'Been looking for a small lathe I can quickly upgrade to CNC.

Among them is the Shop Fox 13x40 M1098. A hands-on look makes it seem like
a pretty well-made machine for an off-shore rig.

Anybody here have any experience with them?

LLoyd

On Mon, 16 May 2011 06:18:32 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

'Been looking for a small lathe I can quickly upgrade to CNC.

Among them is the Shop Fox 13x40 M1098. A hands-on look makes it seem like
a pretty well-made machine for an off-shore rig.

Anybody here have any experience with them?

LLoyd
Have you looked at buying a dead CNC lathe? It does take searching but
you'll be way closer to your goal. I'm partial to Hardinge because so
dang many were made twenty years ago.

That said, looks like a decent enough import lathe. I'd have a design
concept in mind for your ball screws and stepper/servos before you
buy.

Karl

Karl Townsend fired this volley in
:

Have you looked at buying a dead CNC lathe? It does take searching but
you'll be way closer to your goal. I'm partial to Hardinge because so
dang many were made twenty years ago.

That said, looks like a decent enough import lathe. I'd have a design
concept in mind for your ball screws and stepper/servos before you
buy.


I have looked, Karl, but two things stop me. Most of the used CNC machines
I'd have access to (say, in a 200 mile circle of me) are darned-well USED,
and not in stellar condition.

Also, I cannot do the tax re-capture single-year amortization of a used
machine. Buying new gets me an ROI of about 16 months.

The guys at Mach Motion have already done a nice conversion of exactly the
same model lathe of a different badge. I'm not overly impressed with the
Mach3 control, which apparently has trouble doing threading unless you buy
the (additional) MachMotion $2550 stand-alone motion controller that goes
between Mach3 and the drivers.

I'm pretty certain that Iggy has proven EMC will do it without all that
additional computing power and unsupportable embedded proprietary code.

However, since they've converted a lathe that is mechanically identical to
the Shop Fox, I assume it's not to ugly mechanically -- and heck! I'll
have the lathe working in manual mode to do the work G.


LLoyd

On Mon, 16 May 2011 07:28:14 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
:

Have you looked at buying a dead CNC lathe? It does take searching but
you'll be way closer to your goal. I'm partial to Hardinge because so
dang many were made twenty years ago.

That said, looks like a decent enough import lathe. I'd have a design
concept in mind for your ball screws and stepper/servos before you
buy.


I have looked, Karl, but two things stop me. Most of the used CNC machines
I'd have access to (say, in a 200 mile circle of me) are darned-well USED,
and not in stellar condition.

Also, I cannot do the tax re-capture single-year amortization of a used
machine. Buying new gets me an ROI of about 16 months.

The guys at Mach Motion have already done a nice conversion of exactly the
same model lathe of a different badge. I'm not overly impressed with the
Mach3 control, which apparently has trouble doing threading unless you buy
the (additional) MachMotion $2550 stand-alone motion controller that goes
between Mach3 and the drivers.

I'm pretty certain that Iggy has proven EMC will do it without all that
additional computing power and unsupportable embedded proprietary code.

However, since they've converted a lathe that is mechanically identical to
the Shop Fox, I assume it's not to ugly mechanically -- and heck! I'll
have the lathe working in manual mode to do the work G.


LLoyd

How about starting with a Lancer lathe? i see a fella here offering a
project lathe cheap. And you wouldn't have to take it apart first
VBG I bet he'd find you some ball screws and servo motors to sweeten
the deal.

Seriously, that would make one hell of a lathe.

Karl

Also, I cannot do the tax re-capture single-year amortization of a used
machine. Buying new gets me an ROI of about 16 months.

I've got a better accountant than you. No problem to section 179 used
equipment and expense it.

Karl

Lloyd, my opinion is worth $0.01, but I feel that I have to state it.

CNC retrofit of a machine that is built as a CNC machine, is a
COMPLETELY different type of project than a CNC retrofit of a manual
machine.

If the difficulty of the former is 6 on the scale of 1-10, then the
latter is 9-10.

You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.

It all seems simple conceptually, until a) you start doing it and b)
make some mistakes that you realize late in the game. For sure it is
NOT cheap, if you price your time at $5 per hour and up.

I agree that a CNC lathe that is not totally clapped out, is harder
to find that a mill or a VMC.

I may be overstating my case or just not experienced enough to breeze
through that sort of thing. But somehow, I feel that retrofitting
manuals machines is not nearly as cost effective as taking a CNC
machine with a bad control.

i

On Mon, 16 May 2011 06:18:32 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

'Been looking for a small lathe I can quickly upgrade to CNC.

