How to get a better Finish

[Dave Harding 1Participant @daveharding1]

I stripped the whole thing down cross slide the carriage every thing then re built it all everything is tight. Its rock solid now. I have projects I want to get on with. Ill have another go at the weekend.

[martyn nutlandParticipant @martynnutland79495]

Hello

I was really intrigued by Dave running his lathe at 3000 rpm. That boggles my mind. Mine can only reach 1260 and my milling machine just over 2000 and I've never been over 600 rpm on either, and at the higher range only with small work and/or a small tool on mild steel.

I still consider myself a relative beginner as I've only had the lathe about 10 years and the 'mill' about six, but am I being very timid? I also would rarely take a cut deeper than a fifth of a millimeter on steel. I don't however, have, for my purposes, a problem with finish using a sharp tool and, on the lathe, automatic feed – not 'mirror' but smooth and even.

By the way, Andy with the stalling Warco (another would be 2000 rpm runner!) was disappointed with his after sales service from this company. So was I with my mill. Great when I was buying it, but very disappointing when I thought I needed a new belt for the gearbox. 'Can't help – go to your belt shop (not so simple when you're in rural France) and anyway, we don't sell those machines anymore; they're obsolete'. Not what you want to hear, about what was then a three-year-old 'mill'.

Martyn

[Neil WyattModerator @neilwyatt]

Maintaining a stock of spares for a large range of hobby machines is one of the biggest costs for the companies supplying the hobby market, and this overhead is one reason why the bigger companies have to charge a bit more.

If customers want them to stock a full range of all the extra consumables, like belts, when they can't compete with specialist suppliers who shift vastly more of them on price, then the cost of the machines would have to increase further.

Don't be afraid to take decent cuts with a small lathe – I go up to 2mm on my mini-lathe in steel.

Neil

[Anonymous]

Posted by martyn nutland on 11/09/2015 09:38:16:

Hello

I was really intrigued by Dave running his lathe at 3000 rpm. That boggles my mind. Mine can only reach 1260 and my milling machine just over 2000 and I've never been over 600 rpm on either, and at the higher range only with small work and/or a small tool on mild steel.

I still consider myself a relative beginner as I've only had the lathe about 10 years and the 'mill' about six, but am I being very timid? I also would rarely take a cut deeper than a fifth of a millimeter on steel. I don't however, have, for my purposes, a problem with finish using a sharp tool and, on the lathe, automatic feed – not 'mirror' but smooth and even.

Yep, 'fraid so! My lathe will run to 2500rpm, although I rarely use top speed due to noise (geared head). Normal turning speeds on low carbon steel up to 2" diameter are 800-1200rpm. For roughing I might use a deep of cut of 0.1" and turn the feedrate up to 8-10thou/rev. Of course I have an industrial size lathe, but 0.2mm DOC seems very small for most lathes?

My manual mill will go to 3750rpm, but I rarely run above 2500rpm, as the varispeed head is a bit shake, rattle and roll. However, I rarely go below 500rpm (bottom of high range). I only switch to low range for boring heads, large (>20mm) HSS drills and when using the coaxial indicator.

The CNC mill will run to 5000rpm, and is pretty quiet at full speed, so it regularly gets run at full speed. For instance the other night I was machining some small oil pockets in steel with a 3 flute 3mm carbide cutter. I ran the mill at 5000rpm; no point in pussy footing around!

Andrew

[mark costello 1Participant @markcostello1]

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On second thought, You might want to move the pot closer as You might want a 2nd or 3rd cup.

[Dave Harding 1Participant @daveharding1]

I had another go this week end. I spent some time with one of the machinists at work on the Hardinge tool makers lathe watching him machine a piece of 1 inch round steel. He demonstrated how different speeds and feeds make a difference.

I had better luck this time I used a HSS tool he ground for me. My lathe digital read out is not working so I don't know exact speed but it was a lot slower than last time I tried. I got a reasonably good finish. I switched to carbide and upped the speed a tad. I think I'm getting some were now. The work pieces are looking a lot better.

[Dave Harding 1Participant @daveharding1]

I bought some stainless 303 and some bright steel EN1A rounds to play with over the week end from M Machine.

A total disaster no matter what speed and feed carbide HSS it makes no difference the finish is terrible. I give up I'm going to get the guys at work to machine the project for me. Enough is enough its just a waste of my time.

[pgk pgkParticipant @pgkpgk17461]

I'd be bribing one of your workplace machinists with a bottle of hooch to come round and find the problem or you own a shed ornament…..

[Ady1Participant @ady1]

29/08/2015 How do I get a better Finish

19/09/2015 I give up

It takes YEARS to get any good at the intricacies of metalwork

That's why it's called "skilled labour"

I bought some stainless 303 and some bright steel EN1A rounds to play with over the week end from M Machine.

