|Will D||12/03/2019 23:01:32|
|10 forum posts|
I currently use hss and have a few carbide insert tools that came with my lathe. However in my quest to fill my workshop with goodies I’ve been wondering if it’s worth buying a tangential tool holder? My next job is turning some loco wheels from castings would these be the tools for the job?
4592 forum posts
No. HSS is perfectly adequate and fancy tools don't make the job easier nor get a better finish. If you are having trouble put the money into free cutting steel and brass bar and reduce it to swarf. getting some hours in is more useful than a special tool.
|duncan webster||12/03/2019 23:20:14|
2112 forum posts
Well I must disagree, I wouldn't be without mine, it makes sharpening so much easier. However if starting again I'd make one, plenty of ideas on Google. I'm going to make one for my little Cowells in the fairly near future
Not the tools for loco wheel castings tho, I use brazed carbide for that, ground to he correct radius for the flange/tread interface
|John Reese||13/03/2019 00:09:32|
|749 forum posts|
I made my own tangential holders, LH & RH. They are my favorite tools for turning and facing. Bits are easy to grind, just a 30* angle on the diagonal.
3651 forum posts
For the job in hand, turning loco wheels with a radius where the flange joins, you could make a tangental tool holder to hold a piece of round HSS the right diameter to give the desired radius. But it would be quicker to grind up a conventional HSS tool bit with the right radius. It does not have to be perfect or even super precise for that application. Alternatively you can buy indexable carbide tool holders that take a round insert. Get one that has an insert of the radius you need for your wheel job. Those tool holders and inserts are often listed online and in catalogs as profiling tools.
|1089 forum posts|
As John, I have made my own tangential tools. They work very well and as others have said, they are easy to grind. If the work has a hard skin I use carbide tipped tools for the roughing cut and a tangential tool for the finishing cuts.
|Neil Lickfold||13/03/2019 06:29:42|
|551 forum posts|
I no longer have a tangential tool and seldom use anything in hss. I don't run my lathe faster than 800 rpm on anything, and the modern carbide tools are just awesome , especially for the amount that can be done on 1 edge.
There is a huge range, and more places are now selling lower numbers of inserts. Only this week, a trade supplier who only last week, the min quantity was a box of 10 or how ever many was in a packet, now offer single inserts or a mix and match option, and they did not make the single inserts more expensive either. So a selection of different radius options is very viable now.
If I was to buy a new tool, it would be a multi turn tool. They groove, turn, and have different geometry inserts from full radius to various bull nose inserts. The 3mm wide tool seems to have the widest range of geometries. Another interesting tool is the MDT tool, where it can drill, bore and outer turn with the same tool.
So there is some really interesting stuff out there for sure.
|474 forum posts|
can u give us the link to this MDT tool...what I found was what looked like a home made spade bit....!!!!!
be interesting to look at.....
|Barrie Lever||13/03/2019 08:23:12|
|253 forum posts|
I agree with Neil, I only now use HSS for special tools like tiny internal threading tools or small boring bars.
The huge range of inserts and carbide tools can mean that a small hobby machine maybe be able to tackle work that would be outside of it's capability if restricted to HSS tools.
Certainly if the tool is likely to get hot or the material being cut is abrasive then carbide is near to essential.
Whilst the carbide tools and insert development is driven by industries needs that does not mean that there is no cross over, these tools are the hobby machines best friend !!!
|290 forum posts|
I suppose personal choice is the key here, what works for you and you're comfortable with.
The majority of my turning is done with an eccentric engineering tangential tool but there's nothing to stop you making your own as some have. It's easy to sharpen and set up for cutting and gives a good finish.
Insert tools tend to be for certain jobs but I use them sparingly.
I also have quite a few old style hss toolbit holders but they sit on the shelf unused.
You dont have stick to one style or system, use whats right for you.
|Will D||13/03/2019 08:41:39|
|10 forum posts|
Thanks for the advice I like the idea of the easy sharpening of the eccentric engineering tool holder but I’ll probably stick to hss for now. Although will my insert tools be better to get under the skin of a casting or should I stick to my hss?
|Niels Abildgaard||13/03/2019 08:51:29|
|217 forum posts|
Homeground carbide in homemade holder:
|2108 forum posts|
I wouldn’t be without my Tangential tool. I’ve even used it with reground broken carbide milling cutters for turning HSS and hard cast iron. Insert tooling is nice for some jobs but the inserts can work out expensive. Once you’ve got a Tangential tool the running costs in small pieces of HSS is negligible. In fact I gave up on insert parting tools due to the cost of inserts.
|Neil Lickfold||13/03/2019 09:46:10|
|551 forum posts|
Here is a link to the Korloy through a UK agent.
They are really ment for cnc with through coolant. But can be used on a manual lathe with a squirt bottle. The smaller 10mm and 14mm work well on a Colchester sized lathe. Not tried them on my myford. I have made my own Dbit tools for non ferrous materials on the Myford as a combination drill turn tool.
With my 1/4 inch carbide , on ali and brass , dont go more than 30mm deep. In plastic and wood I go upto 70mm deep.
|John Haine||13/03/2019 09:47:10|
|2548 forum posts|
Duncan, this might be interesting if you haven't seen it - for the Unimat rather than Cowells but similar size.
|1266 forum posts|
Everyone has their own preferences in these areas - to some extent set by what they are familiar with (technology moves on but some of us oldies don't always).
