开云体育

Craig:
I guess my biggest problem is not having hands on experience with the
new mini lathes. I do not mind paying the price for a sd400 Prazi if
it is that much better than the others. Maybe the sd 300 would be
strong enough to turn 2" & under 420 ss inserts, but I doubt it.
Lingering questions....
1) I'm guesiong that the chinese lathes are good enough to hold +/-
.0005 on a .5 to 2" diameter x 1" Long. so why pay $3500. for the
Prazi, when for $1200 - $1500. you can have the lathe with all
accessories?
2) If this is the case is the lathemaster 8 x 14 the one to have or
is it just a smaller 9x20? (I'm not impresed with the jet 9x20)
3)Is the Micro Mark as good as it looks or are there electrical
problems with the variable speed as in others?
4) Are the older atlas or south bend lathes better or worse at
holding tolerances than the chinese?
I appreciate all the help I can get. The problem is if I ask a
dealer these questions they always try to build up thier product and
downgrade the others.

How far from the chuck are you attempting to part off? You should be
working as close to the chuck as possible (like less than one diameter.)

One concern I have about those quick change tool posts is that they put the
tool way out to the side of the cross-slide/compound instead of centered
over the dovetails as would be Ideal (the downward force of cutting tends to
rock the cross-slide/compound to the side.) So if all else fails I guess
I am recommending turning the compound to 90 degrees from the cross slide
and backing it up for maximum engagement of the dovetails.

Some recommend parting from the rear with an upside down parting tool. On
the 7x10 you can try this from the front, you need an inverted tool holder
then just put the lathe in reverse. I made a parting tool holder for mine
and have tried it both ways but didn't see much difference (it works ok
either way.)

regards
Bob

I've had similar problems. First make sure the "T" type parting tool
is absolutely perpendicular to the work because that type tool has no
side relief. Try lowering the tool a few thousandths below center.

A tool ground from square stock (a lot of grinding) with side reliefs
tends to work better for me, but has some limitation on cutting depth.

Parting off is, to me, difficult and slowing the lathe down as is
necessary for such operations reduces motor power.

Craig

--- In 7x12minilathe@..., "bbftx <bflint@a...>"
<bflint@a...> wrote:

WD
How big a diameter are you trying to part off? A lot of people
have difficulties with this. It gets dicey on my 7x12 on anything
more than 1-1/8" in diameter. I seem to get the best results
slowing the rpms way down, as low as I can go with the speed
control. Also, I make sure I have as little of the parting tool
as possible hanging out from the tool holder.
B Flint


--- In 7x12minilathe@..., "wdannhardt <wdannhardt@y...>"
<wdannhardt@y...> wrote:

The only tool I have problems with is
the cut off tool.

I am using a .062" x .5" HSS tool, cutting brass and Aluminum. I
always seem to get terrible chatter. I made sure the saddle,

cross

slide and compound are very tight to the ways, but it still

happens.

Does anyone have any suggestions to make this better?
I've not heard of anyone else complain about this, so I think it
must be something I am doing.

WD

WD
How big a diameter are you trying to part off? A lot of people
have difficulties with this. It gets dicey on my 7x12 on anything
more than 1-1/8" in diameter. I seem to get the best results
slowing the rpms way down, as low as I can go with the speed
control. Also, I make sure I have as little of the parting tool
as possible hanging out from the tool holder.
B Flint


--- In 7x12minilathe@..., "wdannhardt <wdannhardt@y...>"
<wdannhardt@y...> wrote:

The only tool I have problems with is
the cut off tool.

I am using a .062" x .5" HSS tool, cutting brass and Aluminum. I
always seem to get terrible chatter. I made sure the saddle, cross
slide and compound are very tight to the ways, but it still

happens.

Does anyone have any suggestions to make this better?
I've not heard of anyone else complain about this, so I think it
must be something I am doing.

WD

Roy and Al:
I'm making an adjustable backplate too. One thing I question
in Rick's otherwise great design is the amount of adjustment
he built in. .050" oversize on the diameter seems like too much
to me.
I can't imagine needing to adjust more than a few thou. Wouldn't
a .005 to .010" oversize diameter give a person enough adjustment?
Regards,
B Flint


--- In 7x12minilathe@..., "roylowenthal
<roylowenthal@y...>" <roylowenthal@y...> wrote:

Al,
I agree; I'm in the process of making the same one!

