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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Posted to alt.machines.cnc,rec.crafts.metalworking
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The spring loaded live center is a great idea.
Why not put a spring behind the shank, in a holder, and leave the set screw loose? Most of the shank/holder combo's I encounter have a good fit, and a stiff spring in the holder would likely give you the tension you desire. This should work in cnc/pneumatic tailstocks as well. Here's a little trick I use to get the benefits of spring loading without the $$, in manual machines, which may give you some ideas. Lathe tailstock: The hand wheel is usually pretty free-wheeling, so what I do is bump the work w/ the tailstock/center, turn the handle to the 2 o'clock position (facing the chuck from the bed end), lock the tailstock down, and load the handle w/ cored brass/bronze weights. This puts a constant tension on the live center, and the weights usually stay in the 2 to 4-o'clock positions, for good torque. You could also rig a spring from the handle, hooked under the bed someplace. Works really, really nice. Milling/table tailstocik: These have tougher, smaller wheels, not ideally suited for what I just described. But, by clamping a suff'ly long lever arm to said wheel, you might be able to achieve the same effect. Altho I think here, a simple stiff spring in the holder behind the shank would be more convenient. I haven't used the spring-behind-shank method, cuz I don't currently have a straight-shank live center. But this sounds like a good reason to get one! -- Mr. P.V.'d formerly Droll Troll "Protagonist" wrote in message . .. Any one can point me to, where can I buy economical straight shank (1/2") live centers, if it's spring loaded even better. The one I found in the MSC or Shoptools catalog are expensive $250-$300. Julius |
#2
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On Mon, 13 Feb 2006 20:39:36 -0500, "Proctologically Violated©®"
wrote: smaller wheels Is this about jb again? Or was that "joysticks"? -- Cliff |
#3
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Posted to alt.machines.cnc,rec.crafts.metalworking
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"Proctologically Violated©®" wrote:
The spring loaded live center is a great idea. PV: Here are some examples: ================================================== ================== http://www.cartertools.com/catalog.html #1151 $15.20 ================================================== ================== The one above looks like it could be a 1/2" straight shank like what "Protagonist" was looking for. Economical too. ================================================== ================== http://www.ferret.com.au/articles/53/0c00b353.asp The new live centre allows long jobs held between centres, or a chuck and centre, to expand during turning operations without damage. ================================================== ================== ================================================== ================== http://www.practicalmachinist.com/ub...;f=10;t=000039 Spring loaded design compensates for center variations, without damage to work piece or center tip. This assures operator of uniform constant tension. ================================================== ================== Why not put a spring behind the shank, in a holder, and leave the set screw loose? Lathe tailstock: The hand wheel is usually pretty free-wheeling, so what I do is bump the work w/ the tailstock/center, turn the handle to the 2 o'clock position (facing the chuck from the bed end), lock the tailstock down, and load the handle w/ cored brass/bronze weights. You could also rig a spring from the handle, hooked under the bed someplace. Works really, really nice. Creativity when the needed tooling is not available, or too expensive, is IMO an excellent trait for a machinist to have. -- BottleBob http://home.earthlink.net/~bottlbob |
#4
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Posted to alt.machines.cnc,rec.crafts.metalworking
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I bought a couple of special from these guys, excellent product and had
my specials done in less than a month from the time they got my drawing. http://www.motortoolmanufacturing.co...dcenters.shtml Proctologically Violated©® wrote: The spring loaded live center is a great idea. Why not put a spring behind the shank, in a holder, and leave the set screw loose? Most of the shank/holder combo's I encounter have a good fit, and a stiff spring in the holder would likely give you the tension you desire. This should work in cnc/pneumatic tailstocks as well. Here's a little trick I use to get the benefits of spring loading without the $$, in manual machines, which may give you some ideas. Lathe tailstock: The hand wheel is usually pretty free-wheeling, so what I do is bump the work w/ the tailstock/center, turn the handle to the 2 o'clock position (facing the chuck from the bed end), lock the tailstock down, and load the handle w/ cored brass/bronze weights. This puts a constant tension on the live center, and the weights usually stay in the 2 to 4-o'clock positions, for good torque. You could also rig a spring from the handle, hooked under the bed someplace. Works really, really nice. Milling/table tailstocik: These have tougher, smaller wheels, not ideally suited for what I just described. But, by clamping a suff'ly long lever arm to said wheel, you might be able to achieve the same effect. Altho I think here, a simple stiff spring in the holder behind the shank would be more convenient. I haven't used the spring-behind-shank method, cuz I don't currently have a straight-shank live center. But this sounds like a good reason to get one! -- Mr. P.V.'d formerly Droll Troll "Protagonist" wrote in message . .. Any one can point me to, where can I buy economical straight shank (1/2") live centers, if it's spring loaded even better. The one I found in the MSC or Shoptools catalog are expensive $250-$300. Julius |
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