Table Saw Arbor Question

Classic issue with the table saw arbor: Pop got this dado blade, and guess what -- the arbor won't fit the blade. Doh!

So we're looking at it, figuring we'll need to buy either a different sort of blade, or buy a whole new table saw setup, and got to wondering if there's a way to easily retrofit a longer arber on your table saw without having to buythe whole damned thing again.

Thoughts?

- Saul

Reply to
saulgoode
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You don't say what model saw you have, but chances are the arbor is not long enough because the saw is not powerful enough to properly turn a dado blade. A 1 1/2 HP contractor saw can easily turn an 8" dado, but some benchtops struggle with a 6".

Reply to
Edwin Pawlowski

He doesn't say where he is. In the EU I understand that there is a legal issue with regard to some regulation or other regarding spin-down time--they make the saws with arbors intended specifically to prevent the use of a dado because the added mass of the dado increases the spin-down time beyond what the government allows.

Reply to
J. Clarke

I'm in the USA, using a generic Craftsman (don't say it), but really this is just a general question. I figured the spindle length length was based on some sort of work function for the motor, but wanted to see if there was some simple way to upgrade an existing saw.

I also figured "no" was the default answer, but wanted to see if there was some secret out there I didn't know about.

- Saul

Reply to
saulgoode

saulgoode wrote in news: snipped-for-privacy@m44g2000hsc.googlegroups.com:

Take your saw's model number to Sears and ask. My Craftsman TS had a short shaft, but a dado insert plate was included (perhaps clueless marketing at it again?)

While you're out, you may want to look in to routers and straight bits... Sometimes it's easier to cut dadoes with the router than it is the saw.

Puckdropper

Reply to
Puckdropper

With that they wil popbably point him towards the wobble dado blade that they market, It is narrower than the typical fully loaded stacked dado set.

Reply to
Leon

Thanks, guys. This was exactly the case -- change the dado blade type, not the motor on the saw, spot on. I haven't used the wobble, but my Pop has. I'll ask him if he likes it; I'm a little skeptical about it.

I currently use my router for dados (I was smart enough to get a 1/2" collared router), but I wanted to try the table saw just to compare techniques. Guess I'll stick that dado blade in the toolbox for when I eventually upgrade my table saw, eh.

- Saul

Reply to
saulgoode

So, let's see if I have this straight:

Here in Europe, the law decrees that we're not allowed to fit dado sets to table saws because that'd be dangerous.

Does that mean that it's _safe_ in the good ol' USA?

if I decide to take up smoking (Heaven forbid!!) should I cross the Atlantic first so it won't harm me? Oops, smokings dangerous there too, I hear. Scrub that. O.K. age of consent, beer drinking, age to drive a car... buying ephedrine... blah blah You get the philosophical nuance, I'm sure. Up to around 1938 Marijuana was a frowned-upon eccentricity, but not actually dangerous. After that, one puff would lead to reefer madness and you'd murder your sister.

A parallel - It was only pressure group intervention that stopped the U,K. government legislating in compulsory leg-fairings and, er, _seatbelts_ for motorcycles. That got modified, but the restrictive thinking led to severe horsepower ratings for learners - which meant machines that were too slow to keep up with car traffic unless carburetted to be thrashed out of the tractability power bandwidth. Inexperienced riders were forced to handle a machine with a vertical no-go to full-power throttle response because some idiot had legislated that this would be "safer" than allowing him to have access to a bit of soft, controllable torque.. ?for example.

Is, or is not, the practice of fitting dado blades to table saws actually dangerous?

Opinions, please, gentlefolk.

Reply to
Bored Borg

IMO, the danger - and/or the safety - is determined by the user. Personally, I prefer table to radial arm saw for dadoing with a saw - but I prefer a router to either saw.

Reply to
Morris Dovey

If you check again I think you'll find that the law or regulation places an upper limit on spin-down time after powerdown, and the added mass of a dado blade takes the spin-down time beyond what the regulations allow unless the saw has a blade brake. I don't think you'll find any objection to a dado blade on a saw with a blade brake.

Would you care to explain how a horsepower limit results in this situation? And how does being "carburetted to be thrashed out of the tractability power bandwidth" allow a motorcycle with a given amount of horsepower to keep up with traffic when one with the same horsepower but twice the displacement cannot do so?

Not gonna touch that one.

Reply to
J. Clarke

Why yes, of course that is exactly what it means. Not only are we more refined and dignified, we are more conscientious and skilled at operating complex machinery. And our beer is colder too.

