Silly Tool Question (absolute beginner!)...

DR_G wrote:


I'd definitely recommend starting with HSS tools and a cheap 10 grinder.
If you are set on carbide, get a few brazed tools and try them (or as someone else said, get a good RH indexable tipped carbide tool and four or more inserts - I normally say to get two of things that might break, just in case, but these _will_ break - and you will find it useful sometimes even if you don't end up using carbide by preference).
You need to get someone to show you how to grind HSS tools, preferably an old ex-apprentice - I don't think it's something you can learn from books, at least for the basics, though books may help later. That way you can quickly learn how to grind tools by hand - it took me about four days to get the hang of it, six months to get good at it - so I can grind tools which last - and it will take forever to get perfect :)
You'll begin to see how the cutting action works, without breaking expensive carbide tips. That's what it's all about, cutting metal with metal (or carbide, or..), and it just isn't obvious to the beginner, which I was three or so years ago. I had the idea then that you just moved the handwheels to the right numbers and the workpiece became the shape you wanted - but it doesn't work like that.
If the HSS breaks (it won't, but it might well get blunt quickly) you can just regrind. And please get some good quality HSS - you should be able to get half a dozen good 3/8 or 10 mm HSS blanks for something like 30. Sorry, but the Chinese/Indian HSS tool blanks just aren't good enough unless you are only swarfing aluminium.
Brazed carbide is not for me, but it is cheap and will give you an introduction to carbide, see if you like it - I wouldn't bother with green grit wheels though, use diamond - even the very cheap 20 mm dia diamond wheels in a Dremeloid are better than green grit.
Indexable carbide tipped tools (which are not really indexable if you want to change a tip and use the settings for the previous tip to eg turn to the same diameter with hundredth accuracy) have three great advantages, first you never have to sharpen them, second they cut faster when employed right and third you never have to sharpen them. They have two great disadvantages, first the tips are fragile, and second, you can't sharpen them.
Remember, cutting metal with metal (or..) is what it's _all_ about. If the cutting edge does what you want, that's all you need.
(I do a fair bit of work on hard-to-machine metals with CBN and diamond tipped tools)
--
Peter Fairbrother


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On 10 Apr 2007 01:04:19 -0700, jontom snipped-for-privacy@hotmail.com wrote:

.....and I think you'll have to go a long way to find better advice than that offered by Keith, Norman and Bill. I endorse everything they say - do take their advice and then you can at least come back for more without the risk of pissing people off.
--
Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"
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Sadly I am now too old to be included in 'the Grumpy Old Men'. I mentioned 1948 conscious of the possible backlash. Then, young men were given all of 6 weeks to master the skills of keeping aeroplanes in the air.Oh, yes, keeping the Boss man's favourite Griffon Spitfire in the air fell to a young man who unashamedly admitted that he had not the education from those uncertain days of bombed out London. The years moved on and 'Johnnie' got his pension for the terrible injuries which he sustained from those days. He asked me why I had become involved. The answer was a simple one. Johnnie had also strapped me in the back seat of other aircraft and with only a fragmentary training had ensured that I came back each time. Of course, the Boss's old Spit is still airworthy though in San Diego. Somebody flogged the other old girl which had gravitated to being the hack of the Battle of Britain Memorial Flight and she took off from 'John Lennon' after another engine change. Two more of the old girls are at RAF Cosford keeping company with two of our Antarctic Austers. Naturally, I always drew the short straw- I never even got the 6 weeks training. His Easter greeting card rests on my mantlepiece as a sort of thank you for 'insuring the last bit of his old age. Blame Johnnie, if you must.One can learn a lot from a sprog engine basher! But you have to listen!
Norm
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Oh, dear! Did no one 'do' history at school? Since 1948, things have changed but never quite repeating itself. As far as Garth is concerned, he can now have the choice of lathe and other tooling at what is give away prices because with a bit of lateral thinking what cost many thousands of pounds then, is available for perhaps a 100 now. It translates into a couple of tanks of fuel for the motor car.Moving off further, this works out at less and perhaps only a third of the price of the materials to make up a home tool and cutter grinder for which there is the long term need to actually construct. I've done it on a Quorn and and I have done it on a Stent and I nearly did another Quorn and hastily flogged the plans and castings etc for a locally available Clarkson Mark one which probably came out of the Ark but resided in a barn.The pedestal was too heavy to remove but the rest of it is OK. My luck doesn't take in all the bells and whistles but these came later. It is surprising just how effective B&Q 50mm PAR timber makes tool holders if fastened down with Wilkinsons best bolts! Of course this is for HSS stuff- well? Today, rising to the challenges, diamond wheels and CBN things fit which is more than I can say about my incontinence pads! So are we finished? Nah, let's go for double top! Today, or was it yesterday,? I got a set of 10 diamond pastes of bewildering grades for a modest 20 note.
True, I haven't really been able to get my head around low speed pulleys to hone- err, carbide tooling on the beast.
Now where did I put my Zimmer frame? Bugger, fell over it as usual.
Pity about the 6 week course but I did get the offer of a scale Tornado Bomber 14 foot long- for free. So has anyone got a helicopter which was originally used to do drop tests? It was the Royal Air Force who offered it!
Gurthcha!
Norm
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Whilst Garth awaits the 'words and music' UK style, I thought that it would be helpful to mention that in Home Shop Machinist and Machinist's Workshop's BBS that a guy is doing 'How'd I do( grinding bits)?' and taking advice from his more expert fellows.

de thing called Aviemoron.
The Forum is different but well worth a visit.
N
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