Disk sanders?

The 6" belt, 12" disk JET or Delta combos are sturdy, have real trunnions on
the iron tables, and can be set with precision to use circle-sanding or even
miter-sanding (so long shooting board) jigs. While the most useful part of
the combo is the disc, there are certain applications like reducing proud
dovetails or box joint ends where the belt does a more reliable job.

The safety stop gives full use of the platen, which is the only reliable
part anyway, though I mostly keep the iron table on mine for square.

"Silvan" <[email protected]> wrote in message
news:[email protected]...

> Having said all that, these combination machines aren't as useful as they
> look. I will probably buy another one when this one dies, but that's
> because I lack space. If I had space (and money), I would get a dedicated
> 12" disc sander and a big belt such as the one you're asking about. The
> 36" belt is really too short for work of any size at all. If you keep the
> safety fence on the back, you only get to use 3/4 of the length. You have
> to watch out for rounding long stock in the middle with the crown on the
> front roller too.

SNIP in and out

Gotta do some thinking here.

A given section of belt is in contact with a long edge _much_ longer than a
given section on the disk takes to go across the piece.

Then there's the insulating graphite under the belt, rather than the heat
sink aluminum under the disk....

"Roy Smith" <[email protected]> wrote in message
news:[email protected]...

>
> Is there any reason a disk should heat up less than a belt? In fact, it
> seems like the belt should heat up less, since a belt (even a short one
> like a 6x48) has much more total surface area, so the spot that was just
> touching the wood has more time to cool off before it's touching wood
> again.
>
> I'm not trying to be argumentitive here, I just don't understand why all
> these things you can do with a disk sander can't be done as well with a
> belt sander just as easily?

"Edwin Pawlowski" writes:

> I'm missing something here. I bought a belt/spindle combo over the
disc/belt
> combo because I thought it somewhat redundant. Especially the smaller
ones.
>
> A wide belt moves in one direction. I can hold a piece of wood against it
> and get a flush, smooth surface. I can move the wood free hand and round
> corners, bevel edges, etc.
>
> A disc rotates and one side is going up, the other side is going down. It
> has a 12" cross section and larger overall area than a belt. (my 24" belt
> is probably 11" exposed at best, 4" high), but does it really do more or
> different things? Is the circular pattern better for some sanding?
>
> How does the disc sander make a perfectly round wheel? Are you rotating
the
> piece as you push it against the disc? If so, why would a belt not do the
> same?

A disk sander is sanding across the grain rather than with it when using a
belt.

It provides rapid, accurate stock removal with a minimum of heat build up.

And yes, you mount the wheel blank on an axle pin that is mounted in a miter
bar that is clamped in the table.

The blank is then rotated to finish size.

> The little 1" belt and 5" disc combos looked rather like toys to me and
> close to useless in a shop, but they make them and people buy them, so
> perhaps they have some value.

Yep, they sure are cute. Have used the 1" belt to sharpen a pair if
scissiors a time or two.

--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures

"Roy Smith" <[email protected]> wrote in message
news:[email protected]...
> I've been looking at power sanders. The combo disk/belt sander seems
> pretty popular but I'm having a hard time figuring out what you do with
> the disk part. Or rather, what you can do with the disk part that you
> couldn't with the belt part. And once you've decided the disk part is
> rather pointless, why not spend the same money and get a much bigger
> belt-only machine (like a 6 x 89 belt sander).
>
> Am I off on the wrong track? Is a disk sander something that's actually
> useful in wood shop?

I'm lucky enough to have a 16" Apex Patternmakers disc sander in my shop and
use it for everything wood or metal. I can trim angles on any materials as
accurate as I can set the machine up and it's great for sizing parts to
exact length. I've had discs from 8" to 16" now and think 12" is about the
minimum size that useful, the bigger the better.

Ed Angell

"Lew Hodgett" <[email protected]> wrote in message
>
> If you ever decide to build a boat, you will find no other piece of
> equipment that can do the job of a good disk sander.
>
> Most of the combo units I seen leave a lot to be desired IMHO, but OTOH, a
> disk sander can do magic.
>
> As an example, a disk sander will allow you to cut a wheel form flat stock
> and then sand it to a perfectly round circle.

I'm missing something here. I bought a belt/spindle combo over the disc/belt
combo because I thought it somewhat redundant. Especially the smaller ones.

