Date   

Re: Videos

v.gearheardt@...
 

mrpete222 on youtube. he also sells a Southbend Lathe course for about $140 on a USB drive.
Well worth ot if you are a newbee. He is an ex-shop teacher and explains well.


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

v.gearheardt@...
 

These effects are for VERY high hp motors, over 20HP. When a motor is listed as Inverter ready, mostly after 1992, it means they have higher voltage insulation, usually 2-3KV
I have no knowledge experience with >2HP motors. The article was interesting in an academic way.
Thanks for posting it.


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

david_g4000
 

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.

Dave B.

On 7/10/2020 4:06 PM, glenn brooks wrote:
Thanks Milan,

Most of my motors are older builds. I�ve thought many times about adding VFD�s. After reading your comments, glad I stayed with my RPC.

Glenn


On Jul 10, 2020, at 12:49 PM, Milan Trcka <milan.v.trcka@...> wrote:

Glenn,
My understanding of the problem lies in the damage to the motor bearings. The high frequency components of the drive currents in the stator generate currents in the rotor. Some of these RF currents flow through the balls of the bearings and erode them through discharge machining. This occurs as the balls roll on the surfaces and some spots generate small arc. As the spark damage progresses, more and more of the sparking is concentrated at the site of the original damage until the bearing fails. Newer motors have brushes that ground the rotor to eliminate this problem. I would expect this problem be less severe in low power motors. But the bearings would be smaller so perhaps not.

One of the articles:�https://est-aegis.info/2017/10/how-do-vfds-cause-bearing-damage/

Milan


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

glenn brooks
 

Thanks Milan,

Most of my motors are older builds. I’ve thought many times about adding VFD’s. After reading your comments, glad I stayed with my RPC.

Glenn


On Jul 10, 2020, at 12:49 PM, Milan Trcka <milan.v.trcka@...> wrote:

Glenn,
My understanding of the problem lies in the damage to the motor bearings. The high frequency components of the drive currents in the stator generate currents in the rotor. Some of these RF currents flow through the balls of the bearings and erode them through discharge machining. This occurs as the balls roll on the surfaces and some spots generate small arc. As the spark damage progresses, more and more of the sparking is concentrated at the site of the original damage until the bearing fails. Newer motors have brushes that ground the rotor to eliminate this problem. I would expect this problem be less severe in low power motors. But the bearings would be smaller so perhaps not.

One of the articles: https://est-aegis.info/2017/10/how-do-vfds-cause-bearing-damage/

Milan


Re: Videos

Sam
 


On Fri, Jul 10, 2020 at 3:42 PM davethetechman via groups.io <abners96=aol.com@groups.io> wrote:

Hi, does anyone have any personal videos of the SBL with their own personal tips and hacks?

Recently new to this.

Thanks

 


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

Milan Trcka
 

Glenn,
My understanding of the problem lies in the damage to the motor bearings. The high frequency components of the drive currents in the stator generate currents in the rotor. Some of these RF currents flow through the balls of the bearings and erode them through discharge machining. This occurs as the balls roll on the surfaces and some spots generate small arc. As the spark damage progresses, more and more of the sparking is concentrated at the site of the original damage until the bearing fails. Newer motors have brushes that ground the rotor to eliminate this problem. I would expect this problem be less severe in low power motors. But the bearings would be smaller so perhaps not.

One of the articles: https://est-aegis.info/2017/10/how-do-vfds-cause-bearing-damage/

Milan


Videos

ISC Select
 

Hi, does anyone have any personal videos of the SBL with their own personal tips and hacks?

Recently new to this.

Thanks

 


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

glenn brooks
 

PS, glad to hear your not having difficulties!

Glenn


On Jul 10, 2020, at 3:17 AM, slash2nut via groups.io <lore724@...> wrote:

Glenn
I am sorry I was not clear.  I am not having trouble.  I have a 220v TECO.  I was just curious as to why some pre-1990 electric motors would have issue with a VFD.

Dave


-----Original Message-----
From: glenn brooks <brooks.glenn@...>
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 10:06 pm
Subject: Re: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

Iam a little confused as to if reply is related to the original question about increasing speed on SB 10’s, or you have some trouble getting the VFD to work?

