This seems a little more complicated. Everything that I read and the
people that I talk to say that a quick-change toolpost is more of a
necessity than a luxury.

Choices seem to be:

Buy the Proxxon one

Buy the A2ZCNC 60% of AXA one

Build one, probably of the circular post plus split-bushing type


The Proxxon version costs about $115 with two holders, plus $21 from
another holder. It replaces the existing toolpost, which is a
rectangular chunk of aluminum with a dovetail slide on the bottom and
a threaded hole in the side; it doubles as the top slide! It thus
retains all of the flexibility and deficiencies of the current
slow-change toolpost, but tools get changed quickly.

The primary deficiency seems to be that the tools are fixed at the
same angle as the top slide. One cannot (for example) set the top
slide to 29 degrees and then set the tool perpendicular to the work.


The A2ZCNC version costs about $100 with four holders. It completely
replaces the top slide, mounting to the slot in the cross slide.
Reports are that it is a quality product. It apparently allows you to
set the tool at any angle to the work by loosening the mounting screw,
rotating, and re-tightening. However, there is no top slide with this
unit in place. That means no 29-degree threading (which apparently
cannot be done with any other option either). It also means using the
current slow-change toolpost for tapers. I don't know of any other
function of the top slide, but I am a beginner so I am probably
missing something.


Then there is the DIY option. The advantages are probably educational
value and low monetary cost (but high time cost). It would probably
consist of a circular post mounting to the slot in the cross slide,
plus holders consisting of rectangular blocks with a hold up the
middle with a slot and a clamping screw. The tools could be set at any
angle, but again there is no top slide.


Any other good options?

Any advice?

Bob

"Bob S" wrote in message
...
This seems a little more complicated. Everything that I read and the
people that I talk to say that a quick-change toolpost is more of a
necessity than a luxury.

Bob

QC toolposts save you from fussing with shims under the bits. They are
convenient but certainly not a necessity. I put up with a home-made
lantern post like this for quite a while.
http://www.vannattabros.com/20063rd/post3.jpg

On a small lathe they can hold the bits directly and don't need thin
shims to adjust the height.
http://www.autoartisans.com/Lathe/LANTP.JPG

jsw

On Mar 3, 9:26*pm, Bob S wrote:


Any other good options?

Any advice?

Bob

I would not buy a fancy tool holder right now. Obviously the Proxxon
people think what comes with the lathe is adequate. And if you use
that for a while you may see that it is good for the machining you
do.

Lathes used the lantern type of tool holder for about a hundred years
before the use of better tools, higher speeds and feeds required a
more rigid way to hold tools.

Dan

The unusual design of the Proxxon PD 230 lathe leaves few options for any of
the more commonly available QCTP quick change toolposts.

There is very little space available in the dsign for adapting a common
QCTP, since having a dovetail to match the base of the top/compound slide is
required, so it's not likely that it will be easy to design a QCTP which
will utilize the rotational position feature common to most types of QCTPs.
Also, the feed screw of the top slide is fitted in a way that maintaining a
feed screw feature almost demands the supplied toolpost or the Proxxon
QCTP.. however the Prox model still doesn't rotate except by unlocking and
rotating the top slide.

I think you'll find that the supplied toolpost is adequate for most
operations you'll end up wanting to do.
The supplied TP appears to be capable of 2-way cutting tool mounting, at
least, so that's a definite advantage.
As with most lathe work (and many other tasks), planning out the sequence of
required events/steps is what makes the most practical use of one's time.
Generally, the ability to plan these "time saving" steps effectively, comes
with experience.

On other lathes which can utilize commonly available and easy to install
QCTPs, they are merely luxury conveniences. They have several good features
which make tool changes convenient, but as someone mentioned, lathes with
more primitive tool holders have been used successfully for generations
without QCTPs.
In addition to making many of the machines and weapons for 2 world wars,
manual lathes and rigid or lantern toolposts were used to advance every type
of technological progress which took place since the first lathe was
produced.

As a beginning lathe user, it may be very useful to start with plastic stock
to help you get accustomed to the various general aspects of cutting
rotating material.
Scraps of PVC pipe, empty pen bodies and various parts of items which will
be discarded, should all be seen as potential parts now.. definitely good
materials for practicing anyway.

A shallow chip tray/pan can be fabricated from any number of materials or
unused products which you may have in a cupboard or closet, such as a baking
pan for example.
Many small lathes have features on the bottom to enable the owner to mount
the base to a table or bench. Those features can be utilized to place block
spacers between the base and a chip pan, where rubber feet/pads can be
mounted to the bottom of the pan under the blocks to prevent sliding around
during use.

When metal parts become a regular part of lathe use, you'll discover how
easily chips attach themselves to clothing and shoes, which then transfer
them to various other locations.. so try to set up a work table away from
the busy traffic patterns within a household, and be aware of the parasitic
characteristics and behaviors? of chips.

I'm not familiar with the design of the Prox lathe, but you may find it
useful to have a hand crank for the spindle, if one can be attached on the
left end of the spindle.
Hand cranks are useful for certain operations, and I find them very handy
for short threaded sections such as you may be contemplating for lens
adapters.
It's always the best practice to unplug a machine before installing
something like a hand crank which is likely to cause machine damage or
personal injury if the machine power is accidently turned on with an
unbalanced spindle hand crank in place.

In addition to DoN's excellent recommendations made earlier, one lens type
that I know of has inch-pitch threads, and those are C-mount video lenses,
which are 1" 32 TPI.

A couple of other items needed for machine use would be some small brushes
for cleaning away chips (compressed air can actually force chips into places
on machines where thay may do harm), and an oiler with an oil suitable for
your new machine.
The manufacturer may recommend certain lubricating products for your
machine, and indicate which parts need to be kept very clean, and
lubricated.

Finally, I hope you get a great deal of enjoyment from your new machine.. I
find metalworking projects to be very gratifying.

--
WB
..........


