Parting tool chatter

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SmithDoor

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What type of work did you do???

I started making parts for electronics projects in 1960's later model planes.
I read how some are doing machining and remember doing that way.
Some many think take backlash out the screw. You remember using some old lathes and mill where backlash was full turn of handle be for movement.

Dave

Technical apprentice. Indentured in 1965. Long time out of trade rising through the ranks. Now long time retired. I guess there are more than you imagine.
 

Steamchick

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Geometry: Running forwards, the thrust is down on the slides and front of the saddle, and tending to lift the rear of the saddle. But the lathe makers have designed the slides and saddle to work this way. When you reverse the lathe (with reversed tools) you reverse all the thrusts on the thrust faces so "hang-on" to tapers instead of trusting onto large flat faces. Fundamentally, that is wrong. My design and engineering career tells me "NO"! But I do not have "60 years of toolmaking experience. I would expect (and also respect!) Toolmakers to have well adjusted slides, gib-strips, etc, all well lubricated and not worn, mucky, loose, etc. Not that most modellers are like that, but when I watch utube machining videos I realise that by comparison, I am. I just haven't got 40 hours per week for 60 years at it, more like a couple of hours a month for a dozen years of the 60 since my father and grandfather taught me lathe work..... so I am learning as well as chipping-in with my thoughts.
But please don't ignore Engineering advice. We are highly trained to solve the problems in our heads before cutting metal. Good luck trying it backwards!
 

Richard Hed

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Geometry: Running forwards, the thrust is down on the slides and front of the saddle, and tending to lift the rear of the saddle. But the lathe makers have designed the slides and saddle to work this way. When you reverse the lathe (with reversed tools) you reverse all the thrusts on the thrust faces so "hang-on" to tapers instead of trusting onto large flat faces. Fundamentally, that is wrong. My design and engineering career tells me "NO"! But I do not have "60 years of toolmaking experience. I would expect (and also respect!) Toolmakers to have well adjusted slides, gib-strips, etc, all well lubricated and not worn, mucky, loose, etc. Not that most modellers are like that, but when I watch utube machining videos I realise that by comparison, I am. I just haven't got 40 hours per week for 60 years at it, more like a couple of hours a month for a dozen years of the 60 since my father and grandfather taught me lathe work..... so I am learning as well as chipping-in with my thoughts.
But please don't ignore Engineering advice. We are highly trained to solve the problems in our heads before cutting metal. Good luck trying it backwards!
That's one of the probs with engineers without practical experience--yes, absolutely competent to do engineering work, however, often, the object being made needs something the engineer is not familiar with. Same in the military, but possibly worse: a military school graduate goes to war and expects the soldier to salute crisply and stiffly, but the soldier has been in the field too many days without RnR, the lieutenant may send his soldiers to do something that the sergeant would NEVER do. So a sergeant who is sent to officers school is the better choice for a lieutenant because he has experience in the field. I understand that engineers in Germany have to have a lot of experience in their field -- German engineers are considered, in general, to be better engineers that others.
 

SmithDoor

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You find most do not read data or I do read it is internet {if it on internet it must be true or just like old days if on tv it must be true.}

I have shelf of engineering books some dating back 1940's and machinist books dating back to 1920's. This group that I use. If look it is may be right.
Even my brother use the books for his engineering job with L???????? Labs.

Dave
PS: Some of data in old books was not printed in later books.

Geometry: Running forwards, the thrust is down on the slides and front of the saddle, and tending to lift the rear of the saddle. But the lathe makers have designed the slides and saddle to work this way. When you reverse the lathe (with reversed tools) you reverse all the thrusts on the thrust faces so "hang-on" to tapers instead of trusting onto large flat faces. Fundamentally, that is wrong. My design and engineering career tells me "NO"! But I do not have "60 years of toolmaking experience. I would expect (and also respect!) Toolmakers to have well adjusted slides, gib-strips, etc, all well lubricated and not worn, mucky, loose, etc. Not that most modellers are like that, but when I watch utube machining videos I realise that by comparison, I am. I just haven't got 40 hours per week for 60 years at it, more like a couple of hours a month for a dozen years of the 60 since my father and grandfather taught me lathe work..... so I am learning as well as chipping-in with my thoughts.
But please don't ignore Engineering advice. We are highly trained to solve the problems in our heads before cutting metal. Good luck trying it backwards!
 

TonyM

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I am glad I wrong
What type of work did you do???

I started making parts for electronics projects in 1960's later model planes.
I read how some are doing machining and remember doing that way.
Some many think take backlash out the screw. You remember using some old lathes and mill where backlash was full turn of handle be for movement.

