More beginner questions

Hi everyone,

a couple of things I need help if that’s ok.

in one pic you can see the tools I got with the machine, are they ok or should I buy some new one, also what’s the round one for.

another pic shows the first bit of turning I’ve done since school, along time ago.

it looks very rough to say the least, is it the tool I used or me or maybe the metal.

it not very good at all.

the other pic shows the tool towards the metal bar I was turning, if you can see it, my question is, the tool seems to be very low of the turning piece, should the tool be basically level with the centre of the piece your turning.

one last thing , can anyone recommend a good nvr switch.

thanks for all your help.

chris m……

Edited By JasonB on 30/05/2022 19:29:57

Yes the tool should be exactly on centre

easiest way is to trap a strip of metal about 6” long between tool and work. It should be vertical Use strips of flat, shim or even cut up tin cans to bring it up to height. I

it looks very low opin your photo

keep the questions coming

Chris,

I agree with the centre height comment above but a few other points (I would say that your photo angle is tricky to see how far below your tool point is);

The metal you have used looks like a component rather than a new piece of bar (I'm looking at the recess at the other end). Perhaps you are trying to turn something that is quite rough and or hard? A fresh piece of known bar might help.

Are you aware of the correct speeds and maybe depth of cuts - or are these your next questions?

Some of your tools look like high speed steel (HSS). Do you have a bench grinder and or have you ever used one before. If you stick with HSS, you are likely to need one.

> the tools I got with the machine, are they ok or should I buy some new one, also what’s the round one for

The material they are made out of will be just fine, but they will need to be sharpened - even if they happen to be sharp now, they won't stay that way for long. Sharpening can be a bit of an intimidating topic to start off with, but watch a few videos and read a few books and then get your hands dirty and it will make sense. A basic bench grinder is all you need - there are usually loads on Gumtree and Facebook Marketplace for not very much.

Round tools are generally used when you want to be able to fine tune the orientation of the cutting point, such as in a boring bar. Not quite sure what this particular one is ground to do, but people do all sorts of things with HSS cutters.

> is it the tool I used or me or maybe the metal

It could be a bit of all three. The biggest problem is that the tool does indeed need to be at centre height - one easy way to text this is by almost touching the tooltip and a centre in the tailstock. People will say to be a tiny bit over or under for different applications but the basic principle is it has to be on the centre, or your tool is at the wrong angle to the material it's cutting. Your tool there is quite low so the material itself is trying to "climb" over the tool - that's why the finish is worst at the tip, where it's most slender.

The tool could be not-sharp, and your tool-holding might not be rigid - everything has to be tight all the way from the tool-tip down into the carriage, through the bed and back into the headstock. And the metal you are cutting might not be ideal, though it looks like you've chewed it up pretty well! In general though having material of a known standard and thus properties means you have one less thing to second-guess.

In the pictures I can see at least one of the clamping studs is missing indicating that installation/lathe set-up is not done properly. A good turning result starts with a good set-up of your lathe, generally called “leveling”. although it is not the correct expression. You can find much information about it on this form since it is a popular topic. Niko.

It's difficult to see, but it looks from the first picture like you're using a slotting/parting tool on it's side? This would explain the poor finish and low tool height.

First things first; if you don't know what the metal is then bin it and get a known grade of metal. The ideal would be EN1A leaded. If, with a known grade of metal, the finish is still poor then the tool shape and position can be considered.

Andrew

Looking at your selection, the tools all seem still serviceable, perhaps with some judicious re-grinding.

The shiny ones are of High-Speed Steel (HSS).

It's not entirely clear to me if some are lying on their sides; so the clearance angle, if that is what it is, on the fourth down is a bit large but that should not matter. For steel and phosphor-bronze, the top of the tool should slope 2-3º or slightly more, diagonally down away from the very cutting-corner. Aluminium - the slightly more. Brass - flat (0º ), giving more scraping than shearing. In all, the flank and front face below the cutting-edge is angled back below itself for clearance.

