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Parting tool chatter

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Steamchick

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Love the cartoon - sums it all up very well. - Especially the use of his Tea as lubricant? - if I have interpreted the cartoon correctly? - Wonder if Black coffee will work? - No Milk, so no grease, and coffee is acidic so has higher friction I believe? - something "molecular" someone told me - but maybe I am wrong? I'll drink it instead...
Using my back toolpost yesterday with a home ground high-speed steel insert I cut half way into 1"mild steel without any problem at 300rpm - moving up to 450rpm at about 3/4" dia., but when I changed to the Cobalt steel (narrower) blade on the front toolpost to get deeper the other tool could reach (at 600rpm), it dug-in and stalled the lathe twice.... and has blown something internal in the electrics of the Variable speed drive! "Ham-fisted me" rushing the last 3/8" when the steel was moving so much slower? I do notice that sometimes my muscle control isn't as perfect as when I was younger.... maybe when my blood sugar drops a bit? - it was just before meal time... so maybe it is the "people factor" that causes most problems? Also the cobalt steel tool was "singing" - not heard that before? - Not affected by speed, feed, lube or dry, so I think it was its natural resonance at being stuck-out further than my usual setting, so I could get 1/2" deep into the work-piece. I guess that at my usual "extension" of that tool it was singing above the natural range of my old and knackered ears, but on this setting the frequency was low enough so I could hear it? It's unknown, hard, Bright steel bar I was given... maybe more than just Mild Steel? Certainly much harder than cast iron, or brass. or my "cheap bought" steel bar. The hack-saw completed the job, but now I have to investigate the VSD electronics to see what has gone O/C? Ho hum!
K
 

Steamchick

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Hello Goldstar31:
I re-use hacksaw blades for many things: Without teeth for Spacing tools to the correct centre height, or against a round bar in the chuck to check the centre height of tools. As slim tools for grooves - and parting - when re-ground. As blades for scrapers and crude knives for cleaning surfaces. As long slim scoops for applying flux when silver soldering. For stirring paint: (heat one cherry red, apply a twist for part of the length - like making a twisted poker in school - Did you go to school?) - then holding a flat portion between jaws of the battery drill chuck for stirring your paint. As a "twanger" - like you did at school with a 12" wooden ruler - hold one end on the bench/desk and twang the other bit that sticks out away from the surface. You remember that one, surely? - Or many other uses!
"Now-a-days": Many use angle grinders with cutting discs instead of hacksaws - and similarly in place of filing.... But some of us old f#%ts still use tools we learned to use some decades ago.... Like slide rules, calculators, Drawing boards, pencils, fountain pens, sewing needles and sewing machines (well, my wife uses sewing tools). And in the garden there is still a place for trowels, forks and spades. I paint the house using paint brushes and rollers. I fix woodwork using saws, chisels and affix screws with screwdrivers and use hammers on nails. It is what I call "occupation". I also get a mental reward from completing a job well, and maybe some financial reward from having money left in the bank to pay for Holidays.... Finally, I have companionship by discussing this with all of you interesting people on the HMM Thread-site. - And the mental challenge of beating spell-checker!
What satisfaction! 3 necessities to happiness: Occupation, Reward and Companionship! = I have a happy retirement!
May you enjoy yours as much!

Oh, forgot why I was coming back to the Thread... I found the fuse hidden in the back of the control box. F 10A, 250V glass tube empty of the fuse wire! (That's the "thread" of today's lesson). More care to be taken next time I am parting-off from the front!
K
 

Steamchick

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Here's a view of a hacksaw blade in later life.... showing my parting tool just a tad below centre. Probably why it digs-in! But a shim cured that.
Hope you can learn from my mistakes? (And teach me about other mistakes I have yet to make!).
K
 

Steamchick

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Sorry, pressed the "Post" button accidentally:
Here's the pictures. You can identify the hacksaw blade used between the tool and the surface of round bar and compared to the square. I deliberately used a photo of a WRONG setting as it is easier to appreciate how this set-up makes the actual tool-set position very visible. a few thou" extra shim made the tool level with the centre of the workpiece, when the hacksaw blade became in-line with the edge of the square. - Try it and learn.
Also, viewing teeth of the hacksaw blade against the flat surface of the chuck face (or other square surface) you can clearly see that the parting tool blade is aligned correctly = perpendicular to the axis of the lathe. The reflection of teeth on a smooth surface easily identifies the slightest "out-of-alignment" of the tool. - I deliberately broke a new blade as using "worn teeth" or "bent blade" doesn't give any accuracy in this application. Of course, you can use any precision parallel - e.g. a HSS tool or rod, or gauge parallel, but seeing the straight edge against the surface of the chuck is not as easy as seeing the points of the teeth of the hacksaw blade meeting their reflections - at least to my eyes. (I was about 14 with excellent eyesight being taught by a 60 year old toolmaker to do this). Try it and see?
K
P7062325.JPG
P7062326.JPG

Hope it is useful?
K
 

cds4byu

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Who's the artist?
(Don't see a signature - - - sorry!)
I believe it says B. Terry Aspin under the title. According to Google, Terry is the author of three books on home shop metalwork. I've not read any of them.
 

