Too late I discovered that both my big chucks are just a bit too small to
handle the current batch of dial faces. Thus I was able to clean the outside
edge and the face (using an angle grinder with sand disk followed by sand
paper while the face is rotated in the RedNeck lathe) but doing the inside
of the ring presented a problem as I could not grip it on the outside. In
the end I solved it this way:

http://www.flickr.com/photos/2768312...7608993005196/

Using a mini-mill to bore out a 3.18" ID hole with a 2" boring head probably
comes under the "dogs walking on hind legs" category (on the whole done
badly and probably should not be done at all). Yet in the end it worked (see
the next picture of the semi-finished product). Of course the speed
adjustment was critical and the boring bar advanced by 0.005 at a time.

I thought it would have been better to have the bar clamped in the
transverse hole of the boring head but then the head would have to spin
anticlockwise which my mill does not do. Are there tools that can be used
this way? Presumably one can make a custom boring bar with a carbide insert.
Is that feasible?

--
Michael Koblic
Campbell River, BC

On 2009-06-04, Michael Koblic wrote:
Too late I discovered that both my big chucks are just a bit too small to
handle the current batch of dial faces. Thus I was able to clean the outside
edge and the face (using an angle grinder with sand disk followed by sand
paper while the face is rotated in the RedNeck lathe) but doing the inside
of the ring presented a problem as I could not grip it on the outside.

Are any of your chucks (hopefully, the larger ones) equipped
with two-piece jaws? If so, you could make some soft jaws from aluminum
which extended out to handle larger diameters, given that you don't have
much torque available in the "lathe" anyway. The main question is
whether such extensions would hit the bed of the lathe.

In
the end I solved it this way:

http://www.flickr.com/photos/2768312...7608993005196/

Using a mini-mill to bore out a 3.18" ID hole with a 2" boring head probably
comes under the "dogs walking on hind legs" category (on the whole done
badly and probably should not be done at all). Yet in the end it worked (see
the next picture of the semi-finished product). Of course the speed
adjustment was critical and the boring bar advanced by 0.005 at a time.

It is slow, but it works. That is what matters, as long as this
is a hobby occupation, not one being done for serious income where time
is money.

I thought it would have been better to have the bar clamped in the
transverse hole of the boring head but then the head would have to spin
anticlockwise which my mill does not do. Are there tools that can be used
this way?

Most serious sized mills will rotate the spindle in either
direction. But you need to beware that the shank is screwed into the
head, so too aggressive a cut will unscrew the head.

However -- clamp it in the transverse hole with the cutting edge
pointing up, and back it out of the hole instead of plunging into the
hole and you can use your existing tool in the direction of rotation
that your machine is willing to provide you.

Or -- use the mill to make new top jaws as I suggested above,
and do the boring on your lathe. (Not sure whether you have enough
rigidity to handle the boring there, and you can't get the angle grinder
inside the hole.)

Hmm ... beware that the angle grinder will spit abrasive junk
which can cause accelerated wear in the chuck's jaws where they move in
their ways.

Presumably one can make a custom boring bar with a carbide insert.
Is that feasible?

Yes -- with the right inserts.

And if your lathe is rigid enough (something that I doubt) you
could take a cheap insert turning tool designed for left hand turning
(turning a face on the left hand end of the workpiece), and turn the
shank from square to round for most of its length so you could slide it
into the boring head's holes.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Jun 3, 9:03*pm, "Michael Koblic" wrote:
Too late I discovered that both my big chucks are just a bit too small to
handle the current batch of dial faces.

http://www.flickr.com/photos/2768312.../set-721576089...
--
Michael Koblic
Campbell River, BC

How about screwing the blank to a wooden faceplate through holes in
the scrap outside the OD, turning the face and ID, then reclamping to
the ID and finishing the OD?

jsw

DoN. Nichols wrote:

Are any of your chucks (hopefully, the larger ones) equipped
with two-piece jaws? If so, you could make some soft jaws from
aluminum which extended out to handle larger diameters, given that
you don't have much torque available in the "lathe" anyway. The main
question is whether such extensions would hit the bed of the lathe.

The bigger chuck is actually a wood working chuck. The jaws are held in
their tracks by screws and it that respect the jaw is *4-piece*. I thought
about making some sort of extension but could not get my head around the
process. There is plenty of space under the chuck (I wanted to turn up to 9"
OD).

It is slow, but it works. That is what matters, as long as this
is a hobby occupation, not one being done for serious income where
time is money.

Tell me about it...

Most serious sized mills will rotate the spindle in either
direction. But you need to beware that the shank is screwed into the
head, so too aggressive a cut will unscrew the head.

So you think my mill is a joke? Well, it is. Sort of :-) This was brought
home to me when I visited the Busy Bee shop in Vancouver where my mill is
side by side with other mills. Even the next smallest one was, well, bigger.

