating the dryer. I would push the button, the dryer would come on for a moment, and then shut off. This vicious cycle went on for ages, and my frustration grew. I pushed the button dozens of times, and every time the dryer would come on for two seconds and summarily cut out. Then another gentleman entered the bathroom. The door swung open wide and nearly pinched my finger on the dryer button.

It seemed like a strange place to locate the switch, until I realized I had just met my very first automatic hand dryer, and I had been vigorously pushing on the rubber door stopper.

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G, I appreciate your efforts to make me feel less like a monkey.

I will take full advantage of your intimate disclosure and refrain from revealing any further information about my most private self..

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quote:


Originally posted by:
GMM22

...

I would liken it to misplacing ones keys, something I do with such frequency that if viewed in isolation, it would leave most casual observers wondering how I even manage to function from moment to moment.

Hi G and all:

What's that saying about repeating something and expecting different results...

Cheers,

gtm

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GMM wrote: "I would liken it to misplacing ones keys, something I do with such frequency that if viewed in isolation, it would leave most casual observers wondering how I even manage to function from moment to moment. "

and: "I went to use the men's room to wash my hands. "

Have you checked your fly zipper recently?

I could imagine a little battery-driven, motor-based contraption that has a reel to which is attached a transparent fishing line fastened to the zipper toggle.

The beauty of it all, is that it can be activated by the 'clapper device' so that a simple meeting of moist palms closes the potentially offfensive opening.

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Unlike misplacing my keys, I could count on one hand the number of times I have forgotten to fully assemble, and I think I am typical of most men in that we are more tuned into certain routines. In other words, I do not think your invention will fly, so to speak.

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quote:


Originally posted by:
edi malinaric

As I wrote...

"TSK, TSK, GTM - Us old fogies should know better....

Getting old quickly.

cheers edi

Hi edi:

Speaking of old fogies...

I'm about 90% complete with the Plexi caliper. Actually it's working fine but there is 0.005" of flex when I apply a bit of pressure beyond that of the dial spring. The arms ended up being 1.5 wide and the throat is 9.25 deep to the dial center. I can shorten the arms for it was an arbitrary length based on the original plastic size. I can drill another shorter location for the dial and anvil and leave the existing holes.

An alternative is to determine just how much throat depth is needed for a violin and put a steel or aluminum bar strap bridging the 2 arms. Gut feeling is it would reduce the flex down to .001". The advantages of this are that they could be moved diagonally if I need a deeper throat for violas and maybe cello's. I've needed this tool a few times in my life and have always had to invent some substitute method of measuring.

The other advantage is I can clamp the end in a 3" suction cupped equipped vise and I can run the top plate 3/4 the full length rather than having to work at right angles.

Cant say I'm impressed with some of the tips which have sharp 90' corners for they want to dig into the wood. I'll have to chamfer them or find a plastic cap like a wire nut and sand it smooth. Don't say a word about my screws, they will get changed.

Also thinking of buying just another dial gauge so I don't have to keep breaking down my magnetic base unit.

Here are some picts including an antique hour glass just acquired.

http://home-and-garden.webshot...album/562839445EXdweX

Cheers,

gtm

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Hi GTM - I should have put these up before you started making shavings.

This one works a treat for tracing the plate contours. Much lighter than the metal jobs. I made about half-a-dozen for the class. Guess they were popular - most seem to have gone walkabout.

The little drop of nail polish on the setscrew is useful when tracing the contours. Adjust it by 1 turn and you have the next contour exactly 1mm higher or lower. Half a turn gives you a 1/2mm difference.

Makes beautifully even contours and picks out the high/low spots beautifully.

cheers edi

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quote:


Originally posted by:
edi malinaric

Hi GTM - I should have put these up before you started making shavings.

This one works a treat for tracing the plate contours.

...

The little drop of nail polish on the setscrew is useful when tracing the contours. Adjust it by 1 turn and you have the next contour exactly 1mm higher or lower. Half a turn gives you a 1/2mm difference.

Makes beautifully even contours and picks out the high/low spots beautifully.

cheers edi

Hi edi and all:

No shavings yet, probably a week away at the rate I'm progressing.

That's slick, I like it. Are you using bore gauge, vernier caliper, or inside outside caliper to set the desired thickness?

Do you use these in pairs as a go,no-go gauge? Change pencil lead colors when your work area gets too cluttered with marks?

..............

Hot dang, hot dang, light bulb moment..........

Since I have plenty to work with on the throat with my Plexi caliper why not glue a pair of blocks outside on the upper and lower arms at say 2"-3" inboard of the dial? I can't see any angular torsional deflection causing a problem. For that matter I could glue another pair on the other side at different a location. This way I wouldn't increase the flex I reported earlier by drilling additional holes in the arms.

Good idea???

I would like to install brass threaded Slimsert/Keensert on the adjustable screws. You can find small ones in plastic parts of high end electronics and older computer parts for salvage. These may not have outside threads but splines and molded into the plastic. If you crush them slightly they act like a "nylock" nut and they can be pressed and/or glued into place. We are not talking major tensile or compression loads on any of this.

