Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

ducque wrote:

Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

Me, I grind 'em on my surface grinder. If I had to do it on a mill, I'd use 3M
brand double-sided tape and go slowly with a dead sharp HSS milling cutter.

GWE

ducque wrote:

Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.



There are a couple ways to attack this. One is to make the stock the
correct
thickness first, then drill a hole in it. Now, grip a bolt in the lathe
chuck
with the threads sticking out. Run a nut on the bolt, the stock with hole,
and finish with another nut. Tighten the nuts together with 2 wrenches.
Now, you can turn the OD as desired. I make a number of odd spacers,
etc. like this.

If the entire part needs to be concentric and the faces parallel, make
an arbor
from random stock, by chucking in the lathe and facing true. Superglue
the stock to the arbor. Perform all operations, facing, ID and OD turning,
etc. Both faces will be parallel to the extent the superglue formed a
uniform thickness film. When done, pry thicker parts off the superglue,
or use Acetone to dissolve the superglue and release thin parts.

Jon

ducque wrote:

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

Things like these I make often that way:

Have some stock, bore & turn to desired ID/OD but do not part off.
Clamp it in the vice on a mill and cut off with a circular saw*) (a thin
one; 1mm thick; diameter about 50mm). You can get the thickness to
within 1/100mm. If you want, 0.1mm thick. Astonishing what _sharp_ and
good circular saws can do! I use the "REBO" brand.

Might help to know exactly what you want to make.
It often helps to have quite some stock left for
holding/gripping/clamping and parting that off in the very last step.


*) of course, you need a holder for the blade, but it can be made by
oneself.


Nick

--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

On 1 Dec 2005 13:32:59 -0800, "ducque" wrote:

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

Start with a washer, then do what you need to it. You might need a
custom-made mandrel or a faceplate with a bolt to hold it rather than
an edge-clamping chuck. You might even use a magnetic lathe chuck and a
custom-made recessed faceplate ($$$).

Very thin parts are just a damn nuisance. As "parting them off" is
indeed nigh-impossible, you'll probably start with something that's
already thin, then make it circular. Other good techniques are punch
tooling instead of a lathe, or changing the design so that the thin part
is indeed a plain washer, maybe with a small turned boss added to it.

On Thu, 01 Dec, Jon Elson wrote:
There are a couple ways to attack this. One is to make the stock the
correct
thickness first, then drill a hole in it. Now, grip a bolt in the lathe
chuck
with the threads sticking out. Run a nut on the bolt, the stock with hole,
and finish with another nut. Tighten the nuts together with 2 wrenches.
Now, you can turn the OD as desired. I make a number of odd spacers,
etc. like this.

How do you do this if the hole size doesn't match up with an existing bolt,
though? Assuming you want your hole to be centered in the piece, anyway.


--Donnie

--
Donnie Barnes http://www.donniebarnes.com 879. V.

On 1 Dec 2005 13:32:59 -0800, "ducque" wrote:

Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

In The Home Shop Machinist, Projects Two, Page 22, (Available from
Village Press), D. E. Johnson wrote a piece on "Machining Thin Disks
and Rings. His is a three step process that results in a part of
proper diameter and thickness, but does require a hole in the part.
At the risk of getting flamed for "disseminating copyrighted
material", a paraphrase of the steps follows.
Step 1:
Chuck a piece of stock and turn a stub end, OD to the diameter of the
hole in the finished part and length to allow re-chucking after step
two. Face the shoulder as it will be one of the finished faces. Drill
a hole, centered in the part and as deep as the stub length + the
finished parts thickness + say 1/8". (This hole diameter should be
large enough to allow a boring tool to enter)
Step 2:
Part of the piece allowing for enough material to finish the
thickness. The drilled hole should be deep enough to meet the parting
tool. The result, in cross section, is a 'T' shaped piece with a hole
through it.
Step 3:
Reverse the part in the chuck, chucking now on the stub, finish the
parts OD. Face off to the parts thickness and clean up the edges.
With a boring tool, enlarge the hole to meet the OD of the stub.
Quoting Mr. Johnson here, "... the finished part will fall off leaving
only a slight burr for cleanup. Feeding the boring tool in at an
angle using the compound will produce a countersunk hole"
I've used this process a number of times with good success. It takes
a little longer but the results are worth the time. YMMV

Regards
Bob
rgentry_at_oz_dot_net
_AT_ = @, _dot_ = . to eMail

"ducque" wrote in message
oups.com...
Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

Soft jaws.
Soft jaws.
Soft jaws.