The top one was perhaps of special purpose, and being round bar, unless there is a flat along its underside it needs to be held in a shallow V-groove pad or a clamp-block, in the tool-post . It might cut neat chamfers.

The dark ones: high-carbon steel (like cold-chisels etc.). Fine, but they will not withstand much heat without losing the temper, spoiling them. That with the long slender "neck" will work into the corner of a wide groove. Next down; a general, and very much used, knife tool for straightforwards turning including facing. No.3's semicircular end may have been for profiling grooves for, e.g., sealing- or oil-retaining rings. Don't try to use it as a parting-tool: it will jam in the cut.

The tool in the middle may be another "special". Hard to see its geometry properly but it might turn the right-hand face of wide grooves, cutting towards the tailstock.

.

Height:

I usually set my lathe tools by pointing them at a centre or scribing-block, then fine-adjust if an initial facing leaves any centre-pip on the metal.

A properly-set tool leaves no pip, but by shaving it down, not shearing the last bit by force (tool too high). If the tool obstinately refuses to remove the pip, it is too low.

A tool-post without height adjustment of its own, such as your 4-way one, needs a good assortment of shims for packing the tools to height. Save expensive "shim stock" for its intended use, aligning machine parts. Instead, off-cuts from ordinary strip or sheet metal, including from food tins, etc.

Even semi-rigid plastic. Some of my shims are from expired plastic bank or club membership cards - a fairly tough, precisely-finished material, so ideal shim where it won't become hot.

Many model-engineers make a simple height-gauge for tool-setting.

.

High-speed steel tools are fine, and have advantages over carbide inserts, not only by being much cheaper. (I use both.). They are relatively easy to sharpen many times to a standard that will give you decent results; and are less fussy than inserts which are really made for quite specific materials and cutting conditions. Some aver insert-tooling can only work at very high speeds, but that is not quite so. They work like that in industry for rapid production at very high repeatability. The HSS tools sometimes give a better finish, especially on steel not of free-cutting grade.

[If the work-piece is to be welded, especially for anything critical, it must not be of a free-cutting steel anyway. Their additives, usually lead, embrittle the weld.]

.

Grinding:

As Calum says, a simple bench-grinder is fine for HSS tools. In fact it is necessary!. It takes some practice but you can grind a tool free-hand to give good results, even on the crude rest usually fitted to these grinders.

A final honing by oil-stone or lapping-plate will help give even better finish, but the finish is mainly dependent on tool geometry, speed, feed and material. The very tip should have at least a tiny radius in plan, even for turning into a shoulder as on your sample.

Hence another caution. If the part is to be heavily-loaded (e.g., a crankshaft, a locomotive driving-axle), internal corners need a little root radius for stress-distribution.

It's worth examining industrially-made parts to see how such principles are applied.

.

I would recommend Harold Hall's Tool & Cutter Sharpening - lathe-tools, drills and in a limited way, milling-cutters; No. 38 in the Workshop Practice Series by Special Interest Model Books. (www.specialinterestmodelbooks.co.uk). Buy from them, or as as I did, from TEE Publishing. Mr. Hall's book gives designs for attachments to turn a simple bench-grinder into a moderately comprehensive tool-&-cutter grinder - useful exercises as a bonus. Just a simple plate adjustable for angle in both directions, on brackets screwed to the bench in front of a grinder itself screwed down, will greatly facilitate sharpening lathe-tools.

It goes without saying the grinder should be well away from any machine tools!

Also note that with perhaps some specific, controlled exceptions (see the book's cover photograph!) the side of a grinding wheel should not be used. The concave radius from the wheel's rim does not normally matter.

.

Cutting Fluid:

A cutting fluid is a coolant and lubricates the cutting action, for steel, phosphor-bronze and aluminium; and can help maintain a decent quality of finish (with all other criteria met). Cut brass and cast-iron dry - note as another thread here discusses, cast-iron chips are abrasive.

