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Hi all,

Here is a sketch of what I need to make (> 20 pieces).


The unit will be used for gauges for my, and a friend's
car.

This will be my *excuse* for purchasing a lathe, and other
appropriate tools. Wondering if someone can assist my
letting me know if I'm on the right track.



The Plan:
=========

BEZEL: Only aesthetic part. I'm using 2.25" ID, 1.75" ID
for the ring, as I can get tubing with these dimensions from
places like McMaster. I'd need to cut thin slices (about
3/8" thick) from the tube to make a ring, then use a lathe
to cut back a part of the inside to ~ 2" ID.

BODY: I'll use 2" OD, 1.9" ID tubing here, cut to a length
of approx 2". Only lathe work here is the threads. I can
make the tabs by using a fiberglass cutoff-wheel or other
saw.

BACK COVER: I'll use sheet-metal for this, but not sure
what's the best process to cut clean consistent circles.


My Questions:
=============

- Is the cut on the inside of the bezel easy with a lathe?
I'm still not sure if the cutting tools will get in there
easily.

- Are internal threads easy to cut with a lathe?

- Can I do the bezel w/o damage or marks to the outside
surface?

- What's a good way to cut thin, clean slices of the rings?
I'd like to avoid manual polishing/cleaning as much as
possible. Is there some way I can cut it on a lathe so
any marks are circular (so it looks more like a pattern)?

- Alternate option is to not use threads, and instead let
the body slide snugly into the bezel. Then I'd use a
small set-screw going vertically from the bottom of the
bezel to hold the body on.

- Any easier way to attach the cover to the body? I don't
mind welding (to avoid cutting the tabs), but not sure
how to do this w/o a tig welder, and that's way to
expensive for me now.

I'm trying to make this a science rather than an art, so
I get consistent repeatable results. So I don't mind
making jigs where necessary. Any other info towards these
goals is much appreciated.

Thanks much,
-Neil.

--- In 7x12minilathe@..., "Neil" <cobra_neil@a...> wrote:

Hi all,

Here is a sketch of what I need to make (> 20 pieces).


The unit will be used for gauges for my, and a friend's
car.

This will be my *excuse* for purchasing a lathe, and other
appropriate tools. Wondering if someone can assist my
letting me know if I'm on the right track.



The Plan:
=========

BEZEL: Only aesthetic part. I'm using 2.25" ID, 1.75" ID
for the ring, as I can get tubing with these dimensions from
places like McMaster. I'd need to cut thin slices (about
3/8" thick) from the tube to make a ring, then use a lathe
to cut back a part of the inside to ~ 2" ID.

BODY: I'll use 2" OD, 1.9" ID tubing here, cut to a length
of approx 2". Only lathe work here is the threads. I can
make the tabs by using a fiberglass cutoff-wheel or other
saw.

BACK COVER: I'll use sheet-metal for this, but not sure
what's the best process to cut clean consistent circles.


My Questions:
=============

- Is the cut on the inside of the bezel easy with a lathe?
I'm still not sure if the cutting tools will get in there
easily.

A boring bar (or boring tool) is designed to do this easily.

- Are internal threads easy to cut with a lathe?

Easier than trying to cut a short, large diameter thread any other
way. It's less exciting if there's an unthreaded relief at the blind
end and if you run the lathe in reverse, to have the tool moving away
from the chuck while making a right hand thread.

- Can I do the bezel w/o damage or marks to the outside
surface?

With difficulty. You'll need to make some sort of fixture that's
softer than the bezel, yet, able to hold it securely & accurately.
It'd be easier to machine the outside & front after it's threaded.
(Screw it onto a mandrel for final machining.)

- What's a good way to cut thin, clean slices of the rings?
I'd like to avoid manual polishing/cleaning as much as
possible. Is there some way I can cut it on a lathe so
any marks are circular (so it looks more like a pattern)?

The good way is a parting tool and a lathe large enough to pass the
tubing thru the spindle! The practical way on a 7xX is to rough out
the blanks with a chop/band/hack saw and face them to size.
Alternately, with lots of waste, part some off a piece of tubing held
in a chuck/on a mandrel. After a few are done, start with another
piece of tubing - there's a limited range between too long to fit the
lathe & too short to hold. You may need to use a steady rest, which
tends to mark the outside of the tubing.

- Alternate option is to not use threads, and instead let
the body slide snugly into the bezel. Then I'd use a
small set-screw going vertically from the bottom of the
bezel to hold the body on.

Boring & cross-drilling is easier than boring, threading internal +
threading external.

- Any easier way to attach the cover to the body? I don't
mind welding (to avoid cutting the tabs), but not sure
how to do this w/o a tig welder, and that's way to
expensive for me now.