"Bob S" wrote in message
...
This seems a little more complicated. Everything that I read and the
people that I talk to say that a quick-change toolpost is more of a
necessity than a luxury.

Choices seem to be:

Buy the Proxxon one

Buy the A2ZCNC 60% of AXA one

Build one, probably of the circular post plus split-bushing type


The Proxxon version costs about $115 with two holders, plus $21 from
another holder. It replaces the existing toolpost, which is a
rectangular chunk of aluminum with a dovetail slide on the bottom and
a threaded hole in the side; it doubles as the top slide! It thus
retains all of the flexibility and deficiencies of the current
slow-change toolpost, but tools get changed quickly.

The primary deficiency seems to be that the tools are fixed at the
same angle as the top slide. One cannot (for example) set the top
slide to 29 degrees and then set the tool perpendicular to the work.


The A2ZCNC version costs about $100 with four holders. It completely
replaces the top slide, mounting to the slot in the cross slide.
Reports are that it is a quality product. It apparently allows you to
set the tool at any angle to the work by loosening the mounting screw,
rotating, and re-tightening. However, there is no top slide with this
unit in place. That means no 29-degree threading (which apparently
cannot be done with any other option either). It also means using the
current slow-change toolpost for tapers. I don't know of any other
function of the top slide, but I am a beginner so I am probably
missing something.


Then there is the DIY option. The advantages are probably educational
value and low monetary cost (but high time cost). It would probably
consist of a circular post mounting to the slot in the cross slide,
plus holders consisting of rectangular blocks with a hold up the
middle with a slot and a clamping screw. The tools could be set at any
angle, but again there is no top slide.


Any other good options?

Any advice?

Bob

On Sat, 03 Mar 2012 21:26:32 -0500, Bob S
wrote:

This seems a little more complicated. Everything that I read and the
people that I talk to say that a quick-change toolpost is more of a
necessity than a luxury.

Choices seem to be:

Buy the Proxxon one

Buy the A2ZCNC 60% of AXA one

Build one, probably of the circular post plus split-bushing type


The Proxxon version costs about $115 with two holders, plus $21 from
another holder. It replaces the existing toolpost, which is a
rectangular chunk of aluminum with a dovetail slide on the bottom and
a threaded hole in the side; it doubles as the top slide! It thus
retains all of the flexibility and deficiencies of the current
slow-change toolpost, but tools get changed quickly.

The primary deficiency seems to be that the tools are fixed at the
same angle as the top slide. One cannot (for example) set the top
slide to 29 degrees and then set the tool perpendicular to the work.


The A2ZCNC version costs about $100 with four holders. It completely
replaces the top slide, mounting to the slot in the cross slide.
Reports are that it is a quality product. It apparently allows you to
set the tool at any angle to the work by loosening the mounting screw,
rotating, and re-tightening. However, there is no top slide with this
unit in place. That means no 29-degree threading (which apparently
cannot be done with any other option either). It also means using the
current slow-change toolpost for tapers. I don't know of any other
function of the top slide, but I am a beginner so I am probably
missing something.


Then there is the DIY option. The advantages are probably educational
value and low monetary cost (but high time cost). It would probably
consist of a circular post mounting to the slot in the cross slide,
plus holders consisting of rectangular blocks with a hold up the
middle with a slot and a clamping screw. The tools could be set at any
angle, but again there is no top slide.


Any other good options?

Any advice?

Bob
Shop around for the best price on the AXA toolpost. The quick change
toolpost is a big time saver, meaning more time spent making chips.
It's also easier to use which means less aggravation, which saves
time, time you can spend making chips. When you do get the AXA size
toolpost, make sure to get the wedge type instead of the piston type.
The wedge type repeats better. At least in my experience they do. I
make my living as a machinist. Have been doing so for the last 35
years or so. My opinion is that if you can afford it buy the tools
which will enable you to cut metal the fastest. After you have some
experience you can decide if making your own toolpost for special work
is something you want to do. In the meantime you can learn about
turning, facing, boring, threading, and parting off while you make
your lens parts. You will be using, most likely, a turning/facing
tool, a boring bar, internal threading tool, external threading tool,
and a part off blade. That's 5 tools used to make one part. Get those
tools set and then it is much easier and faster to make your lens
parts. And since the tools are each in a separate, quickly changed
tool holder, you only need to set each tool once.
Eric

Thank you, maybe I should try the older ways for a while...


On Sun, 4 Mar 2012 05:05:16 -0800 (PST), wrote:

On Mar 3, 9:26*pm, Bob S wrote:


Any other good options?

Any advice?

Bob

I would not buy a fancy tool holder right now. Obviously the Proxxon
people think what comes with the lathe is adequate. And if you use
that for a while you may see that it is good for the machining you
do.

Lathes used the lantern type of tool holder for about a hundred years
before the use of better tools, higher speeds and feeds required a
more rigid way to hold tools.

Dan

Thank you for the extensive post.

Comments interspersed:


On Sun, 4 Mar 2012 12:38:21 -0500, Wild_Bill wrote:

The unusual design of the Proxxon PD 230 lathe leaves few options for any of
the more commonly available QCTP quick change toolposts.

[...]

I think you'll find that the supplied toolpost is adequate for most
operations you'll end up wanting to do.

[...]

Yes, I am beginning to see the issues and I will try practicing
patience.



As a beginning lathe user, it may be very useful to start with plastic stock
to help you get accustomed to the various general aspects of cutting
rotating material.
Scraps of PVC pipe, empty pen bodies and various parts of items which will
be discarded, should all be seen as potential parts now.. definitely good
materials for practicing anyway.

Good idea; there is certainly lots of that sort of stuff around here.

A shallow chip tray/pan can be fabricated from any number of materials or
unused products which you may have in a cupboard or closet, such as a baking
pan for example.
Many small lathes have features on the bottom to enable the owner to mount
the base to a table or bench. Those features can be utilized to place block
spacers between the base and a chip pan, where rubber feet/pads can be
mounted to the bottom of the pan under the blocks to prevent sliding around
during use.