Dave, you mentioned your VFD is problematic.  Are you asking about a VFD that doesn’t work, or doesn’t increase the required RPMs?

If it doesn’t work, and it is  a 110v to 220v TECO, and it trips out and shuts off when you try to start it - there is likely a GCFI plug in your house circuit that is causing the issue.  110v TECO’s don’t work with GCFI plugs. A low voltage signal in the TECO unit fools the GCFI into believing it’s a short and the GCFI trips itself.  So replace the GCFI with a standard receptacle and you’ll be good to go.

If it’s a speed issue, then never mind... wouldn’t know what to look at, except possibly something to do with the programming setup.

Glenn 


On Jul 9, 2020, at 3:15 PM, slash2nut via groups.io <lore724@...> wrote:

I am new to my Heavy 10, machining and VFD's.  My SB 10L is from 1967.  I believe the motor to be original, 1hp wired for 460v 3 phase.  I hooked up a TECO FM50 to it.  

Can you explain why a pre-1992 motor is problematic with VFD's?  I will be buying a tach but what rpm's do you think I am getting on my 1hp 220 3 phase motor with my TECO?

Thanks
Dave in MI
All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  



-----Original Message-----
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 4:28 pm
Subject: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

These lathes were designed to run on plain bearings for 8-16 hours a day, with daily oilings. My 10R from 1939 has two countershaft speeds of 300 and 579 from a 2 groove pulley on its 1725 RPM motor. Speed changes via  V belt from the  2” and  3.375”  pulley with a slightly smaller corresponding  groove in large countershaft pulley. This was an option I believe. Bit of a pain as you have to reduce belt tension adjuster to move v belt. 

For the standard 2” pulley the Countershaft runs at 300 RPM and the 3 spindle speeds are 700, 434 and 277 PRM. (Back gear drive neglected ). Shifting V belt  to the larger drive pulley,  the spindle goes to 1357, 837 and 535 RPM. Southbend HTRAL has warnings about bearing adjustments and lubrication at this speed, so this is clearly a maximum.

It is  easy to increase the size of the motor drive pulley in order to create a countershaft speed that will yield a top spindle RPM of 1000, but at less than the 579 countershaft speed that is the maximum for this series of lathes. WARNING. I have no operational measurements for bearing temperatures at anything above 700 which will tell you if you are pushing your lathe too far, and if you do this, I would recommend taking your bearing temperatures before and after. Bearings heat up over time, 20-30 minutes before my lathe flattened  out at a 30 deg rise at a spindle of 700 rpm.They will get hotter at 1000 RPM! . How hot is “too hot” is not clear. The decision for you is how many hours you will run at this speed and how good are your bearings and oil passages.

Doing some  math, you can get your countershaft pulley to 429 RPM, and then your 3 spindle speeds will be 999,  643, 395 RPM by increasing the motor pulley from 2” to 2.75”. I would be careful using backgears with this countershaft speed and not for long periods if you do. Use your ears and make sure backgears are well lubricated, with teflon grease on the shaft and heavy gear oil on the bull gear.  Use only cast iron pulleys, not die cast, and can order any size  from McMaster Carr. You will likely need a gear puller and the set screw may be tough to remove. You may want to make sure you can remove your pulley before ordering new. You will likely have enough belt adjustment range to use the same belt but you can order a size longer from McMaster. Without the 2 groove pulley, this is a semi-permanent change and its use depends upon what speeds you normally run. All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  
 


Re: 9A lever collet closer - spindle pin

LarryS <vision1@...>
 

Mill cutters work fine.

No problem.  Been done longer than anyone around here has been alive.

If you understand machining, you can use a mill cutter chucked in a lathe or a lathe cutter chucked in a mill – if that’s what’s required for the job. 

I’ve done both quite successfully.

Tempest in a teapot.

L.

 

From: SouthBendLathe@groups.io [mailto:SouthBendLathe@groups.io] On Behalf Of eddie.draper@... via groups.io
Sent: Friday, July 10, 2020 3:42 AM
To: southbendlathe@groups.io
Subject: Re: [SouthBendLathe] 9A lever collet closer - spindle pin

 

I'm sure it will say somewhere in the instructions for milling on a lathe, LIGHT milling.  Hold the cutter in the 3 jaw chuck or a proper milling collet holder as used on a miller (as below), not the collet system that is designed for holding workpieces for turning etc. 

