Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Largest Manufacturing Technology Community on the Web
Stay Connected:
SB16 spindle speeds
- Thread starter tar356
- Start date
- Replies 5
- Views 1,417
johnoder
Diamond
- Joined
- Jul 16, 2004
- Location
- Houston, TX USA
Page 64 in Catalog 100-F says the two-speed motor jobs went to 880. Don't know if the bearings were still cast iron as of August 1946 when this was printed
comstockfriend
Hot Rolled
- Joined
- Aug 11, 2013
- Location
- Sun Valley, California, USA
Here's how the college my SB 13" lathe came from handled the speed chart (mounted right above the thread/feed chart on the gear box).
John
John
thomasutley
Hot Rolled
- Joined
- Sep 10, 2014
- Location
- Oro Valley
I once swapped emails with Ted about the max spindle speed for my 16" machine. While we didn't come to a conclusion about what it really ought to be, he did send me the attached clip from old SBL literature showing an external drive option for 10" lathes to accommodate powered feed at spindle speeds from 55-2400RPM. Ted commented that it was needed because the end gears couldn't handle the high end speeds. I'd love to have more detail on this option and to hear if anyone has ever seen this option on a lathe today.
I'd also be interested in a physics-based discussion on what the real top speed of a 16" machine is with both segmented cast iron bearings and bronze sleeve bearings using the recommended lubricants. My mechanical engineer's hunch is that it will be limited by cavitation in the lubricant as the spindle OD surface speed approaches some physical limit within the lubricant, but that's just an educated guess and I can't back it up with anything factual yet.
I'd also be interested in a physics-based discussion on what the real top speed of a 16" machine is with both segmented cast iron bearings and bronze sleeve bearings using the recommended lubricants. My mechanical engineer's hunch is that it will be limited by cavitation in the lubricant as the spindle OD surface speed approaches some physical limit within the lubricant, but that's just an educated guess and I can't back it up with anything factual yet.
johnoder
Diamond
- Joined
- Jul 16, 2004
- Location
- Houston, TX USA
Its a toss up - you want capability or just speed?
Spend some time here - you can see at 750 SFM journal speed (Maybe 1200 rpm on the 16" front journal) you would be limited to 100 psi on the bronze bearing - because PV maxes at 75,000. That is practically nothing for a lathe to be able to do any work - since the bearing material has a limit of 4000 psi
Cast Bronze Bearings, Continuous Cast Solid, Cored, Wearplate & Centrifugal Cast Bronze Bar: Bunting Bearings: Holland, OH
Spend some time here - you can see at 750 SFM journal speed (Maybe 1200 rpm on the 16" front journal) you would be limited to 100 psi on the bronze bearing - because PV maxes at 75,000. That is practically nothing for a lathe to be able to do any work - since the bearing material has a limit of 4000 psi
Cast Bronze Bearings, Continuous Cast Solid, Cored, Wearplate & Centrifugal Cast Bronze Bar: Bunting Bearings: Holland, OH
Thanks for the link John...I usually think of pure spindle speed being determined by bearing running clearance, balance, and the capability of the lubrication "system".
I agree with Ted's statement that an SB16's spindle speed is probably more limited by the gear train than anything else.
Although I like where this discussion is going, I'm more curious about what SB offered as "higher speeds".
Todd
Orange, CA
I agree with Ted's statement that an SB16's spindle speed is probably more limited by the gear train than anything else.
Although I like where this discussion is going, I'm more curious about what SB offered as "higher speeds".
Todd
Orange, CA
Similar threads