Yes, the Proxxon has two notches for mounting bolts. I am now thinking
about just screwing it to a thick wooden cutting board with
rubber-shod feet. That ought to keep it from tipping or moving around.


When metal parts become a regular part of lathe use, you'll discover how
easily chips attach themselves to clothing and shoes, which then transfer
them to various other locations.. so try to set up a work table away from
the busy traffic patterns within a household, and be aware of the parasitic
characteristics and behaviors? of chips.

Good point; I am looking at an out-of-the-way side of the basement...

I'm not familiar with the design of the Prox lathe, but you may find it
useful to have a hand crank for the spindle, if one can be attached on the
left end of the spindle.
Hand cranks are useful for certain operations, and I find them very handy
for short threaded sections such as you may be contemplating for lens
adapters.
It's always the best practice to unplug a machine before installing
something like a hand crank which is likely to cause machine damage or
personal injury if the machine power is accidently turned on with an
unbalanced spindle hand crank in place.

Good idea!

There seem to be two possible ways to attach a hand crank to the
spindle.

One would be to start with a taper that fits the spindle, extend a
shaft from the narrow end of the taper out through the back of the
spindle, and add a crank. The taper and shaft would need to be
inserted before mounting the work and left in place; the crank could
be added and removed.

The other possibility is to remove the spindle "gear" (actually a
timing belt pulley) and mount a crank to the exposed outside of the
spindle shaft.

Any advice?


In addition to DoN's excellent recommendations made earlier, one lens type
that I know of has inch-pitch threads, and those are C-mount video lenses,
which are 1" 32 TPI.

The notorious example is Leica Thread Mount, which is 39mm x 26TPI!
The Royal Microscopical Society thread standard for microscope
objectives (known as the Royal Screw) is .8 inches by 36TPI Whitworth.

The Proxxon thread chart does not include either 26TPI or 36TPI pitch
settings, which is unfortunate from my point of view. Those two
threads could be useful to me.

A couple of other items needed for machine use would be some small brushes
for cleaning away chips (compressed air can actually force chips into places
on machines where thay may do harm), and an oiler with an oil suitable for
your new machine.
The manufacturer may recommend certain lubricating products for your
machine, and indicate which parts need to be kept very clean, and
lubricated.

I got some brushes.

The manual recommends where to oil, but not what oil to use. I assume
that the duty is light enough that almost any lubricating oil (not
penetrating oil or anything else silly) will work fine.

Finally, I hope you get a great deal of enjoyment from your new machine.. I
find metalworking projects to be very gratifying.

Thank you again!

On Sun, 04 Mar 2012 10:08:43 -0800, wrote:


Shop around for the best price on the AXA toolpost. The quick change
toolpost is a big time saver, meaning more time spent making chips.
It's also easier to use which means less aggravation, which saves
time, time you can spend making chips. When you do get the AXA size
toolpost, make sure to get the wedge type instead of the piston type.
The wedge type repeats better. At least in my experience they do. I
make my living as a machinist. Have been doing so for the last 35
years or so. My opinion is that if you can afford it buy the tools
which will enable you to cut metal the fastest. After you have some
experience you can decide if making your own toolpost for special work
is something you want to do. In the meantime you can learn about
turning, facing, boring, threading, and parting off while you make
your lens parts. You will be using, most likely, a turning/facing
tool, a boring bar, internal threading tool, external threading tool,
and a part off blade. That's 5 tools used to make one part. Get those
tools set and then it is much easier and faster to make your lens
parts. And since the tools are each in a separate, quickly changed
tool holder, you only need to set each tool once.
Eric

Would an AXA toolpost fit on a Proxxon lathe? It looks way too big...

Bob

The desired inch/tpi thread pitches may be a bit more difficult if the
machine is made around metric scales on the dials and a metric leadscrew
pitch, but that doesn't mean that inch pitches can't be done.
I don't have the ability (software and I generally aren't on friendly terms)
but some folks brighter than myself have created threading charts for other
lathe models using spreadsheets or other methods, to show that many more
thread pitches can be attained than are shown in a lathe's threading chart.

You might be able to calculate different thread pitches by determining the
leadscrew pitch and various ratios of carriage movement/spindle rotations..
which can be checked by mounting a dial indicator and counting spindle
rotations to see how far the carriage moves when selecting different gear
combinations.

I didn't see dial indicators mentioned earlier, but they are very useful for
various operations on metalworking machines.. you won't likely need one
right away, but practical, as you begin to add tools and accessories.

There may be some online groups or forums dedicated specifically to your
lathe which may be a great source of information in addition to help with
more general advice/recommendations you'll receive here in RCM.
Many of us have small benchtop lathes (or a few), but Proxxon models don't
get mentioned regularly, as far as I've noticed.

After owning metalworking machines for a while, everything starts looking
like useful material for project parts.

As far as useful lubricants for your machine, I suppose most good oils would
be suitable, but I'd avoid anything with silicone in it, as you may want to
add coatings or other finishes to parts, and silicones can be especially
difficult to remove.

Another type of product you will likely want to find for cutting metal parts
would be a good cutting lubricant. Common oils aren't good cutting
lubricants.. instead, there are lubricants that improve the performance of
cutting tools, which will be fairly important with a small, light duty
machine.

I don't know what would be best for your lathe spindle as far as mounting a
hand crank, but the ones I've used are a split-wedge sort of locking device
which clamps securely inside the hollow spindle. There's a name for this
particular locking part, but I don't recall what it is. They were once a
popular method of installing a bicycle handlebar stem into the fork tube.
Then a crank and handle or handwheel can be mounted for those short
threading jobs.

--
WB
..........


"Bob S" wrote in message
...
Thank you for the extensive post.