Steel and bronze: one of the water-soluble oils, pumped or gravity-fed to the tool tip; or applied with an old paint-brush. For Aluminum: paraffin, white spirit or WD-40 (which is mainly white spirit); but note that these will wash out lubricating oil from the lathe. (WD-40 is not a lu

Edited By Nigel Graham 2 on 31/05/2

I disagree with the comment to scrap it just because it's an unknown grade. Quite often, I and many others find a use for bits from the scrap bin. If he can't turn it with a reasonable finish now, put it to the side. He may be able to do so when the lathe and tooling is sorted.

I agree with the suggestion of trying some EN1A Pb. Aluminium alloy such as 6082 is another option.

Agree with what has already been said.

In your picture, the tool is well below centre height. That tool, or any other, will, not cut properly.

It MUST be on centre height. Don't go above. The tool will not cut, just rub.

If the tool is off centre height, when you face across the end of the bar, it will, leave a pip in the middle.

As I said earlier, make yourself a Centre Height Gauge (But fit some more clamping screws into that 4 way toolpost.) Rigidity is important, so clamp the tool securely, and keep tool, overhang as short as possible.

If you want to know how, PM me with an E mail address, and I'll send a picture of one or two that I have made, with a few notes.

Until then, as said, trap a piece of thin steel between tool and work. If the steel is vertical, the tool tip is on centre height. Ifv it not it will not be vertical If it leans away from you, the tool is too high, towards you it is too low.,.

Don't worry about all the different tools, at this stage.

Just learn how to grind a plain knife tool and start learning with that. The fewer variations that you have, the better you will learn the effect of any change that you make.

One of the first techniques that you need to learn is how to hand feed at a steady and consistent rate.

For roughing, you can feed REASONABLY quickly, but. for finishing cuts, tghe feed rate needs to be small, of the order of 0.004" - 0.002" per rev.

No longer have a ML7, but the thread will, or should, be 1/4 BSF, (Probably., unless a previous owner has departed from the original specification )

My preference is for a 4 way toolpost, as opposed to the standard Myford clamp, or the Quick Change Toolposts advocated by others.

(Purely my opinions, but in my view, most of the the time, you can change tools as quickly with a 4 way as with a QCTP, and the 4 way is slightly or rigid, since there is less overhang and fewer mating faces. This is based upon the tool heights having been set previously. You will need to be ingenious to fit more than 3 tools into a 4 way post, though )

The books that I recommended will show the angles at which to grind the tool.

As a personal note, I use a Tangential Turning Tool for a lot of my work. You can buy from Eccentric Engineering (There is an agent in UK ) Probably too soon to suggest that you make your own.

There is only one face to grind, and the "Diamond" tool should come with a grinding jig.

Don't worry about what coolant, if any, to use, for the moment.

Just learn the basics first of all..As you learn, you will be able to try new things and learn more.

Where are you located? In addition to reading up on how to set up and operate a lathe, you can do with some face to face guidance.. Possibly, there is someone near to you who would be prepared to visit and advise you.

Howard

Before you turn the lathe on again put some oil into those oilers as they are empty in the photo.

I've bought two old lathes, they all seem to come with strangely ground HSS that dates back to before the Ark that I had no use for. Some like the three black ones, which if they don't have a piece of carbide brazed on the end are tool steel that requires hardening and tempering skills to even to sharpen them.

That photo of the cut reminds me of a broken tip, but you will hear the difference between a sharp cutting tip on right height versus a broken tip or a tip sharpened unable of cutting, it will not sound good.

Edited By Chris Mate on 31/05/2022 21:26:36

Dave -

Not so. A carbon-steel tool requires re-hardening and tempering only if it has been ground and reground so many times it has gone beyond the originally hard section.

Oh, I too have an assortment of tools of peculiar shapes! Some, in HSS, would need so much metal removing to get back to a "standard" shape I'd need sculpt them with a cutting-disc on an angle-grinder first! It'd probably be more economical to buy new tools or tool-blanks.

Chris -

An interesting point that, one not often made, that listening to the cut can be as useful as watching it. When the metal is being cut properly it is often very quiet.

As much as all these observations, suggestions, recommendations, etc might be helpful, my advice would be to locate your nearest model engineering society and find help from a local, experienced user. It”s a steep learning curve, starting from close to zero.

