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| Firebrand... |
 Posted: Fri Sep 04, 2009 2:10 pm |
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Considering the present unavailability of the beloved Harbor Freight 3
lb rock tumbler, is anyone familiar with this product as an
alternative?
http://www.unitednuclear.com/mills.htm
The HF mill was known to have a fairly limited life span. Would
increased robustness of the above alternative justify the increased
cost? Could this be the answer to those who have a Sponenburg Mill on
their to-do list but want to get something up and running? It can also
be purchased with grinding media. |
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| bobd1001... |
| Posted: Fri Sep 04, 2009 5:01 pm |
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Im With Lloyd on this one,
Build a mill yourself. Its plenty cheap enough, especially if you can
scrounge up an old washing machine motor or the likes. After building
a mill somewhat similar to the one in Lloyd's book, i realized what a
POS the harbor freight was (but the jars the HF comes with work quite
well). The one United sells is identical to the harbor freight, the
original belt it comes with lasts a few days, but any replacement
belts burn up in a few hours.
Bob
__________________________
www.DoranAerospace.com |
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| Firebrand... |
| Posted: Fri Sep 04, 2009 5:45 pm |
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On Sep 4, 8:01 pm, bobd1001 <quadrunner... at (no spam) comcast.net> wrote:
Quote: Im With Lloyd on this one,
The one United sells is identical to the harbor freight, the
original belt it comes with lasts a few days
Bob
__________________________
www.DoranAerospace.com
Thanks Bob, I assume that mill is just same
mass-produced (likely chinese) version that
proliferates everywhere on the web. Just
another label slapped on. |
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| Lloyd E. Sponenburgh... |
| Posted: Fri Sep 04, 2009 6:45 pm |
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Firebrand <voktj at (no spam) esuhsd.org> fired this volley in news:fc242c98-f887-41c9-
92a1-66d6cf349983 at (no spam) s21g2000prm.googlegroups.com:
Quote: Could this be the answer to those who have a Sponenburg Mill on
their to-do list but want to get something up and running?
Not for nothin', but the Sponenmill can be built in one ambitious 2-day
weekend of one diligent cutting and fitting day and one easy finishing and
varnishing/painting day.
LLoyd |
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| spartono'dan... |
| Posted: Sat Sep 05, 2009 4:48 am |
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On Sep 4, 11:45 pm, Firebrand <vo... at (no spam) esuhsd.org> wrote:
Quote: On Sep 4, 8:01 pm, bobd1001 <quadrunner... at (no spam) comcast.net> wrote:
Im With Lloyd on this one,
The one United sells is identical to the harbor freight, the
original belt it comes with lasts a few days
Bob
__________________________
www.DoranAerospace.com
Thanks Bob, I assume that mill is just same
mass-produced (likely chinese) version that
proliferates everywhere on the web. Just
another label slapped on.
Sad to say, but I have the 15# mill.
Bought at a lapidary few years back.
Does the job, unless you're on a mission to make the "best" BP.
I do rocket fuel with mine, not had a bit of problems with it.
Same belt and all.
Does have a lot of duct tape smear on it from overclocking the
rollers.
Made a 50# bag of Kno3 BP/Willow/chry6-8/Lampblack comps.
Metric buttload.
Wore down a lot of bare lead media, I tout the copper jacket stuff now. |
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| Bob... |
| Posted: Sat Sep 05, 2009 10:45 am |
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On Sep 4, 11:01 pm, bobd1001 <quadrunner... at (no spam) comcast.net> wrote:
Quote: Im With Lloyd on this one,
Build a mill yourself. Its plenty cheap enough, especially if you can
scrounge up an old washing machine motor or the likes. After building
a mill somewhat similar to the one in Lloyd's book, i realized what a
POS the harbor freight was (but the jars the HF comes with work quite
well). The one United sells is identical to the harbor freight, the
original belt it comes with lasts a few days, but any replacement
belts burn up in a few hours.
