Change gears a PITA on 6" Craftsman lathe

[BlacksmithED]

I just spent 2 hours again trying to figure out the gear setup to put the lathe (101.07301) back the way it was after cutting some 20 tpi screws as an experiment. I have had the lathe for over 20 years, and always wanted to see how to cut threads. I never want to go through that again. Either I'm missing a gear or spacer or something, but the configuration doesn't jive with either the chart on the lathe, or the chart and description I have in the Thread Cutting booklet.

I'm thinking that when I need to cut threads on something again, I may not attempt it again because it's so difficult to figure it out.
Is there another lathe, not too big, that allows you to change gears without actually pulling them out and changing them. I've seen pictures of lathes with levers to select different gears. Is there a lathe like that that's not super expensive or large? I'm open to buying one.

 

[markba633csi]

Sounds like a South Bend model A would be just the ticket for you- unfortunately they are getting harder to find, in good shape or any shape.
You might also take a look at Sheldon and Logan lathes- they too are less plentiful but have quick change gearboxes as well.
Atlas made 10 inch and 12 inch lathes with quickchange box also- that would probably be your cheapest option
-Mark
PS I have a 6" Atlas lathe too and I admit that changing gears frequently can be a bit of a chore, however if you have the correct hardware
it gets easier the more you do it. Biggest complaint I have heard is how messy the zamak gears can be to handle. They make your fingers black very quickly

 

[chippermat]

Just curious, what feed rate thread per inch are you trying to set it up for?

 

[Aaron_W]

A shortbed 9x17" or 9x23" Southbend Model A which had a gear box (Model B and C used change gears) would be heavier but similar in physical size to the 6x18" Craftsman. You won't be able to manhandle a 9" SB like the 6", but 2 or 3 guys should have little trouble moving one. Logan briefly made a 9" lathe that would be similar but they are far less common than the other options.

Step up from there would be one of the 10x24" lathes from Atlas, Logan or Southbend which were available with change gears or a gear box. These are a fair bit larger than the 6" and not at all mobile (400lbs-ish) but unless you have your current lathe wedged in snug, you can probably find room for one of these. The 10x24 Logan is 43" long so not quite a foot longer. The SB and Atlas lathes should be similar.

I believe the earlier (mid 50s and earlier) 12" Craftsman lathes are nearly the same size as the Atlas 10", the Craftsman lathes basically just adding riser blocks to give additional swing.

If the 10x24s are too big, you can occasionally find an older Atlas 10x18" that somebody has retrofit a gear box to from one of the later lathes.

Those are the common options. Very few of the current lathes under a 12" swing offer a true quick change gear box, the exceptions being quite expensive. Some do have a gear box but they are only good for a few changes and mostly for speeds, not threading so you still need to use chnage gears. Jet did sell a 10x24 in the 1980s with a full quick change gear box, these do turn up occasionally. They have some quirks (weird proprietary spindle thread) but seem to be popular with their owners.

There are other small lathes with a quick change gear box but they are rather uncommon and often expensive. A Myford 7 from England being a good example. They could be bought with a gear box and are supposed to be very nice lathes but rather uncommon to find in the US.

 

[BlacksmithED]

Just curious, what feed rate thread per inch are you trying to set it up for?

I had set it up for a 20 tpi, but would like to be able to set it up for any thread without spending hours trying to figure it out.

 

[BlacksmithED]

Sounds like a South Bend model A would be just the ticket for you- unfortunately they are getting harder to find, in good shape or any shape.
You might also take a look at Sheldon and Logan lathes- they too are less plentiful but have quick change gearboxes as well.
Atlas made 10 inch and 12 inch lathes with quickchange box also- that would probably be your cheapest option
-Mark
PS I have a 6" Atlas lathe too and I admit that changing gears frequently can be a bit of a chore, however if you have the correct hardware
it gets easier the more you do it. Biggest complaint I have heard is how messy the zamak gears can be to handle. They make your fingers black very quickly

Thanks, I’ll see if there’s any around.

 

[Lo-Fi]

Let's work through it

Could you post a pic of your headstock where the change gears go please?

And we'll need to know:

The number if teeth on the gear on the spindle and if it's changeable (they're often not)

What gears you have available

What pitch your leadscrew is

Throw that into the thread and we'll be able to use a tool like this to generate a chart.

 

[BlacksmithED]

A shortbed 9x17" or 9x23" Southbend Model A which had a gear box (Model B and C used change gears) would be heavier but similar in physical size to the 6x18" Craftsman. You won't be able to manhandle a 9" SB like the 6", but 2 or 3 guys should have little trouble moving one. Logan briefly made a 9" lathe that would be similar but they are far less common than the other options.

Step up from there would be one of the 10x24" lathes from Atlas, Logan or Southbend which were available with change gears or a gear box. These are a fair bit larger than the 6" and not at all mobile (400lbs-ish) but unless you have your current lathe wedged in snug, you can probably find room for one of these. The 10x24 Logan is 43" long so not quite a foot longer. The SB and Atlas lathes should be similar.

I believe the earlier (mid 50s and earlier) 12" Craftsman lathes are nearly the same size as the Atlas 10", the Craftsman lathes basically just adding riser blocks to give additional swing.

If the 10x24s are too big, you can occasionally find an older Atlas 10x18" that somebody has retrofit a gear box to from one of the later lathes.

Those are the common options. Very few of the current lathes under a 12" swing offer a true quick change gear box, the exceptions being quite expensive. Some do have a gear box but they are only good for a few changes and mostly for speeds, not threading so you still need to use chnage gears. Jet did sell a 10x24 in the 1980s with a full quick change gear box, these do turn up occasionally. They have some quirks (weird proprietary spindle thread) but seem to be popular with their owners.

There are other small lathes with a quick change gear box but they are rather uncommon and often expensive. A Myford 7 from England being a good example. They could be bought with a gear box and are supposed to be very nice lathes but rather uncommon to find in the US.

Thanks for the info.

 

[BlacksmithED]

Let's work through it

Could you post a pic of your headstock where the change gears go please?

And we'll need to know:

The number if teeth on the gear on the spindle and if it's changeable (they're often not)

What gears you have available

What pitch your leadscrew is

Throw that into the thread and we'll be able to use a tool like this to generate a chart.

I’ll be back home around noon. I’ll send pics then. Thanks.

 

[chippermat]

Is this the chart you are using?