My old Craftsman did, and anti kickback pawls.
"Morris Dovey" <[email protected]> wrote in message
news:[email protected]...
> Joseph Handy (in [email protected]) said:
>
> The RAS doesn't normally have a splitter that keeps ripped wood from
> pinching the blade.
>
> --
> Morris Dovey
> DeSoto Solar
> DeSoto, Iowa USA
> http://www.iedu.com/DeSoto
>
>
On Sun, 19 Mar 2006 22:50:25 GMT, "John Eppley" <[email protected]>
wrote:
[top posted for your convenience]
I believe you've seriously misapplied the "Right Hand Rule". For those
wondering, it's what describes the operation of gyroscopes. The
analogy between gyroscopes and radial arm saws that might permit the
application of the RHR fails when you consider that a gyroscope will
tend to right itself in accordance with the RHR when a force is
applied parallel to its axis and perpendicular to the plane of the
rotating mass (let's call it a disc for this discussion).
However, all the forces applied in the motion of the carriage of a
radial arm saw are perpendicular to the axis and in the plane of the
disc. In order to apply the analog of the gyroscope, you would have to
apply a force to the edge of the saw blade (disc) perpendicular to the
disc, which would be a very dangerous thing to attempt and would trump
all other calamaties attributed to the RAS.
You can turn a gyroscope all day long in the same axis in which the
disc is spinning and no precession will occur. It's the same with the
radial arm saw.
>I have owned several RAS during the last 4 decades. I gave my last RAS to my
>son. There is a mechanical (law of physics) problem with a column mounted
>RAS. It is know as the "Right Hand Rule". Simply put, if you curl your
>fingers in the direction of the spin of the motor, your thumb points to the
>direction of a significant undesirable force that is being applied to the
>motor and blade. Additionally, the further from the column the force is
>applied, the greater the longitudinal pressure is directed to the arm and
>saw.
>
>Basically, this force is trying very hard to force the arm away from a true
>90 degree track. It is also magnified when dadoing in a crosscut mode.
>Again, the greater the depth of cut, the greater the resulting force on the
>arm and the greater the possible inaccuracy. The Delta 12" RAS is
>constructed differently. Notice that it is suspended on a track that is
>centered on the main arm. Theoretically, the error is "averaged out" over
>the travel.
>
>I have learned to minimize the errors to a tolerable degree but I've never
>been able to guarantee myself a truly "square" set of cuts over a large
>area.
>
>I still miss my old RAS.
>
>John
>
--
LRod
Master Woodbutcher and seasoned termite
Shamelessly whoring my website since 1999
http://www.woodbutcher.net
Proud participant of rec.woodworking since February, 1997
email addy de-spam-ified due to 1,000 spams per month.
If you can't figure out how to use it, I probably wouldn't
care to correspond with you anyway.
For what its worth, a few years back I had to rip a few hundred bd ft of
wood to very narrow widths. less the 1/2 inch. I set up the RAS to rip the
boards with the back of the blade slightly canted toward the fence and a
splitting pawl set up about 18" back of the blade. After each cut the
narrow strip would fly out of the saw fly through the shop door and land
about 20 ft out in the yard. They all landed in a "fairly" neat pile and the
kick back was never near me. It was a lot easier then using a push stick to
clear the saw blade with each cut and seemed to work quite well. It is the
only time I have ever tried to get a saw to intently kick back
"Ba r r y" <[email protected]> wrote in message
news:[email protected]...
> On Sun, 19 Mar 2006 17:02:31 -0600, "Morris Dovey" <[email protected]>
> wrote:
>
> >dadiOH (in eXkTf.2718$I7.2200@trnddc03) said:
> >
> >| Someone mentioned that they lack
> >| splitters but I've never seen one that doesn't have a splitter and
> >| pawls to grab any kickback.
> >
> >I've never seen a RAS with a splitter (you can get a look at mine in
> >the top two photos at http://www.iedu.com/DeSoto/RAS_Table.html).
>
> Since most kickback involves the rear of the blade lifting the board,
> would the basic design of a RAS mellow it? The "kickback" would
> actually be forced down into the table.
>
> Barry
Ba r r y (in [email protected]) said:
| Since most kickback involves the rear of the blade lifting the
| board, would the basic design of a RAS mellow it? The "kickback"
| would actually be forced down into the table.
I don't know. When I first got the RAS (early 70's) I shot a 1x6x96
about 30'. It didn't have a pronounced downward vector, nor did it
seem mellowed in any way.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
The particle board table top is not as smooth as cast iron. Other than that,
nothing.