There's not better tool in your arsenal-------

Harold

"Harold and Susan Vordos" wrote in message
...

"ducque" wrote in message
oups.com...
Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

Soft jaws.
Soft jaws.
Soft jaws.

There's not better tool in your arsenal-------

Harold

That, of course, should read "there's no better tool in your arsenal".
Sorry, my fingers got away from me.

You can hold thin sections and face them dead parallel with no effort, and
do it time and again. You can also hold complex configurations the same
way, with the added benefit of the jaws acting as a perfect linear stop.
Great for multiple pieces that must be concentric, perpendicular and the
same length.

Harold

On Thu, 1 Dec 2005 20:53:40 -0800, "Harold and Susan Vordos"
wrote:


"Harold and Susan Vordos" wrote in message
...

"ducque" wrote in message
oups.com...
Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

If the part is flat on one side, and you didn't say, part it off to
thickness. Sharp and rigid parting tool, lots of cutting oil and a
steady hand on the feed.

If neither side is flat and it's small, add soft collet to what Harold
said.

Rich

ducque wrote:
Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.


Laser job shop.

Donnie Barnes wrote:
On Thu, 01 Dec, Jon Elson wrote:

There are a couple ways to attack this. One is to make the stock the
correct
thickness first, then drill a hole in it. Now, grip a bolt in the lathe
chuck
with the threads sticking out. Run a nut on the bolt, the stock with hole,
and finish with another nut. Tighten the nuts together with 2 wrenches.
Now, you can turn the OD as desired. I make a number of odd spacers,
etc. like this.


How do you do this if the hole size doesn't match up with an existing bolt,
though? Assuming you want your hole to be centered in the piece, anyway.
This gets a bit more complicated, but you certainly can do it. One way
is to build a shoulder into the arbor, to support one side of the work.
You turn a smaller diameter out from the shoulder just slightly smaller
than the ID hole in the part. Then you turn down and thread the rest of
the arbor to a convenient thread size. So, one side of the part rests
on the shoulder, the ID is centered by the rod next to the shoulder, and
a nut can be run down to hold the other side of the part. You can also
turn a disc that supports the part almost out to the OD, if it is very
thin and flimsy.

Umm, did I describe this well enough to be understood? I hope so.

Jon

The old machining and watchmaking books suggest soldering thin parts to
a custom fixture. If you tin the part, wipe off the solder and clamp it
in place while heating it the error due to solder thickness should be
small and repeatable.

I cut a shallow recess in a soft collet or the top jaws of a
Microcentric chuck when I need to turn a thin washer that can't be
surface-ground. Sometimes the part also needs clamping pressure from
the tailstock

I've made an aluminum hydraulic pump rotor shim 0.008" thick by etching
a thicker machined part with drain cleaner.

jw

Making jigs is a substantial part of learning machining methods.
I'd probably make up a round block with two slits in it so that it will
compress around the part and hold it. The hole in the front will be
somewhat less than what the part finished surface needs to be so that you
don't cut the jig to finish the part. I'd also recomment a 4 jaw chuck for
this work and that you make sure that everything is clean before doing the
final work.

--
Why do penguins walk so far to get to their nesting grounds?

I have a 45 year old Surface grinder - and noticed the spindle nut was turned
nicely. What made it unique - remember it has to be flat and have the threads
exactly done as they should - very high speed turning and pressure on a rock.

What they did was use an expanding dovetail chuck on the lathe. They likely did
the front, and turned the dovetail - 2" in diameter or so and then bore the hole
and turned the threads. Parted the nut - It is maybe 3/8" thick - held it with
the dovetail in a special lathe or perhaps the same lathe. Once mounted,
the back is faced - and maybe ground.