 

I have always had satisfactory results off my Myford ML7 (7" swing) using the good and concentric 3 jaw, the only drawback being the low spindle speed in relation to small diameter cutters.  It soon tells you if you are overdoing it!  Conversely, I have recently used a solid carbide 16mm 4 flute cutter to reduce the height of a mild steel surface and it quite happily took a quarter turn of the 8 tpi leadscrew as depth of cut, so long as I didn't wind the feed too quickly and took due regard of the direction of thrust against the traverse screws so it didn't jump.  The trickiet job is ball end millers.  The same job needed a quarter circle radius cutting with a 10mm cutter.  I roughed it with an ordinary cutter first and initially, the follow on profile cuts would take 20 thou quite happily, but finishing across the full profile allowed only about 2 - 5 thou at a time.

 

Apologies for the mixed units.  The price differential between metric sized tooling, screw threaded components etc. and Imperial ditto becomes greater by the minute.  Most of the time, it makes no odds whatosever to the job.

 

Eddie

 

On Friday, 10 July 2020, 04:18:21 BST, v.gearheardt@... <v.gearheardt@...> wrote:

 

 

Gentlemen,
Milling cutters are high speed steel and no Collet or chuck is going to hold them. Lathes are not mills! If you are insistent is using your lathe to hold mils you need to use a MT end mill holders and add a drawbar as previous thread states correctly.  I  set up an Atlas and all it wa good for was milling 3/16" keyways, which I can do just as well freehand with a die grinder. If you want to surface flat stock use a 4 jaw and a face tool.
THe right tool for the right job!


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

slash2nut
 

Glenn
I am sorry I was not clear.  I am not having trouble.  I have a 220v TECO.  I was just curious as to why some pre-1990 electric motors would have issue with a VFD.

Dave


-----Original Message-----
From: glenn brooks <brooks.glenn@...>
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 10:06 pm
Subject: Re: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

Iam a little confused as to if reply is related to the original question about increasing speed on SB 10’s, or you have some trouble getting the VFD to work?

Dave, you mentioned your VFD is problematic.  Are you asking about a VFD that doesn’t work, or doesn’t increase the required RPMs?

If it doesn’t work, and it is  a 110v to 220v TECO, and it trips out and shuts off when you try to start it - there is likely a GCFI plug in your house circuit that is causing the issue.  110v TECO’s don’t work with GCFI plugs. A low voltage signal in the TECO unit fools the GCFI into believing it’s a short and the GCFI trips itself.  So replace the GCFI with a standard receptacle and you’ll be good to go.

If it’s a speed issue, then never mind... wouldn’t know what to look at, except possibly something to do with the programming setup.

Glenn 


On Jul 9, 2020, at 3:15 PM, slash2nut via groups.io <lore724@...> wrote:

I am new to my Heavy 10, machining and VFD's.  My SB 10L is from 1967.  I believe the motor to be original, 1hp wired for 460v 3 phase.  I hooked up a TECO FM50 to it.  

Can you explain why a pre-1992 motor is problematic with VFD's?  I will be buying a tach but what rpm's do you think I am getting on my 1hp 220 3 phase motor with my TECO?

Thanks
Dave in MI
All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  



-----Original Message-----
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 4:28 pm
Subject: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

These lathes were designed to run on plain bearings for 8-16 hours a day, with daily oilings. My 10R from 1939 has two countershaft speeds of 300 and 579 from a 2 groove pulley on its 1725 RPM motor. Speed changes via  V belt from the  2” and  3.375”  pulley with a slightly smaller corresponding  groove in large countershaft pulley. This was an option I believe. Bit of a pain as you have to reduce belt tension adjuster to move v belt. 

For the standard 2” pulley the Countershaft runs at 300 RPM and the 3 spindle speeds are 700, 434 and 277 PRM. (Back gear drive neglected ). Shifting V belt  to the larger drive pulley,  the spindle goes to 1357, 837 and 535 RPM. Southbend HTRAL has warnings about bearing adjustments and lubrication at this speed, so this is clearly a maximum.