Roy
--- In 7x12minilathe@..., "fromday2 <aldayis@a...>"
<aldayis@a...> wrote:

Roy, I saw Rick Kruger about a month ago and one of the

intresting

things in his shop is the adjustable backplate. The idea and
execution were clever and well done. I am going to make one
for a 4" 3jaw I have. His was nice looking, the concept is
simple enough that it should be reasonably easy to do.

Al Day

I recently purchased a 7 x 12 mini lathe, and so far it has been
wonderful, I am very satisfied. I purchased a quick change tool
holder from HF, and with a modification to the compound, now have
easy tool height adjustment. The only tool I have problems with is
the cut off tool.

I am using a .062" x .5" HSS tool, cutting brass and Aluminum. I
always seem to get terrible chatter. I made sure the saddle, cross
slide and compound are very tight to the ways, but it still happens.
Does anyone have any suggestions to make this better? I've not heard
of anyone else complain about this, so I think it must be something I
am doing.

Thanks for your help,
WD

Thanks to all who replied to my query. As suggested, I looked at
Rick's design for an adjustable backplate and realized that part of
his solution is a deliberate mis-match between the sizes of the land
and the recess. Given that I had this mis-match already what I
needed was a more controlled method of adjustment rather than my
crude tapping technique -- my lazy man's approach is to use the cross
slide as the adjusting screw for centering the chuck.

What I did was put a large (5/8) center drill in the chuck to use as
a shaft for measuring runout, chucked so it extended enough to allow
access to its HSS shaft. The indicator was set up to measure runout
at the rear of this shaft; the chuck was turned to place the low
point at the rear, thus placing the high point toward the front
(where a tool in the toolpost would contact it).

With the nuts on the chuck barely snug I placed a 1/2" square piece
of mild steel in the tool holder and attempted to use this to push on
the shaft of the center drill to slide the chuck to center. This
didn't work initially, apparently because the force is too far from
the backplate. However, by applying enough force via the cross slide
to move the indicator to the desired reading then loosening and
tightening each chuck nut in succession I was able to set the TIR to
better than .001 fairly quickly on each of several tries. Much more
controlled than my original "thump it" approach.

John



--- In 7x12minilathe@..., "John <moran03@e...>"
<moran03@e...> wrote:

The raised land on my spindle plate measures 2.154 rather than

2.165

as given on the mini-lathe site. Sure enough, the recess in the

chuck

measures 2.165.

In order to mount my 3 jaw chuck I first snug the nuts slightly,

put

a rod in the chuck, and use an indicator on the rod. I rotate the
chuck so the high point is up and tap the chuck on the top with a
block of wood; this is not a well controlled process so it

typically

takes several minutes to get TIR between 1 and 2 mils, when I

tighten

the nuts.

Is there a better way to center the chuck?

Is the mis-match between the land and the recess common? I expected
the chuck to center itself on the spindle land but this mis-match
apparently precludes that.

John

I went through all of this. It would be nice to see and handle the
various machines as can be done with woodworking equipment, but
woodworking is the province of the yuppie and is available everywhere
and metalworking is not.
You stated a couple of things; 1) that you are looking for a toy, so
at some level the question becomes how expensive a toy and how large
is the work to be undertaken.
After suffering the confusion, I bought a Homier 7x12 as the least
expensive toy with which to experiment. Any of the chinese
mini-lathes will be similar and one may expect sample-to-sample
variation to be as great or greater than brand variation.
The CH-350 aluminum ways greatly concern me.
If I wanted to increase the price of admission to the toy, I would
most likely go with the Lathemaster 8x14.
As to tolerance of finished work, the individuals capabilities and
ability to control the machine will play the greatest role. As to
whether or not .0005 is close enough, the engineer of the product
determines that requirement. Any of the lathes properly set up and
operated can reach that tolerance.
I do not remotely claim to be expert on the subject, but this is my
opinion on the subject and hope it is helpful.

