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Lathe horizontal drive motor and pulleys

E A
 

As I sort out my "new" 1942 9A, and look at pictures of many others, it hit me that the drive pulleys on mine have been replaced (along with the motor of course).
Motor shaft measures 1/2"... So, Ebay has a number of the motor pulleys listed, but all say they are for 3/4" shaft...? That seems like a big shaft!
(And I have not seen one of the larger two step pulleys so far.)
Questions... what was the original motor shaft size, and is it worth attempting to find original pulleys to have the extra speed options?
Erik A
david pennington
 

Whatever you do, I was advised that the published speeds in the SB manual should not be exceeded--at least not by much.

When I got my 1946 9C, the drive pulley on the motor (1/2" shaft) was too large. I was able to purchase the correct size at a hardware store.

Good luck.

David W. Pennington
Denver, Colorado
720-442-3744 - Please note the new number.


On Tuesday, December 8, 2020, 09:23:48 AM MST, E A <b-arch@...> wrote:


As I sort out my "new" 1942 9A, and look at pictures of many others, it hit me that the drive pulleys on mine have been replaced (along with the motor of course).
Motor shaft measures 1/2"... So, Ebay has a number of the motor pulleys listed, but all say they are for 3/4" shaft...? That seems like a big shaft!
(And I have not seen one of the larger two step pulleys so far.)
Questions... what was the original motor shaft size, and is it worth attempting to find original pulleys to have the extra speed options?
Erik A
Ray De Jong
 

Interesting; I have two of the stock pulleys and both the one on my lathe and the spare have 5/8 bore. the original motor on my 10K has of course the 5/8 shaft.
I used to have a 1948 9 inch SB and still have the original motor and it also is 5/8" as well. The later 10L etc. may be 3/4" shaft/pulley but there are options listed, some 3PH and single phase 1/2 and 3/4 HP.
My spare pulley is listed as having a 3/4" bore but in fact is 5/8"
Strange is often, me thinks.
Ray

On Tuesday, December 8, 2020, 8:23:48 AM PST, E A <b-arch@...> wrote:


As I sort out my "new" 1942 9A, and look at pictures of many others, it hit me that the drive pulleys on mine have been replaced (along with the motor of course).
Motor shaft measures 1/2"... So, Ebay has a number of the motor pulleys listed, but all say they are for 3/4" shaft...? That seems like a big shaft!
(And I have not seen one of the larger two step pulleys so far.)
Questions... what was the original motor shaft size, and is it worth attempting to find original pulleys to have the extra speed options?
Erik A
comstock_friend
 

Here are the South Bend Forms for the belts and pulleys, and the horizontal and underdrive for 9" and 10K lathes. Also the speed chard from my HTRAL.

Note that while the motor pulleys are V-pulleys, the countershaft is flat. The V-Belt runs on it perfectly.

John

PDF
SB Form 904F Section 1, Horizontal and Under Drives, 10-1-1966.pdf
PDF
SB Form 921F Section 1 _ 2, Belts, Lube _ Motor Pulleys, 4-5-1965.pdf

comstock_friend
 

The spindle speed chart doesn't show up well, here it is in pdf...

John

PDF
SB HTRAL Speed Chart, Edition 56, 1966.pdf

E A
 

Now if I could only find one of those flat countershaft pulleys, I'd be in like Flynn.
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of comstock_friend <jfriend314@...>
Sent: Wednesday, December 9, 2020 10:55 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Lathe horizontal drive motor and pulleys
 
Here are the South Bend Forms for the belts and pulleys, and the horizontal and underdrive for 9" and 10K lathes. Also the speed chard from my HTRAL.

Note that while the motor pulleys are V-pulleys, the countershaft is flat. The V-Belt runs on it perfectly.

John

john kling
 

The manufacture's decision to have a v belt run (on one side) on a large flat  pulley is counter intuitive. Several other manufactures also used this set up. When i noticed that a new to me SB had this set up. I assumed it was a previous owners set up/ mistake. Perhaps a large v pulley  was expansion or increases friction from the side of the belt.

On Thursday, December 10, 2020, 11:34:37 AM EST, E A <b-arch@...> wrote:


Now if I could only find one of those flat countershaft pulleys, I'd be in like Flynn.
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of comstock_friend <jfriend314@...>
Sent: Wednesday, December 9, 2020 10:55 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Lathe horizontal drive motor and pulleys
 
Here are the South Bend Forms for the belts and pulleys, and the horizontal and underdrive for 9" and 10K lathes. Also the speed chard from my HTRAL.

Note that while the motor pulleys are V-pulleys, the countershaft is flat. The V-Belt runs on it perfectly.

John

E A
 

Doesn't the large flat pulley allow you to move the belt easily between the two sizes? Otherwise you have to stretch it over the Vee "sides"...
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of john kling via groups.io <jkling222@...>
Sent: Thursday, December 10, 2020 11:42 AM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Lathe horizontal drive motor and pulleys
 
The manufacture's decision to have a v belt run (on one side) on a large flat  pulley is counter intuitive. Several other manufactures also used this set up. When i noticed that a new to me SB had this set up. I assumed it was a previous owners set up/ mistake. Perhaps a large v pulley  was expansion or increases friction from the side of the belt.

