Thoughts on Mini-Lathes

[SouthernChap]

Many people buy a larger lathe not to be cool

Surely nobody goes through the hassle (and in some cases, cost) of rigging, to-the-kerb-removal, loading, transporting, unloading and from-the-kerb-installation of a non-benchtop lathe to impress anybody else? That would be madness.

Surely everyone buying larger lathes are either buying one because they love the idea of having all that capability or because they need that capability.

As regards Quinn's anti old iron stance. I don't fully agree with it but I think she does make some good points about relative capabilities when you compare lathes of similar size and price from say the 1940s or 1950s on the one hand and modern decent quality lathes on the other.

However, the main argument against buying a vintage lathe, and a pretty compelling one too, remains the inability of the beginner to assess a vintage lathes state of repair.

I feel now, after stripping down and improving my 7x and learning more about how lathes (and machine tools in general) work, I have a decent (but not certain) chance of visiting a seller of an ML7 and assessing its state to a reasonable degree.

When I got my 7x I know I couldn't have done so.

That's not to say beginners shouldn't try but it's understandable that they often don't and buying a 10x22 from PM isn't the worst decision anybody will ever make.

 

[Aaron_W]

I have always liked catalogs for products of interest.

So I took a few minutes to search out some information. Specially about South Bend lathes - and the model that I would consider having been the hobbyist lathe when manufactured. BTW, I hope my posts are seen as at least somewhat objective. I would very much like a Logan or South Bend. The mini-lathe serves for me, but in lathes, if there are no considerations of weight and price, bigger serves better.

Here, briefly, is some historical South Bend information. Any errors in nomenclature may be corrected by the more knowledgeable.

In 1937, a 9 inch SB (series name "Workshop") with motor and horizontal drive was priced at $116.00. That is with change gears, not threading gearbox. In this configuration the weight is 320 pounds. The catalog shows a payment plan. An extremely rough equivalence in specification to the mini-lathe of today - talking features not size or quality.

In 1967, a 9 inch SB (Now with Precision in the name - looks the same lathe) with motor and horizontal drive was priced by $315.00 (With WW2 government sponsored inflation). The 9 inch SB lathes have a 3/4 inch spindle through hole.

Given the specified weight they were (are) some 65-70 pounds heavier than the current Grizzly G4000.

Hope this is useful for new or prospective mini-lathe folks.

What many fail to consider is the price, $116 in 1937 is $2500 adjusted for inflation, $315 in 1967 is $2900 adjusted for inflation. In 1960 you could buy a 6x18" Craftsman (Atlas) lathe for $176 ($1800 today) and that didn't include a motor which could run another $20-40 ($200-400).

A South Bend 9C is a fairly decent comparison to a Grizzly G4000 which today sells for $1200. The imports leave something to be desired at times, but they are far more affordable than in the past.

A 9A (QCGB & power cross feed) or 9B (power cross feed) add some nice features which are not available on any hobby level lathes of the size. A G4000 can cut 38 threads, vs 45 on a 9C or B, 48 on a 9A. A 7" mini can only do 28.

As pointed out in another thread the often dismissed Atlas lathes excel in cutting odd threads, the little 6" Atlas 618 can cut 61 threads including 13 metric.

 

[Aaron_W]

As regards Quinn's anti old iron stance. I don't fully agree with it but I think she does make some good points about relative capabilities when you compare lathes of similar size and price from say the 1940s or 1950s on the one hand and modern decent quality lathes on the other.

However, the main argument against buying a vintage lathe, and a pretty compelling one too, remains the inability of the beginner to assess a vintage lathes state of repair.

Strongly disagree with your first point. There are only 2 lathes I know of under a 12" swing with a quick change gear box, one is the Grizzly / South Bend "Heavy 10" for $9500 (which appears to have been dropped from the catalog), and the Hardinge HLV (and clones) which are priced at "if you have to ask you can't afford it". Most vintage lathes also can cut far more threads.

Of course ELS is beginning to address both of these points, but currently that is a DIY project.

Few lathes under 12" swing have a power cross feed, the PM1022 and LMS 7500 being exceptions.

Lots of vintage lathes were available with both of these features, and many more options, like taper attachments, collet closers, tail stock turrets, milling attachments, lever tail stock etc. Many of these accessories are not available even on many larger lathes.

Spindle bore is the one place where modern lathes tend to do better, and particularly with the smaller lathes. A 7" mini has the same size spindle bore as most of the vintage 9" and 10" lathes and there are some 8-1/2" import lathes with a 1-1/2" spindle bore, bigger than many vintage 11-12" lathes which only had 1-3/8".


Now the ability to assess a vintage lathe is a completely valid issue. It is also often ignored that most vintage lathes need to go through a rehab process which can easily be as much of a process as upgrading a cheap import, and sometimes much more.

 

[CraigH]

What many fail to consider is the price, $116 in 1937 is $2500 adjusted for inflation, $315 in 1967 is $2900 adjusted for inflation. In 1960 you could buy a 6x18" Craftsman (Atlas) lathe for $176 ($1800 today) and that didn't include a motor which could run another $20-40 ($200-400).