Cheers,

gtm

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Hi GYM - you wrote...

"why not glue a pair of blocks outside on the upper and lower arms"

- and why not string it up with a violin E-string on both sides to achieve that extra stiffness and at much less weight! Don't forget to get a good fit at the bridge feet.

cheers edi

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quote:


Originally posted by:
edi malinaric

...

- and why not string it up with a violin E-string on both sides to achieve that extra stiffness and at much less weight! Don't forget to get a good fit at the bridge feet.

cheers edi

Haaay, let's not get carried away with turnbuckles, toggles and marine eye's. :-)

Actually I see no reason these cannot be fitted to your plywood calipers.

.............

Was looking at mm dial indicators and found mention that the indicator stylus is 4-48 thread so that may be an international standard just like ball bearings are in inch sizes.

I'm really not concerned with the flex, as long as it returns to zero when the excess load is taken off. I could buy some flat corner braces in steel and glue or screw them in. Initial checks of the top are mostly on the fat side though there are a couple areas that are already almost at spec.

Cheers,

gtm

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Hi GTM - you wrote...

"Was looking at mm dial indicators and found mention that the indicator stylus is 4-48 thread so that may be an international standard just like ball bearings are in inch sizes."

Negative, negative, negative - on the international standard that is...

Always be aware that the metric system is for real and healthy in the great wide world. The Kafer dial gauge is threaded M2.5mm. The AIRBUS 380 will be metric all over. Ferrari would go dead-white if they used any Imperial thread in it's manufacture. The Mig 29, Sukhoi 27 and Typhoon will all be metric. Why, even the 0.308 is 7.62mm!

I'll even bet that the International Space Station might have gone that way. Anyone know?

There's nothing special about it, just another standardised system like ACME, BA, BSW, BSF, NGT, NPT, SAE, UN, UNC, UNEF, UNF ....

I have both imperial and metric thead gauges to avoid "close enough" engineering.

Wrt to bearings, Google for FAG bearings and have a loook in their catalogue for the range of metric bearings that are available.

As for stringing up my plywood calipers - I've tried a couple of plywood cellos - didn't care to much for them so I'll pass on that one.

Hang loose - cheers edi

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quote:


Originally posted by:
edi malinaric

Hi GTM - you wrote...

...

"found mention that the indicator stylus is 4-48 thread so that may be an international standard just like ball bearings are in inch sizes."

Negative, negative, negative - on the international standard that is...

Always be aware that the metric system is for real and healthy in the great wide world.

...

There's nothing special about it, just another standardised system like ACME, BA, BSW, BSF, NGT, NPT, SAE, UN, UNC, UNEF, UNF ....

I have both imperial and metric thead gauges to avoid "close enough" engineering.

Wrt to bearings, Google for FAG bearings and have a loook in their catalogue for the range of metric bearings that are available.

As for stringing up my plywood calipers - I've tried a couple of plywood cellos - didn't care to much for them so I'll pass on that one.

Hang loose - cheers edi

Hi edi and all:

Strange that the "tip kits" are inch sizes. The mm gauge I was looking at (Chinese?) mentioned they were inch threads sizes. I'm well aware the Metric system is here to stay, I believe it's the standard in engineering schools. My kids will frequently state a size in metric measure and sometimes have difficulty with inch sizes.

Be aware that Japanese metric threads are not the same as European metric. While the measure is metric the actual profile is different. It is their contention that the sharp point of the thread causes galling thus their's is rounded. The difference is subtle but not beyond normal eye inspection. However try to find a tap and die set for these...

I'm well aware that bearing outside measures are mostly metric, it's the actual balls which will be in inch sizes. That's according to a SKF employee many years ago when looking for a highly specialize metric thrust bearing for a roller crank.

A quick Internet search could not establish this. As a matter of course any time I pick up an unknown source ball I'll check with mike only to find it's in inch size. It may be the US has all the important patents for manufacturer tooling and metals including chrome. For many years the balance of trade with Japan was higher because they imported more automotive making machinery than they exported in cars.

You couldn't possibly get by without metric pitch gage if you didn't recognize standards especially in the automotive industry.

............

I seem to recall they do make a bias ply plywood though may be like finding hen's teeth. I've not found any guitar I would own made from plywood, the sonority just _ain't_ there. I suspect you would have better luck laying up your own carbon fiber laminate even if you have to build your own press and molds.

Onward,

gtm

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GTM wrote...

"I suspect you would have better luck laying up your own carbon fiber laminate even if you have to build your own press and molds."

Now, now - stop raising temptations. I've spent a good few hundred hours repairing composite sailplanes. While end injection of the resin between matched moulds gives the best results for aircraft purposes, I wouldn't hesitate to lay up a laminate in a female mould,vacuum it, cure it and then thickness it with an angle grinder - variable speed of course - so that one could match frequencies.

A quick glance in one of my SKF catalogues shows that they list almost twice as many metric sized balls as imperial ones.

cheers edi

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