A wide belt moves in one direction. I can hold a piece of wood against it
and get a flush, smooth surface. I can move the wood free hand and round
corners, bevel edges, etc.

A disc rotates and one side is going up, the other side is going down. It
has a 12" cross section and larger overall area than a belt. (my 24" belt
is probably 11" exposed at best, 4" high), but does it really do more or
different things? Is the circular pattern better for some sanding?

How does the disc sander make a perfectly round wheel? Are you rotating the
piece as you push it against the disc? If so, why would a belt not do the
same?

The little 1" belt and 5" disc combos looked rather like toys to me and
close to useless in a shop, but they make them and people buy them, so
perhaps they have some value.
Ed
[email protected]
http://pages.cthome.net/edhome

You are right.

"Silvan" <[email protected]> wrote in message
news:[email protected]...
> Roy Smith wrote:
>
> > Why any more so than a belt sander? If I put the same grit on both
> > kinds, won't they remove stock at the same rate? Is there any reason
> > the disk should be more accurate?
>
> Don't ask me for the science. All I have is real-world experience. A
disc
> is *much* faster than a belt at the same grit for dealing with end grain.
>
> A disc is not a good choice for sanding the face of a 12" long board.
> Either a disc or a belt could be used to sand the end of such a board, so
I
> think comparing end grain to end grain is reasonable.
>
> Why is it so? I'll make an educated guess.
>
> The motor turns both parts of a combo machine at some fixed speed. I
don't
> know what speed it is off hand, but let's call it 2,000 RPM for the sake
of
> argument.
>
> The 6" disc is spinning at 2,000 RPM, and so is the ~4" power roller on
the
> belt. I have no idea off hand how to calculate the difference, but any
> idiot can see that a point on the outer edge of the disc is travelling
much
> further than a point on the outer edge of the roller in the same span of
> time. It's spinning the paper right along with it, so I would expect the
> surface feet per minute of abrasive making contact with the wood is higher
> with the disc.
>
> People who aren't math retards feel free to step in and explain this with
> all kinds of mind boggling formulae. Maybe I'm not looking at this right.
> There's got to be some allowance for the fact that every point along the
> width of a belt is moving at the same speed, while a disc is slower toward
> the "eye," so that probably mitigates my point somewhat.
>
> Anyway, I have no real idea why it's so. Just experience that it is.
>
> > Is there any reason a disk should heat up less than a belt? In fact, it
> > seems like the belt should heat up less, since a belt (even a short one
> > like a 6x48) has much more total surface area, so the spot that was just
> > touching the wood has more time to cool off before it's touching wood
> > again.
>
> End grain to end grain, my experience is that the disc will heat up much
> faster. Probably because it's moving more abrasive in the same amount of
> time and cutting faster. Probably. :)
>
> --
> Michael McIntyre ---- Silvan <[email protected]>
> Linux fanatic, and certified Geek; registered Linux user #243621
> http://www.geocities.com/Paris/Rue/5407/
>

Roy Smith wrote:
>Am I off on the wrong track?

Yes.

>Is a disk sander something that's actually useful in wood shop?

Yes.

UA100

"Roy Smith" writes:

> I've been looking at power sanders. The combo disk/belt sander seems
> pretty popular but I'm having a hard time figuring out what you do with
> the disk part.
<snip>

If you ever decide to build a boat, you will find no other piece of
equipment that can do the job of a good disk sander.

Most of the combo units I seen leave a lot to be desired IMHO, but OTOH, a
disk sander can do magic.

As an example, a disk sander will allow you to cut a wheel form flat stock
and then sand it to a perfectly round circle.

Sand the end of a piece of molding free hand to some weird shape. It's disk
sander time.

I built mine from about 1/2 sheet of 3/4" ply, an old motor and a 12" disk
from an old ShopSmith. (Took the plans straight out of Fred Bingham's book).

Like American Express, don't leave home without it.

OTOH, my experience is the belt on those combo sanders walks all over the
place, and in general does a poor job.

YMMV.

HTH


--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures

George wrote:

> The 6" belt, 12" disk JET or Delta combos are sturdy, have real trunnions
> on the iron tables, and can be set with precision to use circle-sanding or

Hrm... Didn't know that. I know the machines you're talking about. About
$250ish on sale? Indeed, one of those critters would be a good step up
above my 4" belt 6" disc jobbie.