Craig



--- In 7x12minilathe@..., "russlbowen1958
<moldproducts@a...>" <moldproducts@a...> wrote:

I'm so confused. The more I read about mini lathes, the more
uncertain I become on which one to buy. I've read that Prazi is the
best at close tol.work, but is +/- .0005 close for 1" dia. x 1"long
420 stainless steel? Shouldn't the asian lathes do that? What does
Prazi give you for $1000 - $2500 extra dollars? And which report do
you believe? Is the Taiwan built CH 350 the best or does the

aluminum

bed blow it? Then I read that the LatheMaster 8 x 14 is the new
champ, and the 9 x 20s are crap. Some say that the older american
lathes like atlas or south bend are better than the new chinese
machines but I find that hard to believe. They were probably good

40

years ago but even China is not that far behind. To me the Micro -
Mark 7 x 14 looks good, but without being able to see eone or run

one

I am trying to rely one reports I read on the internet. But they
seem to be of all different opinions. Can you guys help me out? I
Own a company that designs and builds small inserts for the plastics
industry. I am really looking for a toy that can also make small
inserts from 420 Stainless Steel @ 33 HRc. I know large machines
(Mazak, Lablond, Clausen etc. but can't seem to get a straight read
on the small market. You guys know this market. Help!

--- In 7x12minilathe@..., "robertbyer <byer@m...>"
<byer@m...> wrote:

I know this has been asked, but I coudln't find any answers when I
searched...

What's the largest diameter one can turn with an 7x12?

I have a project where I need to turn a 6" piece of alum but not

sure

if a 7x12 can do it.

If the piece of 6" diameter aluminum is of any length (i.e., greater
than that which could be attached to a faceplate), the 7x12 cannot
turn it.
In fact if we are talk about work that must turn over the cross-slide
and be supported by the tailstock, a 9x20 cannot turn it either.
A 9x20 can turn 5" over the cross-slide, and 7x12 can turn about 3"
over the cross-slide. (I don't have the precise number at this time,
but I can get it if necessary)

Craig

There is an old saying that you get what you pay for.

As a general rule, over my 56 years, I have found this to be generally true.

As far as Chinese products are concerned it depends upon whom is controlling
the quality.

An example, the Acme tool company makes a lathe that sells for $2000. It gets
the lathe made in China and now sells it for $1000. Assuming the quality is
the same the saving is in the labour.

This will only stop when the whole planet is at the same economic level.

In my life time Jap Crap has changed rather. Then it was Taiwan, but no more.
At the moment it is mainland China. I know there are others. Here in Europe
it is the old eastern block countries that are cheaper, in the US I believe
much stuff comes from South America.

The country to watch for the future is India, and I reckon South Africa and
Nigeria if they can ever get their acts together. Also, believe it or not,
Egypt and Iraq. All the naughties they have been up to involve quite a bit of
technical expertise. Channel those efforts somewhere useful and watch that
space in the desert.

So, at the end of the day it is down to Caveat Emptor - Let the buyer beware.

I'm so confused. The more I read about mini lathes, the more
uncertain I become on which one to buy. I've read that Prazi is the
best at close tol.work, but is +/- .0005 close for 1" dia. x 1"long
420 stainless steel? Shouldn't the asian lathes do that? What does
Prazi give you for $1000 - $2500 extra dollars? And which report do
you believe? Is the Taiwan built CH 350 the best or does the aluminum
bed blow it? Then I read that the LatheMaster 8 x 14 is the new
champ, and the 9 x 20s are crap. Some say that the older american
lathes like atlas or south bend are better than the new chinese
machines but I find that hard to believe. They were probably good 40
years ago but even China is not that far behind. To me the Micro -
Mark 7 x 14 looks good, but without being able to see eone or run one
I am trying to rely one reports I read on the internet. But they
seem to be of all different opinions. Can you guys help me out? I
Own a company that designs and builds small inserts for the plastics
industry. I am really looking for a toy that can also make small
inserts from 420 Stainless Steel @ 33 HRc. I know large machines
(Mazak, Lablond, Clausen etc. but can't seem to get a straight read
on the small market. You guys know this market. Help!

OTOH, when you're doing repairs/mods to existing stuff, the lack
of concentricity is a problem. I'm using the 4 jaw until I finish
the Rick Kruger style adjustable backplate (I'm too cheap to go the
collet route.)

