Distance between centers

How is the distance between centers measured, and is it consistent among the manufacturers. For example, my PSI 12" midi is listed as 18" between centers. The actual measurement from the end of the headstock spindle to the fully withdrawn tailstock is 19 1/2" (with the tailstock exactly at the end of the ways). If I insert a small 2 MT pronged driver I get 18" from the drive center to the tail stock. If I put my shortest revolving tail center into the tailstock I get 16 1/2". I'm not complaining - we all use various length devices on our lathes, large chucks and long revolving centers - it is impossible for them all to result in the same distance between centers.

I raise the question as I'm looking at the possibility of upgrading my lathe - specifically the Oneway 1224. But I don't know what the "24" means in practice. If it is the distance between the the end of the headstock spindle and the retracted tailstock end then I'd gain only 4 1/2" in spindle length. If it is measured from the tips of a small prong driver to a small revolving center then I might gain more than 6".

My guess is that there is no consistency and one need to measure for one's self. This is not trivial, I have a very small shop and have to allocate space. I have an extension for my PSI that I set up when I'm turning tool handles - the only long spindle application I do. I'm not going to buy a new and longer lathe if I need an extension anyway.

Is there a standard in the specs for distance between centers? Or is it the usual caveat emptor.

It *should* be from tip to tip of centers with the centers provided with the machine, but I'm afraid its 'caveat emptor'. I know some have cheated by having the tailstock as far back as it could still lock down. Since the Jet has self ejecting centers you would gain several inches by measuring to the end of the quill with the quill fully retracted versus measuring to the tip of the live center with it fully seated. I suppose it would be 'fair' if they used dead centers on both ends. At any rate I suspect its marketing that decides what to call it.

Went out to my shop and checked a few measurements:
Jet 1014 -> 14" spindle to quill but only 13" C-C
Jet 1220 -> 20 3/4" spindle to quill but only 18 1/4" C-C
Jet 1642 -> 42" spindle to quill but only 38 1/2" C-C

So I'd say that Jet uses the largest possible measurement - end of spindle to end of quill rounded down to nearest inch. Interestingly, the newer machines are the 1015 and 1221. Not sure what they did to get the extra length although it is a new casting for the bed. Wonder what the new 1642 will be called.

Yeah, I've noticed that Jet REALLY fudged their numbers on that score. You can get what they claim, but only if you're using their stock centers and hang the tailstock off the end of the bed so it's just barely hanging on....

I'd like them to do a little better at their "truth in advertising".

Jon, I checked on my Oneway 1224 and here are the results;
end of spindle to end of tailstock with the tailstock even with the end of the ways 25 1/4"
2 spur drive to Oneway live center 20 1/4"
1 1/4" Stebb center to Oneway live center 20"
end of spindle to generic live center 22 1/4"
Talon chuck with #2 jaws to Oneway live center 19 1/2"
Hope this helps. I use my 1224 more than any of my other lathes(Oneway 2436, Robust Liberty and Jet 1220). I think it is because of the way I have my tools arranged. Good luck in your search.
Joe

Since you are considering a Oneway specifically why not call them directly and get their answers?

Thanks Gents, good information.

Were I to hit the lottery I'd get a Robust Sweet Sixteen short bed, the ability to take the head section of the ways to extend the length is a real plus. One of these days those of you who are members of the AAW may see an article in the monthly journal - it is accepted in principle. The topic, "it ain't just pens" is for the small shop and the beginner - you can do a hell of a lot on a 12" swing midi. Sadly, the vendors who sell midis in their catalogs spend many of their pages on "project kits". OK, I make pens as my wife likes to give them away, and anything that keeps her happy allows me more time on real projects.

My shop is also my bedroom, we are in a two bedroom apartment (and of an age where we don't sleep on the same schedule). The bedroom is 12' x 15', and I've floored half of it over the wall to wall carpet with Home Depot "attic flooring" of tongue and grooved 2' x 4' plywood, the rest is where my bed and bookshelf and desk is. Bandsaw, workbench, drill press and lathe take up most of that - the grinding station is on the carpet on a pedestal mount, as is the 1" belt/5" disk sander.

A lot of verbiage, but a bit of explanation. I don't have the luxury of space for more lathe than I absolutely need. When I use the extension for my PSI 12" x 18" I use an old adjustable "roller" support for long stock on the table saw (which I don't have anymore). I can set it up in five minutes, and take it down in the same - which is good as I can't get to my bed when it is set up. I'll never be able to have a real shop unless I hit the big lottery, I'm long retired at 78 and have one leg that tires from childhood polio, and the other is a prosthetic. Wow, sounds like a complaint - it ain't. The only handicap I have in wood turning is finding the wood - I'm surrounded by forests with dead falls and such, but can't walk into them to collect the wood with my chain saw.

It sounds as if the Oneway 1224 might be the upgrade, I'm getting a bit tired of readjusting the centering of my PSI. No knock on the PSI, it is a fine piece of equipment - but like the Delta and Jet midis it is made from parts from China. They are sound and well made, but don't have the tolerances that companies like Oneway, who make the lathes individually, have.

Pardon the ramble, a few beers after an evening of trying some new turning forms.

Hi Jon,

I have an old Delta reeves drive lathe and a Oneway 1224. The Oneway is a HUGE upgrade over most midi lathes.

I would be concerned that it might not fit very well in your shop that also doubles as a bedroom. The Oneway comes with a built-in cabinet with the motor and controller hanging below. The footprint of the lathe and cabinet is quite large.

It is painful for me to say it, but it sounds like the PSI with removable extension is a good solution for you.

Steve