Pie Jaw chucks
Royston Vasey
little googling around and generally understand their benefits.
Do you machine the gripping bore to suit the work?
Why do the jaws in the pic have the radial profile rather than solid - just
to save material & weight?
cheers.
Wes
I think you are looking at soft jaws. Soft jaws are often used on cnc lathes to hold
parts. The jaws are clamped on a ring to keep them from fully closing and the profile of
the part is cut into them.
Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
DoN. Nichols
> I stumbled across this website
Which website? Did you find a web site which mirrors this
usenet newsgroup rec.crafts.metalworking? Normally, there are (and
should be) no images here.
> and the pics of the "pie jaw chucks". I did a
> little googling around and generally understand their benefits.
>
> Do you machine the gripping bore to suit the work?
It depends. There are "soft" pie jaws which can be machined to
fit a specific workpiece. But there are also hard jaws -- multiple
steps which are a precise fit for standard diameters and a pretty good
fit for in between sizes.
> Why do the jaws in the pic have the radial profile rather than solid - just
> to save material & weight?
Again -- which pic? And what do you mean by "radial profile"?
pie shape of the jaws, or the radiused gripping surface?
The pie shape is so when fitted to a six-jaw chuck, the chuck
can be closed to the maximum amount, allowing the sides of the jaws to
just barely touch.
The radial profile is to fit standard diameters -- and grip
fairly well diameters just a little smaller.
Are what you saw for six-jawed chucks? The combination of the
six jaws and the curved gripping surface allows gripping rings with
minimal distortion compared to the same thin walled object gripped by a
three-jaw chuck.
Enjoy,
DoN.
--
Email: <dnic...@d-and-d.com> | 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 ---
Royston Vasey
"DoN. Nichols" <dnic...@d-and-d.com> wrote in message
news:slrnhl9qb8....@Katana.d-and-d.com...
[.....]
Sorry Don & all - my apologies, I stuffed up & didn't paste the link:
http://mechanicalphilosopher.blogspot.com/2008/02/making-plastic-front-aperture-sight.html
in particular:
http://3.bp.blogspot.com/_aNjK3CTQ0DE/R8cwKpQP3DI/AAAAAAAAAis/OW-hy0R-x44/s400/02280802.jpg
cheers.
Royston Vasey
"Wes" <clu...@lycos.com> wrote in message
news:D245n.103528$IU1....@en-nntp-04.dc1.easynews.com...
Cheers Wes, I neglected to post the link to the website (my apologies!).
Yeah they look like they might be soft jaws, but ones that provide more
support around the part.
DoN. Nichols
>
> "DoN. Nichols" <dnic...@d-and-d.com> wrote in message
> news:slrnhl9qb8....@Katana.d-and-d.com...
>> On 2010-01-18, Royston Vasey <roy...@vasey.com> wrote:
>>> I stumbled across this website
>>
>> Which website? Did you find a web site which mirrors this
>> usenet newsgroup rec.crafts.metalworking? Normally, there are (and
>> should be) no images here.
[ ... ]
> Sorry Don & all - my apologies, I stuffed up & didn't paste the link:
>
> http://mechanicalphilosopher.blogspot.com/2008/02/making-plastic-front-aperture-sight.html
O.K. I recognize those. They are the alternative soft jaws for
the chuck supplied with the Taig lathe. They are aluminum (as are the
normal jaws) and bolt to the steel master jaws in the body.
I *think* that these are made from a stock which was originally
made as heat sink stock, and which made a good pie jaw stock for the
size of the Taig 3-jaw chuck. (Taig is called "Peatol" in the UK, I
believe.)
Yes -- this style is supplied as blanks and is turned to fit
just like steel or aluminum soft top jaws on larger chucks. It is not
like the steel top jaws for use on 6-jaw chucks and which are turned as
steps hardened and ground in some cases for real precision jaws.
The use of the heat sink stock reduces material costs, and the
fingers grip at enough places (on larger diameters) so they work well
for the purpose.
The earlier photos are of slightly larger 4-jaw chuck on the
same machine. The Taig/Peatol looks like a good match to the task
shown.