On Thursday, December 10, 2020, 11:34:37 AM EST, E A <b-arch@...> wrote:


Now if I could only find one of those flat countershaft pulleys, I'd be in like Flynn.
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of comstock_friend <jfriend314@...>
Sent: Wednesday, December 9, 2020 10:55 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Lathe horizontal drive motor and pulleys
 
Here are the South Bend Forms for the belts and pulleys, and the horizontal and underdrive for 9" and 10K lathes. Also the speed chard from my HTRAL.

Note that while the motor pulleys are V-pulleys, the countershaft is flat. The V-Belt runs on it perfectly.

John

David R8
 

I have a 1975 SB10K with the original countershaft system and guard. It has a two step v-groove motor pulley, flat countershaft pulley and cone pulleys. 
I think part of the reason for the flat countershaft is ease of changing v-belt positions because it is a royal pain in the behind to loosen the motor mount to release belt tension.
But with the flat countershaft, the belt can be eased off the side of the countershaft and moved without releasing the tension.
David

On Dec 10, 2020, at 8:42 AM, john kling via groups.io <jkling222@...> wrote:

The manufacture's decision to have a v belt run (on one side) on a large flat  pulley is counter intuitive. Several other manufactures also used this set up. When i noticed that a new to me SB had this set up. I assumed it was a previous owners set up/ mistake. Perhaps a large v pulley  was expansion or increases friction from the side of the belt.

On Thursday, December 10, 2020, 11:34:37 AM EST, E A <b-arch@...> wrote:


Now if I could only find one of those flat countershaft pulleys, I'd be in like Flynn.
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of comstock_friend <jfriend314@...>
Sent: Wednesday, December 9, 2020 10:55 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Lathe horizontal drive motor and pulleys
 
Here are the South Bend Forms for the belts and pulleys, and the horizontal and underdrive for 9" and 10K lathes. Also the speed chard from my HTRAL.

Note that while the motor pulleys are V-pulleys, the countershaft is flat. The V-Belt runs on it perfectly.

John

john kling
 

Thanks for the understanding of the probable motivation for the  design. I have an atlas lathe (also) that has V pulleys on both ends of the motor to counter shaft connection. The large pulley was damaged and I replaced it with a flat pulley of a logan (and it works). The motor on the atlas is on a hinge so shiffting step is relatively easy.

On Thursday, December 10, 2020, 11:55:24 AM EST, David R8 <davidwrate1@...> wrote:


I have a 1975 SB10K with the original countershaft system and guard. It has a two step v-groove motor pulley, flat countershaft pulley and cone pulleys. 
I think part of the reason for the flat countershaft is ease of changing v-belt positions because it is a royal pain in the behind to loosen the motor mount to release belt tension.
But with the flat countershaft, the belt can be eased off the side of the countershaft and moved without releasing the tension.
David

On Dec 10, 2020, at 8:42 AM, john kling via groups.io <jkling222@...> wrote:

The manufacture's decision to have a v belt run (on one side) on a large flat  pulley is counter intuitive. Several other manufactures also used this set up. When i noticed that a new to me SB had this set up. I assumed it was a previous owners set up/ mistake. Perhaps a large v pulley  was expansion or increases friction from the side of the belt.

On Thursday, December 10, 2020, 11:34:37 AM EST, E A <b-arch@...> wrote:


Now if I could only find one of those flat countershaft pulleys, I'd be in like Flynn.
Erik A

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of comstock_friend <jfriend314@...>
Sent: Wednesday, December 9, 2020 10:55 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Lathe horizontal drive motor and pulleys
 
Here are the South Bend Forms for the belts and pulleys, and the horizontal and underdrive for 9" and 10K lathes. Also the speed chard from my HTRAL.

Note that while the motor pulleys are V-pulleys, the countershaft is flat. The V-Belt runs on it perfectly.

John

Milan Trcka
 

I confirm (on my 9A) that the flat countershaft pulley makes changing speeds much easier (almost pleasant). I also find that the V belt needs to be quite accurate and straight otherwise it wanders side to side and tends to rub on one side. This happens especially when the belt is cold. I had to "file" the belt sides to straighten its tracking. Countershaft alignment is also important.
Milan
glenn brooks <brooks.glenn@...>
 

I have a couple of lathes with these three speed countershaft pulley’s: a SB 9x48” and and an old 1919 7x36” Dalton.  If you run grooved automotive flat belts on the pulley’s you won’t have any trouble. The countershaft pulley’s are all made with a slight crown that aides in self centering.  The only v belt I use connects the drive motor pulley with the large counter shaft drive pulley.

Glenn B.


On Dec 10, 2020, at 9:37 PM, Milan Trcka <milan.v.trcka@...> wrote:

I confirm (on my 9A) that the flat countershaft pulley makes changing speeds much easier (almost pleasant). I also find that the V belt needs to be quite accurate and straight otherwise it wanders side to side and tends to rub on one side. This happens especially when the belt is cold. I had to "file" the belt sides to straighten its tracking. Countershaft alignment is also important.
Milan

john kling
 

I have a 415 (converted to an A). On this machine and many of the early ones, there is but a single pulley (i.e. one  step or speed) between the motor and counter shaft so the benefit from easier shifting does not exist.

On Friday, December 11, 2020, 12:38:03 AM EST, Milan Trcka <milan.v.trcka@...> wrote:


I confirm (on my 9A) that the flat countershaft pulley makes changing speeds much easier (almost pleasant). I also find that the V belt needs to be quite accurate and straight otherwise it wanders side to side and tends to rub on one side. This happens especially when the belt is cold. I had to "file" the belt sides to straighten its tracking. Countershaft alignment is also important.
Milan

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