Comments interspersed:


On Sun, 4 Mar 2012 12:38:21 -0500, Wild_Bill wrote:

The unusual design of the Proxxon PD 230 lathe leaves few options for any
of
the more commonly available QCTP quick change toolposts.

[...]

I think you'll find that the supplied toolpost is adequate for most
operations you'll end up wanting to do.

[...]

Yes, I am beginning to see the issues and I will try practicing
patience.



As a beginning lathe user, it may be very useful to start with plastic
stock
to help you get accustomed to the various general aspects of cutting
rotating material.
Scraps of PVC pipe, empty pen bodies and various parts of items which will
be discarded, should all be seen as potential parts now.. definitely good
materials for practicing anyway.

Good idea; there is certainly lots of that sort of stuff around here.

A shallow chip tray/pan can be fabricated from any number of materials or
unused products which you may have in a cupboard or closet, such as a
baking
pan for example.
Many small lathes have features on the bottom to enable the owner to mount
the base to a table or bench. Those features can be utilized to place
block
spacers between the base and a chip pan, where rubber feet/pads can be
mounted to the bottom of the pan under the blocks to prevent sliding
around
during use.

Yes, the Proxxon has two notches for mounting bolts. I am now thinking
about just screwing it to a thick wooden cutting board with
rubber-shod feet. That ought to keep it from tipping or moving around.


When metal parts become a regular part of lathe use, you'll discover how
easily chips attach themselves to clothing and shoes, which then transfer
them to various other locations.. so try to set up a work table away from
the busy traffic patterns within a household, and be aware of the
parasitic
characteristics and behaviors? of chips.

Good point; I am looking at an out-of-the-way side of the basement...

I'm not familiar with the design of the Prox lathe, but you may find it
useful to have a hand crank for the spindle, if one can be attached on the
left end of the spindle.
Hand cranks are useful for certain operations, and I find them very handy
for short threaded sections such as you may be contemplating for lens
adapters.
It's always the best practice to unplug a machine before installing
something like a hand crank which is likely to cause machine damage or
personal injury if the machine power is accidently turned on with an
unbalanced spindle hand crank in place.

Good idea!

There seem to be two possible ways to attach a hand crank to the
spindle.

One would be to start with a taper that fits the spindle, extend a
shaft from the narrow end of the taper out through the back of the
spindle, and add a crank. The taper and shaft would need to be
inserted before mounting the work and left in place; the crank could
be added and removed.

The other possibility is to remove the spindle "gear" (actually a
timing belt pulley) and mount a crank to the exposed outside of the
spindle shaft.

Any advice?


In addition to DoN's excellent recommendations made earlier, one lens type
that I know of has inch-pitch threads, and those are C-mount video lenses,
which are 1" 32 TPI.

The notorious example is Leica Thread Mount, which is 39mm x 26TPI!
The Royal Microscopical Society thread standard for microscope
objectives (known as the Royal Screw) is .8 inches by 36TPI Whitworth.

The Proxxon thread chart does not include either 26TPI or 36TPI pitch
settings, which is unfortunate from my point of view. Those two
threads could be useful to me.

A couple of other items needed for machine use would be some small brushes
for cleaning away chips (compressed air can actually force chips into
places
on machines where thay may do harm), and an oiler with an oil suitable for
your new machine.
The manufacturer may recommend certain lubricating products for your
machine, and indicate which parts need to be kept very clean, and
lubricated.

I got some brushes.

The manual recommends where to oil, but not what oil to use. I assume
that the duty is light enough that almost any lubricating oil (not
penetrating oil or anything else silly) will work fine.

Finally, I hope you get a great deal of enjoyment from your new machine..
I
find metalworking projects to be very gratifying.

Thank you again!

On Tue, 6 Mar 2012 13:11:26 -0500, Wild_Bill wrote:

[...]

I don't know what would be best for your lathe spindle as far as mounting a
hand crank, but the ones I've used are a split-wedge sort of locking device
which clamps securely inside the hollow spindle. There's a name for this
particular locking part, but I don't recall what it is. They were once a
popular method of installing a bicycle handlebar stem into the fork tube.
Then a crank and handle or handwheel can be mounted for those short
threading jobs.

That's a good idea. Sort of an inside collet, with a sleeve forced
open by a wedge?

Bob

I'm not sure that I could find a picture of the type of hand crank
attachment I made, but I'll try to describe the methods used.

Turn a length of stock to within a couple of thousadths of the ID of the
spindle (ID minus ~.002") and long enough to reach into the spindle maybe
about half the depth.
The stock should be long enough to have a shoulder just outside of the end
of the spindle, and a suitable amount of remaining stock for the attachment
of a handle/crank (flat bar stock or handwheel with a speed knob).

Drill a center axial hole into the stock that includes the full length..
which may require drilling from both ends (depending upon available length
of twist drills).

The stock then needs to be cut at an angle (a little less than 45 degrees
worked well), so that when a bolt/stud passing thru the hole draws the two
pieces together, the angled cut causes the parts to shift off-axis,
expanding in the spindle to securely lock it in place.
The sharp edges around the angled cut of both pieces should be rounded over
with a file so as to not cause digging or gouging inside the spindle bore.

The ends of the holes nearest the angled cut can be filed out-of-round or
oval shaped to allow the shift to take place without too much tightening of
the bolt/stud.

A stud can be threaded into the shorter end (deepest in the spindle) in
tapped threads and staked to lock it in place, or pinned etc. and the stud
extends outward to the left passing thru the longer section enough to allow
a nut to be installed on it.

So, with the shoulder of the longer section against the left end of the
spindle, there should be ample stock sticking out for attaching the
preferred handle/crank.
As the nut is tightened firmly but not extremely tight, the angled cut
causes the two sections to wedge securely in the spindle bore.

I tried using a split expanding collet type of locking bar (quartered
sections), but it didn't grip as well as the second model utilizing the
wedge type bar.. which doesn't mean that it wouldn't be a good choice for
others.
I think the wedge type is actually easier to fabricate, though.

