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Parting tool chatter

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ajoeiam

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As far as theory is concerned, I have passed that and for more years than I wish to recall, I CAN PART OFF SUCCESSFULLY.
The only possible problem which could arise is that the part - parted off will nip between centres.
None of these 'taking endless bites of the cherry' and that plunge cutting and starting a new cut and all sorts of variations which would baffle . Paganini. My set up is designed to part off TWO whole inches in diameter- and that's it. Enough to say that I have another lathe-- and have the casting to make another satisfactory parting tool. All That I have to do is put a sub plate under the thing and chew a few millimetres off the casting 'foot'
I won't suggest that parting off 2" dia is nothing but it really isn't a large cut.
When you part off even a 2" dia piece it is important that you 'catch the cutoff - - - - if you aren't stabilizing the piece and it starts to wobble - - - well it can take out not only the part off tool but can drag the piece right out of the chuck - - - - things get interesting then - - - - NOT a lot of fun though!
I've found trying to using a parting tool on the end of the piece can get very challenging.
In this case the smaller the diameter the tougher it gets.
 

goldstar31

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Not really-- I do not have a clue what you were trying to say :(:(:(
For those who are following this saga, I checked the drawings for the newer rear tool post from Hemingway kits and found that the turret which hitherto had taken two parting tools has been altered to take one but the other part of the holder actually holds an inverted conventional lathe tool- upside down of course.
My immediate thoughts were 'why is lathe tool not inclined' It would have saved a lot of grinding for those who find it difficult.
No, I am NOT confusing the issue but merely reporting what was created by others.
Of course, I have the Quorn which is- with the introduction of the Mark3 from Hemingwaykits seemingly easier- Ye Gods?- it is not only confusing for mw who built one- a Mark1- but the kit price is almost as dear as the Chinese Deckel/Alexander clone which is complete- ready to perform- that is if you can understand it. Again, I'm not theorising, I have one.
 

Steamchick

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Hi Goldstar,
On the sash weight material, After heating in a muffle furnace, to a nice red glow, the round weight was "D" shaped from softening with the heat. (Left inside the muffle furnace to cool slowly). So hitting parts of it with a centre punch, in some places nice and soft, but in others, the centre punch was the "soft" metal! Cutting with an angle grinder meant that the sparks changed at various points of the cut, as zones of different hardness steel were passed.... I wrote off one angle grinder as the steel in one zone was simply to hard... the carborundum didn't touch it and the motor burned-out, with the grinding disc glowing red on the edge...
So it makes a good weight to hold jobs steady when I have a blow-lamp job to do...
On grinding tools "by-hand" - I do have a few pieces of hard wood spacer that I put on the rest to elevate the work-piece to give an angle that I want against the stone. And another grinder has a sloping tool-rest to give yet another angle setting. And I made a jig for re-grinding bits for a Diamond Tool holder that I made.... But measuring 7 degrees, as opposed to 6 or 8 degrees, on the end of a tool with an engineers' protractor isn't as accurate as having a precision tool grinder. But I am happy with the tools I make, for the work I do. (It's what I was taught by the time-served machinists in the 1960s in a machine-shop where I worked).
And thanks for the advice on projecting angles and the use of geometry, that was good new information. Curiously, my wooden spacer on the grinder is 3/8" thick above centre - which is pretty close to your 7 degrees angle...
 

Steamchick

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Wow! - Just looked on £buy and the tool and cutter grinders are all professional bits of kit - mostly in the thousands of £... just a few in the mid~high hundreds of £. I.E. Worth more than the rest of my workshop. - Yes, I am a penny-pinching pensioner. So I'll stick to my "hand" skills on my £20 grinder.... suits my needs. Thanks for all your advice anyway.
K
 