Among them is the Shop Fox 13x40 M1098. A hands-on look makes it seem like
a pretty well-made machine for an off-shore rig.

Anybody here have any experience with them?

LLoyd

Define "small lathe"

I currently own (3) Omniturns that are available for sale

www.omniturn.com
www.omni-turn.com

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

"Lloyd E. Sponenburgh" wrote:

Karl Townsend fired this volley in
:

Have you looked at buying a dead CNC lathe? It does take searching but
you'll be way closer to your goal. I'm partial to Hardinge because so
dang many were made twenty years ago.

That said, looks like a decent enough import lathe. I'd have a design
concept in mind for your ball screws and stepper/servos before you
buy.


I have looked, Karl, but two things stop me. Most of the used CNC machines
I'd have access to (say, in a 200 mile circle of me) are darned-well USED,
and not in stellar condition.

Also, I cannot do the tax re-capture single-year amortization of a used
machine. Buying new gets me an ROI of about 16 months.

The guys at Mach Motion have already done a nice conversion of exactly the
same model lathe of a different badge. I'm not overly impressed with the
Mach3 control, which apparently has trouble doing threading unless you buy
the (additional) MachMotion $2550 stand-alone motion controller that goes
between Mach3 and the drivers.

I've followed the Mach3 forums for years and I've not heard of anyone
reporting problems with threading. Sounds more like a sales pitch to
sell the extra hardware.


I'm pretty certain that Iggy has proven EMC will do it without all that
additional computing power and unsupportable embedded proprietary code.

Mach3 is based on EMC. Mach3 is also well supported.


However, since they've converted a lathe that is mechanically identical to
the Shop Fox, I assume it's not to ugly mechanically -- and heck! I'll
have the lathe working in manual mode to do the work G.

Always good to be able to follow an existing design vs. rolling your own
design.

Ignoramus18335 fired this volley in
:

You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.


Ig, I take your advice seriously, but I have the advantage that they have
already converted one of these. Only two small issues must be resolved
on my end:

I must make a ball nut bracket for each of the Z and Y feeds, and I must
add thrust bearings to the ends of the screw brackets to take out end
play. They have motor mounts and couplers designed to purpose, and the
adaptor plates and couplers only add about $50 to the total bill --
saving me much layout and machining time.

I have pretty much exhausted the near-regional used CNC lathe market
looking for anything that doesn't have so much wear as to require a full
screw and motor upgrade (and way scraping), and I think I'd rather do the
conversion. I intend not to kill the manual functions until everything
is ready (although I'll probably do several disassemblies and re-
assemblies of everything before I'm done).

Things like mounting limit switches are just not that much of a
challenge.

As for mistakes? Yeah... but they're all "recoverable", so long as I
don't invest in motors or ball screw assemblies that are sub-standard.
To that end, I'll be using some proven motors, and precision-ground
screw/nut combinations. The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

LLoyd

Gunner Asch fired this volley in
:

Define "small lathe"

I currently own (3) Omniturns that are available for sale

I need a pretty good-sized work envelope. That's one reason I'm going with
a 13x40 manual.

What models do you have, how much, what condition of mechanics, and how
much for shipping one to Florida?

LLoyd

On 2011-05-16, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus18335 fired this volley in
:

You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.


Ig, I take your advice seriously, but I have the advantage that they have
already converted one of these. Only two small issues must be resolved
on my end:

I must make a ball nut bracket for each of the Z and Y feeds, and I must
add thrust bearings to the ends of the screw brackets to take out end
play. They have motor mounts and couplers designed to purpose, and the
adaptor plates and couplers only add about $50 to the total bill --
saving me much layout and machining time.

I have pretty much exhausted the near-regional used CNC lathe market
looking for anything that doesn't have so much wear as to require a full
screw and motor upgrade (and way scraping), and I think I'd rather do the
conversion. I intend not to kill the manual functions until everything
is ready (although I'll probably do several disassemblies and re-
assemblies of everything before I'm done).

Things like mounting limit switches are just not that much of a
challenge.

As for mistakes? Yeah... but they're all "recoverable", so long as I
don't invest in motors or ball screw assemblies that are sub-standard.
To that end, I'll be using some proven motors, and precision-ground
screw/nut combinations. The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.


Keep us posted Lloyd, I do not want to discourage you in any way.

i

Ignoramus18335 fired this volley
in :
Keep us posted Lloyd, I do not want to discourage you in any way.

i


In any case, this will be pretty rapid-fire, except, perhaps, for the
budget. The motors and drivers will cost me $1200 for new, proven AC-
Brushless Servos and 2500 line encoders. That's the biggest rub. The
screws are pricey anywhere you get them, when you go to the 0.0005"/ft.
versions.

