I need to come up with a way to feed bar stock on my Hardinge CHNC. As I
don't have room for a real bar feeder, I'm looking for a way to feed short
bar stock, maybe 4' or 6'.

I seen this on eBay http://tinyurl.com/2sp8qz I'm sure it won't fit my
machine but it looks easy to build. Then I could just have a support tube
behind the spindle.

Anybody used one? Do they work well? I'm assuming you just use spring
tension/ deflection to hold and pull the bar stock as I see no air cylinder.
Correct?

Other good ideas to feed bar stock for an HSM type?

Karl

Karl Townsend wrote:

Other good ideas to feed bar stock for an HSM type?


I bought a Dunham bar puller setup. Page 1675 in the current
MSC catalog. These certainly work well. I have an Omniturn,
but no control over spindle or collet closer yet. Looking to
shave some time and save wear and tear on the brake, I made
up a bearing adapter for the Dunham setup. It pulls stock
through an open rotating collet just fine, but it's too long
for most of the work I do. I've been thinking about a
redesign to shorten it but haven't gotten a roundtuit.

I also wonder a bit about collet/spindle taper wear if the
bar stock is not running nice and true on the spindle
centerline....

I made a dedicated puller based loosely on the Dunham, but
milled the sides off. I have a part I'm running where I have
no room for the full width of the Dunham style. Whole
toolbar is custom and laid out in CAD. With anticipated use
of up to 1" stock, there is a scant .100 clearance between
tools and material, shaving the sides off allowed me to
squeeze the custom puller in place.

Something I'm looking for is an inexpensive spindle liner
setup. Something more in the HSM cost range. Yeah, I'm just
a cheap *******.... lol.

If you're interested in seeing my dedicated puller and the
rotating one, I'll see about taking a couple pics and
posting to the dropbox.


Jon

On Fri, 1 Feb 2008 10:51:01 -0500, "Karl Townsend"
wrote:

I need to come up with a way to feed bar stock on my Hardinge CHNC. As I
don't have room for a real bar feeder, I'm looking for a way to feed short
bar stock, maybe 4' or 6'.

I seen this on eBay http://tinyurl.com/2sp8qz I'm sure it won't fit my
machine but it looks easy to build. Then I could just have a support tube
behind the spindle.

Anybody used one? Do they work well? I'm assuming you just use spring
tension/ deflection to hold and pull the bar stock as I see no air cylinder.
Correct?

Other good ideas to feed bar stock for an HSM type?

Karl


A simple bar puller may be made on the lathe.

Take a piece of bar stock at least .25 larger than the bar you are
trying to pull.

turn one one to fit your tool holder, typically 5/8"

Drill/bore the other end at least .010 smaller than the bar you want
to pull. Champher the end well.

Slit it all the way across with a hacksaw. Small stuff works ok with
a single slit, you may have to slit in a cross pattern for larger
stuff. If you are feeling yancy..consider heat treating it with a
torch if the puller material will heat treat to spring like
properties.

Bar is held in collet. Program slide move, so the new bar pullet
slides over the end of the bar. Friction grabs the bar.

Open collet closer. Retract bar to proper length, close collet, then
retract turret away from bar, bar slips out of puller, and index
turret to first work position. OR, use side of cutoff tool holder as
positioning device, open collet, move side of cutoff tool (or anything
you want to use for a stop), and push bar to proper length. Close
collet and make chips.

You can use pipe, conduit etc etc as a bar holder outside the machine.
All it needs to do is keep it centered and keep it from whipping.

Ive made literally hundreds of these bar pullers for clients

They work, are cheap and easy. You do need one for each different
diameter material you are working on, but simply write a program to
turn you out a couple dozen blanks, then as needed bore and slit.
If the bar puller wears, simply squeeze it down a smidge with a basic
regular old hose clamp.

These are also regularly used as a matter of course, in very small
stock diameters that preclude a pusher type bar feeder. Try using a
pneumatic bar feeder on a 1o' length of .020 wire G It bird cages in
the feeder tube. Like pushing string ...chuckle

Gunner

On Fri, 01 Feb 2008 09:53:57 -0800, Jon Anderson
wrote:

Something I'm looking for is an inexpensive spindle liner
setup. Something more in the HSM cost range. Yeah, I'm just
a cheap *******.... lol.

PVC pipe from Home Depot

Gunner

Gunner, Thanks for the ideas. Looks simple cheap and effective.