"Joseph Handy" <[email protected]> wrote in message
news:[email protected]...
> What make the RAS an inferior tool for ripping?
>
> Joseph
>
"Morris Dovey" <[email protected]> wrote in message
news:[email protected]...
> dadiOH (in eXkTf.2718$I7.2200@trnddc03) said:
>
> | Someone mentioned that they lack
> | splitters but I've never seen one that doesn't have a splitter and
> | pawls to grab any kickback.
>
> I've never seen a RAS with a splitter (you can get a look at mine in
> the top two photos at http://www.iedu.com/DeSoto/RAS_Table.html). The
> anti-kickback pawls _are_ pretty much standard; but it's a whole lot
> better to prevent kickback in the first place. I do _all_ my ripping
> on the TS - and nearly always with all three of splitter, hold-down
> rollers, and featherboard.
I had a Craftsman TAS and the splitter was a small plastic wheel that was
located between the kick back paws.
I have owned several RAS during the last 4 decades. I gave my last RAS to my
son. There is a mechanical (law of physics) problem with a column mounted
RAS. It is know as the "Right Hand Rule". Simply put, if you curl your
fingers in the direction of the spin of the motor, your thumb points to the
direction of a significant undesirable force that is being applied to the
motor and blade. Additionally, the further from the column the force is
applied, the greater the longitudinal pressure is directed to the arm and
saw.
Basically, this force is trying very hard to force the arm away from a true
90 degree track. It is also magnified when dadoing in a crosscut mode.
Again, the greater the depth of cut, the greater the resulting force on the
arm and the greater the possible inaccuracy. The Delta 12" RAS is
constructed differently. Notice that it is suspended on a track that is
centered on the main arm. Theoretically, the error is "averaged out" over
the travel.
I have learned to minimize the errors to a tolerable degree but I've never
been able to guarantee myself a truly "square" set of cuts over a large
area.
I still miss my old RAS.
John
"John Eppley" <[email protected]> wrote in message
news:[email protected]...
>I have owned several RAS during the last 4 decades. I gave my last RAS to
>my son. There is a mechanical (law of physics) problem with a column
>mounted RAS. It is know as the "Right Hand Rule". Simply put, if you curl
>your fingers in the direction of the spin of the motor, your thumb points
>to the direction of a significant undesirable force that is being applied
>to the motor and blade. Additionally, the further from the column the force
>is applied, the greater the longitudinal pressure is directed to the arm
>and saw.
>
Well, that explains why my router table keeps levitating!
You are kidding right? My full width cuts are dead square.
dadiOH (in eXkTf.2718$I7.2200@trnddc03) said:
| Someone mentioned that they lack
| splitters but I've never seen one that doesn't have a splitter and
| pawls to grab any kickback.
I've never seen a RAS with a splitter (you can get a look at mine in
the top two photos at http://www.iedu.com/DeSoto/RAS_Table.html). The
anti-kickback pawls _are_ pretty much standard; but it's a whole lot
better to prevent kickback in the first place. I do _all_ my ripping
on the TS - and nearly always with all three of splitter, hold-down
rollers, and featherboard.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
"Joseph Handy" <[email protected]> wrote in message
news:[email protected]...
> This is an extension of the earlier post regarding RAS's and Miters Saws.
> How about RAS versatility? It will do crosscuts, and rips, and miters and
> dados. How about bevels? Anything else? Is there any reason not to do
> dados on a table saw? What make the RAS an inferior tool for ripping?
>
Crosscut dados are much easier on the RAS. Rip dados are much easier on the
TS. For the same reason crosscuts are easier on a RAS and ripping is easier
on a TS.
RAS will do anything a CMS will do, but is awkward to set up. I would not
have gotten rid of my CMS if I did many. However, the RAS will do many
things a CMS will not do, like dado. But it will also go into positions
that can only be done with a RAS, like horizontal cuts. I have not had
occassion to do any of them, but might someday.
Ripping is undesirable for several reasons. You are restricted to a 19 wide
cut. The table is not as big, so support can be a problem. You are working
with MDF instead of cast iron and steel/aluminum, so it just doesn't work as
well. But the biggest problem is with kickback, which is much worse on a
RAS than a TS. It's just a bad idea.