Dave
My potted history.
As a ''Technical apprentice'' in Killingworth we spent a year each in turning, milling, fitting, toolroom or drawing office, college was in three month blocks. I went on to refurbing multi spindle automatics mainly Acme Gridley and Wickman for a company in Ashington. Then moved to the southwest as a maintenance and development fitter for Hattersleys. In the 70's I moved to Avon Rubber as a development engineer later moving onto project and facilities manager. Took early retirement in 2003 and started working for the missus. Got my lathe Warco 240 about three years ago after restoring the basement to give me workshop space.
 

Steamchick

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I appreciate and respect the experience of toolmakers, experienced machinists et al, which is why I read this discussion. But maybe I wasn't clear in my view. To drive a machine contrary to the way the designer intends may work satisfactorily in some cases, particularly those of larger stiffer machines, especially when well maintained and set-up for minimal play, back-lash, etc.
However, many, but not all, model "engineers" do not have such machines, but have second-hand, worn, or used but not maintained tools which are often much smaller and therefore not as stiff as is suitable for the cuts being discussed. Therefore I do not advocate the "blanket statements" of "driving the cut hard" or "running backwards". First set-up the machine to the best you can, then run it the way the designer and manufacturer intends, with the tools set as sharp as you are able, and positioned as accurately as you can. Care in set-up is everything a toolmaker does to ensure he has the best possible conditions before cutting. Please teach me correctly if I am wrong, and don't knock Engineers. It is likely that the Engineers wrote the text books revered here, or taught many of the apprentices the theory and background foundation of their trade. I do not doubt or challenge the expertise of the experienced who write here, just caution that some of their statements are subject to their particular application or condition. Please teach me if I am wrong. I read to learn, but don't appreciate your "sour grapes". Incidentally, while I have met, worked with and have learned a lot from German, Japanese, American, British, Scandinavian, Canadian, etc. Engineers, I cannot criticise, nor classify, any nationality for having "better" or "worse" Engineers. Some differences, but all work to the same principles. Think, check, think again, check, check, check, and only then "commit to the cut".
If you can't do the Engineering "thinking", then please follow the rules. I.E. run the machine the way the manufacturer intended.
 

Richard Hed

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I appreciate and respect the experience of toolmakers, experienced machinists et al, which is why I read this discussion. But maybe I wasn't clear in my view. To drive a machine contrary to the way the designer intends may work satisfactorily in some cases, particularly those of larger stiffer machines, especially when well maintained and set-up for minimal play, back-lash, etc.
However, many, but not all, model "engineers" do not have such machines, but have second-hand, worn, or used but not maintained tools which are often much smaller and therefore not as stiff as is suitable for the cuts being discussed. Therefore I do not advocate the "blanket statements" of "driving the cut hard" or "running backwards". First set-up the machine to the best you can, then run it the way the designer and manufacturer intends, with the tools set as sharp as you are able, and positioned as accurately as you can. Care in set-up is everything a toolmaker does to ensure he has the best possible conditions before cutting. Please teach me correctly if I am wrong, and don't knock Engineers. It is likely that the Engineers wrote the text books revered here, or taught many of the apprentices the theory and background foundation of their trade. I do not doubt or challenge the expertise of the experienced who write here, just caution that some of their statements are subject to their particular application or condition. Please teach me if I am wrong. I read to learn, but don't appreciate your "sour grapes". Incidentally, while I have met, worked with and have learned a lot from German, Japanese, American, British, Scandinavian, Canadian, etc. Engineers, I cannot criticise, nor classify, any nationality for having "better" or "worse" Engineers. Some differences, but all work to the same principles. Think, check, think again, check, check, check, and only then "commit to the cut".
If you can't do the Engineering "thinking", then please follow the rules. I.E. run the machine the way the manufacturer intended.
Sorry Steam, If I sounded critical, I didn't mean to be. It is just a statement about any set of peeps who go into any professional line of work without knowing the practicalities involved. It is true too. The "beginning" professional thimks he/she knows it all when he doesn't. When he/she comes in contact with a person lower on the professional ladder, they can be a real pain in the "you know what". As far as the Germans, they really DO have a general reputation as being better than most other groups. As for Americans, I'd be surprised if half of them could screw on a nut to bolt. (I'm an American so I can knock them.)

The thing about lathes is that they are MADE to do many things more than what is obvious--that is all I know about the subject. And people who own them often modify them to do even MORE things.
 

