On 2010-06-25, Searcher7 wrote:
On Jun 24, 1:12 am, "DoN. Nichols" wrote:
On 2010-06-24, Searcher7 wrote:
[ ... ]
It looks like this whole thing must be re-thought. I had been thinking
of the black part as the base and can believe I didn't think of
something before. IT is actually the fron when screwed intot he silver
body. And the collet fits in it nicely.
http://s290.photobucket.com/albums/l.../Tools/?action...
O.K. That is *good*. you only need access to the back to
change collets. The large black ring is used to close the collets onto
the workpiece, and it is in front so you don't have to work between
jaws.
I can then screw the ring on at the rear.
http://s290.photobucket.com/albums/l.../Tools/?action...
So obviously this was not made for a normal lathe set-up, and the
black front is obviously how it is supposed to be secured in whatever
machine it is supposed to be used.
Absolutely not! The black front is what is adjusted to close or
open the collets. It is *not* for mounting the thing to something else.
And -- it has an advantage over normal collet chucks. Normally
the collet is drawn back in the process of closing the collet, and
slightly different diameters are drawn back differing amounts. With
*this* one, the collet is held at a constant depth and the closing taper
moves towards the tailstock to close the collet.
Ok. Understood. But that brings up a possible issue I'll mention
below.
O.K.
[ ... ]
I can see it being held in a large collet in a really large
lathe.
I assume that such a lathe would have the option of using a variety of
these collets with different standards along with 5C.
Such a lathe would have (if any) a very large collet -- useful
for large diameter workpieces at slow spindle speeds. they typically
don't have very fast maximum spindle speeds, as those can cause a big
chuck to "grenade". Each chuck should have a maximum speed rating,
though small ones are likely to not have it marked.
I can also see it being used in a fixture to hold workpieces in
a mill.
I'd like to see a picture/video of such a fixture. :-)
Well ... there are dozens of possibilities depending on what is
being held and machined.
There, one of the threaded holes would get a short bar screwed
into it with a large ball handle on the end for tightening and
loosening. (Not when using it in a rotating chuck of course, because
the handle would unbalance things -- unless you had three identical
handles screwed in at 120 degree intervals.
Actually, that would be four at 90 degrees.
Oh -- eight holes total, not the six I thought there were? I
never had a view which made it truly clear.
[ ... ]
The small bar I still think might be used to turn the small ring
onto the end of the collet and back off.
There is no place for the small bar. The ring that threads onto the
rear of the collet is solid, and actually threads about halfway on
before it bottoms out.(But I assume that is enough).
The small ring has a series of depressions around the OD. If
the spacing between that and the wall surrounding it is just right, the
pin on one end could be slid into a depression and used to chase it
around with the outer wall keeping it engaged.
So I'd have to create an adapter that secures this chuck *at the
front*, while also creating a seat for it at the rear.
No! You would create an adaptor which mounts on the spindle
nose which has a cylindrical bore which is a slip fit for the OD of the
device, is deep enough to hold the body, but to leave the large black
ring accessible, and with a thin slot along the length of the bore and
some means of compressing it to hold the body.
Like a large collet or split bushing I assume. (Since the body of the
collet chuck is 2.75" long that would be a deep seat).
Yes -- except that the bushing would mount directly on the
spindle nose instead of through an adaptor.
[ ... ]
Toss those ideas. The threaded holes are *not* for mounting it,
they are for rods to turn the large black ring to tighten the collet and
loosen it. The smooth holes used when in a lathe chuck type setup with
the large bar slid in to turn it and removed before spinning the
spindle. The threaded holes for a ball-ended bar for opening and
closing it when it is mounted in a mill.
Ok, the small ring is to secure the collet, and the large front part
of the collet chuck is to secure the work in the collet.
Yes.
So here is the problem. What is to keep the front of the collet chuck
from rotating clockwise relative to the body under cutting forces,
which would result in opening the collet.(And making things really
exciting). :-)
Well ... normally the anti-rotation pin is not expected to
handle much torque -- but here it might have to.
Can you verify which direction of rotation closes the collet
(moves the large black ring away from the body)? Is it left-hand thread
or right-hand thread? If it is a left-hand thread, the cutting forces
would *tighten* it, thus preventing your problem.
If not -- then it is likely intended to hold a workpiece on a
surface grinder or other low force operation.
[ ... ]
Again -- forget it. You're thinking of the large black ring the
wrong way. It *has* to be free to turn so you can loosen and tighten
the collets.
But how does one keep it from turning under cutting forces?
Pray that the anti-rotation pin works? Look for a place where
the small pin slides into to prevent it from turning? Add provisions
for clamping the ring to the sleeve which holds the body? Run your
lathe spindle in reverse? (I think that is not an option on your lathe
anyway.)
And instead of using the ring at the rear of the chuck, I'd use a
drawtube, if I can modify the machine to use a modified 5C spindle.
(Just throwing out ideas). :-)
You can't make your current machine have a large enough through
diameter to work that way. For a 5C collet closer, you need at least a
1-3/8" through bore, not your near 3/4".