goldstar31

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Wow! - Just looked on £buy and the tool and cutter grinders are all professional bits of kit - mostly in the thousands of £... just a few in the mid~high hundreds of £. I.E. Worth more than the rest of my workshop. - Yes, I am a penny-pinching pensioner. So I'll stick to my "hand" skills on my £20 grinder.... suits my needs. Thanks for all your advice anyway.
K
Ken
Thanks for the reply. Glad to have helped another 'penny pinching perisher'.
I paid rather more than you for a 2nd hand Clarkson. It was all of £100 and after I nhad built my Quorn from castings- I needed a better motor than the one from a scrap washing machine. I followed up an ad for one and 'parted' with £100 and came home not only with the motor but a complete Stent tool and cutter grinder which in my opinion- is more versatile than the Clarkson.
5 Yesars ago, I'd been virtually bankrupt at the time my wife suddenly died. By a rather nasty stockbroker and when things returned to 'normal'I bought a Chinese thing as a sort of something to occupy vast swathes of being alone. Of course, Covid-19 has only made things worse but I'm actually accruing money.
Returning to cast iron window weights, I had much the same dreadful problems. Life was improved with the purchase of a once useful marking out table which I bought for £3. It turned out to be Meehanite !
Joy unconfined!
As for HSS and welded carbide tools, these were bought for very little.
As for your £20 grinder, my experience was to throw the rests away and also buy proper cool running wheels which will produce almost mirror reconditioned tools in hss and I bought a diamond wheel or two to mirror finish both hss and carbides.
So sometimes I spend money recklessly and others - more than carefully

So kind regards, keep well

Norman
 

djh

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This is my first posting on this site and I would try if you havnt got a rear toolpost lot of people havn't, front toolpost. tool upside down machine run in reverse, but i have never had any problem with chatter or the dredded snatch providing you use the tailstock to support the work use a running centre if you can just forcing the centre in will be sufficient or a flat support in a chuck maintaining pressure as you cut and if your machine slide is loose just locate one jib screw and tighten as you cut and loosen when you have finished.
The old machinists used to have parting tool holders with a spring slot almost all the way thru but ive never liked them so never used them.
hope this helps someone.
David(djh}
 

goldstar31

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David

Welcome to the Forum. I hope that you will enjoy the communications.
Whilst I have a rear parting tool holder( A GHT one) for my Myford Super 7B PXF, I have no problems with parting off from the front of my Sieg C4 using the parting tool in a similar way as a conventional lathe tool.

Me thinks it is 6 of one and a half dozen of the other!

As for the spring tool thing- beloved of a past generation, at 90 years, I had one for parting and another for fine finishing. The snag is that mine were fashioned on the anvil from carbon steel and then tempered.
That means that using carbon tools results in far quicker wear and in any event now, I can achieve a finer finish using my own ground HSS blanks.

At one time- or should I say before 1973, tool and cutter grinders were nigh impossible to have whereas, there are both second hand professional ones and also designs and kits to make them.

For those who are interested Ian Bradley wrote it all up in his somewhat dated Lathe and Shaper Tools book and also the Grinding Machine which is even more archaic. I'm archaic too.

My view on things?

Best wishes

Norman
 

goldstar31

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Going through what has to pass as my memory, I began to recall that Mosel Engineer magazine published another rear parting tool which had an adjustable tilt. No idea but it may jolt another memory. This lead me a more modern parting tool gadget but like David's references to earlier tools was made with a mild steel body but it was 'split to allow it to go out of cut if circumstances went wrong. I saw it, was amused but again someone might expand the topic.

Going back over a number of years, I mentioned and interesting series of articles by a Conrad Hoffman who with his his wife wrote a series of articles- still on the 'net but called 'The Messy Basement'.
Having read how peole here here manage to sharpen tools, might I repeat Hoffman's Advanced Tool Sharpening for the Lathe- with special emphasis on Threading Tools.

It does deal with carbide tools as well as hss stuff and whilst I may not totally agree with it, I did find it stimulating.
For those who are history buffs, it suggests a modern version of the Goniostat which first appears at the beginning of people like Maudsley but was for something called 'Ornamental Turning'

Yes, a mate of mine made a Goniostat
Enjoy?

Norman
 
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BaronJ

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Hi Norman, Guys,

Not quite on topic, but I thought that Norman would like to see what has happened to the motor he so kindly passed on to me !

17-10-2020-013.JPG
17-10-2020-012.JPG
17-10-2020-011.JPG


These pictures are of the work head of the tool and cutter grinder that I'm building. My design of the grinding spindle cartridge is in the carrier. The cartridge is 30 mm diameter with a 12 mm spindle.

Though you can't see it the end caps which are threaded contain the pair of Teflon labyrinth seals at each end
 

goldstar31

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BaronJ

I'm glad to see that it has finally become useful again.

Regarding the spindle, the labyrinth seals to exclude dust are impressive.


Oh and more plans are afoot( or 12 inches:D)
More Anon.

Regards to All

N
 

BaronJ

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BaronJ

I'm glad to see that it has finally become useful again.

Regarding the spindle, the labyrinth seals to exclude dust are impressive.


