Re: loose quill

Hi Ballendo,

I am going to measure the gap as accurately as possible then use some
shim stock as the first attempt.

The HF Mini-drill press 1/4 hp motor, 1/2" chuck $39 on sale is
simple. but the QC is very poor.

The bearings on a sister unit slip easily in the quill. not even a
close to press fit. Seems like if I bought 3 units, I could make
one good one.

The bore of the cast on this one is way oversized.

I used a pair of brass screws at an angle to push the quill back on
another unit. Not too happy with the results. The nylon setscrews
offer a good option. Many better quality combine a slit casting with
locking screw for a combination quill lock and variable tightening
for accuracy. This unit does not have enough casting to put in
anything above a 10-32. Then it would only squeeze the lower casting.

Since I am drilling 3/8 holes in aluminum as the largest size, I did
a very quick check to see what else would be available. As I
understand, there are some different heads available. I chose the HF
as the cost of the whole machine is low, but it started out as a
proof of concept.

The mini-mill head, in it's entirety (motor and speed control) goes
for around $250.00 from LittleMachineShop, or just the spindle part
goes for around $60.00 you add the motor.

I tried looking at the Sherline stuff, but the best I could find was
an exploded view and not a full sub-assembly nor a pricing.

I think there is a definite spot where a sub-assembly could make the
whole Z axis an easy CNC candidate. just mount the whole subassembly
on a gantry and you're off to the races.

I haven't gotten to the point of making a higher quality unit myself,
and will probably go with the mill head replacement next year.

Dave









--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo <ballendo@y...>"
<ballendo@y...> wrote:

> Dave,
>
> The moglice people sell a paste wax which they claim will result
> in .0001 clearance per "layer". Putting this on the quill,and then
> injecting should do the trick. BUT...
>
> The idea about the clamp screws seems most "appropriate", given the
> cost and inherent accuracy of the drill press. (can't be that good,
> or it wouldn't have the sloppy fit in the first place!)
>
> Another similar idea is to place a few nylon or brass tipped
> setscrews (two vertical rows, about 90 degrees apart) to bear on

the

> quill, and pre-load it against one side of the bore. this would be
> VERY quick to implement, and if it didn't work, would not mess
> anyhting up permanently... I drill,tap, and put a screw with handle
> (shear-loc knob) on the left side of the HF drill presses to make

up

> for the lack of a quill lock. (the dog-point screw rides in the

slot

> which keeps the quill from rotation. Doing it here means that if

any

> burrs are raised, they will not affect the quill travel.)
>
> Anyway, to keep this on topic; if we think about the problem as how
> to make a sloppy spindle (from a cheap machine) better, so that we
> can use it for CNC...
>
> Then why not use stainless steel or brass shim stock???
>
> It comes in the thickness(es) needed, and the 1/2 width "tape" type
> would seem easy enough to secure with cyanoacrylate or epoxy. Won't
> work if the bore is not truly round tho...
>
> Hope this helps,
>
> Ballendo
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Marv Frankel

<dcdziner@p...>

> wrote:
> > Dave,
> > Don't forget one thing. All of those castable materials
> require a
> > release agent to keep from sticking to one of the surfaces. If

you

> try to
> > pump the material in to fill the gap, without the release agent
> inside the
> > quill, (almost impossible) you're going to eliminate all of the
> play, but
> > your quill will not move. It will almost be welded solid. Have

you

> tried my
> > previous suggestion of contacting an engine rebuilder yet?
> >
> > Marv Frankel
> > Los Angeles
> >
> > ----- Original Message -----
> > From: <davemucha@j...>
> > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > Sent: Monday, January 20, 2003 9:30 AM
> > Subject: [CAD_CAM_EDM_DRO] Re: loose quil
> >
> >
> > > Interesting idea.
> > >
> > > seems the thin gap, less than 2 mil makes it hard to get the
> stuff in
> > > there. With a thin gap, I cannot see how to fill the void
> > >
> > > Also it would seem that any type of epoxy or other plastics

would

> > > provide a slipery surface and fill the gap. Since there is no
> > > pressure on the material and no grit it should have a long

service

> > > life.
> > >
> > > Coating the quill before filling is important too.
> > >
> > > so,it seems like I would wind up with a smooth bore or solid
> part.....
> > >
> > > any ideas on how to inject the stuff evenly ? sounds like a
> grouve
> > > would allow for the material to be carried around the quill,

and

> then
> > > just pressurize until it comes out along the circumference.
> > >
> > > Dave
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "vrsculptor
> > > <vrsculptor@h...>" <vrsculptor@h...> wrote:
> > > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:
> > > > > In a message dated 1/19/2003 6:19:23 PM Central Standard

Time,

> > > > > david_mucha@y... writes:
> > > > >
> > > > >
> > > > > > I thouhgt about chrome/nickle plating or some sort of
> > > > > > electroplating. I am also considdering just using some

shim

> > > > stock.
> > > > > >
> > > > > > The frame is cast iron and the quill is steel.
> > > > > >
> > > > > > any ideas ?
> > > > >
> > > > Dave,
> > > > How about one of the castable (is that a word?) plastic

bearing

> > > > materials like turcite?
> > > >
> > > > Roger S
> > >
> > >
> > > Addresses:
> > > FAQ: http://www.ktmarketing.com/faq.html
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