I'll be working hard to preserve all of the manual features except for
threading (I have a 6x18 that can do for the time being), until that very
last moment when I "switch over".

LLoyd

"Lloyd E. Sponenburgh" wrote:

Ignoramus18335 fired this volley in
:

You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.


Ig, I take your advice seriously, but I have the advantage that they have
already converted one of these. Only two small issues must be resolved
on my end:

I must make a ball nut bracket for each of the Z and Y feeds, and I must
add thrust bearings to the ends of the screw brackets to take out end
play. They have motor mounts and couplers designed to purpose, and the
adaptor plates and couplers only add about $50 to the total bill --
saving me much layout and machining time.

I have pretty much exhausted the near-regional used CNC lathe market
looking for anything that doesn't have so much wear as to require a full
screw and motor upgrade (and way scraping), and I think I'd rather do the
conversion. I intend not to kill the manual functions until everything
is ready (although I'll probably do several disassemblies and re-
assemblies of everything before I'm done).

Things like mounting limit switches are just not that much of a
challenge.

As for mistakes? Yeah... but they're all "recoverable", so long as I
don't invest in motors or ball screw assemblies that are sub-standard.
To that end, I'll be using some proven motors, and precision-ground
screw/nut combinations. The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.


I've only seen two used lathes in my area in two years, and you
wouldn't have wanted either of them. At least one was scrapped because
it needed so much work.


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

On Mon, 16 May 2011 16:10:02 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Gunner Asch fired this volley in
:

Define "small lathe"

I currently own (3) Omniturns that are available for sale

I need a pretty good-sized work envelope. That's one reason I'm going with
a 13x40 manual.

What models do you have, how much, what condition of mechanics, and how
much for shipping one to Florida?

LLoyd

Ive got (2) Hardinge HC retrofits and one GT75

None are new, need paint badly, one might..might need either a thrust
bearing or a ballscrew.

Envelope is only 9x14 at most.

www.omni-turn.com

Ill get $5k for any of them as is, $7k-9k if I paint em and fix em up.

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

Gunner Asch fired this volley in
:


Ill get $5k for any of them as is, $7k-9k if I paint em and fix em up.

Gunner

And that, plus heavy-duty shipping. That's why I'm keeping my look to a
200 mile radius.

I sold my F.E. Reed and Cincinnatti #2 to a guy three hours away, and he
took them grinning. But, then, the only diseases they had were pure age
-- ways scraped, bearings running close and smooth.

LLoyd

Ignoramus18335 wrote:
Lloyd, my opinion is worth $0.01, but I feel that I have to state it.

CNC retrofit of a machine that is built as a CNC machine, is a
COMPLETELY different type of project than a CNC retrofit of a manual
machine.

If the difficulty of the former is 6 on the scale of 1-10, then the
latter is 9-10.

You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.

It all seems simple conceptually, until a) you start doing it and b)
make some mistakes that you realize late in the game. For sure it is
NOT cheap, if you price your time at $5 per hour and up.

I agree that a CNC lathe that is not totally clapped out, is harder
to find that a mill or a VMC.

I may be overstating my case or just not experienced enough to breeze
through that sort of thing. But somehow, I feel that retrofitting
manuals machines is not nearly as cost effective as taking a CNC
machine with a bad control.

i


Old Okuma cnc lathes are very good candidates for retrofitting. Find
one with an old OSP 2000 control and you will have a very good start.
The biggest problem is that they used absolute encoders which were great
on the original lathe setup. No homing was necessary.

John

Lloyd E. Sponenburgh wrote:
fired this volley in
:

You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.


Ig, I take your advice seriously, but I have the advantage that they have
already converted one of these. Only two small issues must be resolved
on my end:

I must make a ball nut bracket for each of the Z and Y feeds, and I must
add thrust bearings to the ends of the screw brackets to take out end
play. They have motor mounts and couplers designed to purpose, and the
adaptor plates and couplers only add about $50 to the total bill --
saving me much layout and machining time.

I have pretty much exhausted the near-regional used CNC lathe market
looking for anything that doesn't have so much wear as to require a full
screw and motor upgrade (and way scraping), and I think I'd rather do the
conversion. I intend not to kill the manual functions until everything
is ready (although I'll probably do several disassemblies and re-
assemblies of everything before I'm done).

Things like mounting limit switches are just not that much of a
challenge.

As for mistakes? Yeah... but they're all "recoverable", so long as I
don't invest in motors or ball screw assemblies that are sub-standard.
To that end, I'll be using some proven motors, and precision-ground
screw/nut combinations. The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

LLoyd




The option is to use glass scales with a rolled screw. AS long as the
ball screw has no backlash the glass scale will give accurate position
with no backlash.