Supposedly, you can buy drawn cups. I've never done it, so I'm just
passing along a shop rumor <g> If the end can be thicker, you can
turn a shoulder on a purchased disc or blank some out of plate with a
hole saw. If you've got a drill press, a hole saw without the pilot
drill will produce solid discs (it also howls enough to panic the
cats & annoy SWMBO <G>)

Roy

I'm trying to make this a science rather than an art, so
I get consistent repeatable results. So I don't mind
making jigs where necessary. Any other info towards these
goals is much appreciated.

Thanks much,
-Neil.

Hey Roy,

Thanks for the info. Comments interspersed below...

- Is the cut on the inside of the bezel easy with a lathe?
I'm still not sure if the cutting tools will get in there
easily.

A boring bar (or boring tool) is designed to do this easily.

I'll assume this is one of the cutting tools available for a
lathe.

- Are internal threads easy to cut with a lathe?

Easier than trying to cut a short, large diameter thread any other
way. It's less exciting if there's an unthreaded relief at the blind
end and if you run the lathe in reverse, to have the tool moving away
from the chuck while making a right hand thread.

After much thought, I've decided to get away from the threads
and make the parts snug-fit, with a small set screw to hold them
together.

- Can I do the bezel w/o damage or marks to the outside
surface?

With difficulty. You'll need to make some sort of fixture that's
softer than the bezel, yet, able to hold it securely & accurately.
It'd be easier to machine the outside & front after it's threaded.
(Screw it onto a mandrel for final machining.)

Sound like you're saying that the threading process will
be the problem in this respect. Sounds plausible since
the bezel will need to be gripped tight. Since I'm leaning
away from threading now, I may be okay? If not, I guess I
can lightly machine the outside to clean it up.

- What's a good way to cut thin, clean slices of the rings?
I'd like to avoid manual polishing/cleaning as much as
possible. Is there some way I can cut it on a lathe so
any marks are circular (so it looks more like a pattern)?

The good way is a parting tool and a lathe large enough to pass the
tubing thru the spindle! The practical way on a 7xX is to rough out
the blanks with a chop/band/hack saw and face them to size.
Alternately, with lots of waste, part some off a piece of tubing held
in a chuck/on a mandrel. After a few are done, start with another
piece of tubing - there's a limited range between too long to fit the
lathe & too short to hold. You may need to use a steady rest, which
tends to mark the outside of the tubing.

I'm a bit confused about what you mean here, since I'm not that
familiar with the lathe yet, until I get one. But I'll look it up
in the lathe docs I downloaded.

- Alternate option is to not use threads, and instead let
the body slide snugly into the bezel. Then I'd use a
small set-screw going vertically from the bottom of the
bezel to hold the body on.

Boring & cross-drilling is easier than boring, threading internal +
threading external.

Good. This (threading) option eliminated.

- Any easier way to attach the cover to the body? I don't
mind welding (to avoid cutting the tabs), but not sure
how to do this w/o a tig welder, and that's way to
expensive for me now.

Supposedly, you can buy drawn cups. I've never done it, so I'm just
passing along a shop rumor <g> ...

Have never been able to find this, but I recently realized that I
need the back cover off to assemble the unit (mounting a part on
the cover for use as a heat-sink).

... If the end can be thicker, you can
turn a shoulder on a purchased disc or blank some out of plate with a
hole saw. If you've got a drill press, a hole saw without the pilot
drill will produce solid discs (it also howls enough to panic the
cats & annoy SWMBO <G>)

Yep. This was my first thought, but I thought I'd ask otherwise
since I need to experiment with the available standard hole-saw
sizes to see if one fits my app.


Cheers,
-Neil.

I recently made a housing for a small halogen
reflector lamp that is very similar to your plan -
including the threaded bezel. You can hold the bezel
or the tubing from the inside by extending the chuck
jaws outwards until they firmly grip the inside
surface of the work.

Frank Hoose



--- "roylowenthal <roylowenthal@...>"
<roylowenthal@...> wrote:

--- In 7x12minilathe@..., "Neil"
<cobra_neil@a...> wrote:

Hi all,

Here is a sketch of what I need to make (> 20

pieces).

The unit will be used for gauges for my, and a

friend's

car.

This will be my *excuse* for purchasing a lathe,

and other

appropriate tools. Wondering if someone can

assist my

letting me know if I'm on the right track.



The Plan:
=========

BEZEL: Only aesthetic part. I'm using 2.25" ID,

1.75" ID

for the ring, as I can get tubing with these

dimensions from

places like McMaster. I'd need to cut thin slices

(about

3/8" thick) from the tube to make a ring, then use

a lathe

to cut back a part of the inside to ~ 2" ID.

