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 bastard.... 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.
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 It bird cages in the feeder tube. Like pushing string ...chuckle
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.
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
These links all show bar pullers mounted on the end of a cutoff tool. One hell of a good idea cause its right there when you need it. Would really cut cycle time. I think I'll look at building my own as they all cost more than