Making a drum sander, problem truing the drum
 

Ok, making a drum sander than I found he

http://www.rockslide.org/drum%20sander.html

The only difference is that I'm making it approx 24" wide... I've got
it all built, but having trouble truing the drum. I get an ocillation
effect when then drum hits the sand paper, and I get a bunch of flat
spots on the drum all the way around it. It's kind of like a
washboard effect on a dirt road.

Any advice for this?

Larry
I made one of those a million years ago. I chucked the hole assembled drum
head in the lathe and trued it up. If you can't do that can you glue
sandpaper to a board and run the drum without paper and feed the sandpaper
glued to the board under the drum?
max

Ok, making a drum sander than I found he

http://www.rockslide.org/drum%20sander.html

The only difference is that I'm making it approx 24" wide... I've got
it all built, but having trouble truing the drum. I get an ocillation
effect when then drum hits the sand paper, and I get a bunch of flat
spots on the drum all the way around it. It's kind of like a
washboard effect on a dirt road.

Any advice for this?

If the drum is vibrating you are either taking too big a cut or the axle
shaft you chose is too small a diameter. These drum sanders can only sand a
few thousands at a time
max

Ok, making a drum sander than I found he

http://www.rockslide.org/drum%20sander.html

The only difference is that I'm making it approx 24" wide... I've got
it all built, but having trouble truing the drum. I get an ocillation
effect when then drum hits the sand paper, and I get a bunch of flat
spots on the drum all the way around it. It's kind of like a
washboard effect on a dirt road.

Any advice for this?

On 1 Feb 2005 05:26:23 -0800, "Larry Bud"
wrote:

Ok, making a drum sander than I found he

http://www.rockslide.org/drum%20sander.html

The only difference is that I'm making it approx 24" wide... I've got
it all built, but having trouble truing the drum. I get an ocillation
effect when then drum hits the sand paper, and I get a bunch of flat
spots on the drum all the way around it. It's kind of like a
washboard effect on a dirt road.

Any advice for this?

I was looking at this plan the other day... seems pretty good if
directions are followed...

A- Are all of your disks round and of the same size?

B- Did you follow the instructions regarding truing the drum on the
sandpaper attached to the bed, or whatever?

I was thinking of turning the drum on a lathe, but that's a precision
chore... maybe truing it up on a lathe or DP after it's glued up?



mac

Please remove splinters before emailing

On 1 Feb 2005 05:26:23 -0800, "Larry Bud" wrote:

BTW, how much did you spend on this project with or without the motor?

Thanks

Ok, making a drum sander than I found he

http://www.rockslide.org/drum%20sander.html

The only difference is that I'm making it approx 24" wide... I've got
it all built, but having trouble truing the drum. I get an ocillation
effect when then drum hits the sand paper, and I get a bunch of flat
spots on the drum all the way around it. It's kind of like a
washboard effect on a dirt road.

Any advice for this?

I was looking at this plan the other day... seems pretty good if
directions are followed...

A- Are all of your disks round and of the same size?

Yes. I cut them all with a router.

B- Did you follow the instructions regarding truing the drum on the
sandpaper attached to the bed, or whatever?

Yes, that's what I'm trying to do, is to true it up by putting
sandpaper on the bed.

Max had a suggestion that I was taking too much off at once... That's a
possibility.

I was thinking of turning the drum on a lathe, but that's a precision
chore... maybe truing it up on a lathe or DP after it's glued up?

I don't see how that helps. The point of truing it is to make sure
it's parallel to the bed.

As far as cost, pretty minimal. I built it out of 2x4, except for the
support for the pillow block bearings, which I used Ash. Bought the
bearings on ebay for under $20.

Also bought the motor on ebay. 1.5 HP, single phase, for $50 plus 15
for shipping!

The table I already had from another product. 2" thick, with a
laminate. Maybe spend another $10 on hardware for the lift mechanism,
already had the piano hinge... The belt and pulleys were perhaps
another $20 from an online place... So maybe I'm into this $125 with
motor??

It'll be interesting to see how well it works.

max wrote:
If the drum is vibrating you are either taking too big a cut or the
axle
shaft you chose is too small a diameter. These drum sanders can only
sand a
few thousands at a time
max

Perhaps too big a cut... Seemed like the vibration was VERY sudden,
however. I'm wondering if I have the feet/min of the drum too fast as
well...

On 1 Feb 2005 09:53:33 -0800, "Larry Bud" wrote:

Oops, I for got to ask you when did you bought the 1.5hp on Ebay, I was lurking
on and off for a long time waiting to bid for one. I also forgot to add the drum
sander is brand NEW.

As far as cost, pretty minimal. I built it out of 2x4, except for the
support for the pillow block bearings, which I used Ash. Bought the
bearings on ebay for under $20.

Also bought the motor on ebay. 1.5 HP, single phase, for $50 plus 15
for shipping!

The table I already had from another product. 2" thick, with a
laminate. Maybe spend another $10 on hardware for the lift mechanism,
already had the piano hinge... The belt and pulleys were perhaps
another $20 from an online place... So maybe I'm into this $125 with
motor??

It'll be interesting to see how well it works.

On 1 Feb 2005 10:05:55 -0800, "Larry Bud"
wrote:


max wrote:
If the drum is vibrating you are either taking too big a cut or the
axle
shaft you chose is too small a diameter. These drum sanders can only
sand a
few thousands at a time
max

Perhaps too big a cut... Seemed like the vibration was VERY sudden,
however. I'm wondering if I have the feet/min of the drum too fast as
well...