By all means speak for yourself, but don't invoke the unknown masses to support your 'case'.

I have extensive offcut bins, but I know what the materials are. Over the years I've been given a lot of unknown material. Many of them proved difficult to machine or form, in the end I realised i never used them, so they went for recycling. I value my time and don't wish to waste it on materials that are not suitable for purpose.

Over time there have been quite a few beginner posts about problems with finish when turning, almost always when using unknown material. Moving to a known material often solves the problem, so I stand by my advice.

NB: I have offered some suitable material to the OP, he needs to read his private message(s).

Andrew

NDIY -

A good point. I agree that Chris is best finding a welcoming model-engineering club near him.

Really, skills such as metal-working are best taught in person. A forum can be valuable but risks creating a lot of well-meaning but confusing information as different contributors put forwards what may be valid but seem different approaches to the same things.

Andrew -

Oh, I know that problem only too well! I can work round it by trying the best approaches to some bit of rusty steel; so if it proves not suitable for one application it may prove suitable for another. Fine if you've machined lots of bits of pre-loved steel so have some judgement to draw on; but not the best route for a beginner less likely to know if the fault is material, tool or machine-settings.

For example, I have some 18mm diameter steel bars that were big cable-drum tie-rods. It is grotty stuff, and a carbide tool just tears it. It will cut fairly well with a suitably-ground HSS tool, so I know I can use it for static parts not needing a bearing-surface or attractive display finish - but I would certainly not give it to someone learning to use a lathe.

When I started I bought a lathe to keep me busy after retirement. I did repair my own stuff over the years.

I started by watching youtube videos to:
1-Get the feel of it by looking at others.
2-How do they talk about everything, the sections of the lathe.
3-Safety:I watch accident videos, and from that I wired my chuck & toolpost keys a position with a trip switch beneath each in series with the lathe door protection switch, and add a foot switch below etc. So if the chuck or toolpost key is not in position, the lathe cannot start, if it runs and I pull out the key, it trips and needs to be reset, if the key lay around, it cannot start.
4-I then found sharpening the HSS bits confusing at 1st, till I decided which angle to grind 1st, 2nd, 3rd etc, then suddenly it becme easy. I then make a point of understanding how a tip should be grinded just to be able to cut, from there I grind any shape I need. I looked at stickout, height setting, carefull feed, .
5-Spacial awareness on a lathe. I make a big point, to be slow and patient not to crash the thing by how the crosslide is set and changed and then forget the tool may be back but the crosslide can run into chuck, spend time with lathe swwitch off and look at these crash possibilities. Also the auto feed can atch you out. Tailstock can be in the way etc.
6-You sort of lean in circles, never stopping. I can lean something from every body good or bad at it.
7-Got some tips from carreer machinist as well, thankfull for him making we aware of setting the lathe height so you work comfortable.
8-I the bought me a set of Nr-3 & NR-4 good quality magnifying glasses, the more expensive ones with the proper reading glass inserts. A vet thanked me the other day for making them aware of these glasses, Optivisor Original, they tested mine and immediate ordered it for them to use..
9-Lightning...Added lightning to my lathe to see properly.
10-And so I learn every day something from somebody somewhere, one can decide for yourself as well if it sounds ok depending on life experiences.
11-I think it will help if you have a clue going to somebody for assistance.
12-I never buy equipment new to me without lookig about it for 3 months.
Hope some of this helps...
.

Edited By Chris Mate on 01/06/2022 21:45:35

I noticed a couple of references to EN1A and Pb - but I don't think it was made clear that this is a free machining grade of STEEL.

How can you say that a stud is missing ? Just because a few are missing from the rest of the toolpost does not mean that there are not 3 holding the tool. It is probably behind the toolpost centre bolt. In any case 2 clamping bolts are more than adequate for the size of tool being used which as AndrewD says appears to be in the wrong orientation.

regards

Oldiron -

With respect I think there is a bit of confusion there.

Looking back from your quote, shows Speelwerk is talking about the lathe levelling-studs, not the tool-post screws.