Joseph Handy (in [email protected]) said:
| This is an extension of the earlier post regarding RAS's and Miters
| Saws. How about RAS versatility? It will do crosscuts, and rips,
| and miters and dados. How about bevels? Anything else? Is there
| any reason not to do dados on a table saw? What make the RAS an
| inferior tool for ripping?
There's no reason not to do dados on a TS. I've found that _angled_
(diagonal) dados are somewhat easier on my RAS than on my TS; but I
use whichever seems to best fit what I'm doing.
The RAS doesn't normally have a splitter that keeps ripped wood from
pinching the blade.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
Ba r r y (in [email protected]) said:
| On Sun, 19 Mar 2006 17:59:19 -0600, "Morris Dovey"
| <[email protected]> wrote:
|
|
||
|| I don't know. When I first got the RAS (early 70's) I shot a 1x6x96
|| about 30'. It didn't have a pronounced downward vector, nor did it
|| seem mellowed in any way.
|
| Now that I think of it, it would trap the board, just like routing
| with the board between the bit and the fence.
|
| Ouch! <G>
There wasn't any 'ouch' - at least not a human one. The good news is
that was also my _last_ incidence of RAS kickback. Since then I've
used that machine to rip, mold, and rebate thousands of feet without a
second 'event' - and I'm inclined to chalk that one up to ignorance,
over-confidence, and failing to set the anti-kickback pawls properly.
It wasn't long after that I made my first featherboard and hold-down
fixture for ripping.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
On Sun, 19 Mar 2006 17:02:31 -0600, "Morris Dovey" <[email protected]>
wrote:
>dadiOH (in eXkTf.2718$I7.2200@trnddc03) said:
>
>| Someone mentioned that they lack
>| splitters but I've never seen one that doesn't have a splitter and
>| pawls to grab any kickback.
>
>I've never seen a RAS with a splitter (you can get a look at mine in
>the top two photos at http://www.iedu.com/DeSoto/RAS_Table.html).
Since most kickback involves the rear of the blade lifting the board,
would the basic design of a RAS mellow it? The "kickback" would
actually be forced down into the table.
Barry
Joseph Handy wrote:
> This is an extension of the earlier post regarding RAS's and Miters Saws.
> How about RAS versatility? It will do crosscuts, and rips, and miters and
> dados. How about bevels? Anything else? Is there any reason not to do
> dados on a table saw? What make the RAS an inferior tool for ripping?
>
> Joseph
Joseph,
Concerning the posts you're seeing on ripping, I have to disagree. Ripping
works great on a RAS -if- you use a sled. A sled is simply a flat piece of
material, usually larger than the working piece. A big piece of MDF works
great. By firmly clamping the work piece onto the sled, it's nearly
impossible to get the work piece to bind. And even if it does, you're
nowhere near where the material will be sent flying. Plus, your fingers
have no reason at all to even approach the spinning blade.
When I use a sled to rip, the cuts are straight enough to glue together
without jointing. I can send you pics if you like.
The only down side is the weight and bulkiness. So for really big pieces,
you're gonna need table extensions or rollers. But the same would hold
true for a table saw. And, for really big pieces, it'd be true without the
sled.
--
Michael White "To protect people from the effects of folly is to
fill the world with fools." -Herbert Spencer
Joseph Handy wrote:
> This is an extension of the earlier post regarding RAS's and Miters
> Saws. How about RAS versatility? It will do crosscuts, and rips, and
> miters and dados. How about bevels?
Sure.
_____________
> Anything else?
There are tons of accessories for them...sanding disk plates, sanding
drums, router collets, molding heads, soft sanding pads, rotary planers,
etc. Some work well, others don't.
_____________
> Is there any
> reason not to do dados on a table saw? What make the RAS an inferior
> tool for ripping?
It's not so much that it is inferior (the result, i.e.), just that a
table saw is *designed* for ripping. When ripping with a RAS, you have
to contend with the saw itself being in the way. Additionally, the
blade motion wants to lift the work (same with dados) so one has to be
alert. Someone mentioned that they lack splitters but I've never seen
one that doesn't have a splitter and pawls to grab any kickback.
--
dadiOH
____________________________
dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico
On Sun, 19 Mar 2006 17:59:19 -0600, "Morris Dovey" <[email protected]>
wrote:
>
>I don't know. When I first got the RAS (early 70's) I shot a 1x6x96
>about 30'. It didn't have a pronounced downward vector, nor did it
>seem mellowed in any way.
Now that I think of it, it would trap the board, just like routing
with the board between the bit and the fence.
Ouch! <G>
Barry