OK, say you buy one for $70 (which seems ridiculously cheap with jar &
media) + shipping. How much time & money to replace the belt every
milling if need be?
And are the replacement belts really inferior to the original? Or
does something happen to the wheels, like coming out of alignment,
that chews up the belts faster after a while?
Robert |
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| Lloyd E. Sponenburgh... |
| Posted: Sat Sep 05, 2009 4:05 pm |
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Bob <robgood at (no spam) bestweb.net> fired this volley in news:406c8ceb-04db-467d-
ba87-10cca077aa0c at (no spam) d21g2000vbm.googlegroups.com:
Quote: OK, say you buy one for $70 (which seems ridiculously cheap with jar &
media) + shipping. How much time & money to replace the belt every
milling if need be?
And are the replacement belts really inferior to the original? Or
does something happen to the wheels, like coming out of alignment,
that chews up the belts faster after a while?
It's not only the durability. "Tumblers" don't turn the RPMs necessary
to mill efficiently, and they cannot handle the media loads that a
properly loaded _milling_ jar will carry. They are perfectly suited to
wet-grinding of small loads of stones, grit, and water, lightly loaded,
and turning slowly. For that purpose, they are a good buy.
LLoyd |
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| Firebrand... |
| Posted: Tue Sep 08, 2009 10:00 am |
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On Sep 5, 3:05 pm, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote:
Quote: Bob <robg... at (no spam) bestweb.net> fired this volley in news:406c8ceb-04db-467d-
ba87-10cca077a... at (no spam) d21g2000vbm.googlegroups.com:
OK, say you buy one for $70 (which seems ridiculously cheap with jar &
media) + shipping. How much time & money to replace the belt every
milling if need be?
And are the replacement belts really inferior to the original? Or
does something happen to the wheels, like coming out of alignment,
that chews up the belts faster after a while?
It's not only the durability. "Tumblers" don't turn the RPMs necessary
to mill efficiently, and they cannot handle the media loads that a
properly loaded _milling_ jar will carry. They are perfectly suited to
wet-grinding of small loads of stones, grit, and water, lightly loaded,
and turning slowly. For that purpose, they are a good buy.
LLoyd
Assuming charging with 2.5 lb of .5 inch hardened lead media and about
200 g of BP mix, what rpm for the jar
would be necessary to achieve optimal performance? |
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| Firebrand... |
| Posted: Tue Sep 08, 2009 10:06 am |
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On Sep 8, 1:02 pm, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote:
Quote: Firebrand <vo... at (no spam) esuhsd.org> fired this volley in news:747a1af6-db1c-4aab-
a1bc-99318a9b6... at (no spam) u16g2000pru.googlegroups.com:
Assuming charging with 2.5 lb of .5 inch hardened lead media and about
200 g of BP mix, what rpm for the jar
would be necessary to achieve optimal performance?
what diameter (i.d.) jar?
LLoyd
I believe the standard jar size for the HF style mill is 4" |
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| Firebrand... |
| Posted: Tue Sep 08, 2009 10:09 am |
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On Sep 8, 1:06 pm, Firebrand <vo... at (no spam) esuhsd.org> wrote:
Quote: On Sep 8, 1:02 pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com> wrote:
Firebrand <vo... at (no spam) esuhsd.org> fired this volley in news:747a1af6-db1c-4aab-
a1bc-99318a9b6... at (no spam) u16g2000pru.googlegroups.com:
Assuming charging with 2.5 lb of .5 inch hardened lead media and about
200 g of BP mix, what rpm for the jar
would be necessary to achieve optimal performance?
what diameter (i.d.) jar?