Reply to
Edwin Pawlowski

My opinion, for what it's worth, is that, all other things being equal, using a dado blade on a table saw is less dangerous than using a "regular" saw blade - buried cut with no sharp spinning objects exposed to nip unwary fingers, according to some, less danger of kickback, etc. But it all comes down to the operator. Unsafe procedures will bite regardless of the type of blade.

I believe, as said elsewhere, the European (all countries?) restrictions are due to the spin down time. Without some form of braking, a full width stacked dado takes significantly longer to come to a stop than a "regular" blade.,

Tom Veatch Wichita, KS USA

Reply to
Tom Veatch

"Edwin Pawlowski" wrote

And barbecue, we got barbecue.

Reply to
Lee Michaels

Exactly right! Apparently some people are less prone to accidents or getting sick. If you live in California you are much more prone to getting cancer if you cook out doors with charcoal.

Reply to
Leon

On Thu, 21 Aug 2008 19:15:58 +0100, J. Clarke wrote (in article ):

I was taking that for granted, My point of irony _included_, and was essentially about, the definition of protracted spin-down time being dangerous and was the whole point of the query, hence my asking for opinion on that very issue.

THAT was the very issue you ducked out of answering.

I think most people spotted that :-)

It's very hard explaining to someone how to "get" a joke. Maybe I'll wear a red nose next time. (insert emoticon of limey wearing red nose and baggy pants with a custard pie down his shorts)

Ok, I obviously explained this rather badly.

The tractability thing is all about torque, not horses gained from high rpm. If you have, say, a 1200cc motor (convert it yourself, but I think it's 74 cubes) running at low revs, it may well produce the same bhp as a 200cc motor running at higher revs, but the torque will be very much greater.

In practical terms, this means that the big motor will produce _usable_ power throughout its rev range while the small engine needs to be revved to near its limit to, say, prevent stalling or to produce "acceleration" (used in the popular rather than the "scientific" sense - I note that there are pedants about.) An inexperienced rider is therefore presented with a throttle control which turns under his hand with no appreciable effect on the road until suddenly, the usable power cuts it like throwing a switch. Contrast that with the smooth and predictable power available from the bigger, slower-revving engine where the relationship between throttle position and road speed is (perceptibly) linear.

A 125cc 10 bhp will typically need to be revved to (guessing) 10-14000 rpm to produce the same road speed as a 60 horse motor ticking away at (again guessing - don't pick a fight over the exact figures) 2 or 3 thousand rpm. The low displacement motor needs very precise gear-stick dancing to keep it running in its usable power range. If the revs drop as traffic speed drops, power will not be available to keep up with the next increase in mean traffic speed unless the motor is revved back into its power band and the rider controls road speed with the gears. A bigger engine can just be tailed off and picked up again on the throttle.

This relationship breaks down as one begins to approach the speed of light, of course, which makes it harder to draw graphs in crayons of only one colour.

The point I _thought_ I was making was that U.K. legislation has decreed that inexperienced riders must use machines which really need more experience to drive safely on the road than the bigger machines that they are banned from using.

Therefore, legislation is not the arbiter of truth.

Come on, you like to prod me on the side-issues - have the courage to answer the question :-)

Reply to
Bored Borg

Guess that's better than cooking indoors with charcoal and choking to death.

Reply to
Upscale

Motorcycles don't have gear-sticks. At least not modern ones. They shift with a pedal, with each pedal movement shifting one gear up or down.

You still haven't explained how a horsepower limit causes the problems you describe.

Here are two 35 hp motorcycles that are popular in the US.

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has 500 cc, producing 34 horsepower at 6400 RPM and 32 foot-pounds of torque at 3200 RPM.

The other has 250 cc, producing 36 horsepower at 11,000 RPM and 16 foot-pounds of torque at 9500 RPM.

A 1200 cc VW also produces 36 horsepower at even lower RPM and with even more torque and before you say something ignorant about VW engines being unsuited to use in motorcycles you might want to google "Amazonas Motorcycle", which was series produced in Brazil using a VW engine.

So you see that there is nothing in a _horsepower_ limit that requires that an engine be intractable. A large engine can easily be detuned to produce low power and in the process it gains tractability.

The concerns that you express would be the result of a _displacement_ limit, not a horsepower limit.

I figured you were trolling and the comments you made above ("pompous waffle" etc) tend to confirm that. Sorry, Borg, but I'm not going to alleviate your boredom that way.

Reply to
J. Clarke

In California, you are prone to get cancer when you buy and use darn near anything.

Reply to
Mark & Juanita

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