Sizing of tooling and tooling up a lathe

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Wallied

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Hello all. I'm a beginner from Finland getting into turning. For a few years now I've been making projects (mostly guitar related) on hand tools and a Ooznest/Openbuilds Workbee CNC (750x1000x~70 / 30x40x3)router, mostly wood, but some small brass and aluminum parts as well. No hiccups there, partly due to my background in mechanical engineering, so I'm familiar with the CAD and CNC side of things in particular.

Skip to this summer, I started renovating my grandparents old house from the 50s, with the intent to move there before Christmas. My grandfather was an electrician and a metalworker by trade, working at a large paper mill. During his time there, and after retiring, he brought a lot of tools and equipment from there to his home.

After his passing, I've now come to possession of a plethora of equipment, largely welding and sheetmetal (gas, MIG/MAG, stick welders, gas torches, large shears and a shop-made sheet metal bender with a capacity of approx. 2 m /6ft...)
The most interesting item for me, though, is his engine lathe, a 1961 make Zbrojovka/TOS SV-18R (http://www.lathes.co.uk/zbrojovka/), a 7.5" center height, 50" length between centers beast with a 8hp motor giving speeds from 14 to 2800 rpm. The 2000kg/4400lbs lathe was, according to my father, brought in the basement by making a hole in the foundation wall, building a track of railroad beams, and bringing it inside, mounting it on top of a ~4in concrete slab cast on top of the basement floor.

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So, the lathe is not going anywhere in one piece, and since I'm not tight on space, I've decided to keep it. It appears to be in good shape, though I've already bought new belts and now am in the process of cleaning it up and replacing the oils (spindle has bronze bearings, lubricated with rather elusive ISO VG ~5 spindle oil circulated by a pump). It has a lot of tooling, mostly HSS, but also a decent amount of old carbide inserts, mostly SECO, some Sandvik and Kennametal). These however, being old, brittle carbide with obsolete designations and missing a lot of correct holders, are probably not going to see a lot of use.

Now we get to the actual topic of this post. Since I'm going for a fresh start, I'm asking for recommendations on what cutting tools I should get. The lathe, again, is a 15x50, 8hp 2800rpm one, currently with a 4-way toolpost with a capacity of 32mm, with 25mm seemingly being the most correct size holder height-wise. I'm going to go for insert-tooling, though I'll grind the common HSS tools as well, since I have a decent pile of HSS already.
The work I'm going to be doing will mostly be cylindrical parts from 1/4 to 2", mild steel and 4140 for the most part, the usual beginner projects for a start. I'm thinking I'll be mostly veering towards the smaller work. So the first thing would be the question of whether I should go for the largest 25mm holders for the rigidity, or tone it down to 16mm or even 12mm for better visibility and control? I don't care about chasing the best MRR (for now at least), but would like to be able to take decent size cuts anyway. The prices of the sizes are worlds apart as well...

Currently, I'm torn between the C-D-W shapes for a general use insert. The D would give the better reach, but it's the least durable (which for the use will probably not matter much, hell, I've thought about even the 35 degree V-diamond), the C-diamond and W-trigon are apparently pretty much equal. The negative-positive rake is another issue. I don't think the machine cares (grandpa had a 25mm, negative rake square holder), but finish quality is something I care a lot about, and from what I've read, the positive rake inserts are better for that.

So, in a nutshell: what would YOU get to get started on a heavy, 8hp 15x50 lathe for hobby use?
 
I have a LeBlond 15 X 60 inch lathe and faced much the same thing. Fortunately most of the tooling had inserts with it, so my task is easier.

If you have the standard chucks, you will be hard pressed to do really small work. After getting at least one tooling option working, I'd check out the smallest diameter you can hold in your lathe chucks. Mine necessitated in buying a small 4" offshore chuck and making a mandrel for it to hold it in the 4 jaw chuck. this way I can use it like a set-tru chuck, and turn very small things on the big lathe.

You will find that buying a VCMG or similar holder, for these inserts will give you access to common finishing inserts, which are handy for small work. I particularly like the ones ground for aluminum finishing, even though I use them on steel all the time.

Id choose the 300 series inserts and make the holder fit your lathe....
 
If you search on YouTube for Chris Maj, you will see in some if his videos using a smaller chuck in a big one like Dabble described. Instead of making a mandrel, I think he chucked it directly in his big 4 jaw chuck.

For what you described, I would probably start with a C style tool, that can do turning and facing with the same tool. You have the power to use negative rake inserts, so a CNMG would work for you. Many of us here have smaller lathes and use the screw down inserts, CCMT, those are positive rake inserts and take less horsepower, but are only one sided. The CNMG can use both sides of the insert, so you have twice as many cutting edges. For smaller work, you might want to use the positive rake inserts anyways to reduce deflection in your workpiece.

Another good one to have is a D style so that you can get into places the C inserts can’t. I haven’t used a V style yet, so can’t comment on those.

I think you will be fine with 1/2” (12mm) tools as long as you are not taking big depths of cuts, once you start wanting to do some heavy roughing, then the bigger ones would be more appropriate.
 
Thank you both. On the chucks, I already have the large three-jaw already on the lathe, a four-jaw of the same size, and a 3 or 4" three-jaw. And for roughing, I have a Sandvik 2525 shank P-max holder for snmg120408 inserts, which should chew through whatever I throw at it.
Well, I guess I'll be getting a DCLNR2525 with some CNMG1204(04?) inserts for the general stuff, and a SLCR with some CCMT and CCGC for the smaller stuff and non-ferrous. Boring shall be done with pre-existing bars and reamers for now. Still need to get some threading insert tooling looked up. A lot to do and to make, and too little time.

We'll see if I can refrain from DROs or a full blown conversion on this, as that's been tingling in the back of my mind for a while now :rolleyes:
 
That is a fantastic lathe. My experience with Eastern Block machines is they are heavy and well made. Condition of the bronze bearings will be important, as well as the apron oiler. Failed apron oil delivery is something I always check out on old machines. Wear is more a function of oil delivery than use. Very unusual to see that speed range in that size lathe. It looks like the machine stole a little of the design from Holbrook and CVA, both pick of the litter machines.

Give it lots of love. You have a special machine if condition is as good as it looks. Dave
 
So to agree with the above , we had a TOS lathe in the original tool and die shop . It was a beauty , a little larger than the one you have , but never any issues with the lathe . Ran many jobs for the nuclear subs , large diameter knurled rollers etc . Ours had a rapid traverse on the z axis which was a major plus .

Nice looking lathe you scored there . :encourage:
 
Wallied said:
So, the lathe is not going anywhere in one piece, and since I'm not tight on space, I've decided to keep it. It appears to be in good shape...
Click to expand...

Indeed it does! That lathe looks very well kept, and many TOS machines are still alive and running out there. Congrats!
 
Wow, that's quite a "starter" lathe! You're a lucky man.

I would look into a QCTP (quick change tool post), either an Aloris style or Multi-fix depending on budget and availability.
As for tooling, a good place to start is one of the import sets available on eBay or Aliexpress in 12 or 16mm shanks.

Something like this will provide all the basics without breaking the bank.

I have purchased a lot of this type of tooling and it has all been of decent quality. The Chinese carbide inserts may not be as good as the name brands, but at 1/10 the cost they are more than adeqate. Buy a pack of each of the type of inserts.

and welcome, we have fine group here.
 
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