Roy
--- In 7x12minilathe@..., Frank Hoose <fhoose@y...> wrote:

Something to keep in mind: a little runout of the
chuck, say .002 or .003 won't affect most projects as
long as you don't remove the workpiece from the chuck
until all operations are completed.

The reason is that as soon as you turn the workpiece
down by more than .004, the resulting workpiece is
exactly concentric with the lathe axis within the
accuracy of the spindle bearings (typically .0002 -
.0005 on the minilathes).

This is why I was able to turn a piece of brass down
to .034 dia. and then drill a .016 hole through it.

lathe.com/Mini_lathe/Capabilities/Capabilities.htm#tiny

More recently, I needed some test pins for making
temporary connections to a tiny DIN connector on a
video camera. I turned the pins from brass to a dia.
of .020. They were concentric even though the 4" chuck
holding the 1/8 brass stock I started with probably
has about .003 runout.

Frank Hoose


--- "Craig C. Hopewell
<chopewel@r...>"
<chopewel@r...> wrote:

John,
I have not heard of this problem before, but I am
new
to the hobby, and if any lathes had this problem I
would
have expected it on mine ( 8^) or 8^( - don't know
which).

I would want this to be accurate, especially if
removing
and mounting the chuck regularly. If under
warranty I
would request a new spindle. If not under warranty
a
new spindle is available from
www.littlemachineshop.com
for $29.95. Alternatively, an adapter plate
similar to
those necessary for a four inch chuck could be
made.

Craig

--- In 7x12minilathe@..., "John
<moran03@e...>"
<moran03@e...> wrote:

The raised land on my spindle plate measures 2.154

rather than 2.165

as given on the mini-lathe site. Sure enough, the

recess in the
chuck

measures 2.165.

In order to mount my 3 jaw chuck I first snug the

nuts slightly, put

a rod in the chuck, and use an indicator on the

rod. I rotate the

chuck so the high point is up and tap the chuck on

the top with a

block of wood; this is not a well controlled

process so it typically

takes several minutes to get TIR between 1 and 2

mils, when I
tighten

the nuts.

Is there a better way to center the chuck?

Is the mis-match between the land and the recess

common? I expected

the chuck to center itself on the spindle land but

this mis-match

apparently precludes that.

John

To unsubscribe from this group, send an email to:
7x12minilathe-unsubscribe@...



Your use of Yahoo! Groups is subject to

__________________________________________________
Do you Yahoo!?
Yahoo! Shopping - Send Flowers for Valentine's Day

Al,
I agree; I'm in the process of making the same one!

Roy
--- In 7x12minilathe@..., "fromday2 <aldayis@a...>"
<aldayis@a...> wrote:

Roy, I saw Rick Kruger about a month ago and one of the intresting
things in his shop is the adjustable backplate. The idea and
execution were clever and well done. I am going to make one for a

4"

3jaw I have. His was nice looking, the concept is simple enough

that

it should be reasonably easy to do.

Al Day
.--- In 7x12minilathe@..., "roylowenthal
<roylowenthal@y...>" <roylowenthal@y...> wrote:

Even if the land/recess match closely, 3-jaw chucks are not
precise. An adjustable backplate solves both problems:

Roy, I saw Rick Kruger about a month ago and one of the intresting
things in his shop is the adjustable backplate. The idea and
execution were clever and well done. I am going to make one for a 4"
3jaw I have. His was nice looking, the concept is simple enough that
it should be reasonably easy to do.

Al Day
.--- In 7x12minilathe@..., "roylowenthal
<roylowenthal@y...>" <roylowenthal@y...> wrote:

Something to keep in mind: a little runout of the
chuck, say .002 or .003 won't affect most projects as
long as you don't remove the workpiece from the chuck
until all operations are completed.

The reason is that as soon as you turn the workpiece
down by more than .004, the resulting workpiece is
exactly concentric with the lathe axis within the
accuracy of the spindle bearings (typically .0002 -
.0005 on the minilathes).

This is why I was able to turn a piece of brass down
to .034 dia. and then drill a .016 hole through it.



More recently, I needed some test pins for making
temporary connections to a tiny DIN connector on a
video camera. I turned the pins from brass to a dia.
of .020. They were concentric even though the 4" chuck
holding the 1/8 brass stock I started with probably
has about .003 runout.

