Average top spindle speed?

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Batmanacw

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On a 14x40 flat belt driven lathe, running on a jack shaft off a steam engine, what would be a normal top spindle speed?

We are talking 1917, the era of high carbon steel tool bits. Way before high speed steel.
 
HSS starts in the 1880s-1890s and is well established by 1917, Refer to "on the art of cutting Metals" by F.W. Taylor and Maunsel White, C. 1897. As to RPM, I'd guess around 4 - 500 RPM. Figure that the line shaft would have likely run about 250 - 350 rpm, and the countershaft about the sam cone pulley sizes could compute spindle RPM.
 
I would agree with John. I've attached a link to a copy of the 27th edition of the Seneca Falls lathe catalog. It gives the spindle speeds of each of their machines. The speeds for the Star screw cutting engine lathes are on page 27. These machines were originally built as line shaft machines. The text on page 27 shows what is necessary to convert them to an electric motor drive.

Note the 9" machine uses a 1/2 hp motor and has an rpm range from 18 to 366. My 9" machine has been running on a 1 hp motor for over 50 years it has a maximum rpm of about 650. It can run all day at that speed without getting overheated or wearing the out the bearing material.

http://www.vintagemachinery.org/pubs/734/3416.pdf
 
RaisedByWolves said:
Something that should not be overlooked.

These machines were never intended to be used at high spindle speeds and getting fancy repowering them can lead to disaster.

500-600rpm tops is all I would want.
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To me, it would depend on the bearings and how they are oiled. My South Bend is a lot closer in technology to the OP's lathe than to modern lathes, being that it is belt-driven and uses a hardened steel spindle running in solid bronze journal bearings. But those journals are designed to allow adjustment to balance between oil-film space and precision, with a lot of detailed instructions for doing so. Those journals are oiled using a felt wick that draws oil from a reservoir below the bearing, to which the oil drains after doing its job. The fluid pressure of the oil film when the spindle is turning tightens it right up, and the specified 7-12 tenths of end play (using 75 pounds of force at the end of an bar in the spindle bore extending 18") gets a lot closer to zero. The oil is pretty thin stuff, too. That lathe's top speed is a little over 1000 RPM, and it can run at that speed continuously for hours with the journals only becoming slightly warm to the touch.

The bearings on the motor jackshaft matter, too, but those are non-precision roller bearings, not precision journals.

I'm assuming the bearings on the lathe in question are similarly constructed, but may not have the same adjustment capability. The top speed for me would be dictated by the lubrication system more than anything.

Rick "hasn't really needed to turn anything at 1000 RPM in any case" Denney
 
rwdenney said:
To me, it would depend on the bearings and how they are oiled. My South Bend is a lot closer in technology to the OP's lathe than to modern lathes, being that it is belt-driven and uses a hardened steel spindle running in solid bronze journal bearings. But those journals are designed to allow adjustment to balance between oil-film space and precision, with a lot of detailed instructions for doing so. Those journals are oiled using a felt wick that draws oil from a reservoir below the bearing, to which the oil drains after doing its job. The fluid pressure of the oil film when the spindle is turning tightens it right up, and the specified 7-12 tenths of end play (using 75 pounds of force at the end of an bar in the spindle bore extending 18") gets a lot closer to zero. The oil is pretty thin stuff, too. That lathe's top speed is a little over 1000 RPM, and it can run at that speed continuously for hours with the journals only becoming slightly warm to the touch.

The bearings on the motor jackshaft matter, too, but those are non-precision roller bearings, not precision journals.

I'm assuming the bearings on the lathe in question are similarly constructed, but may not have the same adjustment capability. The top speed for me would be dictated by the lubrication system more than anything.

Rick "hasn't really needed to turn anything at 1000 RPM in any case" Denney
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I'm at 417 rpm.and looking at going to 520 rpm.
 
I got the new pulley installed. No matter what, 20 rpm is hilarious. Lol! My new top speed is 509 rpm. I had calculated 521. Pretty close.
 
I can max out my G0602 at over 5K rpm but rarely run over 400 rpm.
 
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