Tarnow lathes?


Anyone run into one of these? (bet you barked your shins if you did...)
Done a good G**gle on them, found the manufacturer's site, seems they still
make machine tools (but all my enquiry emails bounce back from their
server...), one I'm looking at (remotely, 8-hour drive away, longer towing
2&1/2 tons of machinery) is a 32cm swing (about 12-13") 100cm (about 40")
between centres *possibly toolroom* lathe from the 60's, wondered if anyone
knew anything of 'em? The guy's after scrap-by-weight value for it, but
thinks it's too good to melt down, says it's just too big for his shop! Not
a lot of tooling with it (maybe just a 3-jaw), apart from what looks like a
taper-turning attachment?
Thanks,
Dave H.
Reply to
Dave H.
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If it's in good shape it not a bad lathe. The one's I ran were built in the late 70's and early 80's. They seem to chatter easy on long shafts. I think they needed more iron in the bed on the longer lathes. (20" swing 10' centers) Seemed fine for chuck work though, which is most of what we did on it. Can't say much about a small one like the one you are looking at. It may be just fine. Although if I was in the market for a new lathe they would be near the bottom of the list.
Richard W.
Reply to
Richard W.
Thanks for the feedback, Richard, may I pick your brains a little more?
I'd mostly be using it for work in the chuck, things like machining hubs and clutches I guess, and boring smallish castings on the carriage with a b/c boring bar, occasional work on driveshafts etc., it'd be an addition to my tools for working on / modifying motorcycles - I don't imagine I'm likely to be doing anything that would tax it too much :)
I'd be interested to know why you'd put them at the bottom of the list, though - rigidity? This one (the TUB32 model) comes in at around 2.2 tons for the 12" swing, 40" and is quite a bit heavier than a Colchester of that size, sounds like it should have plenty of iron in it! Newer ones may have gone the same way as a lot of manufacturers' kit though, lighter castings, 18g sheet steel where cast iron would have once been used...
If it's a matter of "fit and finish", I wouldn't be expecting too much from the eastern bloc (I've seen their motorcycles from the 60's!), if it's down to durability and reliability that's a whole 'nother thing?
While I think of it, it runs (as delivered from the factory) a 10HP 3-phase motor - reckon I'd get away with a lower-output VFD if I kept the cuts fairly light? 7.5KW VFD's cost an Imperial Arm and Leg (more than I can pick the lathe up for, anyway) as does getting the 'lectric co. to install 3-phase power, but here in the UK 3KW (4HP) are getting to be reasonable - and 10HP in a 12" swing lathe seems kinda generous anyway! I'm still at the stage of factoring in rental of a plant trailer and truck to tug it, new reinforced concrete base for the 'shop, 50 yards of heavy armoured cable, VFD etc. and want to keep the collateral damage to my wallet down...
Thanks, Dave H.
Reply to
Dave H.
If you bolt the lathe to the concrete floor you can make it a lot moe rigid. Also proper leveling makes a big difference. There is an art to doing long thin parts without getting chatter, a steady rest or follower rest being manditory.
I would not recommend using an underrated VFD. I would spring for a single phase motor of about 5 hp or so and eliminate all your other electrical problems. It would probably be cheaper in the long run and would also make the lathe easier to sell.
John
Reply to
john
True, but a lathe with wide ways helps a lot. Tarnows have narrow ways. At least the ones I have used.
I would run a rotary phase. My P&W has a 7.5 HP motor and it works just fine.
Richard W.
Reply to
Richard W.
I think you would find it fine for that. I could take .400" out of 6" bore running a .020 feed. Didn't even know it was cutting.
Rigidity for longer shafts. I have had 6" shafts chatter, yet the same shaft in a different lathe cut just fine. The ways are narrow. Also the cross travel is limited. In order to face a large part in one cut, you would have to positition the tool just right in the cross slide travel. I didn't like the electric clutch. For long heavy parts it engages to fast. Sounds like they wouldn't be a problem for you. They seem to be a nice accurate lathe otherwise. I don't remember the model, but one of these had a weak clutch. It's been close to 20 years since I ran one of these lathes.
I run a rotary phase on my lathe and it works just fine. That is what I would get. I just got a 20 hp 3 phase motor that I plan to hook up to my 3 phase welder. But I am in no hurry since I lost my job.
Richard W.
Reply to
Richard W.
Checking the spec' (translated as best I can from the original Polish, will go see my Polish friend Mata if I get the manufacturer's handbook!), it looks like the width of the ways on the smaller ones like this is about equal to twice the centre height, and not having a bed gap might help rigidity some? A new reinforced concrete floor (6" or 8" slab with top and bottom steel mesh on insulation slab over compacted rubble and sand blinding) is on the cards whatever I end up buying, and ragbolts into the concrete would be wise, IMHO, to minimise vibration. I've seen machinery dance across the floor when it hit resonant frequency, don't fancy 2 tons of lathe chasing me out the door... 1/4 ton of rock'n'rolling ICL chain-printer was bad enough.
I was thinking of a VFD as a measure of future-proofing as at some point I'd like to add a smallish mill to the toolkit, and rotary convertors take a fair amount of real-estate - not something I'm particularly blessed with (SWMBO would rather have other luxuries and space for our motorcycles in the Big Shed!) - and it looks like there's not a lot of difference on price. A single-phase motor in that power bracket is probably going to cost more than the VFD, too, and would still leave me with around half the original horsepower and needing a rewire for the "shop" power...
I've seen a few smaller lathes run on "undersized" VFDs without too much of a problem, and to be honest the lathe has speeds from 17 to 2800 RPM and plenty in between straight off the motor, with drive clutches so the motor would be able to spin up without the added mass / moment of the spindle and workpiece? I appreciate that it might limit the amount of chips I could make per minute, but this is for serious hobby use, not a production shop, and my concern is more that runing the motor on an undersized VFD could cause issues for the motor - not being an expert on induction motors (more optics, RF and microwaves, really) I'm open to the collective wisdom of the group!
Thanks again, Dave H.
Reply to
Dave H.
I agree with Don. An idler motor doesn't take up much room. You are going to need a short bench to hold your extra lathe chucks and the idler can sit on the floor under it or on a lower shelf. Idler motors that are made to sit with the shaft vertical are a space saver also.
Richard W.
Reply to
Richard W.

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