Frank Hoose


--- "Craig C. Hopewell
<chopewel@...>"
<chopewel@...> wrote:

John,
I have not heard of this problem before, but I am
new
to the hobby, and if any lathes had this problem I
would
have expected it on mine ( 8^) or 8^( - don't know
which).

I would want this to be accurate, especially if
removing
and mounting the chuck regularly. If under
warranty I
would request a new spindle. If not under warranty
a
new spindle is available from
www.littlemachineshop.com
for $29.95. Alternatively, an adapter plate
similar to
those necessary for a four inch chuck could be
made.

Craig

--- In 7x12minilathe@..., "John
<moran03@e...>"
<moran03@e...> wrote:

The raised land on my spindle plate measures 2.154

rather than 2.165

as given on the mini-lathe site. Sure enough, the

recess in the
chuck

measures 2.165.

In order to mount my 3 jaw chuck I first snug the

nuts slightly, put

a rod in the chuck, and use an indicator on the

rod. I rotate the

chuck so the high point is up and tap the chuck on

the top with a

block of wood; this is not a well controlled

process so it typically

takes several minutes to get TIR between 1 and 2

mils, when I
tighten

the nuts.

Is there a better way to center the chuck?

Is the mis-match between the land and the recess

common? I expected

the chuck to center itself on the spindle land but

this mis-match

apparently precludes that.

John

To unsubscribe from this group, send an email to:
7x12minilathe-unsubscribe@...



Your use of Yahoo! Groups is subject to

__________________________________________________
Do you Yahoo!?
Yahoo! Shopping - Send Flowers for Valentine's Day

Even if the land/recess match closely, 3-jaw chucks are not
precise. An adjustable backplate solves both problems:



Roy
--- In 7x12minilathe@..., "John <moran03@e...>"
<moran03@e...> wrote:

The raised land on my spindle plate measures 2.154 rather than

2.165

as given on the mini-lathe site. Sure enough, the recess in the

chuck

measures 2.165.

In order to mount my 3 jaw chuck I first snug the nuts slightly,

put

a rod in the chuck, and use an indicator on the rod. I rotate the
chuck so the high point is up and tap the chuck on the top with a
block of wood; this is not a well controlled process so it

typically

takes several minutes to get TIR between 1 and 2 mils, when I

tighten

the nuts.

Is there a better way to center the chuck?

Is the mis-match between the land and the recess common? I expected
the chuck to center itself on the spindle land but this mis-match
apparently precludes that.

John

I know this has been asked, but I coudln't find any answers when I
searched...

What's the largest diameter one can turn with an 7x12?

I have a project where I need to turn a 6" piece of alum but not sure
if a 7x12 can do it.

Any suggestions?

Thanks.

Well, there's a lot of history there. This group was
one of several that have been started in response to
the high volume of Off Topic messages on the original
Yahoo 7x group. Unfortunately, the moderated groups,
such as this one, often seem to die off due to lack of
participation. So far, this one has been more
successful than its predecessors. Then again, we are
now engaged in OT discussion. For more info, see this
link:



Frank Hoose


--- Jerry Smith <jfsmith@...> wrote:

Ryan,
They may be out shoveling snow.

Jerry and Sam the shop cat.

At 02:33 AM 2/10/2003 +0000, you wrote:

Just wondering why nobody ever posts any messages

in this group.

Ryan The Sign Guy



To unsubscribe from this group, send an email to:
7x12minilathe-unsubscribe@...



Your use of Yahoo! Groups is subject to the
<>Yahoo! Terms of

Service.



To unsubscribe from this group, send an email to:
7x12minilathe-unsubscribe@...



Your use of Yahoo! Groups is subject to

__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.

Ok people I have some questions about small mills from HF:
Does anyone out there have any experience with the Micro-mill HF is selling
now? ($279 in the local store.) As I see it it has 2 plus's, a small
footprint and only weighs about 100 lbs. One giant question, is it as
prone to broken gears as the mini-mill apparently is? 2nd question is: Is
it sufficently rigid/powerful to mill steel?
Yeah I know this is a lathe list not a mill list but there is so much
unreasoned prejudice (on the subject of mills) over on the other lathe list
that thought I would throw it out here and see what is said.
Regards
Bob

Ryan,
They may be out shoveling snow.

Jerry and Sam the shop cat.