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I measured my 5-C spring collets and found less than .001" taper from
the threads to the closing cone!

I wonder if the brass collet is part of the problem. Coming from
e-bay, there's no telling what sort of abuse it may have suffered.
Steel collets are "spring hard" to avoid distortion during use; they
eventually wear eccentric. (Long eventual, except in high volume
production.)
Trying to work to tenths is sort of frustrating - surface finish
of mating parts has a disproportionate effect on readings. Actually,
surface finish on the part being indicated can "drag" the indicator
to a slightly false reading. Presumably, your measuring technique
gives the same reading on return to the same point. There's enough
flex in these machines to get a measurable deflection from resting
your forearm on the headstock.
Except for really critical work, ignoring any runout under .001"
or .002" saves a lot of set-up time.

Roy

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

Hi Roy,

Thanks for the link. I looked at the site and wrote to the owner,
Dave Audette, who provided a considerable amount of information in

a

detailed reply. One key bit of data is that his runout is about 4
tenths, similar to mine when the collet settles in the chuck
properly. I also found a CNC site which gave collet runout as 5
tenths max so apparently my collet chuck's performance is in the
ballpark.

However, it is interesting that Dave gets 4 tenths runout with a SB
collet holder which I assume is probably concentric to the

headstock

MT3 socket. Makes me think my headstock may be poorer than most
since I find the following when indicating various points on the
backplate:

Outer rim = 5 tenths
Land for chuck registry = 2
Inside of MT3 socket = 6+
Inside of 3C chuck = 2
Piece in collet = 2-4 typical, sometimes 10 (tapping with a block

of

wood causes it to pop into alignment yielding 2-4)

Logically, a perfectly concentric collet chuck's runout could be no
better than the socket it is mounted in.I use a witness mark to

align

my collet chuck to the backplate/MT3 socket so the socket runout
should be cancelled because the chuck was machined in that socket

and

replaced in the same orientation. That is, my collet chuck is
slightly eccentric but in a way which compensates for the MT3
socket's runout.

The above figures indicate (no pun intended) that the runout of the
MT3 socket in my backplate is larger than desirable and that Dave's
machine seems to run truer by quite a bit since he gets the same
runout without having machined his chuck in place.

Based on the above I would guess that during manufacture the
backplate is turned to size on a production machine with the chuck
land left slightly larger than final size. The backplate is then
mounted on the lathe and the chuck land is machined to final size

in

place to minimize runout.

I intend to polish the inside of the collet chuck in an attempt to
cause it to register the collet the same way each time so I don't
sometimes have to tap the work with a block of wood.

John

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

See if there's anything here that helps:


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

I recently attempted to make a 3C collet chuck to fit the 3MT

taper

in my lathe. This seemed to go OK but the first try was not a

good

fit (rear of the collet fit sloppy) so I made another which fit
better. The chuck is based on an article by Exactus, 2984

found

here:

As a newbie, I've never seen a collet chuck in action so I

don't

know

exactly what to expect from it. What I hoped was that it would
provide simple, non-marking gripping of work with zero runout.

My

chuck may be poorly made or perhaps I'm overly optimistic on

how

it

should work.

I bought a 3C South Bend 3/8 brass collet on eBay as a model to

judge

fit; my goal was to eventually make steel collets to fit the

chuck.

When I put this collet into my chuck I find that the runout

varies

each time I tighten the drawbar, typically 2-4 tenths,

sometimes

up

to 1 mil. When the runout is large it gets larger as I move

farther

from the chuck so apparently it is angled somewhere (the work

or

the

collet itself); if I tap the test piece on the high side with a

block

of wood it generally will settle to the more typical 2-4 tenths
anywhere along the length of the 1 inch long test piece (a

commercial

3/8 D bit shaft.

Ths narrow part of the SB collet tapers about 6 mils, getting

larger

as one goes from the threads toward the steep taper. I made the

chuck

so it is an easy fit for the first part of the collet but I

have

to

press firmly to fully insert it due to the collet's taper.

