I've got a little 1x30 belt grinder I use for gentle deburring some
aluminum parts. I use the slack belt portion and it does a decent job
with a 400 grit belt. I get a lot of life out of the belts by using a
belt eraser.

The one thing it won't do is give a light sand to a flat surface. The
slack belt will just sand the edges, and the hard platen leaves streaks
of shinny spots. I was wondering if something in between might be the
trick.

Yeah a random orbit sander might work (it has a soft pad), but then I
need to clamp the parts first taking more time. Also, I'm not sure I
can get the same life out of the discs or if a belt eraser would work
very well on it to extend their lives.

--
Bob La Londe
CNC Molds N Stuff

--
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On 9/18/23 12:23 PM, Bob La Londe wrote:
> I've got a little 1x30 belt grinder I use for gentle deburring some
> aluminum parts.  I use the slack belt portion and it does a decent job
> with a 400 grit belt.  I get a lot of life out of the belts by using a
> belt eraser.
>
> The one thing it won't do is give a light sand to a flat surface.  The
> slack belt will just sand the edges, and the hard platen leaves streaks
> of shinny spots.  I was wondering if something in between might be the
> trick.
>
> Yeah a random orbit sander might work (it has a soft pad), but then I
> need to clamp the parts first taking more time.  Also, I'm not sure I
> can get the same life out of the discs or if a belt eraser would work
> very well on it to extend their lives.
>

If the parts are box shaped with flat parallel sides you could use a
vacuum fixture so clamping and releasing would be quick. Use a cheap
one-stage rotary pump and assume about 5-7 lbs of clamping force per
square inch, with a foam rubber oring as gasket. We used 3/16" or 1/4"
foam rubber cord stock from McMaster Carr, in square grooves depth about
1/2 to 2/3 the cord diameter. Just butt the ends or superglue them
together if you must. Don't use regular solid firm orings, they don't
seal unless you are clamping a large surface area. For reliability we
needed at least 16 square inches of clamp surface in the CNC mills but
for sanding you could probably cut that in half.

For a pad on your belt sander platen I'd suggest polyethylene foam,
maybe 1/8" thick or less. Would have the best lubricity so the belt
doesn't drag and chew it up immediately.

Interesting problem. Ok, back to lurking :-).

--
Regards,
Carl

On 9/18/2023 11:23 AM, Bob La Londe wrote:
> I've got a little 1x30 belt grinder I use for gentle deburring some
> aluminum parts.  I use the slack belt portion and it does a decent job
> with a 400 grit belt.  I get a lot of life out of the belts by using a
> belt eraser.
>
> The one thing it won't do is give a light sand to a flat surface.  The
> slack belt will just sand the edges, and the hard platen leaves streaks
> of shinny spots.  I was wondering if something in between might be the
> trick.
>
> Yeah a random orbit sander might work (it has a soft pad), but then I
> need to clamp the parts first taking more time.  Also, I'm not sure I
> can get the same life out of the discs or if a belt eraser would work
> very well on it to extend their lives.
>

There is a graphite (I think) fabric backed material designed just for
platen use . The main factor we were looking at (Corian fabrication) was
the low friction thus low heat . It's just "soft" enough to conform as
you want . I'll have to look , I might have a small piece that followed
me home from work here somewhere .
--
Snag
Men don't protect women because they're weak .
We protect them because they're important .

On 9/18/2023 1:02 PM, Snag wrote:
> On 9/18/2023 11:23 AM, Bob La Londe wrote:
>> I've got a little 1x30 belt grinder I use for gentle deburring some
>> aluminum parts.  I use the slack belt portion and it does a decent job
>> with a 400 grit belt.  I get a lot of life out of the belts by using a
>> belt eraser.
>>
>> The one thing it won't do is give a light sand to a flat surface.  The
>> slack belt will just sand the edges, and the hard platen leaves
>> streaks of shinny spots.  I was wondering if something in between
>> might be the trick.
>>
>> Yeah a random orbit sander might work (it has a soft pad), but then I
>> need to clamp the parts first taking more time.  Also, I'm not sure I
>> can get the same life out of the discs or if a belt eraser would work
>> very well on it to extend their lives.
>>
>
> There is a graphite (I think) fabric backed material designed just for
> platen use . The main factor we were looking at (Corian fabrication) was
> the low friction thus low heat . It's just "soft" enough to conform as
> you want . I'll have to look , I might have a small piece that followed
> me home from work here somewhere .