It is  easy to increase the size of the motor drive pulley in order to create a countershaft speed that will yield a top spindle RPM of 1000, but at less than the 579 countershaft speed that is the maximum for this series of lathes. WARNING. I have no operational measurements for bearing temperatures at anything above 700 which will tell you if you are pushing your lathe too far, and if you do this, I would recommend taking your bearing temperatures before and after. Bearings heat up over time, 20-30 minutes before my lathe flattened  out at a 30 deg rise at a spindle of 700 rpm.They will get hotter at 1000 RPM! . How hot is “too hot” is not clear. The decision for you is how many hours you will run at this speed and how good are your bearings and oil passages.

Doing some  math, you can get your countershaft pulley to 429 RPM, and then your 3 spindle speeds will be 999,  643, 395 RPM by increasing the motor pulley from 2” to 2.75”. I would be careful using backgears with this countershaft speed and not for long periods if you do. Use your ears and make sure backgears are well lubricated, with teflon grease on the shaft and heavy gear oil on the bull gear.  Use only cast iron pulleys, not die cast, and can order any size  from McMaster Carr. You will likely need a gear puller and the set screw may be tough to remove. You may want to make sure you can remove your pulley before ordering new. You will likely have enough belt adjustment range to use the same belt but you can order a size longer from McMaster. Without the 2 groove pulley, this is a semi-permanent change and its use depends upon what speeds you normally run. All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  
 


Re: 9A lever collet closer - spindle pin

eddie.draper@btinternet.com
 

I'm sure it will say somewhere in the instructions for milling on a lathe, LIGHT milling.  Hold the cutter in the 3 jaw chuck or a proper milling collet holder as used on a miller (as below), not the collet system that is designed for holding workpieces for turning etc. 

I have always had satisfactory results off my Myford ML7 (7" swing) using the good and concentric 3 jaw, the only drawback being the low spindle speed in relation to small diameter cutters.  It soon tells you if you are overdoing it!  Conversely, I have recently used a solid carbide 16mm 4 flute cutter to reduce the height of a mild steel surface and it quite happily took a quarter turn of the 8 tpi leadscrew as depth of cut, so long as I didn't wind the feed too quickly and took due regard of the direction of thrust against the traverse screws so it didn't jump.  The trickiet job is ball end millers.  The same job needed a quarter circle radius cutting with a 10mm cutter.  I roughed it with an ordinary cutter first and initially, the follow on profile cuts would take 20 thou quite happily, but finishing across the full profile allowed only about 2 - 5 thou at a time.

Apologies for the mixed units.  The price differential between metric sized tooling, screw threaded components etc. and Imperial ditto becomes greater by the minute.  Most of the time, it makes no odds whatosever to the job.

Eddie

On Friday, 10 July 2020, 04:18:21 BST, v.gearheardt@... <v.gearheardt@...> wrote:


Gentlemen,
Milling cutters are high speed steel and no Collet or chuck is going to hold them. Lathes are not mills! If you are insistent is using your lathe to hold mils you need to use a MT end mill holders and add a drawbar as previous thread states correctly.  I  set up an Atlas and all it wa good for was milling 3/16" keyways, which I can do just as well freehand with a die grinder. If you want to surface flat stock use a 4 jaw and a face tool.
THe right tool for the right job!


Re: 9A lever collet closer - spindle pin

v.gearheardt@...
 

Gentlemen,
Milling cutters are high speed steel and no Collet or chuck is going to hold them. Lathes are not mills! If you are insistent is using your lathe to hold mils you need to use a MT end mill holders and add a drawbar as previous thread states correctly.  I  set up an Atlas and all it wa good for was milling 3/16" keyways, which I can do just as well freehand with a die grinder. If you want to surface flat stock use a 4 jaw and a face tool.
THe right tool for the right job!


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

v.gearheardt@...
 

