Re: Getting my SB 9C working
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SB´s statement about plain, journal, bearings versus antifriction, rolling, bearings was a justification for its lack of progress and innovation, which finally led to it´s demise. As for chatter marks caused by rolling bearings, that´s total horse shit.
I´ve used cast iron bearings during on-site machining. They run well at low speed with a little grease because cast iron is somewhat self-lubricating.
On the other hand, SB made its cheapest lathes with just reamed headstock bearings to save money.
On Saturday, December 19, 2020, 07:21:31 AM EST, Davis Johnson <davis@...> wrote:
I wish I still had the paper.
The segmented bearing (and the segments are important) is a highly effective bearing design. Something about eddy current circulation in the oil film.
The bottom line is that they work well and last long when when
On 12/19/20 6:50 AM, john kling via groups.io wrote:
Thanks for the discussion of "iron bearings". Although, is have no experience with or ever seen air bearings in a way they seem in some ways an extension of the iron bearings with friction further reduced from the thin spindle oil and drag of babbitt or roller bearings.
On Saturday, December 19, 2020, 4:25:16 AM EST, eddie.draper@... via groups.io <eddie.draper@...> wrote:
I think you'll find that rolling element bearings, shaft loadings & speeds due to superior tool materials, and analytical methods have come on a bit since 1956...
------ Original Message ------ From: "Mark Moulding" <mark@...> To: SouthBendLathe@groups.io Sent: Saturday, 19 Dec, 20 At 09:10 Subject: Re: [SouthBendLathe] Getting my SB 9C workingWas the simple use of headstock iron by South Bend on there entry level lathes such as the workshop lathes simply a cost cutting measure.According to South Bend's own literature, it definitely wasn't a cost-cutting measure: There is prevalent much misunderstanding and misinformation relative to the respective merits of so-called anti-friction bearings. Certainly they are unequalled for certain applications where low cost or low starting torque are of greater importance than precision and durability. However, it has been our experience that for the spindles of precision lathes such as we manufacture, properly designed and fitted plain bearings are superior, and even though more costly than other types of bearings, their performance justifies the added expense. The principle advantages of the plain bearing are that it provides better support for the spindle, permits using a larger spindle diameter, eliminates the possibility of chatter marks in the work due to vibration set up by the balls or rollers, runs more smoothly and quietly, wears longer, and is adjustable. (From the 1956 50th anniversary catalog.) ~~