Similarly,

it requires a push with the drawbar to get enough to protrude

so

it

can be pulled out.

With the above as background, I have a number of newbie

questions

on

collets and collet chucks:

1. What is the expected runout when using a collet?

2. Is the taper on the narrow part of the collet machined in or

does

this happen when they add the slits? Will this also be present

on

steel collets or just on brass?

3. What surface(s) are critical in providing the collet

centering.

That is, is the fit of the chuck onto the rear of the collet
critical? Does the chuck need to be tapered in the narrow bore

to

match the collet? Is there a specification for the steep angle

on

a

3C?

Any help here would be appreciated. I've put quite a bit of

time

into making this chuck and now don't know whether it is useful

or

just a fancy doorstop.

John

Hi Roy,

Thanks for the link. I looked at the site and wrote to the owner,
Dave Audette, who provided a considerable amount of information in a
detailed reply. One key bit of data is that his runout is about 4
tenths, similar to mine when the collet settles in the chuck
properly. I also found a CNC site which gave collet runout as 5
tenths max so apparently my collet chuck's performance is in the
ballpark.

However, it is interesting that Dave gets 4 tenths runout with a SB
collet holder which I assume is probably concentric to the headstock
MT3 socket. Makes me think my headstock may be poorer than most
since I find the following when indicating various points on the
backplate:

Outer rim = 5 tenths
Land for chuck registry = 2
Inside of MT3 socket = 6+
Inside of 3C chuck = 2
Piece in collet = 2-4 typical, sometimes 10 (tapping with a block of
wood causes it to pop into alignment yielding 2-4)

Logically, a perfectly concentric collet chuck's runout could be no
better than the socket it is mounted in.I use a witness mark to align
my collet chuck to the backplate/MT3 socket so the socket runout
should be cancelled because the chuck was machined in that socket and
replaced in the same orientation. That is, my collet chuck is
slightly eccentric but in a way which compensates for the MT3
socket's runout.

The above figures indicate (no pun intended) that the runout of the
MT3 socket in my backplate is larger than desirable and that Dave's
machine seems to run truer by quite a bit since he gets the same
runout without having machined his chuck in place.

Based on the above I would guess that during manufacture the
backplate is turned to size on a production machine with the chuck
land left slightly larger than final size. The backplate is then
mounted on the lathe and the chuck land is machined to final size in
place to minimize runout.

I intend to polish the inside of the collet chuck in an attempt to
cause it to register the collet the same way each time so I don't
sometimes have to tap the work with a block of wood.

John

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

See if there's anything here that helps:


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

I recently attempted to make a 3C collet chuck to fit the 3MT

taper

in my lathe. This seemed to go OK but the first try was not a

good

fit (rear of the collet fit sloppy) so I made another which fit
better. The chuck is based on an article by Exactus, 2984 found

here:

As a newbie, I've never seen a collet chuck in action so I don't

know

exactly what to expect from it. What I hoped was that it would
provide simple, non-marking gripping of work with zero runout. My
chuck may be poorly made or perhaps I'm overly optimistic on how

it

should work.

I bought a 3C South Bend 3/8 brass collet on eBay as a model to

judge

fit; my goal was to eventually make steel collets to fit the

chuck.

When I put this collet into my chuck I find that the runout

varies

each time I tighten the drawbar, typically 2-4 tenths, sometimes

up

to 1 mil. When the runout is large it gets larger as I move

farther

from the chuck so apparently it is angled somewhere (the work or

the

collet itself); if I tap the test piece on the high side with a

block

of wood it generally will settle to the more typical 2-4 tenths
anywhere along the length of the 1 inch long test piece (a

commercial

3/8 D bit shaft.

Ths narrow part of the SB collet tapers about 6 mils, getting

larger

as one goes from the threads toward the steep taper. I made the

chuck

so it is an easy fit for the first part of the collet but I have

to

press firmly to fully insert it due to the collet's taper.

Similarly,

it requires a push with the drawbar to get enough to protrude so

it

can be pulled out.