LLoyd
I believe the standard jar size for the HF style mill is 4"
I'm referring to the HF style jar, (3 lb) which seems well regarded. |
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| Firebrand... |
| Posted: Tue Sep 08, 2009 12:45 pm |
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On Sep 8, 1:13 pm, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote:
Quote: Firebrand <vo... at (no spam) esuhsd.org> fired this volley innews:6be07aa6-118b-4517-8e0f-c14c8c9049af at (no spam) a39g2000pre.googlegroups.com:
I believe the standard jar size for the HF style mill is 4"
Jar Dia. Ball Size Critical Optimum
6" 1" 119 77
6" 1/2" 113 73
5" 1/2" 125 81
4" 1/2" 142 92
Optimum RPM is 65% of Critical Speed
LLoyd
In the HF jar are these speeds affected by hot glueing of dowels
inside the jar? Is it true these bars can help preserve the grinding
media lifespan?
There is another issue I find odd. With the UN mill from my original
post they are claiming
that it can be used for BP and they are selling it with heavy Pb
grinding media.
It would seem like they might have a lot of customer issues selling a
system
that has a likely short MTTF (mean time to failure). I assume they
sell their system
to use as is without modification for their advertised purpose. |
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| Lloyd E. Sponenburgh... |
| Posted: Tue Sep 08, 2009 2:02 pm |
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Guest
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Firebrand <voktj at (no spam) esuhsd.org> fired this volley in news:747a1af6-db1c-4aab-
a1bc-99318a9b6801 at (no spam) u16g2000pru.googlegroups.com:
Quote:
Assuming charging with 2.5 lb of .5 inch hardened lead media and about
200 g of BP mix, what rpm for the jar
would be necessary to achieve optimal performance?
what diameter (i.d.) jar?
LLoyd |
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| Lloyd E. Sponenburgh... |
| Posted: Tue Sep 08, 2009 2:13 pm |
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Guest
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Firebrand <voktj at (no spam) esuhsd.org> fired this volley in
news:6be07aa6-118b-4517-8e0f-c14c8c9049af at (no spam) a39g2000pre.googlegroups.com:
Quote: I believe the standard jar size for the HF style mill is 4"
Jar Dia. Ball Size Critical Optimum
6" 1" 119 77
6" 1/2" 113 73
5" 1/2" 125 81
4" 1/2" 142 92
Optimum RPM is 65% of Critical Speed
LLoyd |
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| Lloyd E. Sponenburgh... |
| Posted: Wed Sep 09, 2009 5:20 am |
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Guest
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Firebrand <voktj at (no spam) esuhsd.org> fired this volley in news:a1d79d0f-90ee-
42b0-ba17-6b3590277f23 at (no spam) p10g2000prm.googlegroups.com:
Quote:
In the HF jar are these speeds affected by hot glueing of dowels
inside the jar? Is it true these bars can help preserve the grinding
media lifespan?
For dry milling, if the jar is correctly charged with media and material,
lifter bars are not necessary, and they can complicate cleaning of the
jar. They do not contribute to improving media life IF the jar is
correctly charged. When a jar is drastically under-charged, or run at
excessively slow speeds, they are necessary.
Quote:
There is another issue I find odd. With the UN mill from my original
post they are claiming
that it can be used for BP and they are selling it with heavy Pb
grinding media.
It would seem like they might have a lot of customer issues selling a
system
that has a likely short MTTF (mean time to failure). I assume they
sell their system
to use as is without modification for their advertised purpose.
I don't remember specifically about the construction of the United
Nuclear mills. Most inexpensive mills have very short belt life.
LLoyd |
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| Mike... |
| Posted: Thu Sep 10, 2009 6:24 pm |
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"Lloyd E. Sponenburgh" wrote:
Quote:
Jar Dia. Ball Size Critical Optimum
6" 1" 119 77
6" 1/2" 113 73
5" 1/2" 125 81
4" 1/2" 142 92
Optimum RPM is 65% of Critical Speed
LLoyd
Would you have a RPM suggestion for a 5 Qt. capacity hexagon barrel like
the Model B ?
Thanks! |
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