I've searched the archives on r.w. and the internet about building my
own drum sander, but one question remains about the operation these
sanders:

Let's say I build a 20" wide unit. Am I able to sand a 40" wide piece
by sending it through twice, or will a sanding line develop? If I
can't do this satisfactorily, is a 20" useful enough to build?

Thx.

On 22 Nov 2004 11:20:44 -0800, (Larry Bud)
wrote:

I've searched the archives on r.w. and the internet about building my
own drum sander, but one question remains about the operation these
sanders:

Let's say I build a 20" wide unit. Am I able to sand a 40" wide piece
by sending it through twice, or will a sanding line develop? If I
can't do this satisfactorily, is a 20" useful enough to build?

Thx.
I saw an interesting home brew setup at a local artisan (Keith Allen).
He had a long sanding belt (6 to 8 inch wide) strung over a sliding
table that slid crossways back and forth under the belt. The belt was
driven directly by a 1/2 HP motor with a 4 inch drive. In operation
the workpiece would be blocked up so it was slightly below the
underside of the belt and he had a pressure block that he moved by
hand on the inside of the belt to apply varying degrees of pressure.
So he would work the pressure block along the inside of the belt
(lengthwise with the workpiece) while sliding the workpiece from one
side to the other so the full length and width of the board could be
sanded. The sanding rate was a function of grit (which I think he
never changed) and the amount of pressure he applied with the pressure
block. The length was limited by the length the belt (I think he
could sand something up to six feet long) and the width was limited by
how far he could reach with the pressure block.

A very interesting and relatively easy thing to build.

TWS

Unless you have a source for metal casting, it's going to be VERY DIFFICULT
to build a drum sander on a cantilevered frame that is rigid enough for
even, consistent thickness sanding. By far, the most effective way to
homebrew something like that would be to support the sanding drum at both
ends.

Unless you're going to be doing tabletops or something like that, a 20"
capacity should be good enough for most projects. You can always make
glue-ups for anything wider.

"Larry Bud" wrote in message
om...
I've searched the archives on r.w. and the internet about building my
own drum sander, but one question remains about the operation these
sanders:

Let's say I build a 20" wide unit. Am I able to sand a 40" wide piece
by sending it through twice, or will a sanding line develop? If I
can't do this satisfactorily, is a 20" useful enough to build?

Thx.

On 22 Nov 2004 11:20:44 -0800, (Larry Bud)
wrote:

Let's say I build a 20" wide unit. Am I able to sand a 40" wide piece
by sending it through twice, or will a sanding line develop?

There are two ways to build a sander - single or double ended. A
single-ended machine has a cantilevered beam that's open at one end.
You can indeed sand double-width boards by this method. However the
obvious problem is that of the beam bending upwards under the working
load - this isn't large, because drum sanders only take a light cut,
but equally we're talking about fine surface finishing here. It's OK
if you machine does deflect a little, but the real killer for
home-built machines seems to be if they're poorly damped and they
start to "bounce". Bad finishes seems to involve a regular oscillation
and regularly-spaced divots.

One day I'll build my own (and a pad sander), but it'll be welded from
1" x 2" steel box, because I know how to make rigid structures out of
that. The thickness adjustment will probably be recycled milling
machine parts or a lathe cross-slide. In many ways a single-ended
machine is easier - fewer, bigger parts will achieve the same result
as a double-ended machine that relies on accurate synchronisation.

I've seen one home-built machine that was single-ended, but had a
(retro-fitted) end clamp to turn it into a double ended machine. This
was awkward to fit and was only useful for the last pass, as it needed
to be carefully re-adjusted with each thickness change.

For working "double width", you cant the single-ended arm upward
slightly, so that the free end is a degree or two higher (this is a
critical adjustment and it's timber-dependent for best results). This
leaves a surface that's effectively a shallow triangle in section, but
it avoids a tramline from the edge of the roller (this is very
obvious). Any ridge is invisible in most materials, easily
hand-sanded off it it is visible.

I've no idea how to build a drum. Still haven't seen one that's an
ugly pig to change abrasives on. If I did build one, I'd probably
build several and enable myself to change grits with a quick drum
change, not a lengthy belt change.
--
Smert' spamionam

On Mon, 22 Nov 2004 20:11:36 GMT, "Chuck Hoffman"
wrote:

Unless you have a source for metal casting, it's going to be VERY DIFFICULT
to build a drum sander on a cantilevered frame that is rigid enough

Weld it. Why would you need to cast ?
--
Smert' spamionam

On Mon, 22 Nov 2004 20:05:57 GMT, TWS wrote:

I saw an interesting home brew setup at a local artisan (Keith Allen).
He had a long sanding belt (6 to 8 inch wide) strung over a sliding
table that slid crossways back and forth under the belt.

That's a pad sander. Much easier to make than a drum sander - there's
a sketch in the Taunton "Workshop Book". You can make a successful
one from wood, but I've not yet seen a wooden framed drum sander that
worked right.