With the above as background, I have a number of newbie questions

on

collets and collet chucks:

1. What is the expected runout when using a collet?

2. Is the taper on the narrow part of the collet machined in or

does

this happen when they add the slits? Will this also be present on
steel collets or just on brass?

3. What surface(s) are critical in providing the collet

centering.

That is, is the fit of the chuck onto the rear of the collet
critical? Does the chuck need to be tapered in the narrow bore to
match the collet? Is there a specification for the steep angle on

a

3C?

Any help here would be appreciated. I've put quite a bit of time
into making this chuck and now don't know whether it is useful or
just a fancy doorstop.

John

--- In 7x12minilathe@..., "mikeaita1" <aita1@a...> wrote:

7X10 is not on the server :(
mike

<

ead.txt>

Download it, print out a copy, and take it to the lathe.

The link got broken by Yahoo. Its a common problem. I'll try to
rejoin it here, but if that doesn't work (I won't know for sure until
I see the new message on the web site) you can cut and paste it back
together.



ad.txt

Hope that helps,
RA

See if there's anything here that helps:


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

I recently attempted to make a 3C collet chuck to fit the 3MT taper
in my lathe. This seemed to go OK but the first try was not a good
fit (rear of the collet fit sloppy) so I made another which fit
better. The chuck is based on an article by Exactus, 2984 found

here:

As a newbie, I've never seen a collet chuck in action so I don't

know

exactly what to expect from it. What I hoped was that it would
provide simple, non-marking gripping of work with zero runout. My
chuck may be poorly made or perhaps I'm overly optimistic on how it
should work.

I bought a 3C South Bend 3/8 brass collet on eBay as a model to

judge

fit; my goal was to eventually make steel collets to fit the chuck.
When I put this collet into my chuck I find that the runout varies
each time I tighten the drawbar, typically 2-4 tenths, sometimes up
to 1 mil. When the runout is large it gets larger as I move

farther

from the chuck so apparently it is angled somewhere (the work or

the

collet itself); if I tap the test piece on the high side with a

block

of wood it generally will settle to the more typical 2-4 tenths
anywhere along the length of the 1 inch long test piece (a

commercial

3/8 D bit shaft.

Ths narrow part of the SB collet tapers about 6 mils, getting

larger

as one goes from the threads toward the steep taper. I made the

chuck

so it is an easy fit for the first part of the collet but I have to
press firmly to fully insert it due to the collet's taper.

Similarly,

it requires a push with the drawbar to get enough to protrude so it
can be pulled out.

With the above as background, I have a number of newbie questions

on

collets and collet chucks:

1. What is the expected runout when using a collet?

2. Is the taper on the narrow part of the collet machined in or

does

this happen when they add the slits? Will this also be present on
steel collets or just on brass?

3. What surface(s) are critical in providing the collet centering.
That is, is the fit of the chuck onto the rear of the collet
critical? Does the chuck need to be tapered in the narrow bore to
match the collet? Is there a specification for the steep angle on a
3C?

Any help here would be appreciated. I've put quite a bit of time
into making this chuck and now don't know whether it is useful or
just a fancy doorstop.

John

Based on building a 5-C adaptor I believe that the bore should be
straight to align the collet body coaxially with the lathe axis.

Bill in Boulder "Engineering as an Art Form!"

Did you try the above? Works for me.

Charlie

7X10 is not on the server :(
mike

<

ead.txt>

Download it, print out a copy, and take it to the lathe.

Useing

something that is easy to machine like PVC pipe or aluminum

conduit,

practice, practice, practice. At first, read each step as you

go.

Then when you feel more comfortable, do a few steps at a time,

until

you can do it in your sleep.

The method works. I learned to thread using it.

You can buy ER4/5/6 or EL4/5/6 (size to fit your lathe) as

cemented

carbide or you can grind your own HSS tools. I recommend you

grind

your own bits for practice, using one of the carbide ones as an
example. Don't forget to leave clearance for the helix angle

of

the

thread. Don't try to cut threads using one of the el-cheapo

carbide

bits. You will be frustrated because they seem to have no

clearance

on any edges.