No more than I use it though, I'd still rather sink the cashola into more
hand planes and related whatnots though.

--
Michael McIntyre ---- Silvan <[email protected]>
Linux fanatic, and certified Geek; registered Linux user #243621
http://www.geocities.com/Paris/Rue/5407/

I wrote:

> > A disk sander is sanding across the grain rather than with it when using
a
> > belt.

"Roy Smith" asks:

> Isn't that just a function of how you put the piece of wood on the belt
> sander table?

The answer is a definite "maybe"; however, most of the time a disk sander
will be operating across the grain.

I wrote:
> > It provides rapid, accurate stock removal with a minimum of heat build
up.

"Roy Smith" asks:
> Why any more so than a belt sander? If I put the same grit on both
> kinds, won't they remove stock at the same rate? Is there any reason
> the disk should be more accurate?

In addition to sanding across the grain, the disk paper is uaually crossing
the wood at a higher rate of speed than with a belt.

The disk also has a more limited contact surface than a belt. Think of it as
a line of contact.

This will result in faster and more accurate stock removal.

"Roy Smith" asks:

> Is there any reason a disk should heat up less than a belt?

Yes, since the surface area in contact with the sand paper is smaller when
using a disk, less heat will be generated.

"Roy Smith" asks:

> In fact, it
> seems like the belt should heat up less, since a belt (even a short one
> like a 6x48) has much more total surface area, so the spot that was just
> touching the wood has more time to cool off before it's touching wood
> again.

It's just the opposite. The material being sanded is the source of the heat,
not the sand paper.

"Roy Smith" asks: >
> I'm not trying to be argumentitive here, I just don't understand why all
> these things you can do with a disk sander can't be done as well with a
> belt sander just as easily?

No problem.

IMHO, a belt sander, unless it is the type found in cabinet shops having a
cost around $1,500-$2,500, is not a very useful tool.

HTH


--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures

Roy Smith wrote:

> Why any more so than a belt sander? If I put the same grit on both
> kinds, won't they remove stock at the same rate? Is there any reason
> the disk should be more accurate?

Don't ask me for the science. All I have is real-world experience. A disc
is *much* faster than a belt at the same grit for dealing with end grain.

A disc is not a good choice for sanding the face of a 12" long board.
Either a disc or a belt could be used to sand the end of such a board, so I
think comparing end grain to end grain is reasonable.

Why is it so? I'll make an educated guess.

The motor turns both parts of a combo machine at some fixed speed. I don't
know what speed it is off hand, but let's call it 2,000 RPM for the sake of
argument.

The 6" disc is spinning at 2,000 RPM, and so is the ~4" power roller on the
belt. I have no idea off hand how to calculate the difference, but any
idiot can see that a point on the outer edge of the disc is travelling much
further than a point on the outer edge of the roller in the same span of
time. It's spinning the paper right along with it, so I would expect the
surface feet per minute of abrasive making contact with the wood is higher
with the disc.

People who aren't math retards feel free to step in and explain this with
all kinds of mind boggling formulae. Maybe I'm not looking at this right.
There's got to be some allowance for the fact that every point along the
width of a belt is moving at the same speed, while a disc is slower toward
the "eye," so that probably mitigates my point somewhat.

Anyway, I have no real idea why it's so. Just experience that it is.

> Is there any reason a disk should heat up less than a belt? In fact, it
> seems like the belt should heat up less, since a belt (even a short one
> like a 6x48) has much more total surface area, so the spot that was just
> touching the wood has more time to cool off before it's touching wood
> again.

End grain to end grain, my experience is that the disc will heat up much
faster. Probably because it's moving more abrasive in the same amount of
time and cutting faster. Probably. :)

--
Michael McIntyre ---- Silvan <[email protected]>
Linux fanatic, and certified Geek; registered Linux user #243621
http://www.geocities.com/Paris/Rue/5407/

"Lew Hodgett" <[email protected]> wrote in message
> A disk sander is sanding across the grain rather than with it when using a
> belt.
>
> It provides rapid, accurate stock removal with a minimum of heat build up.

OK, that makes a lot of sense. Thanks for the explanation.
Ed

Roy Smith wrote:

> rather pointless, why not spend the same money and get a much bigger
> belt-only machine (like a 6 x 89 belt sander).