Assuming that there is insigificant play in the drum assembly, the
most like cause is that the drum is still out of round. Feed the drum
gently onto the sandpaper, give it time to work and it will round
itself out.

When rounding slow speeds and feeds are the way to go.

--RC
"Sometimes history doesn't repeat itself. It just yells
'can't you remember anything I've told you?' and lets
fly with a club.
-- John W. Cambell Jr.

On 1 Feb 2005 05:26:23 -0800, "Larry Bud"
wrote:

Ok, making a drum sander than I found he

http://www.rockslide.org/drum%20sander.html

The only difference is that I'm making it approx 24" wide... I've got
it all built, but having trouble truing the drum. I get an ocillation
effect when then drum hits the sand paper, and I get a bunch of flat
spots on the drum all the way around it. It's kind of like a
washboard effect on a dirt road.

Any advice for this?


change speeds.

On 1 Feb 2005 09:53:33 -0800, "Larry Bud"
wrote:

I was thinking of turning the drum on a lathe, but that's a precision
chore... maybe truing it up on a lathe or DP after it's glued up?

I don't see how that helps. The point of truing it is to make sure
it's parallel to the bed.

Maybe "truing" was the wrong word....
What I'd want to do first is be sure that all the disks were round and
identical....
It seems like if even one disk was out of round or out of line in the
glueup, it could provide enough variation to not sand flat??

As in wood turning, you can have something parallel to the bed that
isn't necessarily treu/round and lined up with the shaft... it can be
off center and still parallel, I think...
Hell, it's too late at night to have to think.. *g*



mac

Please remove splinters before emailing

mac davis wrote:
On 1 Feb 2005 09:53:33 -0800, "Larry Bud"
wrote:

I was thinking of turning the drum on a lathe, but that's a
precision
chore... maybe truing it up on a lathe or DP after it's glued up?

I don't see how that helps. The point of truing it is to make sure
it's parallel to the bed.

Maybe "truing" was the wrong word....
What I'd want to do first is be sure that all the disks were round
and
identical....
It seems like if even one disk was out of round or out of line in the
glueup, it could provide enough variation to not sand flat??

As in wood turning, you can have something parallel to the bed that
isn't necessarily treu/round and lined up with the shaft... it can be
off center and still parallel, I think...

Again, that's what the point of truing the drum is. The sandpaper goes
on the table, and as the drum turns the high spots hit the sandpaper,
and eventually the drum is a perfect circle relative to the centerline.

I finally got it to work last night. What I did was take a 50 grit
belt sander disk, contact cement it to a piece of 1/2" hardboard the
same size as the belt.

I first drew some relief marks on the drum with a pencil as the drum
rotated so I could see high and low spots. Then I raised the table so
the belt just touched the drum, and moved it along the length of the
drum (with the hardboard down on the table). Stopped the machine and
checked to see if there were still low spots. If there was, I'd raise
the table by probably about .05" and repeat.

This worked better because the whole drum didn't grab the piece of sand
paper as was happening before...

Took about an hour to get it completely round.. Just waiting for my
velcro and sand paper strip to come it to complete this project.

On 2 Feb 2005 10:02:34 -0800, "Larry Bud" wrote:

Good job :-)
You should take pics before and after you have completed the project and post it
in abpw. I am sure many of us would like to admire your handicraft and possibly
questions about the construction of your drum sander.

Again, that's what the point of truing the drum is. The sandpaper goes
on the table, and as the drum turns the high spots hit the sandpaper,
and eventually the drum is a perfect circle relative to the centerline.

I finally got it to work last night. What I did was take a 50 grit
belt sander disk, contact cement it to a piece of 1/2" hardboard the
same size as the belt.

I first drew some relief marks on the drum with a pencil as the drum
rotated so I could see high and low spots. Then I raised the table so
the belt just touched the drum, and moved it along the length of the
drum (with the hardboard down on the table). Stopped the machine and
checked to see if there were still low spots. If there was, I'd raise
the table by probably about .05" and repeat.

This worked better because the whole drum didn't grab the piece of sand
paper as was happening before...

Took about an hour to get it completely round.. Just waiting for my
velcro and sand paper strip to come it to complete this project.

On 2 Feb 2005 10:02:34 -0800, "Larry Bud"
wrote:


As in wood turning, you can have something parallel to the bed that
isn't necessarily treu/round and lined up with the shaft... it can be
off center and still parallel, I think...

Again, that's what the point of truing the drum is. The sandpaper goes
on the table, and as the drum turns the high spots hit the sandpaper,
and eventually the drum is a perfect circle relative to the centerline.

I finally got it to work last night. What I did was take a 50 grit
belt sander disk, contact cement it to a piece of 1/2" hardboard the
same size as the belt.

I first drew some relief marks on the drum with a pencil as the drum
rotated so I could see high and low spots. Then I raised the table so
the belt just touched the drum, and moved it along the length of the
drum (with the hardboard down on the table). Stopped the machine and
checked to see if there were still low spots. If there was, I'd raise
the table by probably about .05" and repeat.

This worked better because the whole drum didn't grab the piece of sand
paper as was happening before...

Took about an hour to get it completely round.. Just waiting for my
velcro and sand paper strip to come it to complete this project.

That's great....
I guess it gets back to an earlier reply that suggested that the cuts
might have been too aggressive... I've been guilty of that on the
lathe, where light cuts true and aggressive cuts follow the wood and
accent don't..

Let us know how it does when it's up and running... I've thought of
making one for things like drawer faces and other thin stuff..


mac

Please remove splinters before emailing