Here's one ... probably a lifetime supply for what you're doing .

https://www.amazon.com/Graphite-Carbon-Graphite-Lubrication-Abrasive-Resistant/dp/B09NPVJRYJ
--
Snag
Men don't protect women because they're weak .
We protect them because they're important .

On 9/18/2023 11:57 AM, Snag wrote:
> On 9/18/2023 1:02 PM, Snag wrote:
>> On 9/18/2023 11:23 AM, Bob La Londe wrote:
>>> I've got a little 1x30 belt grinder I use for gentle deburring some
>>> aluminum parts.  I use the slack belt portion and it does a decent
>>> job with a 400 grit belt.  I get a lot of life out of the belts by
>>> using a belt eraser.
>>>
>>> The one thing it won't do is give a light sand to a flat surface.
>>> The slack belt will just sand the edges, and the hard platen leaves
>>> streaks of shinny spots.  I was wondering if something in between
>>> might be the trick.
>>>
>>> Yeah a random orbit sander might work (it has a soft pad), but then I
>>> need to clamp the parts first taking more time.  Also, I'm not sure I
>>> can get the same life out of the discs or if a belt eraser would work
>>> very well on it to extend their lives.
>>>
>>
>> There is a graphite (I think) fabric backed material designed just for
>> platen use . The main factor we were looking at (Corian fabrication)
>> was the low friction thus low heat . It's just "soft" enough to
>> conform as you want . I'll have to look , I might have a small piece
>> that followed me home from work here somewhere .
>
>   Here's one ... probably a lifetime supply for what you're doing .
>
> https://www.amazon.com/Graphite-Carbon-Graphite-Lubrication-Abrasive-Resistant/dp/B09NPVJRYJ

That might be just the ticket, and I could use it on the 2x72 I keep
telling myself I am going to build someday.

--
Bob La Londe
CNC Molds N Stuff

--
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"Bob La Londe" wrote in message news:ue9tik$1r7ul$1@dont-email.me...

The one thing it won't do is give a light sand to a flat surface. The
slack belt will just sand the edges, and the hard platen leaves streaks
of shinny spots. I was wondering if something in between might be the
trick.

----------------------------

I haven't noticed that problem on mine. Can you check the platen for
flatness and the belt for thicker areas?

On 9/18/2023 1:24 PM, Jim Wilkins wrote:
> "Bob La Londe"  wrote in message news:ue9tik$1r7ul$1@dont-email.me...
>
> The one thing it won't do is give a light sand to a flat surface.  The
> slack belt will just sand the edges, and the hard platen leaves streaks
> of shinny spots.  I was wondering if something in between might be the
> trick.
>
> ----------------------------
>
> I haven't noticed that problem on mine. Can you check the platen for
> flatness and the belt for thicker areas?
>

I'm trying to pretty up "as extruded" surfaces without having to setup
up and take a skim cut with a fly cutter.... and I am sure my falling
apart 1x30 belt grinder is not as flat is it could be.

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

"Bob La Londe" wrote in message news:ueaeco$1upok$1@dont-email.me...

I'm trying to pretty up "as extruded" surfaces without having to setup
up and take a skim cut with a fly cutter.... and I am sure my falling
apart 1x30 belt grinder is not as flat is it could be.

Bob La Londe

----------------------------

Rubbing the platen on fine sandpaper face-up on a milling machine table will
quickly show you high spots and reduce the worst of them. Mill tables are
somewhat better protected from abrasive grit and easier to clean than lathe
ways, especially at the ends.

I found a very flat cast iron lapping plate and the multipurpose vee block I
mentioned earlier in a second-hand furniture store, of all places. He had
bought an estate lot that included a machinist's tool chest. Both make good
and easily cleaned flatness test surfaces and sanding blocks. 1-2-3 blocks
work well too.