South Bend 10k Clean Up

[SLK001]

BTW, your second QCGB is for a 9" lathe. I don't think that the two gear boxes are interchangeable. Just sell the extra one to offset the cost of the lathe and to purchase desired tooling.

The CL644R is the model number for a 9" lathe with a 4-1/2 foot bed.

What is the model number shown on the attached QCGB? Is should be something like CL670R.

 

[Danshell]

First of all, thanks to everyone who has taken the time to reply, I really appreciate the advice and helpful links.

BTW, your second QCGB is for a 9" lathe. I don't think that the two gear boxes are interchangeable. Just sell the extra one to offset the cost of the lathe and to purchase desired tooling.

The CL644R is the model number for a 9" lathe with a 4-1/2 foot bed.

What is the model number shown on the attached QCGB? Is should be something like CL670R.

The plate on the original gearbox is really worn out but yes it does say something very similar CL670A it has an A not an R. Does that mean anything? Is there a definitive way to find out if this 'spare' gear box is usable on this lathe? The spare is brand new. Well I am sure it was manufactured many years ago, however it has never been used.

Wow, a "spare" change-gear box? (although it may not fit your lathe....)

I cannot quite tell from the photos, is there a still a plate on the gear-box attached to the machine?
I can't see if it's just dirty, or if it was removed.

That should have the common imperial threading and feed chart on it.
Also, it should give a catalog number, which also might help with the date.

By the way, Grizzly bough the Southbend name and still offers:
some parts here: https://www.grizzly.com/brands/south-bend-lathe/parts
and can supply a PDF copy of the original sales record (see the box on the right-hand side at the above link)

I also suggest you find a copy of the old Southbend book "How to Run a Lathe".
As a site supporter you can download a copy right here, there are multiple versions available:
SB How to Run a Lathe for Beginners - 1914 15th Edition
SB How To Run a Lathe - 1966 27th Edition (56).pdf

Here's a link to the Southbend area in our "Downloads" section:
https://www.hobby-machinist.com/resources/categories/south-bend.34/

Welcome to the group!
-brino

Thank you very much. Now I know where to buy parts. I wish the Aussie dollar was a bit stronger against the mighty USD though

The "K" indicates a Light 10, aka a 10K. I don't think the heavy 10 was ever sold as a benchtop lathe. The heavy 10 looks like a mini version of the 13-16 UMD lathes.

I am not an expert on this, but I understand that motor ratings today are much more optimistic than they were back then. Peak potential under ideal conditions vs average real operating conditions, or some such. If it came with a motor rated at 1/2hp back then, I would venture you need a 1hp in today's mini-horse ratings. I would not part with my VFD.


http://vintagemachinery.org/mfgIndex/detail.aspx?id=1617&tab=3


Happy reading.

I am torn between a single phase motor using the original belts and going the 'modern' way of 3ph with a VFD. I just dont know what the right decision is here.

I believe South Bend recommended a 1/2 horsepower motor for this lathe:

South Bend Lathe Works - Publication Reprints - Model 10-K Precision Lathes | VintageMachinery.org

Re powering with a VFD, there are quite a few threads here on the considerations for doing that. Whether it is worth it is up to you. How badly does changing belts bother you?

You got a tonne of stuff with your lathe. Including an 'extra' quick change gear box. It might be for the 9 inch South Bend?!? Also appears you got a collet drawbar (with red handle). Did you get a collet chuck and collets, too? Also very nice that you got a quick change tool post and holders.

Craig

Thanks Craig, yes it appears as though the gear box is wrong for this machine, which suggests to me that the gent I bought it off didnt really know what it was exactly either. The collet holder is actually for a Maximat V10 Lathe. I bought this south bend, a maximat v10 and an atlas 7b shaper all from the one person. I paid $2000 USD for all 3 machines, I thought is was a reasonable price even though all of them need restoring but they are all complete enough and work.

 

[DavidR8]

Other than the colour, that looks identical to my 10K

 

[Danshell]

I made the decision to buy a 3ph motor and use a VFD. I was torn between authenticity and ease of use.......Ill probably never be able to make this a perfectly restored unit so I went with ease of use.

 

[Weldingrod1]

You want to keep the belts. You need the first step down to get the rpm right! I ran my Southbend for years each way (single speed and vfd). I rarely changed belts after going to the vfd. The drawback of slowing down a motor on a vfd is you dont get more torque below rated speed

Sent from my SM-G892A using Tapatalk

 

[Danshell]

You want to keep the belts. You need the first step down to get the rpm right! I ran my Southbend for years each way (single speed and vfd). I rarely changed belts after going to the vfd. The drawback of slowing down a motor on a vfd is you dont get more torque below rated speed

Sent from my SM-G892A using Tapatalk

Do you mean the first step down on the motor pulley or are you talking about the large flat belt cone pulleys?

 

[RandyWilson]

I keep my belt on a middle step. All speed control is done with the VFD and backgear. And I learned a trick this evening. When facing with carbide, there is a point towards the center where the surface finish goes rough due to low surface speed. First pass I note where that is, the second pass I give the VFD knob a little twist just before reaching that spot.

 

[Weldingrod1]

You want to keep both the motor to jack shaft belt and the jack shaft to spindle belt. OR, find a low speed motor who's top speed is about jack shaft speed. I think the stock motor is already 1800 RPM, so you might want a 900 Rpm motor to directly drive the belt to the spindle (just guessing, though). Those are rare! That said, I DID find one and put it on my drill press...

Sent from my SM-G892A using Tapatalk

 

[Danshell]

I pulled the old girl down and 'tidied' her up a little.

This was not a rebuild or restoration by any means, it was simply a quick tear down, wash, repaint and put back together to see where the old lathe was in regards condition.

I put a 3 phase motor on with a VFD and that works really well.

I have to say the old Lathe is really nice. It runs very smooth and for the most part seems pretty tight.

So far I have a list of things I need to do.

1, Its gear train was geared all wrong. I have ordered the correct 56 tooth gear for the end of the gearbox to drive the 100/127 toothe gear and I have a set of metric transponding? gears.

2, When engaging in the half nut in forward directing the carriage is 'notchy'. It is fine in reverse direction though. And it is fine when just using the clutch so I think the half nut needs some investigation. Solved

3, The whole gear box can lock up randomly when the half nut is engaged so again I need to investigate in the carriage assembly. Solved

4, The gear train can be quite rattly in one direction (i cant recall if its forward or reverse) but the way the larger 100/127 gears mount is a bit dogdy so I need to investigate that as well.

5, The clutch doesnt disengage sometimes so I need to have a look at that.

Besides that, I think Ill buy a felt kit and slowly replace them.

I am open to any suggestions for my issues above?

 

[Danshell]

I took the apron off and check the half nut, it appears to be in very good condition.

So I held the half nut on the lead screw and ran the lathe and it appears as those it is the lead screw that is causing the carriage notchyness in the forward direction.

There is quite a lot of side to side slop in the lead screw, so given that i have put a new gear box on, I can almost be certain there should be some shims to take up the slop. The slop is causing the notchyness in the forward direction. In reverse the lead screw pushed towards the gear box and hence taking up the slop.

Ill go investigate further........I have a good book that gives a massive amount of information but it doesnt tell me how much side play I should have. Im guessing not a lot.