table saw blade question

[Doug Winterburn]

Be careful - remember what happened to Galileo ;-)

-Doug

[Igor]

What branch of science or math or what school of thought are you relying on for that statement? Or, are you making some claim on a true meaning of the English language -- that body of work that never changes and has no shades?

I may not know much about birthin' no babies or even about woodworking, but language has long made my world go around.

Consider that in normal discourse, a "plane" is flat. In some branches of science, planes are not flat -- well, at least not as "flat" is understood in normal, vulgar discourse. So, right and wrong usage depends on the context.

Consider that in the US Senate it is possible for May 15 to be the "legislative day" of March 10. Yet, outside the context of the US Senate, if I walked up to you on May 15 and insisted -- without more -- that it was truly "March 10", I'd be out of order, and even arguably incorrect. Alternatively, if I explained the context, I'd be correct and (in order) even if you remained confused.

Since satellites in geosynchronous orbit are (1) described as being so many miles above/relative to the _surface_ of the Earth, not its axis, and (2) described as being in _orbit_ at such altitude, then such satellites can be seen as orbiting/revolving around the _Earth_.

In sum, the only part of what you have written with which I disagree (if I understand you correctly) is the part that says that there is no reasonable understanding of the English language that can be employed to state logically that satellites in geosynchronous orbit actually orbit the _Earth_. Within the confines of the definitions you are implicitly employing, what you have written about "going around" makes some sense. You are saying that "revolution" requires "X", "X" is not present, so there has been no revolution. QED. While I can see that approach being used for the sake of a discussion in order to prove some additional point, I think it is a silly point of view standing alone. Yet, again, it is logical within the confines of your use of the language.

OT-enough?

Now, back to laying the new concrete floor in my basement for the arriving TS. What a messy job.

[Ernie Jurick]

Not the very, very center. Think about it. There has to be a point where the rotary motion changes direction. Just ahead of that there has to be a point where it doesn't move at all. In Zen it's called the "still point of the turning wheel."

-- Ernie

[Leon]

My statement, Yes and or the wrong words used to describe an event and or situation, was meant to infer that some statements and stories such as the squirrel story can be worded to lead one to think in one way but actually not make enough true statements to justify its direction that it may lead you.... HUH? LOL

Like in geometry, and I saw the squirrel story as a geometry puzzle, for certain conclusions there have to be absolute qualifiers. While the story indicated that there was rotation around an area, a second needed element was missing to prove a condition.

I was not referring to know it all.. LOL I was using common definitions for the words in that story.

New concrete floor for the new TS? The DeWalt? That is hard and heavy work too... Keep us informed on your progress and the arrival of the saw.

[Leon]

IMHO, the very very center as you describe it would have to be floating to not move. Perhaps on the atomic level when looking at the center atom and the electrons circling the nucleus. But then perhaps the nucleus is spinning also...

Now consider this, blade is spinning and directly connected to the arbor. The very very center still must have sides. Any real object will have sides. With the blade spinning along with the arbor, how does the center and its sides stay still?

What we may be quibbling about here is the definition of movement. Does movement require a distance to be traveled or simply to change direction although it remains at the same point?

[Robert Bonomi]

Don't you guys know *NUTHIN*?!! That's why there's a _hole_ in the middle of the blade. There is *no* center, so the rest of the blade _can_ move.

[Igor]

Here's a coincidence: A news story from this week about how the Earth revolves around the Earth -- even by your definition, if I get that correctly.

New concrete floor for the new TS? The DeWalt? That is hard and heavy work >too...

Thanks for asking. Yes. DeWalt 746. Probably pick it up next weekend. Still deciding on the DC. Planned on the 1HP Delta but read some reviews that were not great -- including stuff getting caught because there is a cross bar at the 4" inlet of the DC. (Then again, the 746 has a 2.5" DC hookup, but who knows -- maybe some day I'll get a planer.) Then I figured the 1HP Grizzly would be good -- good reviews and about the same price, though the specs are listed as lower (more honest?). But, for about $35 more, delivered, I can get the Jet 1HP which everyone seems to like. Jet is probably the choice. Already ordered the hoses, etc., from Grizzly. And the plastic cyclone garbage can lid.

What I am most looking forward to is making and using jigs. They are gadgets without the (unfair) negative connotation.

If the budgeting holds up, I will be getting a digital camera and then can try to post some stuff -- if they look post-worthy. Frankly, I have been, well in advance, quite humbled by the many website postings others have made and linked from here. Not just the depicted shops themselves, but the detail about the install and the projects. I have been helped and inspired immensely by these sites. Not only with how-tos, but how-not-tos and so many proper warnings about safety. I recently bought a face shield (works better than expected).

[Trent©]

Exactly correct. You should not back down from this statement.