Doug White
news:EdKdnTO7TJdEPMjW...@westnet.com.au:
<snip>
> http://mechanicalphilosopher.blogspot.com/2008/02/making-plastic-front-
aperture-sight.html
This reminded me of a project I need to complete before Spring. I have 22
mm RPA front sights (http://www.rpainternational.co.uk/sights.asp) on the
two rifles my wife & I shoot in a league. I like the clear plastic
apertures as described in the link Royston posted. The RPA is an odd
size, and the only commercial apertures that fit are from Anschutz. They
are expensive, and available in a a limited size range. With the
somewhat short sighting length of AR-15 style rifles, the smallest
Anschutz aperture (2.9 mm hole) is just a little too big for me. I'm
used to shooting a 2.8 mm aperture on a longer rifle, so 2.6 mm might be
about right.
There is a guy in Canada that makes them commercially for other sights,
and I spoke with him about making them for the RPA, but the market is too
small. He makes a big deal about his "secret" process for making the
apertures all in one setup, so the hole is guaranteed to be concentric
with the outside diameter.
I figure I can come close enough by cutting a bunch of disks as described
in the first web link, and then cutting a step collet to closely fit the
disks. I can then bore out the holes with pretty good concentricity,
especially if I don't remove the collet until they are all done.
I'm curious about the "secret" process, and was wondering if folks have
any ideas that might be better than the step chuck. I thought about
gluing the disks to something, but even attaching to the paper on acrylic
sheet could allow a little wiggle.
Any ideas or suggestions?
Thanks!
Doug White
Gunner Asch
wrote:
He is probably using a CNC lathe and doing the threading, and aperture
boring in the same setup. Or a good turret lathe. Once you hold the
eypiece by the outside..any drilling and threading is gonna be all in
line. Hold the outside of the rim in a bored 5C collet..and everything
you do to it is gonna be inline.
Good looking sights. Im not familar with the brand. Im still using up
the 20 or so Lymans and Redfields I snagged NOS over the years.
My Anshutz has the factory sights. Cost me $80 for the rifle from a
buddies widow..and when she couldnt find the sights..$150 for new
ones...shrug
Gunner
Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.
Doug White
news:nhoml594r6jtnlrqs...@4ax.com:
The inserts aren't threaded, they get clamped by a threaded ring. They
are basically washers with a conical hole. The clamp ring in this case
is amde by Anshutz, and I may be able to step the aperture to partially
fit inside the clamp ring. That might allow me to cut the outer edge
that registers the aperture in the sight with the same setup that I use
to cut the hole. Unfortunately, I think the taper in the hole faces the
wrong way to do this.
Doug White
sta...@prolynx.com
> "Royston Vasey" <roys...@vasey.com> wrote innews:EdKdnTO7TJdEPMjW...@westnet.com.au:
If they're thin enough, punching could be done in one shot,
concentricity would be as good as the punches and die were. Probably
the way commercial ones are done anyway. Want a tapered hole? Get
out a watchmaker's broach( reamer). That's the way I've made rear
apertures.
Stan
Doug White
news:c289e322-c09a-4641...@e25g2000yqh.googlegroups.com:
> On Jan 23, 8:02�am, Doug White <gwh...@alum.mit.edu> wrote:
>> "Royston Vasey" <roys...@vasey.com> wrote
>> innews:EdKdnTO7TJdEPMjWnZ2dnUVZ
> _o6d...@westnet.com.au:
>>
>> <snip>>http://mechanicalphilosopher.blogspot.com/2008/02/making-plasti
>> c-f
> ront-
>>
>> aperture-sight.html
>>
>> This reminded me of a project I need to complete before Spring. I
>> have 22 mm RPA front sights
>> (http://www.rpainternational.co.uk/sights.asp) on the two rifles my
>> wife & I shoot in a league. �I like the clear plastic apertures as
>> described in the link Royston posted. �The RPA is an odd size, and
>> the only commercial apertures that fit are from Anschutz. �Th
I founds an ad for the commercial ones, and the claim is that they cut
the outside and the hole in one operation, so they are guaranteed
concentric. I suspect they have a trepanning cutter for the OD, and then
an adjustable conical cutter for the hole, all combined into one tool. I
could make such a device, but for the few inserts I need, I don't think
it's worth the bother.
I also found out that they are made from 0.100" thick "aircraft grade"
plastic. From digging around, it's probably Polycast "Poly II". This
seems to be the most popular aircraft grade acrylic that comes in that
thickness.
The trick will be finding high quality cast acrylic in small quantities.
Most stuff is extruded, which doesn't machine as well, and may not have
as good optical quality as the high end cast stuff.
Doug White