One caution about using an expanding bar in the spindle, would be to only
tighten the nut enough for a secure grip in the spindle bore.
Some lathe spindles can be somewhat wimpy as far as wall thickness, so
over-tightening an expanding accessory with a grunt could potentially
distort the spindle.

The scale of the Prox lathe being somewhat small, may present more of a
challenge than the spindle bores of my machines, where I could use a 1/4"
diameter (or larger) stud to draw the wedged sections together.

The 230 model specs show a 10.5mm spindle bore which is considerably smaller
than the bores in my machines, so a different method of attachment may be a
better choice.. it's difficult to try to determine what other methods may be
suitable without knowing what features the spindle may have at the left end
(smooth OD, threaded, locking collar etc).

The length of the crank is a matter of preference and comfort.. one wouldn't
want to use an excessively long crank since that would require a wide range
of arm movement just to advance the small point of a cutting tool with a
light chip load for a short distance.

I prefer accessories to fit the scale of my machines, where operating
performance is tempered by a light duty machine's capabilities.
I don't try to run at excessive rates of metal removal, producing buckets of
hot blue chips, but prefer instead.. just enjoying the experience at more
moderate/less severe rates.

--
WB
..........


"Bob S" wrote in message
...
On Tue, 6 Mar 2012 13:11:26 -0500, Wild_Bill wrote:

[...]

I don't know what would be best for your lathe spindle as far as mounting
a
hand crank, but the ones I've used are a split-wedge sort of locking
device
which clamps securely inside the hollow spindle. There's a name for this
particular locking part, but I don't recall what it is. They were once a
popular method of installing a bicycle handlebar stem into the fork tube.
Then a crank and handle or handwheel can be mounted for those short
threading jobs.

That's a good idea. Sort of an inside collet, with a sleeve forced
open by a wedge?

Bob

On Tue, 6 Mar 2012 13:11:26 -0500, Wild_Bill wrote:

The desired inch/tpi thread pitches may be a bit more difficult if the
machine is made around metric scales on the dials and a metric leadscrew
pitch, but that doesn't mean that inch pitches can't be done.
I don't have the ability (software and I generally aren't on friendly terms)
but some folks brighter than myself have created threading charts for other
lathe models using spreadsheets or other methods, to show that many more
thread pitches can be attained than are shown in a lathe's threading chart.

Good idea!

I went through the available combinations and found one that will give
36 TPI. There were also several other interesting combinations; 2/3 mm
pitch and 4/3 mm pitch sound like they ought to be good for
something...

No 26 TPI though.

So I started trying "what if" combinations. If I had a 26-tooth
leadscrew gear I would have 26 TPI to the same accuracy as all the
usual inch threads on this machine (.0463%). That would require gear
cutting, and I have several things to learn before I try that.

I can also get close (well under 1%) to 26 TPI with a spindle "gear"
of 17 or 19 or 22 "teeth". This "gear" is actually a timing belt
pulley, which is probably more difficult to make than a gear would be.

I didn't explore a new intermediate gear, since that is a double-layer
thing with a belt on one side and a gear on the other.

Bob

On Wed, 7 Mar 2012 00:06:21 -0500, Wild_Bill wrote:

I'm not sure that I could find a picture of the type of hand crank
attachment I made, but I'll try to describe the methods used.

Turn a length of stock to within a couple of thousadths of the ID of the
spindle (ID minus ~.002") and long enough to reach into the spindle maybe
about half the depth.
The stock should be long enough to have a shoulder just outside of the end
of the spindle, and a suitable amount of remaining stock for the attachment
of a handle/crank (flat bar stock or handwheel with a speed knob).

Drill a center axial hole into the stock that includes the full length..
which may require drilling from both ends (depending upon available length
of twist drills).

The stock then needs to be cut at an angle (a little less than 45 degrees
worked well), so that when a bolt/stud passing thru the hole draws the two
pieces together, the angled cut causes the parts to shift off-axis,
expanding in the spindle to securely lock it in place.
The sharp edges around the angled cut of both pieces should be rounded over
with a file so as to not cause digging or gouging inside the spindle bore.

The ends of the holes nearest the angled cut can be filed out-of-round or
oval shaped to allow the shift to take place without too much tightening of
the bolt/stud.

A stud can be threaded into the shorter end (deepest in the spindle) in
tapped threads and staked to lock it in place, or pinned etc. and the stud
extends outward to the left passing thru the longer section enough to allow
a nut to be installed on it.

So, with the shoulder of the longer section against the left end of the
spindle, there should be ample stock sticking out for attaching the
preferred handle/crank.
As the nut is tightened firmly but not extremely tight, the angled cut
causes the two sections to wedge securely in the spindle bore.

I understand. Nice clear description.


I tried using a split expanding collet type of locking bar (quartered
sections), but it didn't grip as well as the second model utilizing the
wedge type bar.. which doesn't mean that it wouldn't be a good choice for
others.
I think the wedge type is actually easier to fabricate, though.

It is interesting that the expanding collet didn't work as well.
Torque-holding ability ought to be proportional to the outward force,
which ought to be greater with the expanding collet because it
probably has a much shallower angle than 45 degrees. Probably there is
some secondary effect that I am not thinking of.

One caution about using an expanding bar in the spindle, would be to only
tighten the nut enough for a secure grip in the spindle bore.
Some lathe spindles can be somewhat wimpy as far as wall thickness, so
over-tightening an expanding accessory with a grunt could potentially
distort the spindle.

The scale of the Prox lathe being somewhat small, may present more of a
challenge than the spindle bores of my machines, where I could use a 1/4"
diameter (or larger) stud to draw the wedged sections together.

The 230 model specs show a 10.5mm spindle bore which is considerably smaller
than the bores in my machines, so a different method of attachment may be a
better choice.. it's difficult to try to determine what other methods may be
suitable without knowing what features the spindle may have at the left end
(smooth OD, threaded, locking collar etc).