Steamchick

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Hi Richard, I'm sorry too, if I over-reacted. But, after 50 years of hearing ordinary people decrying British or other nationalities of Engineers in place of - in your comment - Germans, or often (from this side of the Atlaintic) Americans, I attempt to level the field with my opinion. Competence is nothing to do with the Nationality of the Engineer, but rather his/her intelligence, aptitude experience, etc.
I am an amateur machinist, although I started when I was about 7, making screws for clocks on my Grandfather's lathe - graving, not machine cutting the size and shape of screw, before threading with a die. I graduated to my Father's treadle lathe a year or so later, when big enough to pedal the treadle, before getting on the stool to machine a small cut. Then my sister learned to pedal while I machined.... A couple of thou cut at a time. I later had that lathe (my 3rd) after he died, and it was then powered by a quarter-horse electric motor, then I learned the limitations of over-powered small tools. With a heavy cut on back-gearing I could see the lathe twisting! But with a careful low steady continuous hand feed and good tooling, I could still part-off 1 inch dia steel, cast-iron, brass, stainless steel, wood, etc. on the 1920s lathe. (Old enough that it had RH Whitworth threads on the slides, not the "modern" square LH threads. Vis-a-vis the modern rule, "To the right makes it tight, the left slackens off". Has anyone else experienced RH threaded lathe feeds?). But I think the key is "steady speed" = continuous cutting.
My significant point is that a heavier cut than the stiffness of the lathe can manage will generate chatter, under-cutting, broken tools and worse, damaged parts or even a bent lathe-bed. That's my "Engineer's opinion" for what it is worth, though I do appreciate everyone's advice about their experiences and advice for this "difficult" operation for the amateur.
Perhaps one final comment for my fellow amateur machinists: Practice the 2-handed continuous feed technique using the rim of the wheel of the feed screw, not the handle. As I learned this at an early age it is easily forgotten as a part of the technique that all the older "experts" use naturally. With practice.... you can feel when the cutting speed is risking a dig-in, or needs the shaft speed increasing, or the edge going-off on the tool. Something that an auto-feed cannot do?
Any more comments from the toolmakers? - I love to learn!
And I'm sorry, but I do go on a bit....
 

Steamchick

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Ken I due to the aggressive rake of a wood saw it is best used on aluminum. Aluminum can be cut with wood tool at wood speed. Lacking a metal band saw I use my 10" table saw for aluminum all the times.
I use broken bits of inserts brazed onto whatever steel is to hand, ground with hours of patience GENTLY on a normal carborundum grind stone. But I was taught "the hare and tortoise" technique. Fast is for factories where time is a premium. Otherwise a slower, easier pace will get results and satisfaction. And remember, he factories "doing the fastest possible" have lots of expert Engineers studying how to optimise everything to get maximum performance from machines, for as long as possible, without failures. The failures are found and eliminated during the trial phases. Mailing "one-offs" in your workshop means no engineering trials, just do it right first time, every time. So a little patience goes a long way.
Incidentally, I was site engineer on an aluminium smelter build installing aluminium bus bars (120,000A. At 80V. For the interested readers). The welded joints in 30 inch by 6 inch bars was made with packs of welded 1/2 plates. All cut to fit the joint gaps with hand-held circular saws (for wood) with carbide tipped blades. Lots of blades repaired every day, replacement armatures and gearboxes for the saws every week. The saw doctor was very busy!.
Machined flat faces for the bolted aluminium joints were made in the workshop on a wood machine using a face fly- Cutter - can't remember, maybe 6 in dia? - at 20,000rpm! Slow Hand-feed and a large cut and the swarf flew!
Bolted joint faces were 24 inches square-ish, or there abouts.
Memories.....
 

tornitore45

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Practice the 2-handed continuous feed technique using the rim of the wheel of the feed screw, not the handle.
Such a technique is so naturally instinctive it does not even need to be thought.
Same when turning a taper with the compound.
 