The windings in pre 92 motors are not rated to take the induced voltages, like 2Kv,  from the high rise-time pulses from a VFD. The speed of the motor will be the same at 60Hz as other replies have correctly pointed put,  but the pulses may cause your motors winding insulation to fail.  I am sure you can rewire your motor down from 460 to 230V and this will help in this regards as well as lower the cost of your VFD.  There should be wiring indicator on motor faceplate.
Also, sizing a VFD is complex due to "locked rotor current", or current at start up. In the first msec of start up your motor may dray 20x its faceplate max current and IGBTs in your inverter don't like these spikes. Good VFDs can withstand these spikes better than others. They are all made in China, even Hitachi and Allen Bradley, but brands matter. TECO is a good compromise.


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

glenn brooks
 

Iam a little confused as to if reply is related to the original question about increasing speed on SB 10’s, or you have some trouble getting the VFD to work?

Dave, you mentioned your VFD is problematic.  Are you asking about a VFD that doesn’t work, or doesn’t increase the required RPMs?

If it doesn’t work, and it is  a 110v to 220v TECO, and it trips out and shuts off when you try to start it - there is likely a GCFI plug in your house circuit that is causing the issue.  110v TECO’s don’t work with GCFI plugs. A low voltage signal in the TECO unit fools the GCFI into believing it’s a short and the GCFI trips itself.  So replace the GCFI with a standard receptacle and you’ll be good to go.

If it’s a speed issue, then never mind... wouldn’t know what to look at, except possibly something to do with the programming setup.

Glenn 


On Jul 9, 2020, at 3:15 PM, slash2nut via groups.io <lore724@...> wrote:

I am new to my Heavy 10, machining and VFD's.  My SB 10L is from 1967.  I believe the motor to be original, 1hp wired for 460v 3 phase.  I hooked up a TECO FM50 to it.  

Can you explain why a pre-1992 motor is problematic with VFD's?  I will be buying a tach but what rpm's do you think I am getting on my 1hp 220 3 phase motor with my TECO?

Thanks
Dave in MI
All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  



-----Original Message-----
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 4:28 pm
Subject: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

These lathes were designed to run on plain bearings for 8-16 hours a day, with daily oilings. My 10R from 1939 has two countershaft speeds of 300 and 579 from a 2 groove pulley on its 1725 RPM motor. Speed changes via  V belt from the  2” and  3.375”  pulley with a slightly smaller corresponding  groove in large countershaft pulley. This was an option I believe. Bit of a pain as you have to reduce belt tension adjuster to move v belt. 

For the standard 2” pulley the Countershaft runs at 300 RPM and the 3 spindle speeds are 700, 434 and 277 PRM. (Back gear drive neglected ). Shifting V belt  to the larger drive pulley,  the spindle goes to 1357, 837 and 535 RPM. Southbend HTRAL has warnings about bearing adjustments and lubrication at this speed, so this is clearly a maximum.

It is  easy to increase the size of the motor drive pulley in order to create a countershaft speed that will yield a top spindle RPM of 1000, but at less than the 579 countershaft speed that is the maximum for this series of lathes. WARNING. I have no operational measurements for bearing temperatures at anything above 700 which will tell you if you are pushing your lathe too far, and if you do this, I would recommend taking your bearing temperatures before and after. Bearings heat up over time, 20-30 minutes before my lathe flattened  out at a 30 deg rise at a spindle of 700 rpm.They will get hotter at 1000 RPM! . How hot is “too hot” is not clear. The decision for you is how many hours you will run at this speed and how good are your bearings and oil passages.

Doing some  math, you can get your countershaft pulley to 429 RPM, and then your 3 spindle speeds will be 999,  643, 395 RPM by increasing the motor pulley from 2” to 2.75”. I would be careful using backgears with this countershaft speed and not for long periods if you do. Use your ears and make sure backgears are well lubricated, with teflon grease on the shaft and heavy gear oil on the bull gear.  Use only cast iron pulleys, not die cast, and can order any size  from McMaster Carr. You will likely need a gear puller and the set screw may be tough to remove. You may want to make sure you can remove your pulley before ordering new. You will likely have enough belt adjustment range to use the same belt but you can order a size longer from McMaster. Without the 2 groove pulley, this is a semi-permanent change and its use depends upon what speeds you normally run. All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  
 


Re: Thread dial for circa 1938 13”

m. allan noah
 

On Thu, Jul 9, 2020 at 4:32 PM <v.gearheardt@...> wrote:

Any thread dial gauge for a 9-13 will work. Not the later, '50s 9s nor 10Ks. What do you mean you have no mounting holes? Maybe they are just painted over but they are there for sure.
You are just making stuff up now- Many 13" lathes have 6 TPI
leadscrews, so you want a 24 tooth gear instead of 32 used on the
smaller lathes. Also, the apron will not be drilled for a dial if the
lathe never had one.

allan
--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


Re: Thread dial for circa 1938 13”

David Beierl
 

Maybe they are just painted over but they are there for sure.  

