Hello all. First post. I've lurked here awhile and decided to join today having learned so much on this forum. I have a Southbend 10K light 10" lathe that has a 42" bed. Restoring antique firearms as a hobby, and also building large telescopes to help with my astronomy hobby, I find my lathe bed is often a bit short. The 48" bed would do wonders for me. Since I really like my lathe otherwise decided to simply get the longer bed and rebuild the lathe. Wound up with a nice 48" bed and a nice leadscrew for the gear box. Both the screw and the bed are actually nicer than the 42" ones I had been using. Great. Here we go. Switched out the bed, leveled it, rebuilt the lathe, switched out the leadscrew and tried her out.
Problem #1. On the 42" bed, when I tighten the two bolts in the back of the saddle that hold the saddle retaining plate on, the saddle is a nice slide fit on the bed. With the 48" bed, I need to leave the bolts loose about an 1/8" or the saddle is firmly locked onto the bed! Kind of odd. Comments? Should I machine a spacer the exact thickness I need so I can tighten these bolts?
Problem #2. Severe accuracy issues. Turning an aluminum or brass rod I find the diameters are out about 0.0015"/inch. I tested a 6" run at the headstock and also near the middle of the bed. In both cases the diameter was 0.009" to 0.010" out! I then tried it next to the headstock unsupported by the tailstock. Same issue. The 42" bed certainly didnt do that. Thinking maybe some chips got under the headstock I took the headstock back off and cleaned it again, looking for any burrs etc. Put it back together and still had the same issue. The large diameter is the cut away from the headstock, so its almost as if the headstock is aligned at an angle away from the front of the bed. Left it alone awhile as my mothers health issues (she is 92) took me away from my lathe, and then getting back home I had an urgent job on it, so I rebuilt it with the 42" bed again. That's where it stands now but I may have some spare time soon and want to get the 48" bed going. Any ideas? Thanks to all.
Problem #1. On the 42" bed, when I tighten the two bolts in the back of the saddle that hold the saddle retaining plate on, the saddle is a nice slide fit on the bed. With the 48" bed, I need to leave the bolts loose about an 1/8" or the saddle is firmly locked onto the bed! Kind of odd. Comments? Should I machine a spacer the exact thickness I need so I can tighten these bolts?
Problem #2. Severe accuracy issues. Turning an aluminum or brass rod I find the diameters are out about 0.0015"/inch. I tested a 6" run at the headstock and also near the middle of the bed. In both cases the diameter was 0.009" to 0.010" out! I then tried it next to the headstock unsupported by the tailstock. Same issue. The 42" bed certainly didnt do that. Thinking maybe some chips got under the headstock I took the headstock back off and cleaned it again, looking for any burrs etc. Put it back together and still had the same issue. The large diameter is the cut away from the headstock, so its almost as if the headstock is aligned at an angle away from the front of the bed. Left it alone awhile as my mothers health issues (she is 92) took me away from my lathe, and then getting back home I had an urgent job on it, so I rebuilt it with the 42" bed again. That's where it stands now but I may have some spare time soon and want to get the 48" bed going. Any ideas? Thanks to all.