Get odds and sods from scrapyards, a tenner will buy you a hundredweight to turn into swarf

Then practice practice practice

practice practice practice practice practice practice

It's a tough road unless you are a natural

I think I'm getting some were now. The work pieces are looking a lot better.

The first couple of years are the hardest, the victories are small.

You do have a head start if you can visit a decent machine shop whenever you like

Perhaps the best thing you can do is join your local ME society

Edited By Ady1 on 20/09/2015 11:53:22

[Ady1Participant @ady1]

The biggest improvement on the finish of a job for me was once I started using the tailstock to support the work

A decent live centre in the tailstock was a huge help, it can never make a job worse, only better. (For best results use a dead centre)

Now I use it all the time

Edited By Ady1 on 20/09/2015 12:04:15

[Dave Harding 1Participant @daveharding1]

I'm beginning to think its more to do with the way the lathe is set up than the actual tools etc. I noticed that the tool post was moving slightly when looking down on it. I had a good tug on the cross slide and saddle etc. Thee is a lot of play/slogger. I took the carriage off and reset everything then put it back together it took a few attempts to get it some were near. I adjusted the cross slide and started again. Using a honed HSS cutter things are looking better. The cross slide still needs some attention and I'm struggling to get rid of back lash. But we will see what happens.

We don't have these problems with the Hardinge lathe at work it just works. LOL. These Chinese lathes take some fettling.

[KWILParticipant @kwil]

By your own admission you are still learning and do not "know" what you are doing. Take advice of pgk pgk above and get someone who does, to set up your lathe. Then try again to restart your practice sessions. Incidently, how are you putting the traversing cut on, saddle or topslide set at 90 degrees?

We would all like a good Hardinge at home but sadly there are not enough to go round.

[Ady1Participant @ady1]

We don't have these problems with the Hardinge lathe at work it just works. LOL.

These Chinese lathes take some fettling.

Eventually, given time, you will become the master of your machine.

You learn a lot more on a smaller lathe because you have to master it's weaknesses to get the best results

[Neil WyattModerator @neilwyatt]

The last new price for a Hardinge HLV-H was $55,000.

I bet a beginner would still have trouble getting a decent surface finish with one.

Neil

[AjohnwParticipant @ajohnw51620]

CVA's can be amazing too but £25000 in the 80's a touch expensive. Cheap used but I shudder to think what replacement bearings would cost. Some might not need other work but everything tends to wear a bit what ever they do. These with a gap bed also have a very large swing in them. It really is large compared with other machines with similar normal swings. They built some on a spinning bed. It's a massive thing.

My choice would be a DSG, the one they did a diamond turning attachment for. Better spec than some common cylindrical grinders of the day had. Oh for the super thick concrete floors needed and the cost of them if they were new.

Finish is all about rigidity including the headstock bearings and cutter grinding. Rigidity mean a certain weights for a given size for the simple reason that when a very high quality finish is achieved minor vibrations will cause micron deep marks to appear in the work as metal flexes to some degree as minute as it might happen to be. Go far enough and the ripple from bearings that have rolling elements in them become a problem.

John

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Edited By John W1 on 21/09/2015 14:51:13

[Ady1Participant @ady1]

Go far enough and the ripple from bearings that have rolling elements in them become a problem.

Apparently watchmakers prefer solid bearings because of that sort of thing

[CotswoldsPhilParticipant @cotswoldsphil]

Clicked in wrong place

Edited By CotswoldsPhil on 22/09/2015 09:20:42

[CotswoldsPhilParticipant @cotswoldsphil]

Posted by CotswoldsPhil on 22/09/2015 09:17:48:

Posted by Ady1 on 22/09/2015 08:54:53:

Go far enough and the ripple from bearings that have rolling elements in them become a problem.

Apparently watchmakers prefer solid bearings because of that sort of thing

Is this why the Myford Super 7 has a bronze cone front bearing?

Phil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by CotswoldsPhil on 22/09/2015 09:19:57:

Posted by CotswoldsPhil on 22/09/2015 09:17:48:

Posted by Ady1 on 22/09/2015 08:54:53:

Go far enough and the ripple from bearings that have rolling elements in them become a problem.

Apparently watchmakers prefer solid bearings because of that sort of thing

Is this why the Myford Super 7 has a bronze cone front bearing?

Phil

.

Well yes; that's certainly what the Marketing Man would have told you.

… Of course, we might also note that the headstock casting is rather too light to accept a Taper Roller Bearing carring a decent size spindle.

MichaelG.

[Author]

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