We have a 1927 gap bed 13" -- no mounting holes for thread dial.

Yrs,
d


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

Jim_B
 

VFD’s start by converting the House AC to DC. The DC is then used to approximate (3) sine waves of the same but variable frequency and 120 degrees phase difference. In that process the approximation uses amplitude steps. There may be hundreds of steps but there are steps.  The sharp transitions contain very high frequency components. 
Some older motors may not like them.  
However if your motor ran at 1750 rpm on 60 Hz before it will still run at 1750 rpm at 60 Hz from the VFD. It will also run at 875 rpm at 30 Hz from the VFD. And so on. 

-8
Jim B,

On Jul 9, 2020, at 6:15 PM, slash2nut via groups.io <lore724@...> wrote:


I am new to my Heavy 10, machining and VFD's.  My SB 10L is from 1967.  I believe the motor to be original, 1hp wired for 460v 3 phase.  I hooked up a TECO FM50 to it.  

Can you explain why a pre-1992 motor is problematic with VFD's?  I will be buying a tach but what rpm's do you think I am getting on my 1hp 220 3 phase motor with my TECO?

Thanks
Dave in MI
All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  



-----Original Message-----
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 4:28 pm
Subject: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

These lathes were designed to run on plain bearings for 8-16 hours a day, with daily oilings. My 10R from 1939 has two countershaft speeds of 300 and 579 from a 2 groove pulley on its 1725 RPM motor. Speed changes via  V belt from the  2” and  3.375”  pulley with a slightly smaller corresponding  groove in large countershaft pulley. This was an option I believe. Bit of a pain as you have to reduce belt tension adjuster to move v belt. 

For the standard 2” pulley the Countershaft runs at 300 RPM and the 3 spindle speeds are 700, 434 and 277 PRM. (Back gear drive neglected ). Shifting V belt  to the larger drive pulley,  the spindle goes to 1357, 837 and 535 RPM. Southbend HTRAL has warnings about bearing adjustments and lubrication at this speed, so this is clearly a maximum.

It is  easy to increase the size of the motor drive pulley in order to create a countershaft speed that will yield a top spindle RPM of 1000, but at less than the 579 countershaft speed that is the maximum for this series of lathes. WARNING. I have no operational measurements for bearing temperatures at anything above 700 which will tell you if you are pushing your lathe too far, and if you do this, I would recommend taking your bearing temperatures before and after. Bearings heat up over time, 20-30 minutes before my lathe flattened  out at a 30 deg rise at a spindle of 700 rpm.They will get hotter at 1000 RPM! . How hot is “too hot” is not clear. The decision for you is how many hours you will run at this speed and how good are your bearings and oil passages.

Doing some  math, you can get your countershaft pulley to 429 RPM, and then your 3 spindle speeds will be 999,  643, 395 RPM by increasing the motor pulley from 2” to 2.75”. I would be careful using backgears with this countershaft speed and not for long periods if you do. Use your ears and make sure backgears are well lubricated, with teflon grease on the shaft and heavy gear oil on the bull gear.  Use only cast iron pulleys, not die cast, and can order any size  from McMaster Carr. You will likely need a gear puller and the set screw may be tough to remove. You may want to make sure you can remove your pulley before ordering new. You will likely have enough belt adjustment range to use the same belt but you can order a size longer from McMaster. Without the 2 groove pulley, this is a semi-permanent change and its use depends upon what speeds you normally run. All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  
 

--
Jim B


Re: Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

slash2nut
 

I am new to my Heavy 10, machining and VFD's.  My SB 10L is from 1967.  I believe the motor to be original, 1hp wired for 460v 3 phase.  I hooked up a TECO FM50 to it.  

