WARNING: Metalworking Revisited - Deburring With Surface Conditioning Products - HARBOR FREIGHT SURPRISE

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Bob La Londe

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Nov 13, 2021, 7:47:42 PM11/13/21
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Off Topic Portion: The warning is for trolls like the one who replied
once to the last metalworking post confused and finding the title hard
to read. Hopefully when trolls realize its real metal working content
they can move on to other topics they will find more enjoyable.

On Topic Portion: After Jim Wilkins comment about abrasive discs I stuck
one of my little mandrels in a drill press and cranked up the RPM. The
discs were part of a batch I bought from Benchmark Abrasives. Suface
conditioning pads. Not knowing which would work best I bought a pack of
two different ones. A "red" one and a "grey" one. For some reason I
thought they were green on the website. The grey one felt way to
coarse, so I tried the red on. Working under the head of the drill
press is a little awkward, but it works ok. You are working blind
except when working on the side of the disc, but its not to bad. It
will deburr the part, and leaves a generally nicer finish than sand
paper. After just three molds (6 parts) the disc was about toasted.
Being a cheapskate I could get a little more work out of it, but that
wasn't really my goal. My goal was faster, cleaner, and more efficient
deburring. Given that it wore out so quickly it also left a lot debris
on the parts. I'll rinse them all anyway before going back on the
machines, but they do need to go back on the machines. The back side
needs customer name and catch phrase engraved yet. Still there was a
lot of red abrasive bits all over everything.

Randy and Jim both mentioned belt sanders. I prefer to call them belt
grinders, because that's the way I use them. Recently I made some
repairs on the little Harbor Freight 1x30 bench top belt grinder.
Mostly I just adjusted it and tightened up a bolt that holds the
tensions tracking assembly in place. I was not hopeful that it would
run the surface conditioning belts any better (at all) than it did the
first time I tried them, but I tried one anyway. I had gotten a couple
each of two different ones. Also from Benchmark Abrasives. I selected
the one that felt finer (grey/green this time) and left the red ones in
the drawer. It was difficult to get on. I had to wrap my arm around
the machine and pull it against my body to pull the tensioner far enough
forward to get the belt on. After turning it by hand a couple times I
plugged it in back and and turned it on. No pleasant surprises there at
all. It still would not turn the belt. Just being a little obstinate I
started spinning the large lower idler wheel by hand with a finger tip.
A little help didn't get it going, but I noticed it would turn fraction
of a rotation before stopping. I decided to manually spin it a little
faster. When I pulled my finger to safety the belt grinder kept going
and then it sped up. It wasn't as quick as normal, but within a second
or two it was turning at what visually appeared to be its normal speed.
I still was not hopeful, but I wanted to see what the conditioning belt
would do. I don't think I really ever thought about the machine again
as I deburred moderately complex edges on 7 more mold (14 more parts.)
Straight edges were easy, but walking round edges for hinge bosses
around on the belt and cleaning up inside and outside corners was pretty
easy to control. Sure it looks like it was done by hand but it looks
good. Those parts are not all covered with a large cloud of abrasive
debris. There is some I am sure, but nothing like from the little disc.
The belt looks used, but its not worn out. I am sure I could do
atleast another dozen parts with it. More since I'm a cheap skate and
I'll push it to the end. After the little belt grinder came up to speed
I don't recall it seeming to bog down one time while I was using it.

I mentioned two companies previously in this post purely for reference.
So people wouldn't find it odd if their Combat Abrasives or their Wen
belt grinder performed differently than I described. I am not endorsing
or putting down any of the companies named. Just describing how the
products I used performed.

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Jim Wilkins

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Nov 14, 2021, 7:12:27 AM11/14/21
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"Bob La Londe" wrote in message news:smpmb9$n3s$1...@gioia.aioe.org...

> ...Randy and Jim both mentioned belt sanders. ...

I have a cheap clone of the Dynafile 1/2" x 12" air belt sander. I bought it
in the early 80's and converted it into a close-quarters right angle drill
for auto body pop riveting. The shortened 1/8" drill bit is mounted in a
1/4-20 bolt that screws into the spindle hole. A setscrew in the hex head
retains the drill bit. That made it short enough to fit between a fender and
the wheel well liner etc. Rust from road salt is a big problem here in New
England.

Recently when I needed to sand welds on a reverse curved fender repair I
reassembled it as a sander and bought some belts. When I squeezed the
trigger the 40-year-old rubber rollers flew apart so I had to make new ones
from rubber tubing on custom mandrels.