> Am I off on the wrong track? Is a disk sander something that's actually
> useful in wood shop?

You're not really on the wrong track. It's a good question to ask.

As others have said, the main thing a disc gets you is speed. Real world
example, making trucks for BRIO-style train parts. The ones I make are
rounded gently to a sort of plateau at the top. I could produce this shape
in other ways, but the disc on my combo sander rips through these little
pine blocks in a few seconds each. Brrrt, brrrt, done.

Another use is squaring stock. Say you cut a dowel freehand with a backsaw
or something, and the end isn't quite square. Slap the miter gauge on the
table, hold the dowel against the fence, and sand it square in no time.
Also useful for squaring the ends of angle iron and such.

Having said all that, these combination machines aren't as useful as they
look. I will probably buy another one when this one dies, but that's
because I lack space. If I had space (and money), I would get a dedicated
12" disc sander and a big belt such as the one you're asking about. The
36" belt is really too short for work of any size at all. If you keep the
safety fence on the back, you only get to use 3/4 of the length. You have
to watch out for rounding long stock in the middle with the crown on the
front roller too.

The effective length of work that can be sanded in a tidy, secure fashion is
something shy of a foot, I'd say. A bigger belt would be *considerably*
more useful if you make anything human-sized. They're great for small
projects, but near useless for furniture. Not much good for larger picture
frame parts either.

Now that I've discovered the joy of hand planes and scrapers, my belt/disc
sander sees more use for regrinding chipped up bevels on plane irons than
anything else. I rarely sand wood with it anymore.

--
Michael McIntyre ---- Silvan <[email protected]>
Linux fanatic, and certified Geek; registered Linux user #243621
http://www.geocities.com/Paris/Rue/5407/

"Lew Hodgett" <[email protected]> wrote:
> A disk sander is sanding across the grain rather than with it when using a
> belt.

Isn't that just a function of how you put the piece of wood on the belt
sander table?

> It provides rapid, accurate stock removal with a minimum of heat build up.

Why any more so than a belt sander? If I put the same grit on both
kinds, won't they remove stock at the same rate? Is there any reason
the disk should be more accurate?

Is there any reason a disk should heat up less than a belt? In fact, it
seems like the belt should heat up less, since a belt (even a short one
like a 6x48) has much more total surface area, so the spot that was just
touching the wood has more time to cool off before it's touching wood
again.

I'm not trying to be argumentitive here, I just don't understand why all
these things you can do with a disk sander can't be done as well with a
belt sander just as easily?

In article <Fl7Gb.186218$_M.849487@attbi_s54>,
"Ed Angell" <[email protected]> wrote:

> "Roy Smith" <[email protected]> wrote in message
> news:[email protected]...
> > I've been looking at power sanders. The combo disk/belt sander seems
> > pretty popular but I'm having a hard time figuring out what you do with
> > the disk part. Or rather, what you can do with the disk part that you
> > couldn't with the belt part. And once you've decided the disk part is
> > rather pointless, why not spend the same money and get a much bigger
> > belt-only machine (like a 6 x 89 belt sander).
> >
> > Am I off on the wrong track? Is a disk sander something that's actually
> > useful in wood shop?
>
> I'm lucky enough to have a 16" Apex Patternmakers disc sander in my shop and
> use it for everything wood or metal. I can trim angles on any materials as
> accurate as I can set the machine up and it's great for sizing parts to
> exact length. I've had discs from 8" to 16" now and think 12" is about the
> minimum size that useful, the bigger the better.
>
> Ed Angell
>
>

OK, I understand that you can do those things on a disk sander, but
could you not also do them on a belt sander? Is there something special
about the disk that makes it better for these things than a belt?