However -- clamp it in the transverse hole with the cutting edge
pointing up, and back it out of the hole instead of plunging into the
hole and you can use your existing tool in the direction of rotation
that your machine is willing to provide you.

Aaaargh! So close! I got it set up like that but did not think of *backing
out* .

Or -- use the mill to make new top jaws as I suggested above,
and do the boring on your lathe. (Not sure whether you have enough
rigidity to handle the boring there, and you can't get the angle
grinder inside the hole.)

But Dremel and various rotary sand heads will :-)
I think the rigidity is a concern. The preliminary tests have left me
unimpressed but I have not got the tooling fixed to the bed properly

Hmm ... beware that the angle grinder will spit abrasive junk
which can cause accelerated wear in the chuck's jaws where they move
in their ways.

Oh yes! It threw it all over the part of the workshop where I did not really
want it. Half an hour clean up...

Presumably one can make a custom boring bar with a carbide
insert. Is that feasible?

Yes -- with the right inserts.

And if your lathe is rigid enough (something that I doubt) you
could take a cheap insert turning tool designed for left hand turning
(turning a face on the left hand end of the workpiece), and turn the
shank from square to round for most of its length so you could slide
it into the boring head's holes.

Or just hold it in a tool post. The stuff I got from auction has one or two
small boring bars that the guy made to fit just like that.

I did a detour: I tried to finish a 4.5" ring on my Taig to see if it is a)
feasible and b) what is the result. It was a bit tricky as 4.5" is about
1/16" inside the taig swing but I sort of managed it. I haven't finished it
yet as I need to shim the ring to get at the innermost aspect without
knocking the jaws but it can be done. whether the finish obtained is
something that will be useful (many concentric rings instead of smooth)
remains to be seen.

Again, it was a very slow process given the lowest speed of 570 rpm. The
most difficult part was moving the carriage by very small amounts without a
leadscrew (another project for the future!). And the place swims in coolant.

--
Michael Koblic
Campbell River, BC

Jim Wilkins wrote:
On Jun 3, 9:03 pm, "Michael Koblic" wrote:
Too late I discovered that both my big chucks are just a bit too
small to handle the current batch of dial faces.

http://www.flickr.com/photos/2768312.../set-721576089...
--
Michael Koblic
Campbell River, BC

How about screwing the blank to a wooden faceplate through holes in
the scrap outside the OD, turning the face and ID, then reclamping to
the ID and finishing the OD?

I though about that but did not finish the thinking through. I was so hung
up on doing the outside first. You are quite right. Gotta get me one of
those. In terms of practical details: When making the wooden face plate
would you drill a central hole, tap it for 1"-8 and then finish the outside
with a gauge/skew chisel or would you make a smaller metal face plate (I
milled a 1"-8 nut some time ago with a view of welding a metal disk to it to
make one like that) and screw a piece of wood to it (finish as before)?

--
Michael Koblic
Campbell River, BC

On 2009-06-05, Michael Koblic wrote:
DoN. Nichols wrote:

Are any of your chucks (hopefully, the larger ones) equipped
with two-piece jaws? If so, you could make some soft jaws from
aluminum which extended out to handle larger diameters, given that
you don't have much torque available in the "lathe" anyway. The main
question is whether such extensions would hit the bed of the lathe.

The bigger chuck is actually a wood working chuck. The jaws are held in
their tracks by screws and it that respect the jaw is *4-piece*. I thought
about making some sort of extension but could not get my head around the
process. There is plenty of space under the chuck (I wanted to turn up to 9"
OD).

Did you try turning the chuck jaws around? That should give
increased grip.

[ ... ]

However -- clamp it in the transverse hole with the cutting edge
pointing up, and back it out of the hole instead of plunging into the
hole and you can use your existing tool in the direction of rotation
that your machine is willing to provide you.

Aaaargh! So close! I got it set up like that but did not think of *backing
out* .

:-)

Or -- use the mill to make new top jaws as I suggested above,
and do the boring on your lathe. (Not sure whether you have enough
rigidity to handle the boring there, and you can't get the angle
grinder inside the hole.)

But Dremel and various rotary sand heads will :-)
I think the rigidity is a concern. The preliminary tests have left me
unimpressed but I have not got the tooling fixed to the bed properly

When using the sanding tool, you will not need that much
rigidity by comparison with true metal turning.

[ ... ]

I did a detour: I tried to finish a 4.5" ring on my Taig to see if it is a)
feasible and b) what is the result. It was a bit tricky as 4.5" is about
1/16" inside the taig swing but I sort of managed it. I haven't finished it
yet as I need to shim the ring to get at the innermost aspect without
knocking the jaws but it can be done. whether the finish obtained is
something that will be useful (many concentric rings instead of smooth)
remains to be seen.

You did not get the 3-jaw chuck for it did you -- only the
4-jaw?