One question. The back support tube for the bar does not rotate. Correct?
We'll be running at 4000 RPM for many hours at a time. Do we have to worry
about banging up the stock and tube? Looks like a lot of friction here.

Karl

"Karl Townsend" wrote:

I need to come up with a way to feed bar stock on my Hardinge CHNC. As I
don't have room for a real bar feeder, I'm looking for a way to feed short
bar stock, maybe 4' or 6'.

I seen this on eBay http://tinyurl.com/2sp8qz I'm sure it won't fit my
machine but it looks easy to build. Then I could just have a support tube
behind the spindle.

Anybody used one? Do they work well? I'm assuming you just use spring
tension/ deflection to hold and pull the bar stock as I see no air cylinder.
Correct?

Other good ideas to feed bar stock for an HSM type?

Karl


Some use coolant pressure to actuate.

Check mscdirect use 'bar puller'

Wes

On Fri, 1 Feb 2008 16:33:52 -0500, "Karl Townsend"
wrote:

Gunner, Thanks for the ideas. Looks simple cheap and effective.

One question. The back support tube for the bar does not rotate. Correct?
We'll be running at 4000 RPM for many hours at a time. Do we have to worry
about banging up the stock and tube? Looks like a lot of friction here.

Karl


Could always take Gunners design and mount it in a couple of ball bearings.
Should still work.


Mark Rand
RTFM

On Fri, 1 Feb 2008 16:33:52 -0500, "Karl Townsend"
wrote:

Gunner, Thanks for the ideas. Looks simple cheap and effective.

One question. The back support tube for the bar does not rotate. Correct?
We'll be running at 4000 RPM for many hours at a time. Do we have to worry
about banging up the stock and tube? Looks like a lot of friction here.

Karl


Nah...it will likely make some noise. Use as small a tube as you can
get away with, perhaps stick some Sched 80 PVC inside. The tube is
just to keep if from whipping. If the noise is loud, simply get some
of that split foam insulation from HD, used to insulate water pipes,
and put it on the tube. Helps bunches

Gunner

On Sat, 02 Feb 2008 00:46:27 +0000, Mark Rand
wrote:

On Fri, 1 Feb 2008 16:33:52 -0500, "Karl Townsend"
wrote:

Gunner, Thanks for the ideas. Looks simple cheap and effective.

One question. The back support tube for the bar does not rotate. Correct?
We'll be running at 4000 RPM for many hours at a time. Do we have to worry
about banging up the stock and tube? Looks like a lot of friction here.

Karl


Could always take Gunners design and mount it in a couple of ball bearings.
Should still work.

??? Mount WHAT in ball bearings?


Mark Rand
RTFM

On Fri, 01 Feb 2008 18:36:22 -0800, Gunner
wrote:

On Sat, 02 Feb 2008 00:46:27 +0000, Mark Rand
wrote:

On Fri, 1 Feb 2008 16:33:52 -0500, "Karl Townsend"
wrote:

Gunner, Thanks for the ideas. Looks simple cheap and effective.

One question. The back support tube for the bar does not rotate. Correct?
We'll be running at 4000 RPM for many hours at a time. Do we have to worry
about banging up the stock and tube? Looks like a lot of friction here.

Karl


Could always take Gunners design and mount it in a couple of ball bearings.
Should still work.

??? Mount WHAT in ball bearings?




Oops... I was thinking about friction in the puller, not the support tube.
I'll crawl back under my rock, out of the nasty bright light now.


Mark Rand
RTFM

In article s.com, "Karl
Townsend" wrote:

I need to come up with a way to feed bar stock on my Hardinge CHNC. As I
don't have room for a real bar feeder, I'm looking for a way to feed short
bar stock, maybe 4' or 6'.

I seen this on eBay http://tinyurl.com/2sp8qz I'm sure it won't fit my
machine but it looks easy to build. Then I could just have a support tube
behind the spindle.

Anybody used one? Do they work well? I'm assuming you just use spring
tension/ deflection to hold and pull the bar stock as I see no air cylinder.
Correct?

Other good ideas to feed bar stock for an HSM type?

Karl

Karl,

You did not say what msize bar you want to pull.
I pull up to 7/8 inch on my cnc with the Dunham pullers.
They are just like what Gunner said, but you don't have to make them:

http://www.dunhamtool.com/cnc_lathe_bar_puller.html

A rattle-tube out the back end to keep stock from whipping works just fine.
Do find some plastic tube to line with that is just a bit bigger than your
stock.

G'luck

--
Paul S.
Remove Before Flight