BODY: I'll use 2" OD, 1.9" ID tubing here, cut to

a length

of approx 2". Only lathe work here is the

threads. I can

make the tabs by using a fiberglass cutoff-wheel

or other

saw.

BACK COVER: I'll use sheet-metal for this, but

not sure

what's the best process to cut clean consistent

circles.

My Questions:
=============

- Is the cut on the inside of the bezel easy with

a lathe?

I'm still not sure if the cutting tools will get

in there

easily.

A boring bar (or boring tool) is designed to do this
easily.

- Are internal threads easy to cut with a lathe?

Easier than trying to cut a short, large diameter
thread any other
way. It's less exciting if there's an unthreaded
relief at the blind
end and if you run the lathe in reverse, to have the
tool moving away
from the chuck while making a right hand thread.

- Can I do the bezel w/o damage or marks to the

outside

surface?

With difficulty. You'll need to make some sort of
fixture that's
softer than the bezel, yet, able to hold it securely
& accurately.
It'd be easier to machine the outside & front after
it's threaded.
(Screw it onto a mandrel for final machining.)

- What's a good way to cut thin, clean slices of

the rings?

I'd like to avoid manual polishing/cleaning as

much as

possible. Is there some way I can cut it on a

lathe so

any marks are circular (so it looks more like a

pattern)?

The good way is a parting tool and a lathe large
enough to pass the
tubing thru the spindle! The practical way on a 7xX
is to rough out
the blanks with a chop/band/hack saw and face them
to size.
Alternately, with lots of waste, part some off a
piece of tubing held
in a chuck/on a mandrel. After a few are done,
start with another
piece of tubing - there's a limited range between
too long to fit the
lathe & too short to hold. You may need to use a
steady rest, which
tends to mark the outside of the tubing.

- Alternate option is to not use threads, and

instead let

the body slide snugly into the bezel. Then I'd

use a

small set-screw going vertically from the bottom

of the

bezel to hold the body on.

Boring & cross-drilling is easier than boring,
threading internal +
threading external.

- Any easier way to attach the cover to the body?

I don't

mind welding (to avoid cutting the tabs), but

not sure

how to do this w/o a tig welder, and that's way

to

expensive for me now.

Supposedly, you can buy drawn cups. I've never done
it, so I'm just
passing along a shop rumor <g> If the end can be
thicker, you can
turn a shoulder on a purchased disc or blank some
out of plate with a
hole saw. If you've got a drill press, a hole saw
without the pilot
drill will produce solid discs (it also howls enough
to panic the
cats & annoy SWMBO <G>)

Roy

I'm trying to make this a science rather than an

art, so

I get consistent repeatable results. So I don't

mind

making jigs where necessary. Any other info

towards these

goals is much appreciated.

Thanks much,
-Neil.

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I think we're reaching the readability limit for interspersed
replies!
There's a machining manual here:

20Manual%20TC%209-524/
and another one here, for people who can read without moving their
lips (guess which branch I served in):



--- In 7x12minilathe@..., "Neil" <cobra_neil@a...> wrote:

Hey Roy,

Thanks for the info. Comments interspersed below...

- Is the cut on the inside of the bezel easy with a lathe?
I'm still not sure if the cutting tools will get in there
easily.

A boring bar (or boring tool) is designed to do this easily.

I'll assume this is one of the cutting tools available for a
lathe.

- Are internal threads easy to cut with a lathe?

Easier than trying to cut a short, large diameter thread any

other

way. It's less exciting if there's an unthreaded relief at the

blind

end and if you run the lathe in reverse, to have the tool moving

away

from the chuck while making a right hand thread.

After much thought, I've decided to get away from the threads
and make the parts snug-fit, with a small set screw to hold them
together.

- Can I do the bezel w/o damage or marks to the outside
surface?

With difficulty. You'll need to make some sort of fixture that's
softer than the bezel, yet, able to hold it securely &

accurately.

It'd be easier to machine the outside & front after it's

threaded.

(Screw it onto a mandrel for final machining.)

Sound like you're saying that the threading process will
be the problem in this respect. Sounds plausible since
the bezel will need to be gripped tight. Since I'm leaning
away from threading now, I may be okay? If not, I guess I
can lightly machine the outside to clean it up.

- What's a good way to cut thin, clean slices of the rings?
I'd like to avoid manual polishing/cleaning as much as
possible. Is there some way I can cut it on a lathe so
any marks are circular (so it looks more like a pattern)?

