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Re: Indexable carbide insert turning tools

 

Yes, I have had to grind the insert holder on some tools.? It was easy and not particularly critical.? Just support the edge of the insert as well as you can.? After that they worked fine.
Re: Indexable carbide insert turning tools

 

I'm assuming TCMT tooling? ?I use this on my SB9A and SB13 all the time, no issues. ?What type of material? ?Let's see a picture of your setup.
Re: Indexable carbide insert turning tools

 

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Bill: Could you provide suggested part numbers?

On Mar 5, 2024, at 10:06 AM, William Nelson <wnnelson@...> wrote:

The type of insert may be the problem. I recently had to turn 5" diameter 304 stainless and my "normal" inserts just were not doing a good job. Talked to a tooling guy and got some Sumitomo inserts which cut that stuff like butter. The edges appeared to be much sharper than my other inserts and last a lot longer too. I'm hooked on the new inserts and won't go back to the cheap ones.??
--
Bill From Socal

Re: Indexable carbide insert turning tools

 

The type of insert may be the problem. I recently had to turn 5" diameter 304 stainless and my "normal" inserts just were not doing a good job. Talked to a tooling guy and got some Sumitomo inserts which cut that stuff like butter. The edges appeared to be much sharper than my other inserts and last a lot longer too. I'm hooked on the new inserts and won't go back to the cheap ones.??
--
Bill From Socal
Re: Indexable carbide insert turning tools

 

A picture would sure help here. I have put a little extra clearance on certain insert tools at times but these were for unusual cuts. Is this just normal OD turning??
--
Bill From Socal
Indexable carbide insert turning tools

 

I recently went modern and purchased a box of subject tool bits.? I had been led to believe that tool preparation was a thing of the past.
My 9" Model A? complained with growling and chattering, making a mess of a cut.? Investigation showed that the tool had no clearance between the shank and the work.?
Setting the point on centre helped for a few seconds but then the growling restarted.?

It appears to me that although the triangular insert is shaped, and might have necessary clearances, these are only on the thin insert.? The shank is only cut away parallel to one side of the triangle, the leading edge is vertical (shaped like a WWI destroyer bow).? Is it intended that we grind the shanks to provide the necessary clearances?? ?
Re: interesting

 

Very interesting. I may have to investigate this when making rocket parts. Make a spinning tail chuck then release instead of quickly shutting down the lathe. I forsee a loud band, something breaking, then embedding in my fore head but it sounds plausible.?
--
Bill From Socal
Re: interesting

 

Friend of mine said he tried it before and it worked okay. He said you have to stop fast to get a good bond. The lathe he used was pretty big and had a foot brake which disengages the motor and brakes the chuck.
Re: interesting

 

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Yea , I'm not so sure it's a job for these old lathes , but it was something new to me .

animal

On 2/25/24 1:36 PM, Jerry Cc via groups.io wrote:


I wonder if could get enough speed though. Sounds like his really winds up


On Feb 25, 2024, at 3:11 PM, Mark Z via groups.io <bode528@...> wrote:

?I thought that was super cool!? Thanks for sharing.
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: interesting

 

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I wonder if could get enough speed though. Sounds like his really winds up


On Feb 25, 2024, at 3:11 PM, Mark Z via groups.io <bode528@...> wrote:

?I thought that was super cool!? Thanks for sharing.
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: interesting

 

I thought that was super cool!? Thanks for sharing.
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........
interesting

 

this popped up after a tube I was watching
Re: Set Up my 16" - Test Cut

 

Brilliant! I'd planned to do the two collar test and the 12" long cut test, but I'm going to add this one to the list, probably at the beginning. Still have to mount my chuck, making the back plate this week.
Re: Set Up my 16" - Test Cut

 

To be clear once I used the 2 1/2 inch bar and skimmed the final coat, over 9 inches I got measurement error.? So roughly within 0.00005".? That is crazy good for a machine like this.
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........
Re: Set Up my 16" - Test Cut

 

Tailstock ram must also be level. You'll find a lot of tailstock bases worn on the front end from heavy handed operators shoving them around. You might have to shim

it level and then you should shim it so the center is .0005"- .001" high.