The center of the blade...and the outer edge of the blade...all turn at the speed of the motor.

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Trent©]

Its the material passing OVER the pulley that makes the difference, Harry. This is not the same thing as RPM.

The larger the circumference of the pulley, the longer it will take something (belt) to transverse its entire perimeter.

But, if you take a 2" pulley and a 8" pulley...and put them both on the same shaft turning 3,000 RPM, they will both turn at 3,000 RPM.

And ALL parts of both pulleys will turn at 3,000 RPM...both the inner edge and the outer edge.

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Edwin Pawlowski]

They are turning the same RPM,. but not moving at the same speed. Follow one tooth on the blade. At 4000 rpm, the 7 1/4" blade tooth will travel 1.43 miles in a minute, or about 86 mph. The tooth of a 10" blade will travel 1.98 miles/minute at a speed of 118.9 mph.

I'd say maybe. If you compare a Skil blade for cutting 2 x 4's to a Forrest WWII they are better. The intended end result from a circular saw differs from a saw designed for fine woodworking, thus different choices. You can get 10" crap also. Ed [e-mail]

[Doug Winterburn]

Same frequency/revolutions - yes. Same speed - no.

The speed will increase in direct proportion to the distance from the center of rotation(radius) as long as the frequency(RPMs) remain constant.

The teeth on a 7.25" circular saw blade will travel at 72.5% of the speed of the teeth on a 10" circular saw blade when spinning at the same frequency(RPM).

-Doug

[Bruce]

Are you trying to be pedantic or are you just stupid? This is a serious question.

[Upscale]

No they don't. They turn at the same RPM, but the outer edge travels a greater distance and greater speed to match the RPM of the of the center. If you think otherwise, then you're pretty dumb or you're trolling just for the hell of it.

[Charlie Self]

Bruce responds:

Sure it is. It's right up there with the philosophical question about how many angels can dance on the head of a pin. Charlie Self

"On account of being a democracy and run by the people, we are the only nation in the world that has to keep a government four years, no matter what it does." Will Rogers

[Bruce]

No, I'm trying to determine whether he understands that the farther from center the blade circumerence is, the faster the teeth move. Obviously, since the blade is a solid object, the rotational speed is the same.

[Trent©]

Are you saying the RPM's would be different? lol

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Trent©]

Or...

If God can do anything, can he create a stone so large that he can't lift it?! lol

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Trent©]

The SPEED of any blade attached to a motor is measured the same as the MOTOR...in RPM's.

And the inner part of the blade turns at the same rate as the outer part of the blade.

If you wish to coin some definition of outer-edge speed, please do so. But the RPM's...on the same plane anywhere on the blade...are at the same speed...the same RPM's.

Larger blades are thicker for a reason. They produce more centrifugal force at the other edge...and need to be thicker to handle air currents against the larger total surface, etc.

Did you mean 'stupid'?...or 'ignorant'? This is a serious question. Some people are too stupid to know the difference.

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Doug Miller]

You must've been an English major.

The circumference of a 7-1/4" blade is 7.25 * 3.14 = 22.77". The circumference of a 10" blade is 10 * 3.14 = 31.4".

On a 7-1/4" blade spinning at 3500 rpm, the tips of the teeth move at 22.77 *

3500 = 79,695 inches per minute.

On a 10" blade spinning at 3500 rpm, the tips of the teeth move at 31.4 * 3500 = 109,900 inches per minute

OK, show me a 7-1/4" blade that's the equivalent to a Forrest WoodWorker II, or any of the better blades from Freud or Oldham.

When you gain more experience, you'll understand the difference.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

Save the baby humans - stop partial-birth abortion NOW

[Leon]

> Look at "Amazing Earth Facts" #51: "Does all of Earth spin at the same

I think I saw that story and or 101 facts about the earth you never knew... Apparently the earth is molten 50 down from the surface until the inner core is reached and the solid crust is about 41 miles thinck..

I still use the fan at my back blowing rowards the open double wide garage door method of dust collection. ;~) I have however had my eye on the New Jet canister models of DCers. I like the idea of being able to throw away the bottom bag instead if sturing up all that dust trying to empty the cloth bag. And then again a cyclone set up would be nice but it may take up more precious room in my case.

Yeah I have quite a few jigs myself. I have one design that I came up with myself about 2 years ago. It lets you cut dados with your router. You use the material that will fit into the dado to set the jig up for for a perfect fit. I sent the design into WoodSmith about a year ago....ironically they featured a very similar jig in their latest issue. Mine is rather compact compared to their version.

Speaking of being humbled...;~) Have you seen Tom Plamanns web page? Tom visits this news group regularly. He has the shop and does the work that we all aspire to. Have a look here if you have not seen his site. You will be impressed. The opening page will knock your socks off... ;~)