John

"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

"Pete C." fired this volley in news:4dd28edf$0
:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.


Yes, true enough, but the one thing I don't have is the gear to measure
that over 30-some inches of carriage travel. On the one hand, the
hardware would be cheaper, on the gripping hand (using precision screws),
I wouldn't need the instruments (I can live with a thou. over three
feet). Maybe I could get someone who does have the tools to come do the
mapping...

LLoyd

"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:4dd28edf$0
:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.


Yes, true enough, but the one thing I don't have is the gear to measure
that over 30-some inches of carriage travel. On the one hand, the
hardware would be cheaper, on the gripping hand (using precision screws),
I wouldn't need the instruments (I can live with a thou. over three
feet). Maybe I could get someone who does have the tools to come do the
mapping...

LLoyd

Most people use a dial indicator and map the screw an inch at a time.

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Pete C." fired this volley in news:4dd28edf$0
:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.


Yes, true enough, but the one thing I don't have is the gear to measure
that over 30-some inches of carriage travel. On the one hand, the
hardware would be cheaper, on the gripping hand (using precision screws),
I wouldn't need the instruments (I can live with a thou. over three
feet). Maybe I could get someone who does have the tools to come do the
mapping...

LLoyd

There are calibration service companies that will do the job with laser
interferometers. There are home-made solutions, but they're very tedious and
slow. And I forget what they are. d8-)

--
Ed Huntress

"Pete C." fired this volley in news:4dd2914a$0$10550
:

Most people use a dial indicator and map the screw an inch at a time.


Not hardly, Pete. I've watched that procedure before on big VMCs. You
want not only "localized" errors, but cumulative errors to be mapped.

As Ed stated below, the Japanese techs were using laser devices. The could
map a 6' travel to half a tenth, cumulative, easily. (I'm betting it was
better than that)

LLoyd

"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:4dd2914a$0$10550
:

Most people use a dial indicator and map the screw an inch at a time.


Not hardly, Pete. I've watched that procedure before on big VMCs. You
want not only "localized" errors, but cumulative errors to be mapped.

My reference was to people doing CNC retrofits, not big commercial
machines. Whe we replaced ball screws on the big machines the new ball
screws came with a pitch error table to enter into the control.

Also, measuring an inch at a time does not "localize" errors, you map
continuously from one end to the other and unless you are quite sloppy,
you introduce no cumulative error into that mapping.


As Ed stated below, the Japanese techs were using laser devices. The could
map a 6' travel to half a tenth, cumulative, easily. (I'm betting it was
better than that)

Yep, the ball screws for real machines are laser mapped. You can
probably buy your ball screws mapped with a pitch error table included
for an extra charge.

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

True indeed.

Others, such as OmniTurn..use high quality ballscrews and dont have to
worry about screw mapping.

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

On Tue, 17 May 2011 11:10:47 -0500, "Pete C."
wrote:


As Ed stated below, the Japanese techs were using laser devices. The could
map a 6' travel to half a tenth, cumulative, easily. (I'm betting it was
better than that)

Yep, the ball screws for real machines are laser mapped. You can
probably buy your ball screws mapped with a pitch error table included
for an extra charge.

Most ballscrews today..have very very very little error in their entire
length.

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

Gunner Asch wrote:

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

True indeed.

Others, such as OmniTurn..use high quality ballscrews and dont have to
worry about screw mapping.

I worked on some very high quality machines back when I did CNC service,
and *all* of them did screw mapping. Replacement ball screws came with
pitch error tables to enter into the (Fanuc) controls.

Gunner Asch wrote:

On Tue, 17 May 2011 11:10:47 -0500, "Pete C."
wrote:


As Ed stated below, the Japanese techs were using laser devices. The could
map a 6' travel to half a tenth, cumulative, easily. (I'm betting it was
better than that)

Yep, the ball screws for real machines are laser mapped. You can
probably buy your ball screws mapped with a pitch error table included
for an extra charge.

Most ballscrews today..have very very very little error in their entire
length.

I would expect that with the drive for higher and higher accuracy on the
high end stuff, that would trickle down to the lower end stuff as well.

On 2011-05-17, Pete C. wrote:

Gunner Asch wrote:

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

True indeed.

Others, such as OmniTurn..use high quality ballscrews and dont have to
worry about screw mapping.

I worked on some very high quality machines back when I did CNC service,
and *all* of them did screw mapping. Replacement ball screws came with
pitch error tables to enter into the (Fanuc) controls.

