tinkerfive Posted June 10, 2009 Report Share Posted June 10, 2009 Thanks all for your earlier replies. Well I happened to step back and look at the spindle assy. then I measured. It's 24" from the face of the chuck to the Left spindle opening. Add about 3" to clear the chuck jaws to thread. Add another 2" at least for the spider and you are at a 29" barrel. I don't think that the occasion will arise too often that I'll be threading 29" barrels. Tanglewood had an interesting idea for a self centering cone insert to the spindle. Tinker Link to comment Share on other sites More sharing options...
z1r Posted June 10, 2009 Report Share Posted June 10, 2009 The two most frequent complaints about old southbends is the spindle bore is too small and the length too long. Still, you can get a smaller chuck the will not be as deep. Three inches hanging out of the chuck to thread is a bit much, and the screws for the spider can be darn near at the edge of the spindle. All that will gain you a few extra inches. Now you know why so many preferred to thread between centers and chamber in a steady. I lived many years with my SB. I used to subscribe to the spider notion but nowdays, I primarily use it for crowning to keep the barrel from slipping back in the chuck. For threading and chambering I first make sure the barrel is straight by truing the area I will grip in the chuck between centers first. As long as the sides are parallel once chucked in the lathe I don't care where the muzzle is pointed. One day, I'll upgrade the chinese lathe I have for a newer one with an even larger spindle bore. I use it for metric threads and BIG barrels or barrels with integral or soldered on sights. Link to comment Share on other sites More sharing options...
Limpid Lizard Posted June 10, 2009 Report Share Posted June 10, 2009 T5, I chamber through the headstock in a Takasawa 800 series lathe. It too has a long spindle. There are several things you can do. Which you will pursue depends on you and the type of rifles you intend to build. A few of the benchrest crowd gets rid of the chuck altogether and runs a spider on both ends. This reduces the length of the headstock considerably. Look over on benchrest.com for the idea. This will be my next project. My spindle is ground on the inside. It runs quite true at the offside. I make bushings out of delrin that are a tight fit both in the offside bore and on the barrel. I taper the inside hole so that the barrel is only resting on a small area. That way it can pivot slightly as I adjust the chuck end. If you do the math, you will find that a thou runout at the muzzle end turns into a neglible amount at the chamber end. It is certainly not enough runout to matter until you are way, way beyond your current skill level. I say this about your skill level only because the answers are obvious to one who has run a lathe much. With practice, you only need about a quarter inch extra beyond the chuck to thread to a shoulder. If your spindle does not run true at the offside, consider making a spider to replace the chuck a first project. That will be the easiest way for you to get around the long headstock. There are other ideas, and solutions, on benchrest.com. I'd almost bet one of those folks has the same lathe you do and a solution. I crown and cut off in the steady. LL Link to comment Share on other sites More sharing options...
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