?If you're only out 2/10's of a thou along the length of that bar....that's as good as that machine is going to be. It's not a Hardinge.

Bill

On Sunday, February 18, 2024 at 07:28:24 AM EST, Chips <sakr4360@...> wrote:


Assuming the twist is out of the bed here's an easy one to set the tailstock.

Say the diameter of the? quill in the tailstock is 1.4985 inches.
Turn a short piece of metal in the chuck to that dimension.
Put the tailstock at the far end and lock it down.
Set up a dial indicator in a tool post and zero it on the piece you turned to 1.4985.
Run the carriage down and put the indicator on the tailstock quill. It should read zero.
Now you just tweak the tailstock alignment screws until it reads 0.
You don't need an x feet long bar to work with, just a 1 inch stub of scrapbinium.

Re: Set Up my 16" - Test Cut

 

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.0002" taper sounds pretty good on a 55 year old machine.

What are you trying to test because your setup has at least 5 variables?

On 2/16/2024 11:00 PM, Mark Z via groups.io wrote:

Having problems with zeroes! Worst is 0.0002" per inch.? Missed a zero there too!? Its late.............? LOL!
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: Set Up my 16" - Test Cut

 

Assuming the twist is out of the bed here's an easy one to set the tailstock.

Say the diameter of the? quill in the tailstock is 1.4985 inches.
Turn a short piece of metal in the chuck to that dimension.
Put the tailstock at the far end and lock it down.
Set up a dial indicator in a tool post and zero it on the piece you turned to 1.4985.
Run the carriage down and put the indicator on the tailstock quill. It should read zero.
Now you just tweak the tailstock alignment screws until it reads 0.
You don't need an x feet long bar to work with, just a 1 inch stub of scrapbinium.
Re: Set Up my 16" - Test Cut

 

THANKS!!? that was the Best I've seem!!? Figures!!? It'd take a meticulous girl
to show us how to get it done!!? lol

On Saturday, February 17, 2024 at 10:59:32 AM CST, Rogan Creswick <creswick@...> wrote:


For aligning a lathe, I use the process Blondihacks describes:?

?

On Sat, Feb 17, 2024, 8:24?AM Mark Z via <bode528=[email protected]> wrote:
For sure deflection is a problem in the middle so I discarded the numbers that I felt would have been affected.? But the number I stated included everything but the actual middle.

In retrospect if I was totally serious about this I would cut a 2 1/2" diameter 18" long piece of aluminum and use it to minimize deflection.? Might actually do that at some point.? I started the testing by only cutting a 1" wide cut at the ends.? Once I was happy with that I did a full cut to get a better profile and eliminate tool position error from the DRO.

What do others do?
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

Re: Set Up my 16" - Test Cut

 

Thank you Rogan!? That was very helpful in making me understand that I had a brain cramp.? I should of know better.? My tailstock center alignment was way off and really skewed my numbers.

I redid it with a 12" long 2 1/2" diameter aluminum bar without a center.? I did it just at the ends (9 inch measurement difference) and got it to measurement error.? I then skimmed the whole 9 inches and did a final cut taking 0.002" off the diameter.? Measured every inch over the 9 inches and every measurement was within measurement error (50 millionths of an inch or half a tenth).? I am shocked that its is that good.

--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........
Re: Set Up my 16" - Test Cut

 

For aligning a lathe, I use the process Blondihacks describes:?

?

On Sat, Feb 17, 2024, 8:24?AM Mark Z via <bode528=[email protected]> wrote:
For sure deflection is a problem in the middle so I discarded the numbers that I felt would have been affected.? But the number I stated included everything but the actual middle.

In retrospect if I was totally serious about this I would cut a 2 1/2" diameter 18" long piece of aluminum and use it to minimize deflection.? Might actually do that at some point.? I started the testing by only cutting a 1" wide cut at the ends.? Once I was happy with that I did a full cut to get a better profile and eliminate tool position error from the DRO.

What do others do?
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........

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