A South Bend 9C is a fairly decent comparison to a Grizzly G4000 which today sells for $1200. The imports leave something to be desired at times, but they are a far more affordable than in the past.

A 9A (QCGB & power cross feed) or 9B (power cross feed) add some nice features which are not available on any hobby level lathes of the size. A G4000 can cut 38 threads, vs 45 on a 9C or B, 48 on a 9A. A 7" mini can only do 28.

As pointed out in another thread the often dismissed Atlas lathes excel in cutting odd threads, the little 6" Atlas 618 can cut 61 threads including 13 metric.

Yes, the new Chinese lathes are lower cost when adjusting for inflation, and I think that is relatively well known.

An LMS 8.5x20 (7500/7550) has power cross feed, which I do not find compelling. A QC gearbox is quite another matter and I would quite like to have that.

A 7" mini-lathe can cut a remarkable number of threads, including 27 tpi (with 0% error), which I have done. LMS has a gear calculator for threads which I often use. Adding the 21 tooth "A" gear enable metric threads. There will very small (hundredth of a percent or less) error on metric threads - talking about 16 tpi lead screw. There are metric lead screws.

 

[Aaron_W]

Yes, the new Chinese lathes are lower cost when adjusting for inflation, and I think that is relatively well known.

An LMS 8.5x20 (7500/7550) has power cross feed, which I do not find compelling. A QC gearbox is quite another matter and I would quite like to have that.

A 7" mini-lathe can cut a remarkable number of threads, including 27 1/2 (with 0% error), which I have done. LMS has a gear calculator for threads which I often use. Adding the 21 tooth "A" gear enable metric threads. There will very small (hundredth of a percent or less) error on metric threads - talking about 16 tpi lead screw. There are metric lead screws.

Do you have a link to the calculator? I've looked but have not found anything showing more than the factory listed 18 standard and 10 metric threads for any of the 7" lathes. Sure that covers most of the common threads people need (and honestly so many just use a tap and die), but is far less than the 45 on a SB9, 61 for the Atlas 6" or the 73 a Sherline can do.

 

[CraigH]

Do you have a link to the calculator? I've looked but have not found anything showing more than the factory listed 18 standard and 10 metric threads for any of the 7" lathes. Sure that covers most of the common threads people need (and honestly so many just use a tap and die), but is far less than the 45 on a SB9, 61 for the Atlas 6" or the 73 a Sherline can do.

It is a pain to find (I seem to forget the location). It will provide the gears for any number you insert. Here it is:

Change Gears for Threading

This calculator determines the correct change gears for any thread pitch. Works for all mini lathes and HiTorque Bench Lathes.

littlemachineshop.com

 

[SouthernChap]

Strongly disagree with your first point. There are only 2 lathes I know of under a 12" swing with a quick change gear box, one is the Grizzly / South Bend "Heavy 10" for $9500 (which appears to have been dropped from the catalog), and the Hardinge HLV (and clones) which are priced at "if you have to ask you can't afford it". Most vintage lathes also can cut far more threads.

Of course ELS is beginning to address both of these points, but currently that is a DIY project.

Few lathes under 12" swing have a power cross feed, the PM1022 and LMS 7500 being exceptions.

Lots of vintage lathes were available with both of these features, and many more options, like taper attachments, collet closers, tail stock turrets, milling attachments, lever tail stock etc. Many of these accessories are not available even on many larger lathes.

Spindle bore is the one place where modern lathes tend to do better, and particularly with the smaller lathes. A 7" mini has the same size spindle bore as most of the vintage 9" and 10" lathes and there are some 8-1/2" import lathes with a 1-1/2" spindle bore, bigger than many vintage 11-12" lathes which only had 1-3/8".


Now the ability to assess a vintage lathe is a completely valid issue. It is also often ignored that most vintage lathes need to go through a rehab process which can easily be as much of a process as upgrading a cheap import, and sometimes much more.

Well, now, I had this idea that the PM1022 had a QCGB but just checked and it doesn't. What a swizz.

 

[Aaron_W]

It is a pain to find (I seem to forget the location). It will provide the gears for any number you insert. Here it is:

Change Gears for Threading

This calculator determines the correct change gears for any thread pitch. Works for all mini lathes and HiTorque Bench Lathes.

littlemachineshop.com

Thank you, glad to hear it is not just me, just not easy to find. Even trying to work back from the link I can't find my way back to it without the link.

 

[Aaron_W]

Well, now, I had this idea that the PM1022 had a QCGB but just checked and it doesn't. What a swizz.

Lots of them have a gear box, but it is mostly for controlling the power feed speed. Most will allow a couple of thread changes on a set of gears, but very limited maybe 4 or 5 threads at most without swapping gears. The 9x20 is the same way, it sure looks like a QCGB, but not really.

 

[CraigH]

Thank you, glad to hear it is not just me, just not easy to find. Even trying to work back from the link I can't find my way back to it without the link.

Yes, I have that experience too - working backward at that point does not seem to work. I have entered "reference" to the website search, then of the three banners select "Resource Information".

The threading gear calculator, for some reason, is not in the "Info Center" on the website.