The good way is a parting tool and a lathe large enough to pass

the

tubing thru the spindle! The practical way on a 7xX is to rough

out

the blanks with a chop/band/hack saw and face them to size.
Alternately, with lots of waste, part some off a piece of tubing

held

in a chuck/on a mandrel. After a few are done, start with

another

piece of tubing - there's a limited range between too long to fit

the

lathe & too short to hold. You may need to use a steady rest,

which

tends to mark the outside of the tubing.

I'm a bit confused about what you mean here, since I'm not that
familiar with the lathe yet, until I get one. But I'll look it up
in the lathe docs I downloaded.

With a large lathe, the tubing can pass thru the spindle & be parted
(sliced) off a long piece of tubing. The spindle on the 7xX's only
has about a 13/16" bore, so you have to chuck short sections of
tubing, part a few bezel blanks off the section & start with another
section, leaving a waste piece that was held in the chuck. It's hard
to hold large tubing in a chuck without distorting it, some sort of
mandrel works better, but takes up more of the length of the tube to
hold it. Alternately, use a saw and face each bezel on both sides.

- Alternate option is to not use threads, and instead let
the body slide snugly into the bezel. Then I'd use a
small set-screw going vertically from the bottom of the
bezel to hold the body on.

Boring & cross-drilling is easier than boring, threading internal

+

threading external.

Good. This (threading) option eliminated.

- Any easier way to attach the cover to the body? I don't
mind welding (to avoid cutting the tabs), but not sure
how to do this w/o a tig welder, and that's way to
expensive for me now.

Supposedly, you can buy drawn cups. I've never done it, so I'm

just

passing along a shop rumor <g> ...

Have never been able to find this, but I recently realized that I
need the back cover off to assemble the unit (mounting a part on
the cover for use as a heat-sink).

... If the end can be thicker, you can
turn a shoulder on a purchased disc or blank some out of plate

with a

hole saw. If you've got a drill press, a hole saw without the

pilot

drill will produce solid discs (it also howls enough to panic the
cats & annoy SWMBO <G>)

Yep. This was my first thought, but I thought I'd ask otherwise
since I need to experiment with the available standard hole-saw
sizes to see if one fits my app.

It's possible to tweak a hole saw by modifying the tooth set, but
it's tedious. For Al pieces, I just use carpet tape to hold the
blank to a chucked piece of wood, helped by pressure from a live
center, and take light cuts. For a shouldered part, eyeball
centering before turning both diameters is quicker than accurately
centering an existing major diameter before turning the minor
diameter.

Cheers,
-Neil.

Thanks for the links.
Is the full manual available on the 7x10 site? All I see with your
link below are the index and the table of contents.

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

There's a machining manual here:

USAR%20Machinist%20Manual%20TC%209-524/

Frank Hoose scribbled:

I recently made a housing for a small halogen
reflector lamp that is very similar to your plan -
including the threaded bezel. You can hold the bezel
or the tubing from the inside by extending the chuck
jaws outwards until they firmly grip the inside
surface of the work.

Only prob here is that the inside of the bezel is
also an aesthetic part.

Cheers,
-Neil.

roylowenthal scribbled:

I think we're reaching the readability limit for interspersed
replies!

Really? ...you should join some of the other lists I'm on :-)

There's a machining manual here:

20Manual%20TC%209-524/
and another one here, for people who can read without moving their
lips (guess which branch I served in):

I get an index and TOC on the first link, and I've joined the latter
to get access, so hopefully will get that soon.

In the meanwhile, this is the doc I'm reading...


At the rate I read, I'll be back with you all in a few
months :-)

Cheers,
-Neil.

bflint@... scribbled:

Thanks for the links.
Is the full manual available on the 7x10 site? All I see with your
link below are the index and the table of contents.

Same thing I'm getting. See my prev email for another
good doc.

Anyway, I notice from your email that you're an Austinite
as well. Woo-hoo!

Cheers,
-Neil.

Neil,
Yep, been here almost 6 years. You?

That link you posted for the other manual is chapter 7 of the same
one that we're just getting the index for on the 7x10 group!
I see that we can all go right to the source (the Army) and get
the full manual online at:



B Flint

bflint@... mumbled:

Neil,
Yep, been here almost 6 years. You?

That link you posted for the other manual is chapter 7 of the same
one that we're just getting the index for on the 7x10 group!
I see that we can all go right to the source (the Army) and get
the full manual online at:



B Flint

Speaking of Army docs, read this quick page, and then
download anything you ever thought you wanted asap
before it all disappears...



Been in Austin since 1999, but been unemployed for some time
now, so I rented out my house (Steiner) and have been travelling
for the last four months. Should be back in Austin in Feb
sometime ... for our annual Shelby Cobra event.

Cheers,
-Neil.