Oh and more plans are afoot( or 12 inches:D)
More Anon.

Regards to All

N
Hi Norman, Guys,

Thankyou for the pat on the back !

Those tiny Teflon ring seals were quite difficult to make. They are only 1 mm thick 18 mm diameter with a 14 mm bore running in two grooves 1.5 mm wide and 2 mm apart. They grip the support sleeve quite nicely.
 
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Noel Gordon

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Just some interesting thoughts guys..NO diy machinist should ever need to use carbide tips and should learn how to use HSS this way you will eventually understand about cutting angles and how to use HSS to its max. I have been a toolmaker for the last 60 years and as an apprentice was not allowed to even whisper the word "carbide" and I was not thought about carbide until my 5th year.
I remember telling my boss that I could cut a piece of 4inch ms shafting in two in the workshop power hacksaw faster than he could if he was using a parting off tool,,I then stood and watched him part the shafting in two and the realized my power saw was ONLY half way through...In more than 60 years I broke a parting blade in my first week but that is the ONLY blade that Ive broken in more than 60 years..but Im NO hero but I was just tort how to use one correctly ..Guys STOP over thinking things and just DO IT>
 

Steamchick

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Fair comment Noel. I agree that with a good a the and correct speed and sharp tools lathe work is easy, but if some are using "lightweight" hobby lathes and "tiny" tools then special care needs to be taken to cut with the capabilities of the machine. Although I used an 18 in swing lathe machining cross-heads 10 in diameter for Broom Wade compressors as a teenager, it was a different job machining parts 1/8" dia. in my Dad's 1930 3 in lathe powered by a Singer sewing machine motor. When I inherited that lathe he had converted to a quarter horse motor, and parting 1 in cast iron you could see the bed of the lathe twist with the torque through the back-gearing! So SLOWLY AND CAREFULLY CATCHEE MONKEY! Using the correct application of force on each tool is what we learned as apprentices but is a "black art" to many readers of these threads. So a little patience and we can help them with our skills and knowledge.
Thanks for your help. - As an Engineer, I have worked with some of the best skilled people and love to learn their skills - to improve my amateur work.
K
 

RM-MN

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Just some interesting thoughts guys..NO diy machinist should ever need to use carbide tips and should learn how to use HSS this way you will eventually understand about cutting angles and how to use HSS to its max. I have been a toolmaker for the last 60 years and as an apprentice was not allowed to even whisper the word "carbide" and I was not thought about carbide until my 5th year.
Yesterday I tried to modify a single point threading tool to bring the point nearer the edge to facilitate threading up to a shoulder. My eyesight isn't as good as it was 40 years ago and I speny half an hour with my under powered grinder trying to grind away the unwanted metal only to end up with a point that was not 60 degrees. For $10 I could have bought a carbide insert cutter and for another $10 I could have bought 10 new inserts. All of them would have had the right angle on them and could cut up to that shoulder. If I damage one, a 20 second switch to another insert and I am ready to go again, no grinding necessary. The quality of carbide has improved over time and I find that the inserts I just bought leave a better finish than I can achieve by grinding HSS. I can also cut harder material than HSS is capable of.
 

BaronJ

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Yesterday I tried to modify a single point threading tool to bring the point nearer the edge to facilitate threading up to a shoulder. My eyesight isn't as good as it was 40 years ago and I speny half an hour with my under powered grinder trying to grind away the unwanted metal only to end up with a point that was not 60 degrees. For $10 I could have bought a carbide insert cutter and for another $10 I could have bought 10 new inserts. All of them would have had the right angle on them and could cut up to that shoulder. If I damage one, a 20 second switch to another insert and I am ready to go again, no grinding necessary. The quality of carbide has improved over time and I find that the inserts I just bought leave a better finish than I can achieve by grinding HSS. I can also cut harder material than HSS is capable of.
Hi,
Yes I came to the same conclusion some time ago for very similar reasons. I also try to cut threads away from the chuck, particularly in holes. ;)
 

goldstar31

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[QUOTE="Noel G*************at is the ONLY blade that Ive broken in more than 60 years..but Im NO hero but I was just tort how to use one correctly

..Guys STOP over thinking things and just DO IT>
[/QUOTE]

The spell check is- well, amusing! I hope that it got 'Taught' wrong as the 'Law of Tort' got me quite excited- and I got it 'wrong'. There's pun there:D

Right? Oh, never mind

Norman
 

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