Yes. That is why I am investigating installing a 5C spindle. I just
may have to shorten a drawtube shortening one. And the worse case
scenario would be a need for a different set of gears, if I can't
enlarge the center hole of the existing ones that directly drive the
spindle the spindle.
Of course I'll have to open up the headstock so I can see and measure
what is possible.
I expect that you will find that the entire OD of the spindle is
smaller than the needed bore through the spindle for a 5C collet closer.
Without actually going down and measuring, I think that the OD of the
bearings on my Clausing 12x24" with a 1-3/8" spindle bore is on the
order of 5" -- which I think is larger than the dimensions of your
headstock in the area where the bearings live.
[ ... ]
One possibility is that you could file or sand off some of the
mating surface where the wedge slides against the dovetail. Or if there
is a chip or a burr in there, that could explain the fit problem -- it
would force the dovetail to be too wide.
I assume you mean the filing/sanding the wedge itself, correct? And
wouldn't that put more play into the assembly.
Yes -- but it does not matter -- the wedge is trapped between
the angled surface on the post body's dovetail and the inside of the
holder's dovetail. A little play there won't hurt when you have holders
which will not fit onto the post. And it will not be as critical a
surface as the dovetail itself.
And the wedges are more replaceable than the toolpost body. :-)
They would cost less -- if you could find a place to buy them
separate from the toolpost.
But I think that they would be easier to file or sand down in the
critical area.
[ ... ]
How are you going to maintain the *angle* of the dovetail? That
is important to the proper gripping.
I guess I could think up a jig or some sort.
Perhaps -- but I would go for the side of the wedge myself.
I'm assuming that a jig wouldn't be needed to accurately remove
material equally along the length of the wedges.
If you have a flat surface on the wedge which meets the
dovetail's angles surface, you can probably simply slide that face flat
on some fine emery paper on a hard flat surface.
[ ... ]
In the place which makes it most difficult to *legally* own a
gun. :-)
OT: I've worked with guys who became police officers and some may be
retired by now. I had scored in the 90s on the test but was denied
after the physical.(Possibly because of the four pins in my knee,
which kept me out of the Navy).
When the guns laws were made more stringent the number of security
officers in New York State dropped.
When was that? I thought that the NYC laws have been very tight
since at least about when Kennedy was assassinated.
Washington DC has been forced to relax their firearms laws
recently.
Businesses preferred off duty and
retired police officers because they were cheaper and legally safer.
Cheaper because there are no "middle men"(security company) involved.
And legally safer because off duty and retired cops can do a lot more
legally, and get away with a lot more legally than security guards.
So the ironic thing is that the police officers who make much more,
have more benefits, a competent union, and a pension (that is more
than I make working) are also taking away security guard positions
from armed guards when they are not on the clock.
Until something happens which needs the force working overtime,
leaving a lot of places without guards. :-)
[ ... ]
[ ... Blake Coax indicator ... ]
And they want $90 for a used one: 110548805095 :-(
Depends on your luck. And there are import versions which might
show up on eBay for a lot less than a genuine Blake.
I assume like this: 400127581321
Yes -- that shows you a top price for a new one (I think).
So I'll have to be patient.(Beside equipment for tramming is a bigger
priority at the moment).
Actually -- it is also useful for tramming the mill column, and
for adjusting the lathe tailstock offset back to zero -- or checking if
it is still at zero. :-)
Then I guess that is all I'd need for those purposes.
Yes -- as long as there is room between the spindle and the
workpiece. Sometimes things are just too crowded for a Blake.
Thanks. Tramming is the priority. I can use other ways to measure the
workpiece on the table.
O.K. One thing to keep your eyes open for is a fairly large
diameter outer race for a tapered roller bearing -- one about as large
in diameter as the width of the table. You roughly center that under
the spindle, and run the feeler of the Blake around on that. That way,
you don't have the problem of the feeler dropping into the T-slots every
so many degrees.
Oh yes -- a Blake can be turned under power -- but only up to a
certainly rather slow limit. My lathe, with a 55 RPM minimum speed is
well within that. No bets on yours, so you would have to turn the
spindle by hand. Same is likely for the mill.
[ ... ]
These are all of the *largest* eBay vises I could use:
380087874872
300373085985
280518320722
230486712282
O.K. Nominally 3" chucks. I kind of like the first two more,
for various reasons. But is the second one a shars? And they are the
makers/importers of the troublesome toolpost?
Actually I found the invoice. The tool post I have was gotten from
800watt.(And they are notorious for having bad customer service).
O.K.
Just as a point of information, MSC's price for the AXA
(Series-100) size toolpost alone is $211.02 when not on sale.
[ ... ]
And from what I know pick-up is allowed.(Unless what youorder is
coming from another location).
There is no storefront which I can walk up to here, but I
believe that you can phone in an order to be picked up at the storefront.
That would eliminate problems with delivery times being while you were
at work.
Eliminating shipping costs on the heavier orders would be the real
advantage.
Yes.
Good luck,
DoN.
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