Pad sanders are excellent for finishing and probably better than a
drum sander, although a little slower to use. They're also _much_
better on resinous softwoods, the sort that usually foul up a small
drum sander and need a belt sander (although CSM's anti-static
abrasives would help). What they're not so good at is being a
thicknessing sander, for stock preparation in luthiery and the like.

If you have a pad sander, commercial or self-built, then get a
graphite platen for that pad. They make a huge improvement - less
trouble with the belt clogging from resin and _much_ less belt
heating.
--
Smert' spamionam

"Larry Bud" wrote in message
om...

Let's say I build a 20" wide unit. Am I able to sand a 40" wide piece
by sending it through twice, or will a sanding line develop? If I

I read, in a recent review of a few commercial products, that this happens
on a few. IIRC, the reviewer said it wasn't hard to remove.

On Mon, 22 Nov 2004 21:14:03 +0000, Andy Dingley
wrote:


I've no idea how to build a drum. Still haven't seen one that's an
ugly pig to change abrasives on. If I did build one, I'd probably
build several and enable myself to change grits with a quick drum
change, not a lengthy belt change.
Andy,
the drum on the Performax single end thickness sander has a spiral
wrap paper. The benefit of this is that the paper tightens against
the drum as it runs and there is a simple clip mechanism to take up
the slack. I haven't used one of these so I don't know how well it
operates but I liked the concept.

TWS

On Mon, 22 Nov 2004 22:48:41 GMT, TWS wrote:

the drum on the Performax single end thickness sander has a spiral
wrap paper. The benefit of this is that the paper tightens against
the drum as it runs and there is a simple clip mechanism to take up
the slack.

Trouble with those simple clip mechanisms is that they're easy to make
on a production line, a bit harder to copy for a one-off. I wonder if
you can get the bits as spares ? 8-)

TWS wrote:

I saw an interesting home brew setup at a local artisan (Keith
Allen). He had a long sanding belt (6 to 8 inch wide) strung
over a sliding table that slid crossways back and forth under
the belt. The belt was driven directly by a 1/2 HP motor with
a 4 inch drive. In operation the workpiece would be blocked
up so it was slightly below the underside of the belt and he
had a pressure block that he moved by hand on the inside of
the belt to apply varying degrees of pressure. So he would
work the pressure block along the inside of the belt
(lengthwise with the workpiece) while sliding the workpiece
from one side to the other so the full length and width of the
board could be sanded.

This critter is a "stroke sander" and is commercially available.
I've used one of these (with a graphite mitten) and discovered
that they're great for sanding large panels - but they can also
spoil a surface almost before you can notice; and they can do a
real number on your hand if you're not really careful.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html

For a home brew a better bet would probably be the 24" x 6" x 5" ID @ $68.72
by the same eBay vendor.

Having used an Eastern copy of a 20"/40" cantilevered unit, the media
holding method is critical. That on this model made for very difficult roll
replacement and didn't self tighten, so the results were strips that broke
where they passed through the drum.

Most of the better models I have seen have internal webs to stiffen the
drum, maybe something like a high density foam would help?

Are the pulleys for the feed system? Most of the contilevered drums are
direct drive with a flexible coupling. Also, don't forget a fairly fine
thread adjustment method, ideally for a cantilever system this should be a
form of acme thread. (Assuming the bed is stationary and the drum / motor is
moving).

Lathes are nice, especially metal working ones, but before you part with
your cash, take into account that you could easily double the cost of your
lathe by the time you add tooling and measurement instruments, and then a
little latter on there'll be just this little old mill you just can't live
without :-).

Regards.

BWR

"WD" wrote in message
...
On 22 Nov 2004 11:20:44 -0800, (Larry Bud) wrote:

I too been thinking of making a thickness sander, I just can't make up my
mind
whether to buy a Perform ax 16/32 or make one. This is what I found:

You can buy 5" X12" aluminum (6061 T6) tube 1/2" wall thickness for $32.



http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WD1V

The seller I presume can supply tube length up to 24". I have also found a
website that sell new surplus feed geared fraction motor, cost $10 to $80
each.
They also sell pillar block bearing, pulley etc. I think I have source
all the
necessary parts to make 24" thickness sander, except a lathe. I found an
Atlas/Craftsman 1960s for $1,200 in our local papers. I would love to own
a
lathe and to be able to make all the parts I need... but, is it worth
it???

I was toying an idea, what if I make at cost an aluminum sanding roller
5"X24"
fitted with pillar block bearings, two pulleys ready to install for about
$120,
you provide the motor and each buyers donate a few bucks to pay for the
lathe?

I presume I should also provide a possible dwg of the thickness sander and
necessary rollers for the feed belts and the feed geared motor. Ultimately
I
presume for the sanders should be under $400 including a used 1-1/2hp
motor??

I am serious, I am willing to do it for free and you pay for the all the
materials....

I've searched the archives on r.w. and the internet about building my
own drum sander, but one question remains about the operation these
sanders:

Let's say I build a 20" wide unit. Am I able to sand a 40" wide piece
by sending it through twice, or will a sanding line develop? If I
can't do this satisfactorily, is a 20" useful enough to build?

Thx.