I suppose there are expanding dovetail chucks that are metal lathe rated -
I have them on my wood lathe. I have never seen them.

But I think that was a neat way to do things.

The front of my new one has an internal dovetail (likely used in manufacture) but
a reverse dovetail - so a small dovetailed chunk of metal can be moved and then locked
with an Allen screw.

Neat way if you can live with a dovetail - or grind it off after screwing on the nut...

martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



Harold and Susan Vordos wrote:
"Harold and Susan Vordos" wrote in message
...

"ducque" wrote in message
groups.com...

Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

Soft jaws.
Soft jaws.
Soft jaws.

There's not better tool in your arsenal-------

Harold


That, of course, should read "there's no better tool in your arsenal".
Sorry, my fingers got away from me.

You can hold thin sections and face them dead parallel with no effort, and
do it time and again. You can also hold complex configurations the same
way, with the added benefit of the jaws acting as a perfect linear stop.
Great for multiple pieces that must be concentric, perpendicular and the
same length.

Harold



----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

The old watchmaker book used the technique used in diamond/precious stone
cutting - a 'stick' with hard wax - heat the wax and place object. Now an
object with a handle.
Tin is a harder 'wax' - good idea. Lead might - might be strong enough.
Ca glue is used and might work.
.....
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



wrote:
The old machining and watchmaking books suggest soldering thin parts to
a custom fixture. If you tin the part, wipe off the solder and clamp it
in place while heating it the error due to solder thickness should be
small and repeatable.

I cut a shallow recess in a soft collet or the top jaws of a
Microcentric chuck when I need to turn a thin washer that can't be
surface-ground. Sometimes the part also needs clamping pressure from
the tailstock

I've made an aluminum hydraulic pump rotor shim 0.008" thick by etching
a thicker machined part with drain cleaner.

jw


----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

On 1 Dec 2005 13:32:59 -0800, "ducque" wrote:

Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)

I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.

It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).


For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

try double sided carpet tape.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

ducque wrote:

For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.

What do people do in these situations? Thanks.

There are more options left.
You can put the part between brass shims that you (partialy) mill away.
I call this "lost vice".
Also soft soldering and LockTite often helps. Sometimes, parts get
frozen to a plate (didn't try this, you must be either fast or
constantly cooling).
An other option is casting (and thus clamping) the part in low melding
(100°C) alloys like Wood's metal or some Cerobend alloys. They are very
stiff, you won't have bending. This is often the only way to clamp
irregular shapes. You can play tricks with it when milling very thin
tubes if you fill the tube with the alloy, etc.


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

On Fri, 02 Dec, Jon Elson wrote:
This gets a bit more complicated, but you certainly can do it. One way
is to build a shoulder into the arbor, to support one side of the work.
You turn a smaller diameter out from the shoulder just slightly smaller
than the ID hole in the part. Then you turn down and thread the rest of
the arbor to a convenient thread size. So, one side of the part rests
on the shoulder, the ID is centered by the rod next to the shoulder, and
a nut can be run down to hold the other side of the part. You can also
turn a disc that supports the part almost out to the OD, if it is very
thin and flimsy.

Umm, did I describe this well enough to be understood? I hope so.

I guess basically you're saying to do the same thing (secure part between
two nuts over a bolt), but turn down a shoulder in one nut that matches the
ID of the part in question. Makes perfect sense. Some of this **** is so
*simple* that it's painful when you don't think of it yourself. Duh.


--Donnie

--
Donnie Barnes http://www.donniebarnes.com 879. V.

I once had to make some thin parts for some medical device. These were
printed using the Metalphoto process and needed to be accurate to about
plus or minus 5 thou. They also had adhesive on the back with a paper
liner.
So what I did was....
punch a center hole in them with a Roper whitney hand operated punch
press...
then I stacked them all together on a mandrel, Very fresh HSS cutter
chucked them up in my 6 inch Atlas lathe and turned them to final
outside diameter.
Everyone was happy
what more can you ask for?