Can you explain why a pre-1992 motor is problematic with VFD's?  I will be buying a tach but what rpm's do you think I am getting on my 1hp 220 3 phase motor with my TECO?

Thanks
Dave in MI
All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  



-----Original Message-----
To: SouthBendLathe@groups.io
Sent: Thu, Jul 9, 2020 4:28 pm
Subject: [SouthBendLathe] Increasing the speed on Southbend 10-16” Models. Late 1930s-late 1940s.

These lathes were designed to run on plain bearings for 8-16 hours a day, with daily oilings. My 10R from 1939 has two countershaft speeds of 300 and 579 from a 2 groove pulley on its 1725 RPM motor. Speed changes via  V belt from the  2” and  3.375”  pulley with a slightly smaller corresponding  groove in large countershaft pulley. This was an option I believe. Bit of a pain as you have to reduce belt tension adjuster to move v belt. 

For the standard 2” pulley the Countershaft runs at 300 RPM and the 3 spindle speeds are 700, 434 and 277 PRM. (Back gear drive neglected ). Shifting V belt  to the larger drive pulley,  the spindle goes to 1357, 837 and 535 RPM. Southbend HTRAL has warnings about bearing adjustments and lubrication at this speed, so this is clearly a maximum.

It is  easy to increase the size of the motor drive pulley in order to create a countershaft speed that will yield a top spindle RPM of 1000, but at less than the 579 countershaft speed that is the maximum for this series of lathes. WARNING. I have no operational measurements for bearing temperatures at anything above 700 which will tell you if you are pushing your lathe too far, and if you do this, I would recommend taking your bearing temperatures before and after. Bearings heat up over time, 20-30 minutes before my lathe flattened  out at a 30 deg rise at a spindle of 700 rpm.They will get hotter at 1000 RPM! . How hot is “too hot” is not clear. The decision for you is how many hours you will run at this speed and how good are your bearings and oil passages.

Doing some  math, you can get your countershaft pulley to 429 RPM, and then your 3 spindle speeds will be 999,  643, 395 RPM by increasing the motor pulley from 2” to 2.75”. I would be careful using backgears with this countershaft speed and not for long periods if you do. Use your ears and make sure backgears are well lubricated, with teflon grease on the shaft and heavy gear oil on the bull gear.  Use only cast iron pulleys, not die cast, and can order any size  from McMaster Carr. You will likely need a gear puller and the set screw may be tough to remove. You may want to make sure you can remove your pulley before ordering new. You will likely have enough belt adjustment range to use the same belt but you can order a size longer from McMaster. Without the 2 groove pulley, this is a semi-permanent change and its use depends upon what speeds you normally run. All the VFD users will come out now and point out how it’s easier and better to go that route but my simple phase converter only goes from 60Hz down and my motor is pre-1992 which makes its use with a VFD problematic. This only costs $30.  
 


Re: Thread dial for circa 1938 13”

Jim_B
 

Those are instructions for a early 9” Workshop. Should be in the files section. 
They could act as a guide. 
If you can’t find them let me know. 

-8
Jim B,

On Jul 9, 2020, at 5:27 PM, Davis Johnson <davis@...> wrote:



Somewhere I've seen an instruction sheet from SBL detailing how and where to drill a mounting hole for a thread dial. Didn't have to do it on either of mine, but some apparently left the factory without a hole (or holes, depending on the model).

On 7/9/20 4:32 PM, v.gearheardt@... wrote:
Any thread dial gauge for a 9-13 will work. Not the later, '50s 9s nor 10Ks. What do you mean you have no mounting holes? Maybe they are just painted over but they are there for sure. 

--
Jim B


Re: Thread dial for circa 1938 13”

Davis Johnson
 

Somewhere I've seen an instruction sheet from SBL detailing how and where to drill a mounting hole for a thread dial. Didn't have to do it on either of mine, but some apparently left the factory without a hole (or holes, depending on the model).

On 7/9/20 4:32 PM, v.gearheardt@... wrote:
Any thread dial gauge for a 9-13 will work. Not the later, '50s 9s nor 10Ks. What do you mean you have no mounting holes? Maybe they are just painted over but they are there for sure.