Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.
I don't doubt the validity of the concerns expressed regarding
the potential for damage to bearings and I appreciate being made
aware. However, I was regularly running my OEM 1931 3/4hp GE 3
phase original motor on my 1931 13" SB lathe with a TECO VFD for 5
years without any known problems at all. Recently, I decided to
switch to a 1.5hp modern 3 phase Baldor motor for more horse
power, and the added advantage of lifetime lubricated bearings,
and now that upgrade is running really nicely too. So, I suspect
the bearing damage concerns may be more likely to show up in
commercial type heavy use than the type of use we might see in
hobby machining (about 15-20 hrs per week use in my case). I'm
personally really happy with the flexibility that my VFD provides.
I also added a rubber belt drive with the new motor upgrade
because the leather belt couldn't transmit the upgraded power
without slippage. Now, the lathe motor runs so quietly that I
cannot even tell if the motor is on without looking at the switch
position. And, I can take heavier cuts, even on larger work
pieces. I had to machine out a new 2 groove pulley for the larger
motor shaft diameter. Fortunately, my 9x20 handled that machining
quite well while the SB was apart. In all, I ended up replicating
the OEM rpm specs very closely - just more torque and hp.
On 7/10/2020 4:06 PM, glenn brooks wrote: