# SB Hvy 10 threading issue



## rvsls (Nov 19, 2011)

I purchased a Southbend Heavy 10 last spring and completely took it apart and refurbished it.  The machine was originally purchased by the Navy in 1941 and has a single lever gear box.  I am currently playing with it to get a feel for it as I am a novice.  So, yesterday I decided to try to cut some threads in aluminum.  I set the gear box to 4 tpi which is side gear in, top lever left, and the front lever in the first position on the left.  I was using the back gears for slow speed.  Well, I ended up making 12 tpi.  The threads came out great using the thread dial but obviously not 4tpi as I had planned.  Today, I tried different set up combinations and in every case I got three times as many threads per inch then what was advertised on the gear box.

What might I have done wrong with the rebuild?  Or what am I missing in the set up?

Thanks for your help,

Rod


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## joesmith (Nov 19, 2011)

Rod,  I would suspect the gears on the left of he headstock.  Has the previous owner substituted a larger gear in the geartrain?  I have 2 heavy 10's but they both have the double lever gearbox.

Joe


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## rvsls (Nov 20, 2011)

I knew you guys could figure this out and do I feel like a dummy!  The answer is the half nuts.  I am just starting to fool around with this lathe after rebuilding it and taking a machining class at the local junior college.  I was having a great time with the clutch feed and forgot all about the half nuts.  Tried out the half nuts this morning and all is well.

Thanks for the help,

Rod


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