Hope that helps,
RA

I recently attempted to make a 3C collet chuck to fit the 3MT taper
in my lathe. This seemed to go OK but the first try was not a good
fit (rear of the collet fit sloppy) so I made another which fit
better. The chuck is based on an article by Exactus, 2984 found here:


As a newbie, I've never seen a collet chuck in action so I don't know
exactly what to expect from it. What I hoped was that it would
provide simple, non-marking gripping of work with zero runout. My
chuck may be poorly made or perhaps I'm overly optimistic on how it
should work.

I bought a 3C South Bend 3/8 brass collet on eBay as a model to judge
fit; my goal was to eventually make steel collets to fit the chuck.
When I put this collet into my chuck I find that the runout varies
each time I tighten the drawbar, typically 2-4 tenths, sometimes up
to 1 mil. When the runout is large it gets larger as I move farther
from the chuck so apparently it is angled somewhere (the work or the
collet itself); if I tap the test piece on the high side with a block
of wood it generally will settle to the more typical 2-4 tenths
anywhere along the length of the 1 inch long test piece (a commercial
3/8 D bit shaft.

Ths narrow part of the SB collet tapers about 6 mils, getting larger
as one goes from the threads toward the steep taper. I made the chuck
so it is an easy fit for the first part of the collet but I have to
press firmly to fully insert it due to the collet's taper. Similarly,
it requires a push with the drawbar to get enough to protrude so it
can be pulled out.

With the above as background, I have a number of newbie questions on
collets and collet chucks:

1. What is the expected runout when using a collet?

2. Is the taper on the narrow part of the collet machined in or does
this happen when they add the slits? Will this also be present on
steel collets or just on brass?

3. What surface(s) are critical in providing the collet centering.
That is, is the fit of the chuck onto the rear of the collet
critical? Does the chuck need to be tapered in the narrow bore to
match the collet? Is there a specification for the steep angle on a
3C?

Any help here would be appreciated. I've put quite a bit of time
into making this chuck and now don't know whether it is useful or
just a fancy doorstop.

John

Concerning the sister site
mill, ...I added a message about tramming the mini mill over a week
ago but it was never posted on the board. Also, I notice that there
have been no new messages added since Apr 2. Does anyone know what
the problem is over there?

Hi to all!

New here [and to machining] and having a great ime learning a new
craft.
I got a 7x14 from MicroMark. Lots of small problems, but my big one
is spindle runout. I am getting just under .001" of runout on the
face of the spindle AND on the outer diameter! Of course, this means
that turning anything true is almost impossible.
Anyone have any knowledge/suggestionson this one?

Thanks.

The "restricted" means you have to join the group to access the
files. Since it's an open group, joining is effortless.

Roy
--- In 7x12minilathe@..., "mikeaita1" <aita1@a...> wrote:

Thanks for the advice
unfortunately I can't download the file.
Yahoo says something about them being restricted
But I am practicing and enjoying it
thanks again
mike

<

ead.txt>

Download it, print out a copy, and take it to the lathe. Useing
something that is easy to machine like PVC pipe or aluminum

conduit,

practice, practice, practice. At first, read each step as you go.
Then when you feel more comfortable, do a few steps at a time,

until

you can do it in your sleep.

The method works. I learned to thread using it.

You can buy ER4/5/6 or EL4/5/6 (size to fit your lathe) as

cemented

carbide or you can grind your own HSS tools. I recommend you

grind

your own bits for practice, using one of the carbide ones as an
example. Don't forget to leave clearance for the helix angle of

the

thread. Don't try to cut threads using one of the el-cheapo

carbide

bits. You will be frustrated because they seem to have no

clearance

on any edges.

Hope that helps,
RA

Thank you all for the various replies, they were very helpful

Thanks for the advice
unfortunately I can't download the file.
Yahoo says something about them being restricted
But I am practicing and enjoying it
thanks again
mike

<

ead.txt>

Download it, print out a copy, and take it to the lathe. Useing
something that is easy to machine like PVC pipe or aluminum conduit,
practice, practice, practice. At first, read each step as you go.
Then when you feel more comfortable, do a few steps at a time, until
you can do it in your sleep.