The left end has the "spindle gear" (actually a timing belt pulley) at
the end, with essentially no free space beyond it. In normal turning
the belt is on the outer end of the pulley. For screw cutting it sits
a little further in, some one could think about clamping a handle to
the pulley, but that is a little worrying, and besides there are two
different pulleys for inch and metric threads.

It think that the inside bore is the only attractive scheme.

Bob

It appears that you're well ahead of the curve, Bob, as far as new machine
owners goes.. many just assume that what the chart shows reflects their only
options.

Another possibliity exists to expand the available number of threading
possibilities by adding just one more change gear to the set, as a number of
machine users have done on machines which rely on a set of gears to change
thread pitches.
Proxxon probably has replacement parts available.

And, don't know if it's too early to mention this, but, you may be seeing
other machine purchases in your (near) future.. so your ability to add new
features to existing machines becomes almost endless.

Metalworking on any scale, is full of inspirational ideas and nearly
infinite possibilities.. a very rewarding use of time, IMO.

--
WB
..........


"Bob S" wrote in message
...
On Tue, 6 Mar 2012 13:11:26 -0500, Wild_Bill wrote:

The desired inch/tpi thread pitches may be a bit more difficult if the
machine is made around metric scales on the dials and a metric leadscrew
pitch, but that doesn't mean that inch pitches can't be done.
I don't have the ability (software and I generally aren't on friendly
terms)
but some folks brighter than myself have created threading charts for
other
lathe models using spreadsheets or other methods, to show that many more
thread pitches can be attained than are shown in a lathe's threading
chart.

Good idea!

I went through the available combinations and found one that will give
36 TPI. There were also several other interesting combinations; 2/3 mm
pitch and 4/3 mm pitch sound like they ought to be good for
something...

No 26 TPI though.

So I started trying "what if" combinations. If I had a 26-tooth
leadscrew gear I would have 26 TPI to the same accuracy as all the
usual inch threads on this machine (.0463%). That would require gear
cutting, and I have several things to learn before I try that.

I can also get close (well under 1%) to 26 TPI with a spindle "gear"
of 17 or 19 or 22 "teeth". This "gear" is actually a timing belt
pulley, which is probably more difficult to make than a gear would be.

I didn't explore a new intermediate gear, since that is a double-layer
thing with a belt on one side and a gear on the other.

Bob

I was faced with a similar situation when I wanted to adapt my benchtop
drill press to operate by a hand crank for using the drill press for tapping
holes.

I added a hub/puck of aluminum round stock to the top pulley edge (extending
a flat, thick surface above the spindle pulley) and drilled it to accept 2
pins, which the arm for the crank would have, to facilitate easy
installation and removal of the crank.
On the DP I have, releasing the quill return spring is just a matter of
removing a nut on the spring cover, so it's a fairly simple transition.. and
man, I like simple (just my speed).

After cutting a hole in the belt cover over the hub, I'm able to (First)
unplug the power cord, then release the drive belt, close the cover and drop
the pins of the hand crank into the holes in the hub, for tapping use.
The DP table vise can hold the workpiece in any position, so tapping any
part is very easy to accomplish.. no leaning sideways to try to get a tap
started at a weird angle or various other stunts which sometimes seem
reasonable, heh.

Anyhoo.. a simple modification for utilizing a hand crank for your lathe
will very likely occur to you.. and maybe when you're not even thinking of
it.
(and I hope it will happen at an appropriate moment, wink-wink,
nudge-nudge).

The expanding collet type of spindle adapter may have worked if I'd have
pursued improving it, but I had a shift in ideas when I recalled the type of
joint used on my bike decades earlier, so I went that route.

Another great aspect of metalworking is that scrap from one project has many
possibilities for another part of a new project.. there are no bad parts in
as much as they are excellent learning opportunities.. win-win, as they say.

Are you feeling enthusiastic yet?

--
WB
..........


"Bob S" wrote in message
...

I understand. Nice clear description.

It is interesting that the expanding collet didn't work as well.
Torque-holding ability ought to be proportional to the outward force,
which ought to be greater with the expanding collet because it
probably has a much shallower angle than 45 degrees. Probably there is
some secondary effect that I am not thinking of.

The left end has the "spindle gear" (actually a timing belt pulley) at
the end, with essentially no free space beyond it. In normal turning
the belt is on the outer end of the pulley. For screw cutting it sits
a little further in, some one could think about clamping a handle to
the pulley, but that is a little worrying, and besides there are two
different pulleys for inch and metric threads.

It think that the inside bore is the only attractive scheme.

Bob

I'm not assuming that a similarly designed QCTP design couldn't be done on
the Proxxon late, but I'm fairly sure the standard AXA-series 100 versions
would not just be overkill, but wouldn't be adaptable to the OP's lathe.

Not only would the body of the toolpost not swivel, but the lowest possible
position of a cutting tool would be far above the centerline axis of the
spindle.

Anyone using a QCTP realizes it's obvious advantages of convenience, when
the machine's design and size make adding a QCTP feasible.
The Proxxon lathe doesn't have the flat plinth, or a center bolt for
attaching a QCTP.. nor the available space to easily implement one of any
size and still retain the swiveling infinite positioning feature of a QCTP.

The Proxxon model doesn't have a swiveling, rigid 4-place tool post like
many other larger machines do. The designed method of changing the angle of
the cutting tool are to adjust the angle of the compound/top slide.

With proper planning of sequences the supplied 2-way tool post will provide
substantial use of the lathe as a practical method of supporting the cutting
tool.
Generally, adapting improvised accessories to the cutting tool supporting
elements can lead to poor machine performance in terms of loss of rigidity.

Some shims and time getting used to the machine's characteristics will
likely be far more beneficial than trying to modify a working, new machine..
and potentially creating problems where they didn't initially exist.