I have a Diamond tool holder and it is very useful - mainly because it is convenient general purpose tool and it's simple to sharpen the tooling. I keep a number of spare tool bits ready for it, a 'normal' one (simple to swop if the one in use fails) and several round nose ones with different tip radii (they generally last longer but cannot get into everywhere). So it's very handy, works well and gets used a lot.
I also have insert tooling for parting and screw-cutting because getting these profiles right in HSS is very fiddly (e.g. difficult). Again this is mostly about convenience and time - I once used HSS for these ops but these days would only do it for a one-off or special situation.
I also have a few (now quite old) regular insert and carbide tipped tools (both turning and boring) that I use specifically for roughing out castings - including wheel castings. Some newer (lost wax) castings don't have sand inclusions but most of what I work on do - and you need to get under the crust.
However, once under that crust, I still use the HSS tooling that I have for the purpose because I have the shapes and angles that I specifically need to do certain jobs (like the right radius round-nose tool for the flange/tread root). I don't use the Diamond (Jack-of-all-trades) for my wheel work because specific HSS tools do a better job.
Caveat - I build in 2.5" gauge - so my advice is specific to working in that size and if you are building a large 71/4" loco - then this may not apply to your needs of course.
So my very long-winded reply to your question is that whilst a Tangential tool is very useful to have - it won't serve all purposes and it's often better to use something more suited - in my case my HSS tooling for wheel castings - although others here will no doubt have more modern/convenient/expensive alternatives...
|Will D||13/03/2019 10:30:06|
|10 forum posts|
Thanks Ian , i’m currently building Bat in O gauge so will take your advice with the hss
|4419 forum posts|
Before HSS lathe tools were made of the same sort of carbon tool steel used to make knives and razors. This type of carbon steel can be heat-hardened, sharpened, and it holds a good edge. (Unlike mild-steel which can't be heat-hardened, and won't hold an edge.) The problem with carbon-steel tools is they lose hardness rapidly if the temperature rises above about 150C, which is easily done on a lathe. The tools work well, but the operator has to work slowly, and flood cooling is essential. A great deal of time is wasted resharpening and heat-treating cutting tools.
High Speed Steels are alloys containing Chromium, Molybebdum, Cobalt, Vanadium, Tungsten. Various mixes are used to optimise HSS to a purpose, but the essential effect is to increase the temperature the tool can cut at without softening - up to 400 or 500C. This means HSS can cut metal faster and for longer than Carbon-steel. It out performs tool-steel by about 5:1, and it it rendered most lathes made before 1900 obsolete; they couldn't take the extra stress. HSS isn't harder than tool-steel, but it stays hard when it gets hot. If HSS is overheated whilst cutting when grinding, then it too loses it's hardness, and has to be resharpened. Usually this softening only happens near the cutting edge and - with care - the tool-bit can be ground back to good metal. Industry don't care much for tools that need resharpening because they slow down production which wastes a lot of money. In a home workshop, the main disadvantage of sharpening is the need to own a grinder and know how to use it. The Eccentric holder deskills grinding, and it cuts well.
Carbide is like HSS except it's harder and even more heat-resistant. A further advantage is that it can be cast into standard precision shapes, and the inserts can be changed very quickly without having to reset machines. It out-performs HSS by at least 5:1 but there are a number of new gotchas that reduce it's usefulness in a home workshop. Most serious is that carbide's high performance is good enough to change the tool geometry and the way it's used. HSS is usually sharp and it cuts like a knife. Carbide is usually blunt and it levers metal off rather than cutting it - ideally the point of the tool runs in the empty space created by the wedging action. This way of removing metal is fast and efficient but it means the machine has to have plenty of power, good rigidity, and high rpm. Running carbide too gently is likely to spoil the finish: it works best taking heavy cuts at high-speed.
Might sound as if carbide is useless on an ordinary hobby lathe - not so. The convenience of exchangeable inserts compared with grinding HSS is considerable. They come in all shapes and sizes, round, triangular, sharp, blunt, rectangular, threading etc etc. Carbide punches through hard materials like the skin on cast-iron much better than HSS. Although you may have to experiment it is possible to get a good finish at lower speeds and gentle cuts.
Experience with HSS may be an obstacle to getting the best out of carbide. For example, when HSS chatters, it makes sense to back off by reducing speed, depth of cut and feed rate. Carbide likely requires the exact opposite: more speed and deeper, faster cuts. It follows that chaps brought up on Carbide are liable to misuse HSS! Older tools (designed for HSS) tend not to do well with carbide because they are too slow.
80-90% of my lathe turning is done with carbide, and I only use HSS to make finishing cuts, either for looks, or to remove tiny amounts of metal on a precision job. Other way round on my milling machine; on that I use carbide for roughing out but most work is done with HSS. Horses for courses. I don't think it's wise to generalise about HSS vs Carbide, so much depends on the operator, his machinery, and the type of work he's doing. Nothing wrong with starting with HSS and trying carbide later, or the other way round. Quite likely you'll find as I have that both have their place.
|not done it yet||13/03/2019 10:59:38|
|3029 forum posts|
There are far more bulky items that you could buy, to fill the workshop, at far less cost per litre!!!
I like my tangential tool holders, too.
2401 forum posts
I have a tangential tool for general use too, but also a selection of indexible tipped tools, more a case of nice to have than application. I tend to use the tangential for every day use on MS, brass, & an indexible tip for aluminium although the tangential does just as well. On the few engines I have made I use brazed carbide tipped on cast iron cylinders & flywheels so like others I use what's best for me at the time.
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