Using screw mapping compensation makes any screw more precise.

i

Ignoramus31865 wrote:

On 2011-05-17, Pete C. wrote:

Gunner Asch wrote:

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

True indeed.

Others, such as OmniTurn..use high quality ballscrews and dont have to
worry about screw mapping.

I worked on some very high quality machines back when I did CNC service,
and *all* of them did screw mapping. Replacement ball screws came with
pitch error tables to enter into the (Fanuc) controls.

Using screw mapping compensation makes any screw more precise.

i

Exactly.

On Tue, 17 May 2011 12:11:48 -0500, "Pete C."
wrote:


Gunner Asch wrote:

On Tue, 17 May 2011 11:10:47 -0500, "Pete C."
wrote:


As Ed stated below, the Japanese techs were using laser devices. The could
map a 6' travel to half a tenth, cumulative, easily. (I'm betting it was
better than that)

Yep, the ball screws for real machines are laser mapped. You can
probably buy your ball screws mapped with a pitch error table included
for an extra charge.

Most ballscrews today..have very very very little error in their entire
length.

I would expect that with the drive for higher and higher accuracy on the
high end stuff, that would trickle down to the lower end stuff as well.

It is. Ballscrew tolerences are like those of ball bearings. They have
figured out better and better ways of manufacturing and stuff that was
****ing Fantastic!! but $200, 25 yrs ago..is over the counter at any
bearing house for $10

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

On Tue, 17 May 2011 12:30:54 -0500, "Pete C."
wrote:


Ignoramus31865 wrote:

On 2011-05-17, Pete C. wrote:

Gunner Asch wrote:

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

True indeed.

Others, such as OmniTurn..use high quality ballscrews and dont have to
worry about screw mapping.

I worked on some very high quality machines back when I did CNC service,
and *all* of them did screw mapping. Replacement ball screws came with
pitch error tables to enter into the (Fanuc) controls.

Using screw mapping compensation makes any screw more precise.

i

Exactly.

Indeed it does. However..many machines are built well enough that they
simply dont need mapping, today.

Gunner

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

Cool. Is that built into Mach3?

What do you think of this package for a CNC router: Gecko G540, 3
Nema23 8-wire Steppers 620 oz/in, 3 D9 connectors and shells, latching
E-stop switch, 3 homing buttons, 3 current set resistors, a licensed
copy of Mach3, and a licensed copy of Bobcad Express V21 for $659 +
$25.22 delivery? (modelshopcnc vendor on eBay)

--
It could probably be shown by facts and figures that there is no
distinctively native American criminal class except Congress.
-- Mark Twain

On Tue, 17 May 2011 10:09:27 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Pete C." fired this volley in news:4dd28edf$0
:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.


Yes, true enough, but the one thing I don't have is the gear to measure
that over 30-some inches of carriage travel. On the one hand, the
hardware would be cheaper, on the gripping hand (using precision screws),
I wouldn't need the instruments (I can live with a thou. over three
feet). Maybe I could get someone who does have the tools to come do the
mapping...

Hmm, that's right. You'd need some sort of feedback (DRO?) to do the
mapping, wooncha?

--
It could probably be shown by facts and figures that there is no
distinctively native American criminal class except Congress.
-- Mark Twain

Larry Jaques fired this volley in
:

Hmm, that's right. You'd need some sort of feedback (DRO?) to do the
mapping, wooncha?

Yeah, and the new lathe doesn't come with a DRO, which would run me roughly
$700. I'll bet I can wheedle someone qualified to do it for half that.

The question, then, is would precision, pre-machined-ends screws cost me in
differential cost even less than that. I'm betting yes, but haven't nailed
it down. The precision-ground screw crowd doesn't seem to list their
prices on-line (which could be BADDD!G)

LLoyd

Larry Jaques wrote:

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

Cool. Is that built into Mach3?

Yes.


What do you think of this package for a CNC router: Gecko G540, 3
Nema23 8-wire Steppers 620 oz/in, 3 D9 connectors and shells, latching
E-stop switch, 3 homing buttons, 3 current set resistors, a licensed
copy of Mach3, and a licensed copy of Bobcad Express V21 for $659 +
$25.22 delivery? (modelshopcnc vendor on eBay)

That sounds pretty cheap, don't see a power supply in there, wire,
enclosures, etc. I like the CandCNC stuff personally, I use the
Bladerunner / DragonCut to drive my plasma cutter or my mini mill (swap
cables to share the control and drives). The CandCNC stuff is a bit
more, but is complete ready to hookup and run and is well built and
packaged (it's also built about 30min away from me).

Ignoramus31865 wrote:

(...)

Using screw mapping compensation makes any screw more precise.

More accurate, anyway.

--Winston