Like my 1" x 30" Delta there is a platen for sanding flat plus an
unsupported area that lets the belt conform to curves.

HF swivel whips decouple the sanders from the fairly stiff air hose to
permit finer control.

I don't make and sell molds so I don't know exactly what you need, but these
air sanders have helped me reshape and smooth welds free-hand.
jsw

Bob La Londe

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Nov 14, 2021, 2:37:21 PM11/14/21
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I need to clean burrs off all edges of the over all solid quickly and
efficiently without having any impact on critical features. I've
switched to surfacing to remove burrs from critical features cut into
the primary face. If it has any affect it will be measured in tenths.
I typically leave one tenth (as if the machines could be that accurate)
and then remove the theoretical tenth at the end to de-bur those
features. It leaves the feature edges sharp and crisp, but the customer
doesn't handle it by those edges. The outside edges on the other hand
can't be left sharp much less have a burr on them. If I had fancier CAM
software I might try to program to de-burr/chamfer by machine all edges
that can be reached from the top, but I am still using cheap CAM
software rather than renting high priced CAM software. Someday if I
ever build a real shop...

Jim Wilkins

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Nov 14, 2021, 5:34:52 PM11/14/21
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"Bob La Londe" wrote in message news:smrohd$1r79$1...@gioia.aioe.org...

I need to clean burrs off all edges of the over all solid quickly and
efficiently without having any impact on critical features. I've
switched to surfacing to remove burrs from critical features cut into
the primary face. If it has any affect it will be measured in tenths.
I typically leave one tenth (as if the machines could be that accurate)
and then remove the theoretical tenth at the end to de-bur those
features. It leaves the feature edges sharp and crisp, but the customer
doesn't handle it by those edges. The outside edges on the other hand
can't be left sharp much less have a burr on them. If I had fancier CAM
software I might try to program to de-burr/chamfer by machine all edges
that can be reached from the top, but I am still using cheap CAM
software rather than renting high priced CAM software. Someday if I
ever build a real shop...

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

Have you looked at electropolishing, which preferentially removes tiny
protrusions?

Here's the reason:
https://physics.stackexchange.com/questions/43068/why-is-electric-field-strong-at-sharp-edges

John Doe

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Nov 14, 2021, 11:39:51 PM11/14/21
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There have been many metalworking posts recently...

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Bob La Londe <no...@none.com99> wrote:

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> From: Bob La Londe <no...@none.com99>
> Newsgroups: rec.crafts.metalworking
> Subject: WARNING: Metalworking Revisited - Deburring With Surface Conditioning Products - HARBOR FREIGHT SURPRISE
> Date: Sat, 13 Nov 2021 17:47:39 -0700
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Edward Hernandez

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Nov 15, 2021, 12:28:44 AM11/15/21
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The John Doe troll stated the following in message-id
<sdhn7c$pkp$4...@dont-email.me>:

> The troll doesn't even know how to format a USENET post...

And the John Doe troll stated the following in message-id
<sg3kr7$qt5$1...@dont-email.me>:

> The reason Bozo cannot figure out how to get Google to keep from
> breaking its lines in inappropriate places is because Bozo is
> CLUELESS...

And yet, the clueless John Doe troll has itself posted yet another
incorrectly formatted USENET posting on Mon, 15 Nov 2021 04:39:47 -0000
(UTC) in message-id <smsoaj$p59$1...@dont-email.me>.

ZWNpfk6yFfDP

John Doe

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Nov 15, 2021, 4:42:55 AM11/15/21
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The nym-shifting stalker Corvid/Edward/others is upset because it will
never again troll USENET without its nyms being exposed.

Corvid perpetually proves why it must nym-shift.
Its mission, as always... annoy everybody.

see also...
=?UTF-8?Q?C=c3=b6rvid?= <b...@ckbirds.org>
=?UTF-8?B?8J+QriBDb3dzIGFyZSBOaWNlIPCfkK4=?= <ni...@cows.moo>
Banders <sn...@mailchute.com>
Covid-19 <alway...@message.header>
Corvid <b...@ckbirds.net>
Corvid <b...@ckbirds.org>
Cows Are Nice <co...@nice.moo>
Cows are nice <m...@cows.org>
Cows are Nice <ni...@cows.moo>
dogs <do...@home.com>
Edward H. <dtga...@gmail.com>
Edward Hernandez <dtga...@gmail.com>
Great Pumpkin <pum...@patch.net>
Jose Curvo <jcu...@mymail.com>
Local Favorite <how2r...@palomar.info>
Peter Weiner <dtga...@gmail.com>
Sea <fres...@coast.org>
Standard Poodle <stan...@poodle.com>
triangles <bu...@home.com>
and others...

