Small lathe, large spindle bore...

Do they make something like a 7-9x10-20 benchtop lathe with a 1.5-2" spindle bore? All the ones I look at have around half to three-quarters of an inch.

I'm not aware of such a machine, but if you're not planning on turning really long stuff, you can get much the same effect by making, in effect, a REALLY deep chuck backplate, sort of like a tophat, running the outboard end (behind the chuck) in a steady (for occasional use) or a bearing housing bolted to the bed (for continuous use)

The hole in the 'backplate' can be around 2.5" for a 7" swing late, and if you go for a 20" bed, and a 10" "backplate", you've effectively got a 7x10 lathe with a 2.5" spindle bore. If the things you turn are longer, you'll need to get a longer bed and make a longer tophat.

Radio

I think the smallest sized lathe with a 1 1/2"
spindle bore is the South Bend Heavy 10. One of the reasons gunsmiths like them.


Hal

Heavy ten (and all the big SBs) have 1 3/8 bore

Seems like some of the Logans have big bores for their swing size.

Richard

The short, unfortunate answer is, "no."

If somebody made such an item, it would sell
pretty well I suspect.

Jim

Boxford VSL and possibly others have a 1.375" bore.

bb

My Logan 14" (biggest Logan made) is 1 3/8" spindle bore.

FG

They do not make a 9x20 with a bore that big. Closest is a 10x27 that I carry with a 1-1/16". If they had a machine that size with a bore like you asked, I could sell a lot of them.
Main reason is spindle mount, Even a 14" Machine with a D1-4 can only go to about 1-5/8" or so.
But I am working on it, Just might be a while yet.

FWIW, we had a similar discusion here before...about small lathes with relatively large bores...not as small as you want but, the smallest lathe with a 3 inch bore is a 14 inch model imported by Jet.

I mention this mostly because I have one for sale

because the 9x20 you mention is a cheap belt driven P.O.S. i asume you expectations on fit/finish/ridgidity/power must be rather low

i think if i HAD to have a CHEAP benchtop with a big bore I'd start with a 9x10 I would MAKE an new light duty spindle and headstock for it. with some pipe and some larger tapered roller bearings.

i mention this because I think you can make something yourself to 9x20 quality fairly cheap and easy.

I had a 9x20. i THINK there might even have been room to bore some much bigger bearing bores in the current headstock. (i had mine apart a long time ago)

i believe you could end up with somehting pretty usefull too.

The 'small lathe with a teeny spindle' problem
goes pretty far back. I think he AA products
(109 lathes) is the nadir of that issue.

I figure somebody should build a real quality
machine with seven inch swing, and a three inch
dia bore. At that point you could nearly
build the motor right into the spindle. No
belts or gears.

Would not be cheap but there would be a real
market.

Jim

Hey Milacron,
I have a 14x30 lathe I carry and can order up to a 4-1/8" Spindle Bore in the machine. Even bigger if I want to 6 inch, but the price almost doubles to get that big.
They are about $10,000 for a new machine with the 4".
They are Small in terms of swing, but about 4000 to 5000 pounds. So not really small, just like that Jet you have. 14x40, 4000 pounds.
I think he is looking for 400 pounds.

There are quite a few floor standing lathes around with very short beds, I have seen units 18" x 18", take up the same floor space as a bench lathe (including bench) but are worlds apart in rigidity and power. the spindle bore of these machines is usually 2 1/8" Weight 2000 - 3000lbs, easy to handle on a concrete floor.

I was thinking about this in relation to the thread about the EMCO Compact 8. Looking at the exploded view on Grizzly's web site it looks as though the bearing bores are in a casting section that protrudes into the interior of the headstock casting. I would think that this would pretty much the case in all of the 9x20s. Now granted they are a cheap POS* better suited to doing tinker toy and model work but almost anything can stand dome improvement. Bore the housing to take a cartridge spindle that has a mounting flange that bolts to the front of the headsock casting. this surface would need to be machined square with the bore. Now by this time you gear train for feeds and threads is probably lost because the spindle housing or spindle diameter is too big for the 1.5/2 Module change gears. An 1-1/2 bore is easily gonna need 2"/50mm ID bearings. Do you go with 100 sewries or do you feel brave enough to go with 79100 Series bearings. Now we are talking a quad set to handle the load. Angular contact 791XXs aren't cheap. So now you have opened a whole other can of worms. Never mind you would most likely need a bigger lathe to do all of the modifications in the first place. So by the time you are done with all of your modifications you just might of been better off to buy a different lathe in the first place.

* I feel free to make the POS statement as I do have one in the basement much to my embarassment

I have some comments of a historical nature to add to this discussion.

Back in the 1905-1931 period, Hardinge made their Cataract bench lathes in several sizes. There was a choice of 32 or 38 inch bed length. There was a choice of 7 or 9 inch swing. But to the original question: They made headstocks with spindles that used 3C, 4C, 5C, 6C or 7C collets. The higher the number, the larger the collet dimensions. The C stood for Cataract, since this series of collets was originally designed for the Cataract lathes. Hardinge continued to make more modern 3C, 4C and 5C collet lathes during the 1931 to around 1955 period. They still make 5C lathes of rather small capacity, the HLV-H model. Some years ago, they introduced the big 16C collet, but it is only used in CNC machines.

Now the 3C collet is familiar to small lathe owners because it was the one that also fit the South Bend 9 inch lathes. Several modern lathes used the 4C collets, like the Rockwell 10 inch. And everyone knows the 5C collet has become the most common collet in the world because many lathes and fixtures have been designed to use it. The 5C collet drawbar is 1-3/8 inch diameter and that is why so many lathes in the 10 to 14 inch swing range have that size spindle bore. The Hardinge 5C lathes will only pass a bar of around 1-1/8 inch diameter because they do not have a removable collet adapter at the spindle nose. The bore for the collet body is further restricted by the collet key.

But the 6C collet has a 1-5/8 inch diameter body and the 7C collet has a 2 inch diameter body.

So there is a historic answer to the original question. Hardinge did make lathes with 38 inch beds, 9 inch swing and about 1-1/2 or 1-7/8 inch clear through spindle bores. The bores are actually as large as the collet body, but there is a collet key that reduces the maximum bar size that will pass clear through the spindle.

I have two of the 6C lathes and one of the 7C headstocks. They are quite rare, of course. I have a good selection of 6C collets, which go up to 1-3/8 inch round capacity. Hardinge still offers to make a 6C collet for $660 each. But I have never seen a single example of a 7C collet, which went up to 1-11/16 inch round capacity.

Larry

monarch had one, don't remember the model, it was like a sawed off 12ck, with a extra large bore. I had one for sale from the 40s, don't remember the model. Ironic because Monarch probably had the smallest hole per pound of lathe normally

Not to drift too far away from the "small" part of the topic, but there are 18" Le Blonds and Lodge & Shipleys out there with 5" holes

John

To add to the posts suggesting boring the headstock for larger bearings: if high speed is not needed perhaps plain bearings could be fitted and a larger spindle made to fit. I have an extra 11" Logan headstock that could possibly be fitted to another bed??? Most people equipped to handle these modifications probably have machines superior to any possible result.

Rick

If you can live with 1 7/16", Grizzly has three 12" lathes in the $2100 price range, the G9249, G4002 and the G4003. Their smallest lathe with 1 5/8" bore is the benchtop gunsmith lathe, the G4003G at $2700 including the stand. The Grizzly gunsmith lathes are designed around a larger spindle and also have a larger nose than the plain version. Dennis