The method works. I learned to thread using it.

You can buy ER4/5/6 or EL4/5/6 (size to fit your lathe) as

cemented

carbide or you can grind your own HSS tools. I recommend you grind
your own bits for practice, using one of the carbide ones as an
example. Don't forget to leave clearance for the helix angle of the
thread. Don't try to cut threads using one of the el-cheapo carbide
bits. You will be frustrated because they seem to have no clearance
on any edges.

Hope that helps,
RA

to keep steel rust free, i have a long plant trough with lid that is 30 inch
by 7 inch by 7 inch. it has about an inch deep filling of 50/50 parrafin and
oil. the occaisional swill round keeps everything rust free


DAVID WILLIAMS
BOLTON
ENGLAND
www.smartgroups.com/groups/fliers
davidalan@...

--- In 7x12minilathe@..., Richard Kleinhenz
<woodnpen@o...> wrote:

...

... Or is there some way of tell what you got? I don't mean
telling stainless steel from aluminum, but 12L14 from 1018 or
drill rod.

I found it! JWE posted two articles on this at:

<>

Good luck.

RA

--- In 7x12minilathe@..., Richard Kleinhenz
<woodnpen@o...> wrote:

Basic question: When you buy steel alloys, how can you tell what
you have?

Basically, you have to take the supplier's word for it. If he lies
a lot, find another supplier, or a favorite salesperson.

Is there any kind of color coding? Sometimes rod has some
yellow or blue color on it. Is that meaningful?

Only at that particular supplier's lot. I have 3 suppliers nearby
that I frequent. All 3 use different color codes. There does not
seem to be any standard at all, for any metal I know of.

Secondly, if you bought some stuff and don't use it all - do you
write the alloy on it with permanent marker?

I use a Sharpie (brand) pen. It writes on most everything, and
seems to be close to permanent - but cutting fluid does take it off...

Or is there some way of tell what you got? I don't mean telling

stainless steel from aluminum, but 12L14 from 1018 or drill rod.

James Early posted two from ME (I think), perhaps he will tell us
where they are (my filing "system" does not track sources). Called
"What metal is it?" by R. H. Warring, July 21, 1955.

How do you store it? Inside, of course, in a 'dry' basement that
is unheated and not all that dry. Do you keep the alloys separated?

No, I don't have that much. Yet... Mine is just leaning in a
corner.

Make up your own color coding?

Sounds like a good idea, if you keep a lot of colors of paint
around. I just mark it on the end with a Sharpie.

Do you wipe some oil on it to help prevent surface rust?

I tried that, it worked for a while but then started to rust again.
I think grease will last longer - I'm testing that idea now. It is
definately messier.

RA in rainy(!) Southern California

--- In 7x12minilathe@..., silectric@a... wrote:

(Nothing)

If you meant to leave a message, it didn't get here...

There is not universal color coding system, each metal foundry has
its own, or smaller shops make there own. I worked in a tool and die
shop a couple years ago that used white for d2, yellow for a2, and
there was one other I forget.

Sean

--- In 7x12minilathe@..., Richard Kleinhenz
<woodnpen@o...> wrote:

Basic question: When you buy steel alloys, how can you tell what

you have? Is there any kind of color coding? Sometimes rod has some
yellow or blue color on it. Is that meaningful?

Secondly, if you bought some stuff and don't use it all - do you

write the alloy on it with permanent marker? Or is there some way of
tell what you got? I don't mean telling stainless steel from
aluminum, but 12L14 from 1018 or drill rod.

How do you store it? Inside, of course, in a 'dry' basement that

is unheated and not all that dry. Do you keep the alloys separated?
Make up your own color coding? Do you wipe some oil on it to help
prevent surface rust? Looking for ideas!

--
Regards,
Rich
========================================
Richard Kleinhenz
mailto:woodnpen@o...


========================================

hi

can anyone suggest a site that explains how to set up and use a
vernier height gauge? appreciate any help.

Peter