Compare the $300 wedge-type toolpost (which can't be adapted to fit) to a
few pieces of shim cut from any scrap that may be laying around in a
wastebasket (I mean recycling bin, of course!).

The next piece of "sound advice" the OP would be wise to ignore will be the
recommendations to use carbide tooling for better results.. and coolant etc.

A sad fact of lathe ownership/use is that the operator is best equipped to
learn how to grind HSS cutting tools, but it seems that not many users want
to go thru the effort to learn.. they are more confident in ordering
ready-made carbide cutting tools to use in their expensive QCTPs they
mounted on light duty machines.

--
WB
..........


wrote in message
...
On Sat, 03 Mar 2012 21:26:32 -0500, Bob S
wrote:

This seems a little more complicated. Everything that I read and the
people that I talk to say that a quick-change toolpost is more of a
necessity than a luxury.

Choices seem to be:

Buy the Proxxon one

Buy the A2ZCNC 60% of AXA one

Build one, probably of the circular post plus split-bushing type


The Proxxon version costs about $115 with two holders, plus $21 from
another holder. It replaces the existing toolpost, which is a
rectangular chunk of aluminum with a dovetail slide on the bottom and
a threaded hole in the side; it doubles as the top slide! It thus
retains all of the flexibility and deficiencies of the current
slow-change toolpost, but tools get changed quickly.

The primary deficiency seems to be that the tools are fixed at the
same angle as the top slide. One cannot (for example) set the top
slide to 29 degrees and then set the tool perpendicular to the work.


The A2ZCNC version costs about $100 with four holders. It completely
replaces the top slide, mounting to the slot in the cross slide.
Reports are that it is a quality product. It apparently allows you to
set the tool at any angle to the work by loosening the mounting screw,
rotating, and re-tightening. However, there is no top slide with this
unit in place. That means no 29-degree threading (which apparently
cannot be done with any other option either). It also means using the
current slow-change toolpost for tapers. I don't know of any other
function of the top slide, but I am a beginner so I am probably
missing something.


Then there is the DIY option. The advantages are probably educational
value and low monetary cost (but high time cost). It would probably
consist of a circular post mounting to the slot in the cross slide,
plus holders consisting of rectangular blocks with a hold up the
middle with a slot and a clamping screw. The tools could be set at any
angle, but again there is no top slide.


Any other good options?

Any advice?

Bob
Shop around for the best price on the AXA toolpost. The quick change
toolpost is a big time saver, meaning more time spent making chips.
It's also easier to use which means less aggravation, which saves
time, time you can spend making chips. When you do get the AXA size
toolpost, make sure to get the wedge type instead of the piston type.
The wedge type repeats better. At least in my experience they do. I
make my living as a machinist. Have been doing so for the last 35
years or so. My opinion is that if you can afford it buy the tools
which will enable you to cut metal the fastest. After you have some
experience you can decide if making your own toolpost for special work
is something you want to do. In the meantime you can learn about
turning, facing, boring, threading, and parting off while you make
your lens parts. You will be using, most likely, a turning/facing
tool, a boring bar, internal threading tool, external threading tool,
and a part off blade. That's 5 tools used to make one part. Get those
tools set and then it is much easier and faster to make your lens
parts. And since the tools are each in a separate, quickly changed
tool holder, you only need to set each tool once.
Eric

Sov n'a gun.. I found 2 pics of the 9x20 lathe spindle hand crank.
http://www.flickr.com/photos/5234515...7629540058769/

The 9x20 spindle bore is about 3/4" for a judgement of scale of the size of
the parts.

Talk about never throwing anything away.. well, the pics were transferred to
this PC when it was the new replacement, back when I was still building a
personal metalworking website (concept scrapped since then).

This handwheel model was a second version.. the first one used a length of
flat aluminum bar stock for the crank arm instead of the cast aluminum
handwheel (free upgrade, given to me by a friend, the ball bearing "speed
knob" was added from junk box parts).

--
WB
..........


"Bob S" wrote in message
...
On Wed, 7 Mar 2012 00:06:21 -0500, Wild_Bill wrote:

I'm not sure that I could find a picture of the type of hand crank
attachment I made, but I'll try to describe the methods used.


I understand. Nice clear description.


It think that the inside bore is the only attractive scheme.

Bob

On Thu, 8 Mar 2012 10:26:52 -0500, Wild_Bill wrote:

Sov n'a gun.. I found 2 pics of the 9x20 lathe spindle hand crank.
http://www.flickr.com/photos/5234515...7629540058769/

The 9x20 spindle bore is about 3/4" for a judgement of scale of the size of
the parts.

Talk about never throwing anything away.. well, the pics were transferred to
this PC when it was the new replacement, back when I was still building a
personal metalworking website (concept scrapped since then).

This handwheel model was a second version.. the first one used a length of
flat aluminum bar stock for the crank arm instead of the cast aluminum
handwheel (free upgrade, given to me by a friend, the ball bearing "speed
knob" was added from junk box parts).

It looks much as I pictured it from your description, other than the
snazzy handwheel.

I suppose that it would work the same if both parts of the tube were
drilled for clearance and a pair of locked nuts were jammed on the end
of the threaded rod. It wouldn't look as nice when it was out of the
machine though.

Or it would probably work much the same if the thread on the end piece
was not locked, and you used a screw/bolt instead of a stud and a nut.
The thread turning in the end piece would draw the stuff together.

I guess there are lots of way to do this. The only tricky part seems
to be drilling a fairly small hole down two inches of rod, and I
suppose that is straightforward on a lathe.

Bob

On Thu, 8 Mar 2012 02:16:30 -0500, Wild_Bill wrote:

It appears that you're well ahead of the curve, Bob, as far as new machine
owners goes.. many just assume that what the chart shows reflects their only
options.

Another possibliity exists to expand the available number of threading
possibilities by adding just one more change gear to the set, as a number of
machine users have done on machines which rely on a set of gears to change
thread pitches.
Proxxon probably has replacement parts available.

