Inserted Carbide Parting-off Tool

[barnesrickw]

Rear post helps a lot.

 

[kiwi2]

Tubal Cain has done a series of videos on parting.
[ame]https://www.youtube.com/watch?v=82LtUTBmxwQ[/ame]
He tried a carbide tool and was surprised at how well it did.

Regards,
Alan C.

 

[goldstar31]

Funny but the earlier Tubal Cain( Tom D Walshaw) didn't but designed much of people today are copying. He produced a Gibraltar tool post which flies in the face of his successor.

The difficulty in carbide is that it is difficult( not impossible) to recondition. OK, I can do it on most straight edges but refuse to cock up a decent diamond wheel into a funny shape - and then get it back to flat.
On the other hand, I can alter abrasive disks quickly and more cheaply to do carbon and hss tooling. Repeating myself, I used a worn disk to do my blade instead of the quoted 140 degree Thomas one.

Worth thinking about. My Tubal Cain was- gulp- a lecturer in machining where there was a lot of machining. He argued with Thomas- but that is normal!

Cheers

Norman

 

[pjpickard]

Norman,

Could you post a pic of the angle that is ground in the cut off tool? I have never been able to wrap my head around what GHT was getting at.

Thanks,

Paul

 

[goldstar31]

Norman,

Could you post a pic of the angle that is ground in the cut off tool? I have never been able to wrap my head around what GHT was getting at.

Thanks,

Paul

I have a blockage about photos.

Quite simply, GHT ground 1" on the thickest edge of his parting ground in the shape of a ( female)vee of 140 degrees. I was simpler and created a ( female) round groove.

If you look at it, all that GHT and me have done is created a method of narrowing a ribbon. So the tendency( which has bugged lesser mortals- hic!) of breakage is minimum.


Enjoy

Norman


We are ecstatic, the family has another new piano. One to go with our Grand and I'm more or less free of doctors so I'm going for a month's rest.

My 85th birthday!


Hurrah

Norman

 

[gus]

Hi Kiwi2.

Thanks for posting Tubal Cain's video on parting. Parting off in Trades School was a nightmare. Our C & G aka City & Guilds qualified machining instructors were not really highly skilled turners and was not able to demonstrate parting off to impress Gus. They did parting a wee bit nervous.Years later I witnessed an old hand parting off 2 '' Mild Steel Bar stock skillfully with ease. Too bad I did not spend enough time watching and learning from him. I do parting with LMS ''T'' Parting Tool with success.It best to check tool sharpness and regrind if necessary.
Tubal Cain was a good teacher.

 

[canadianhorsepower]

Finally a good video why to cut in reverse mode
or to install a cutting tool at the back of your cross slide.
When using my Taig lathe I put the tooling always upside down
LOVE it Thm:Thm:Thm:
enjoy

[ame]https://www.youtube.com/watch?v=-RZRq0olsxM[/ame]

 

[barnesrickw]

I have a rear tool post for my Taig, but so far I've used it mostly for parting. I'll have to try some other tools. One good thing about it is if you use a tool other than 1/4 inch square, the center of the tool and stock will still be in align because the tool references on the bottom of the post on the cutting side.

 

[goldstar31]

I have a rear tool post for my Taig, but so far I've used it mostly for parting. I'll have to try some other tools. One good thing about it is if you use a tool other than 1/4 inch square, the center of the tool and stock will still be in align because the tool references on the bottom of the post on the cutting side.

When Hemingwaykits did the little GHT kit, they included the design for a single blade and a lathe tool holder rather than the 2 thicknesses of parting blades. Why, I presume that this was then the alternative to the QCTP because GHT at the time made a rotating and highly accurate 4 way tool post which was better than the original one made by Myfords.
GHT had 2 Myford ones originally -one for steel and one for brass. Aluminium hadn't been much in use then. I suppose you pays your money and takes yer choice.
Me, I made up another rear tool post but to Martin Cleeve's fabricated design( 3 bits of metal bolted up) which held Two lathe tools. Still have it.
I rather like the Cleeve stuff of 'Turrets without milling ' article which utilises cob ends and no cost or need to mill or do anything mind bending.

People have forgotten now all these things because they spend time buying things instead of reading what has been tested and then written about.

Of course, we had no money then. I made scale model aircraft using old single edge razor blades and broken glass scrapers from bombed out buildings! :hDe:


Cheers

Norman

 

[gus]

Hi Big Bro Norman,

I share your idea/practice making DIY Model Aircrafts with what's on hand and saving pennies and pounds. Coming from a poor child/boyhood has more advantages thandisadvantages. We make our own toys for pennies.Walk into any model aircraft shops,and you find enthusiats squandering money on ready makes. Its hard and expensive to buy balsa wood in Singapore as there are not too many who want and can DIY their model aircrafts and fly them. Despite this scenario,I DIY 4 fighter model aircrafts-------Zeros Spitfires Mustangs etc.
Gus must be the only one in 5 million in Singapore who can DIY build his own model aircraft engines.
Now building the Howell V-2. Had no warning the V-2 is a Pandora Box with many surprises.

Take care.

A M.I.C. QCTP from UK or USA will cost Gus a bomb landed in Singapore. So its DIY my own. Cutting the dovetails male and female was scary for first-timer Gus. I am into my second QCTP and enjoy using it every time I work on the lathe.

 

[Brian Rupnow]

After many delays, and much confusion, I finally, today, received the Aloris parting off tool and the inserts to go with it. My total bill, including tax, was an outrageous $226.00 Canadian. I was unable to get .093" inserts, and had to settle for a 0.123" (3 mm) wide carbide insert. I rushed home to try it and see if it would fit in my 10" x 18" Craftex lathe with a quick change toolpost on it. It did fit into my standard cut-off blade tool holder, and I was able to center the tip of the cutting edge on the centerline of the chuck. I ran the lathe at 360 RPM and cut off a piece of 3/4" mild steel rod. It did chatter, same as my old 0.093" HSS blade, but it rapidly cut thru the 3/4" steel with no problem other than some chatter. I immediately picked up the cut off portion to look at, and burned Hell out of my thumb and finger---(won't do THAT again!!) So--Okay, it works. How much better does it work than the HSS blade?--Well, I don't really know at this point. I have found that I was running the lathe at much too low an rpm for even the HSS cutting blade, and that is what was causing so many of my parting off problems. Once I bumped up the speed of the lathe to give me the proper parting off speed in "inches per minute', the old HSS blade cut quite well. I may have wasted $226 but if so, then I consider it a "learning pain"---OUCH!!! Then again, it may be one of my wiser purchases. Only time and use will tell.----Brian.