The 3-jaw has two-piece jaws, with the top jaws made of
aluminum. You can turn the jaws to have a small step and grip just a
bit thinner than the workpiece stock, and this eliminates that problem
at least. (And if you *do* "knock" the jaws, they are easy to replace,
and with your mill you can make spares from scrap aluminum if you so
desire.

Again, it was a very slow process given the lowest speed of 570 rpm. The
most difficult part was moving the carriage by very small amounts without a
leadscrew (another project for the future!). And the place swims in coolant.

Coolant on a Taig? I've never seen that before. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Jun 4, 9:08*pm, "Michael Koblic" wrote:
Jim Wilkins wrote:

[wooden faceplate]


...When making the wooden face plate
would you drill a central hole, tap it for 1"-8 and then finish the outside
with a gauge/skew chisel or would you make a smaller metal face plate (I
milled a 1"-8 nut some time ago with a view of welding a metal disk to it to
make one like that) and screw a piece of wood to it (finish as before)?

--
Michael Koblic

I'd use the largest metal faceplate that fits and attach a wood face
to it. For a home-made lathe the faceplate would probably be a large
cast-iron pulley driven by the rim so there's no torque at the
spindle. This type of shaft mount is considerably stiffer than a
sliding fit and setscrew:
http://www.utterpower.com/bushed_pulleys.htm

There is one on the motor shaft on the left:
http://picasaweb.google.com/KB1DAL/H...07508265721842

Alternately you might salvage the pulley from a broken air compressor.
I think the built-in fan blades make them stiffer against axial
pressure.

jsw

DoN. Nichols wrote:

Did you try turning the chuck jaws around? That should give
increased grip.

I had to to try and grip outside. That is when I discovered the problem.
Foolishly I expected a 6" chuck to grip a 6" workpiece.

[ ... ]

When using the sanding tool, you will not need that much
rigidity by comparison with true metal turning.

Yes. They clean but do not shape. So for instance the face of the dial is
nice and clean but not truly flat.

[ ... ]

You did not get the 3-jaw chuck for it did you -- only the
4-jaw?

The 3-jaw has two-piece jaws, with the top jaws made of
aluminum. You can turn the jaws to have a small step and grip just a
bit thinner than the workpiece stock, and this eliminates that problem
at least. (And if you *do* "knock" the jaws, they are easy to
replace, and with your mill you can make spares from scrap aluminum
if you so desire.

I am heading that way. However, it is a matter of priorities. With the
Father's day coming and all, I did a little prep yesterday should the
children suddenly remember to be grateful: Just the Little Machine Shop
potential tally came to $1048 and they do not even do many Taig things (not
the chuck, but a very nice QCTP!).

Again, it was a very slow process given the lowest speed of 570 rpm.
The most difficult part was moving the carriage by very small
amounts without a leadscrew (another project for the future!). And
the place swims in coolant.

Coolant on a Taig? I've never seen that before. :-)

Coolant on the Taig. Coolant on the bench. Coolant on the floor. Coolant on
the cat...
With the temperatures reachin 37 degC I could have done with the coolant
myself. The 1/4 HP motor did not like working in that heat.

--
Michael Koblic
Campbell River, BC

Jim Wilkins wrote:

I'd use the largest metal faceplate that fits and attach a wood face
to it. For a home-made lathe the faceplate would probably be a large
cast-iron pulley driven by the rim so there's no torque at the
spindle. This type of shaft mount is considerably stiffer than a
sliding fit and setscrew:
http://www.utterpower.com/bushed_pulleys.htm

I think I understand. I found them on McMaster-Carr web-site. Major
re-engineering would be required. If one did that one could use the
faceplate only? There would be no option to change chucks etc.? Maybe I
shall try this first:

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B129018

At the price I cannot make it myself.

There is one on the motor shaft on the left:
http://picasaweb.google.com/KB1DAL/H...07508265721842

If I understand you right for the purpose I intend it for the pulley would
have to be attached "inside out", i.e with the bushing at the back of it,
right?

--
Michael Koblic
Campbell River, BC

On Jun 5, 9:46*pm, "Michael Koblic" wrote:
Jim Wilkins wrote:
...This type of shaft mount is considerably stiffer than a
sliding fit and setscrew:
http://www.utterpower.com/bushed_pulleys.htm

I think I understand. I found them on McMaster-Carr web-site. Major
re-engineering would be required. If one did that one could use the
faceplate only? There would be no option to change chucks etc.?

Change spindles instead. The pulley requires only a plain shaft.

Maybe I shall try this first:

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B129018

At the price I cannot make it myself.

If I understand you right for the purpose I intend it for the pulley would
have to be attached "inside out", i.e with the bushing at the back of it,
right?
Michael Koblic

Yes, but as that website shows the bolts can still go in from the
front, into the threaded removal holes. You'd need some alternate
removal holes in the pulley because those hubs wedge on TIGHT.

jsw