And, don't know if it's too early to mention this, but, you may be seeing
other machine purchases in your (near) future.. so your ability to add new
features to existing machines becomes almost endless.

Metalworking on any scale, is full of inspirational ideas and nearly
infinite possibilities.. a very rewarding use of time, IMO.


I went looking for a 26-tooth metric module 1 gear with a bore 5.5mm
or smaller, and I found Google surprisingly unhelpful. I suppose that
I need a better search term.

The only one that I found was
http://www.rc-monster.com/proddetail...1pinion&cat=40
I have no idea where they are or what they are like.

It has a 5mm bore but that could be bored out.

Proxxon has lots of optional extras, but apparently not more gears.

Bob

"Bob S" wrote in message
...
I guess there are lots of way to do this. The only tricky part seems
to be drilling a fairly small hole down two inches of rod, and I
suppose that is straightforward on a lathe.
Bob

Could you mount a handwheel behind the chuck? You can't spin it fast
but a larger wheel will have more torque to drive a threading cut.

I just pull on the chuck (or the leather drive belt) to finish a
threading cut at a definite stopping point.

Before you start, can you easily disconnect the spindle from the
motor? There may not be much point in this if you can't and have to
fight the drivetrain drag..

Some of us have old industrial lathes with somewhat different controls
from yours:
http://www.practicalmachinist.com/vb...y-dsc04198.jpg

The lever on the base declutches the motor drive from the spindle,
making the chuck very easy to turn by hand.

The similar, smaller lever on the right side of the carriage apron
releases the leadscrew so the handwheel to its left can move the
carriage quickly, or hand-feed a cut.

The tailstock base slides sideways for turning tapers between centers.

The compound has a tee slot in the top to hold a separate tool post,
which looks like it's aligned like yours on that lathe.

AFAIK yours doesn't have these and suggestions that mention them don't
apply. I've used a Prazi which is like yours, but didn't cut threads
on it because it had a broken plastic gear. .

jsw

On Thu, 8 Mar 2012 18:14:10 -0500, Jim Wilkins wrote:


"Bob S" wrote in message
...
I guess there are lots of way to do this. The only tricky part seems
to be drilling a fairly small hole down two inches of rod, and I
suppose that is straightforward on a lathe.
Bob

Could you mount a handwheel behind the chuck? You can't spin it fast
but a larger wheel will have more torque to drive a threading cut.

Well, I suppose that I could turn a disk with spindle and chuck
mounting features fore and aft, and holes for the chuck screws, and
get some longer screws and attach the chuck through the plate.
The handwheel could only be about four inches in diameter to clear the
bed, and only about half of the circumference would be reachable, and
grabbing it would be awkward so close to the chuck, and it couldn't be
installed and removed without re-mounting the chuck. Maybe I am not
visualizing what you are thinking of; it sounds awkward.



I just pull on the chuck (or the leather drive belt) to finish a
threading cut at a definite stopping point.

Before you start, can you easily disconnect the spindle from the
motor? There may not be much point in this if you can't and have to
fight the drivetrain drag..

I could slip off one of the drive belts.

But turning the motor by hand is not difficult on a machine this
small.



Some of us have old industrial lathes with somewhat different controls
from yours:
http://www.practicalmachinist.com/vb...y-dsc04198.jpg

The lever on the base declutches the motor drive from the spindle,
making the chuck very easy to turn by hand.

The similar, smaller lever on the right side of the carriage apron
releases the leadscrew so the handwheel to its left can move the
carriage quickly, or hand-feed a cut.

The tailstock base slides sideways for turning tapers between centers.

The compound has a tee slot in the top to hold a separate tool post,
which looks like it's aligned like yours on that lathe.

On the Proxxon lathe the T-slot is on the cross-slide not the compound
slide.


AFAIK yours doesn't have these and suggestions that mention them don't
apply. I've used a Prazi which is like yours, but didn't cut threads
on it because it had a broken plastic gear. .

jsw



Bob

On Thu, 08 Mar 2012 17:17:01 -0500, Bob S wrote:

Another possibliity exists to expand the available number of threading
possibilities by adding just one more change gear to the set, as a
number of machine users have done on machines which rely on a set of
gears to change thread pitches.

A slightly alternative approach is to get two gears which DO give you the
ratio you want and mount them outboard of existing change gears of
smaller diameter (turn a two-size mandrel, mount, drill & tap three
holes, then bore the new gears large enough to take the axle-fixing
screws). You may have to do some playing about to find a combination that
fits your existing gears and carrier travel.

It beats looking for that ratio in your particular pitch. For Minilathes
in particular, Sherline makes an affordable 127/100 combination.

It's not a good sign when a manufacturer doesn't provide replacement parts.
I wouldn't take one person's opinion as the final word, though.

Then again, it may take some creativity to get someone to go against that
scary, threatening, carved-in-stone company policy, and make an exception.

Something like a letter to the company CEO, spelling out in graphic detail
how your neighbor's dog ate the grear and you've been looking thru steaming
hot piles of stool trying to reclaim the gear, to no avail.. but then again,
s/he might be a cat lover and feel no sympathy at all.

The RC/model industry is fairly vast in terms of accessories and "upgrade"
parts, making a wide variety of small mechanical parts much more commonly
available.

Trouble is, generally, RC and various parts suppliers do such a poor job at
listing actual parts specs, finding something can result in a fairly
complicated research project.

--
WB
..........


"Bob S" wrote in message
...

I went looking for a 26-tooth metric module 1 gear with a bore 5.5mm
or smaller, and I found Google surprisingly unhelpful. I suppose that
I need a better search term.

The only one that I found was
http://www.rc-monster.com/proddetail...1pinion&cat=40
I have no idea where they are or what they are like.

It has a 5mm bore but that could be bored out.

Proxxon has lots of optional extras, but apparently not more gears.

Bob