Richard Hed

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Hi Richard, I'm sorry too, if I over-reacted. But, after 50 years of hearing ordinary people decrying British or other nationalities of Engineers in place of - in your comment - Germans, or often (from this side of the Atlaintic) Americans, I attempt to level the field with my opinion. Competence is nothing to do with the Nationality of the Engineer, but rather his/her intelligence, aptitude experience, etc.
I am an amateur machinist, although I started when I was about 7, making screws for clocks on my Grandfather's lathe - graving, not machine cutting the size and shape of screw, before threading with a die. I graduated to my Father's treadle lathe a year or so later, when big enough to pedal the treadle, before getting on the stool to machine a small cut. Then my sister learned to pedal while I machined.... A couple of thou cut at a time. I later had that lathe (my 3rd) after he died, and it was then powered by a quarter-horse electric motor, then I learned the limitations of over-powered small tools. With a heavy cut on back-gearing I could see the lathe twisting! But with a careful low steady continuous hand feed and good tooling, I could still part-off 1 inch dia steel, cast-iron, brass, stainless steel, wood, etc. on the 1920s lathe. (Old enough that it had RH Whitworth threads on the slides, not the "modern" square LH threads. Vis-a-vis the modern rule, "To the right makes it tight, the left slackens off". Has anyone else experienced RH threaded lathe feeds?). But I think the key is "steady speed" = continuous cutting.
My significant point is that a heavier cut than the stiffness of the lathe can manage will generate chatter, under-cutting, broken tools and worse, damaged parts or even a bent lathe-bed. That's my "Engineer's opinion" for what it is worth, though I do appreciate everyone's advice about their experiences and advice for this "difficult" operation for the amateur.
Perhaps one final comment for my fellow amateur machinists: Practice the 2-handed continuous feed technique using the rim of the wheel of the feed screw, not the handle. As I learned this at an early age it is easily forgotten as a part of the technique that all the older "experts" use naturally. With practice.... you can feel when the cutting speed is risking a dig-in, or needs the shaft speed increasing, or the edge going-off on the tool. Something that an auto-feed cannot do?
Any more comments from the toolmakers? - I love to learn!
And I'm sorry, but I do go on a bit....
+Believe it or don't--that is one of the reasons I like to read the forum, simply to see peeps stories. Do you still have the treadle lathe? I had two jewelers lathes but one has gone missing. I would like to see a photo of that lathe.
 

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Richard
If you want 'hist ory' then might I suggest a Holzapffel OT lathe from the days, I guess of Maudsley.
They cost a street of houses and many of the crowned heads of Europe had one. Of course they were treadle powered and had the family crest moulded into the legs of the treadle part. Records seem to show that the Tsar of Russia had one. Until somebody bumped him off:D
As a youngster I learned to use a treadle sewing machine. It was a Jones but we were terribly poor then.

As for an OT lathe, Newcastle upon Tyne is claimed to have one. Along with Turbinia, I should add.
One of the curators of the Discovery Museum is in one of my lodges, I kept trying to tie him down to have a look but he was always too busy.

I vaguely recall that Tom D Walshaw writing as Tubal Cain produced 'Ornamental Turning' should you be interested. 4 out of 5 of the Charles Holzapffel books are on the 'net. I've the 4 and they are most intersting.

Norman
 

goldstar31

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I use broken bits of inserts brazed onto whatever steel is to hand, ground with hours of patience GENTLY on a normal carborundum grind stone.
Memories.....
Of course, few seem to have brazing facilities and seemingly either the lack of any form of tool grinding. r the knowledge of 'how to do it', hence the purchase of indexables- and the lack of knowledge of what to buy. It's. a vicious circle because there is a continual need for some of us to be asked to 'repeat ourselves'-- and of course-- for free.

Apologies but I have been in lockdown - since the Chinese New Year, have been shielded( whatever that is) and having to go to hospital for an injection for what passes as my reasonably good eye.:(
Where bloody Cramlington is - yet another mystery.
---------------------------------------------------------------------------------------------------------

In that boring wait, I looked at the videos of an English firm, called Enots Engineering.

Earlier I had followed his construction of a tool and cutter.
This time, he grinds a parting tool for his Boxford/ South Bend lathe.

Someone MAY be interested
 
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Steamchick

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Thanks I'll have a look for Enot's videos. Hope you are well with your quarantine. And good luck with your eye. I have a friend on his last 15% of vision in his good eye, and life adjustments are very difficult for him. Puts life in perspective...
Keep on keeping on.
 

Steamchick

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Oh, Cramlington is just north of Newcastle. A couple of miles beyond Gosforth Park.... I live in Sunderland... which translates from Norsk-Viking as "the land between good lands..." (Probably marshy, back then). Not a native of the North-East, I had to learn how to live "in foreign parts" when I came here nearly 40 years ago. It is actually very nice, but stay away from the cold coast in Summer! - Fog on the Tyne today.... 14 deg.C. and raining.
 

goldstar31

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Steamchick

Thanks for the good wishes. Actually, I'm a Geordie born - just on the border which was Durham and Northumberland- now Tyne and Wear( Ugh!) and now live on what is probably bits of the Roman Wall.
 

Steamchick

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I understand that if you are from South of the Tyne there are reasons for your statement re: Cramlington! I manage with the Sunderland accent, But north of the river it gets a bit too broad for me, a Southerner!
 
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