--
Edward Hernandez <dtga...@gmail.com> wrote:

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> From: Edward Hernandez <dtga...@gmail.com>
> Subject: Re: WARNING: Metalworking Revisited - Deburring With Surface Conditioning Products - HARBOR FREIGHT SURPRISE
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Edward Hernandez

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Nov 15, 2021, 8:14:33 AM11/15/21
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The John Doe troll stated the following in message-id
<sdhn7c$pkp$4...@dont-email.me>:

> The troll doesn't even know how to format a USENET post...

And the John Doe troll stated the following in message-id
<sg3kr7$qt5$1...@dont-email.me>:

> The reason Bozo cannot figure out how to get Google to keep from
> breaking its lines in inappropriate places is because Bozo is
> CLUELESS...

And yet, the clueless John Doe troll has itself posted yet another
incorrectly formatted USENET posting on Mon, 15 Nov 2021 09:42:51 -0000
(UTC) in message-id <smta2r$le3$1...@dont-email.me>.

lulDejoSZYt2

Bob La Londe

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Nov 15, 2021, 12:11:57 PM11/15/21
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Inspite of "getting" a surface conditioning belt to run on the Harbor
Freight 1x30 I have decided to go ahead and build a slightly more
powerful 1x30. I found recently that while the surface belt I was using
does a great job on aluminum molds and some steels the hardened burr of
a piece of stainless was to much for it. I was saw cutting 1-1/2 inch
round for inserts in a mold. Then they go over to the lathe to be
finished and finished to length. Before taking them to the lathe I like
to remove the saw cut burr so I don't have to hope I can get it into one
of the gaps in the chuck jaws. The surface conditioning belt might have
taken it off eventually, but as I have said before time is the most
precious commodity in my shop. A blue Zirconia belt remove it in very
short order. Of course there is also the time to swap belts. The
properly sized Zirconia belt goes on pretty quickly, but putting the
surface conditioning belt back on is still a bit of a struggle. I think
I can make a 2 pulley belt grinder that can quickly change from 1 x 30
to 1 x 42 using a 3/4 HP DC mini lathe motor that will not be going back
on the lathe it came off. That lathe is getting a servo spindle motor
for better than tachometer threading and live tool cutting, but that's
another project. The motor is rated for 110V DC, but I'm going to try
it with an almost plug and play DC converter/speed controller I bought
for using 90V servos in non servo applications. The biggest problem
really will be protecting the motor from debris I think.

I was considering using a 3HP treadmill motor I have on the shelf, but
I'm saving that for the ubiquitous 2 x 72 belt grinder I'll build
someday. I've also got a couple 3/4 HP 3 phase motors I considered, but
a DC speed controller is a fraction of the cost of a VFD.

I have used the conditioning belt for an equal number of additional
molds of similar size and it does not appear to have worn significantly
further. I think it has an initial break in where it wears quickly and
then it settles down for a while. In any case its done enough work to
more than justify the cost of the belt. I think I'll stock up on them.

Ah, the group is so much better now. I employed some filters I should
have employed previously. They are as useful as the K key. Maybe more
so. The problem with filtering trolls and nit pickers is once in a
great while they post something interesting or useful. Eventually you
have to decide if their personal SNR is worth putting up with them.

Clifford Heath

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Nov 15, 2021, 4:16:22 PM11/15/21
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On 16/11/21 4:11 am, Bob La Londe wrote:
> Ah, the group is so much better now.  I employed some filters I should
> have employed previously.  They are as useful as the K key.  Maybe more
> so.  The problem with filtering trolls and nit pickers is once in a
> great while they post something interesting or useful.  Eventually you
> have to decide if their personal SNR is worth putting up with them.

I have filters that "Mark as read" some authors. That way you only see
their posts when someone responds, which is a big help. "Ignore
subthread" helps too (in Thunderbird).

Cydrome Leader

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Nov 17, 2021, 3:52:01 PM11/17/21
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Electropolishing is definitely a magical process of sorts when it comes to
surface finishing.
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