On Tue, 23 Dec 2003 22:27:04 -0500, Roy Smith <[email protected]> wrote:

>In article <Fl7Gb.186218$_M.849487@attbi_s54>,
> "Ed Angell" <[email protected]> wrote:
>
>> "Roy Smith" <[email protected]> wrote in message
>> news:[email protected]...
>> > I've been looking at power sanders. The combo disk/belt sander seems
>> > pretty popular but I'm having a hard time figuring out what you do with
>> > the disk part. Or rather, what you can do with the disk part that you
>> > couldn't with the belt part. And once you've decided the disk part is
>> > rather pointless, why not spend the same money and get a much bigger
>> > belt-only machine (like a 6 x 89 belt sander).
>> >
>> > Am I off on the wrong track? Is a disk sander something that's actually
>> > useful in wood shop?
>>
>> I'm lucky enough to have a 16" Apex Patternmakers disc sander in my shop and
>> use it for everything wood or metal. I can trim angles on any materials as
>> accurate as I can set the machine up and it's great for sizing parts to
>> exact length. I've had discs from 8" to 16" now and think 12" is about the
>> minimum size that useful, the bigger the better.
>>
>> Ed Angell
>>
>>
>
>OK, I understand that you can do those things on a disk sander, but
>could you not also do them on a belt sander? Is there something special
>about the disk that makes it better for these things than a belt?

Speed. Since the disk sander is usually cutting cross grain it will
remove material much quicker than a belt which is cutting with the
grain. This feature, plus the others mentioned, is why large disk
sanders are the standard in pattern making shops.

A large disk sander fitted with 40grit paper makes an excellent metal
removal tool.

WRT to your other question regarding making circles, yes the material
is rotated as its held agains the disk. No elaborate jigs are
required as long as your layout line is plainly visible. A surprising
amount of accuracy can be achieved with a good eye and steady hand.

Ideally, to cover all eventualities you'd want a disk, belt and
spindle sander. All serve different functions. If 3 machines isnt an
option you need to examine the type of work you do and fit the machine
to that.

For the grandmother of disk/spindle sanders see
http://www.statemfg.com

No connection, just a very satisfied user here.

"Roy Smith" <[email protected]> wrote in message
news:[email protected]...
> "Lew Hodgett" <[email protected]> wrote:
> > A disk sander is sanding across the grain rather than with it when using
a
> > belt.
>
> Isn't that just a function of how you put the piece of wood on the belt
> sander table?

Yes, if you are sanding the end of a 1" x 1" piece. In most cases you are
laying the flat piece on a table top and pushing it into the moving belt or
disk. The horizontal belt will move in the direction of the grain while the
disk is perpendicular to it. I was just told this yesterday so I have to
real life data as to how much faster the disk would be. I do know that if I
wanted to sand across the grain on a 10" long board, I could not do it on my
4" wide belt.

>
> Is there any reason a disk should heat up less than a belt? In fact, it
> seems like the belt should heat up less, since a belt (even a short one
> like a 6x48) has much more total surface area, so the spot that was just
> touching the wood has more time to cool off before it's touching wood
> again.

Depends on the sizes, of course, but look at this comparison.. Surface area
of a belt may be more, but the actual contact areas may be much less. I use
4 x 24 belts. They are 96 aquare inches of surface. On the sander though,
a 1" thick board may only be contacting 24 sq. inches of the total available
belt. This is because it is laying flat on the table for stability. a 12"
rotating disk has 113 sq. inches of surface that is rotating around the
exposed side of the board. My belt is oscillating so in fact it may contace
30" or 36" of the belt. I've not measured the stroke.


>
> I'm not trying to be argumentitive here, I just don't understand why all
> these things you can do with a disk sander can't be done as well with a
> belt sander just as easily?

I think most can but I'll leave the final answer to those with more
experience than I have. Now if you compare to the really big industrial
models, you can have one huge disk to work against.
Ed
[email protected]
http://pages.cthome.net/edhome

Roy - A disc sander is IMHO a very good tool, provided it is of sufficient
quality to be safe accurate and fast. I just side lined my combo belt/disc
sander for the new JET 708433 12". In just the past week, I have used it a
great deal and have not fired up the combo once. If forced to toss one or
the other it would be the combo without hesitation.

Dave

Jet disc sander.
http://www.amazon.com/exec/obidos/tg/detail/-/B00006J6PS/002-0283797-8768878?v=glance


"Roy Smith" <[email protected]> wrote in message
news:[email protected]...
> I've been looking at power sanders. The combo disk/belt sander seems
> pretty popular but I'm having a hard time figuring out what you do with
> the disk part. Or rather, what you can do with the disk part that you
> couldn't with the belt part. And once you've decided the disk part is
> rather pointless, why not spend the same money and get a much bigger
> belt-only machine (like a 6 x 89 belt sander).
>
> Am I off on the wrong track? Is a disk sander something that's actually
> useful in wood shop?