Shopgeezer

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Great cartoon. I have to weigh in on the side of carbide. Having started in the hobby late in life without the benefit of 40 years experience, trying to free hand grind a complicated lathe tool is beyond me. I took some courses at the local community college and the instructor gave up on my elbow flapping attempts to grind a knife tool. I have a nice collection of pre-shaped carbide tools and enjoy using them.

However I did discover the diamond tool holder and find it very easy to grind and sharpen tools for this system. It cuts beautifully. A round HSS tool and a light cut creates a mirror finish on brass. They offer a method to grind a threading tool for this system but that goes beyond my ability to understand complex shapes, let alone create them. I use carbide for everything else.
 

goldstar31

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Oh Joy unbounded- a bit Gilbertian for some. But I made a Quorn tool and cutter grinder somewhere in my 90 years.
I am assured- oh yes, by the Professor himself that I can sharpen blunt hacksaw blades.
 

fcheslop

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The cartoon was tongue in cheek
Probably when it was drawn elf n safety didna exist or was known a common sense and apprentices would be firmly beaten around the head for misdemeanours as it was the part of the anatomy least likely to be damaged
Most at that time who owned or aspired to owning a lathe would have been middle engineering management and would have had some basic training when at school .Sadly in the UK this is no longer the case .
Just the ramblings of a locked in grumpy old git who converted to a rear parting post 35 years ago and have never gone back .
I find on small model makers lathes including Myfords parting can be a pain and yet on a proper tool room machine of similar size to the Myford the same tool will cut as if going through butter Hmmm just wonder if the better larger slides and machines mass oh and better headstock help just that bit
I dont own any carbide tools so have no idea if they are truly better or just that they are ground correctly in the first place
Coffee is for drinking and makes a poor paint brush cleaner when you dip the brush into the cup instead of the tin although in some cases improves the taste of the coffee. For my sins I worked in the coffee industry for 20 years even teaching Italians how to make an espresso
cheers
 
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BaronJ

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Do people actually use hacksaws in this enlightened age?
I always felt that they were a useful source of parting blades :p
The short answer to that one is yes ! Anything that I can't put in the 6X4 bandsaw, such as shortening screws or making slotted screw heads.

However I would agree about using old and broken ones, power hacksaw blades are useful as parting blades and knives. I've even got a forked screwdriver made from a broken one.
 

RM-MN

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I dont own any carbide tools so have no idea if they are truly better or just that they are ground correctly in the first place
Inserted carbides are not superior to a properly sharpened HSS tool but they come from the supplier sharp and of the correct shape. They often have chip breakers built in that are difficult to match with grinding HSS tools. When damaged it only takes a minute to turn the insert to a new face or replace it and that new one will be exactly the same as the original, plus the OK ones are very cheap. Really good ones cost more but then most superior tools do.

Where the carbide insert tools really come into their own is when you have sufficient power and need to take big cuts fast. Their ability to retain the sharp edge under these conditions makes them the obvious choice in many industries.. until you get to the point where even carbide isn't enough and ceramic takes over or in non-ferrous metals where you can use diamond.
 

goldstar31

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The short answer to that one is yes ! Anything that I can't put in the 6X4 bandsaw, such as shortening screws or making slotted screw heads.

However I would agree about using old and broken ones, power hacksaw blades are useful as parting blades and knives. I've even got a forked screwdriver made from a broken one.
Yes John, I agree but at my experiences- from the time that I was just old enough to watch my father working, I found the so called advice unnecessarily disparaging.
 

fcheslop

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RM-MN, thanks for the reply. I have to admit I do have a carbide bit of tooling its laid in a dark corner with the spiders for soo long. Its a graver and never did get on with it
Most of my machining now is for pleasure and Im happy to live life in the slow lane .Most of my work is done with gravers or form tools made from old files or gauge plate yep another penny pinching perisher or my ancestry kicking in.
Most of the very little paying work tends to be of a horological nature or automata so that leaves me plenty of time to play with the odd model boat or Stirling engine
Concerning parting I guess with a bit of patience and reading on the matter most will find a way that works for them or at least within the capabilities of the machine
Keep well
cheers
frazer
 

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retailer

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This thread has been running for quite while and doesn't seem to want to die so I may as well put in my 2c worth.
My first lathe was an Australian made copy of a Britania made around the early 1900's, while it could do good work once one was aware of the short-comings it was flexy and not very rigid, my first attempt at parting was a disaster so I tried to avoid that operation as much as possible, I attended a tool sale and picked up a tangential parting tool, my guardian angel had guided me in the right direction that day, with care I was now able to part off mild steel - I still had to be careful and use plenty of cutting oil, keep the feed constant etc but at least I no longer had to hack through a 35mm diam mild steel bar with a hand saw and then face off the jagged cut.
 
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