Graziano SAG 12S - Page 11
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  1. #201
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    Quote Originally Posted by noamw View Post
    I took some 35mm brass that I tested before. I made several cuts but this time the surface finish was much better then before.
    Noam,
    Brass or particularly bronze can be a little difficult to machine as it does not like positive tooling and can grab. So your tool can 'jump ahead' occasionally. Result = bad finish. Try zero top rake on lathe turning tools.

    Drills are bad for this. So you grind or stone a tiny flat on the drill cutting edges.

    IMO, the usual cause of a poor finish is with the tooling.

  2. #202
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    Quote Originally Posted by noamw View Post
    Hi Evan,

    Well I decided to make a new part and replace the original warn one. I am talking about the holder of the
    cross slide half nut. I made it from 1020 steel (this is what I had) and I fucked up the most important
    measure, the 45mm (minus 0.02-0.03mm) diameter hole that holds the half nut .

    I was planing to start from scratch but after talking with a friend, he convinced me to salvage it. I enlarged
    the hole to about 48mm and made a 2mm cutoff shoulder.

    I then took some bronze and turned it to make a bushing with a shoulder. I honed and polished the internal until
    I had a tight fit over the half nut. Then I used Loctite 648 and glued it inside the steel part.

    Today I finished it and installed it on the lathe. To my surprise I still have some play. I figured out that this
    is the half nut itself. everything else has minimal play. Maybe it is warn out (makes sens ... its old).

    Any way, I tightened the half nut and after also tightening the Gib I checked again.

    I took some 35mm brass that I tested before. I made several cuts but this time the surface finish was much better
    then before. Maybe at some time in the future I will also replace the half nut but for now I am happy with this result.

    Thanks for reading and commenting.

    My apologies for not taking any images this time...

    Take care,
    Noam.
    Noam,
    There are a lot of contributors to surface finish. Hard to say whether the half-nut is at fault, or your cutting edge/tool, or some other chatter source.

    I'm actually pretty surprised how good (er, not bad) the finish is on my lathe given the rather bizarre motion I measure with a DTI.

    You might try some leaded steel to see the best you can get, or try a shear tool on the brass.

    Skip to about 5:00 in this video...
    The other metal lathe finishing tool - the shear tool - YouTube

  3. #203
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    Hi All,

    In my case it is definitely rigidity. I see the difference in surface.

    I am not saying that a tool does not have a weight on surface finish, sure it has
    but in my case its first and most the play and vibration.

    Thanks,
    Noam.

  4. #204
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    Quote Originally Posted by noamw View Post
    Hi,

    I have repaired the RPM meter in our lathe.. The glass was broken, the finger was out of its place...

    Any way I created a new window from Poly-carbonate and it works :-)

    At 1500 RPM the lathe makes a lot of noise so I think the meter is not accurate.

    I have tested the emergency button (the red one on the right of the console and it seems
    that it does not do anything ?.. it should turn the machine off ?

    I attached some images, have fun,

    Thanks for every one that adds some input, you are great.

    BR,
    Noam.

    Attachment 285281Attachment 285282Attachment 285283Attachment 285284
    Noam,

    How on earth did you get the brown bezel off of the body of the meter? I am trying to repair the one from my 12S and just like yours the needle is stuck below the 0 mark. Also there are a lot of loose, red bits rattling around beneath the glass. There are 4 tabs on the brown cover that snap into indents in the white body, but it seems if I apply any amount of force to pry them out I will surely break the plastic. Thanks!

    Roger
    img_0231.jpg
    img_0232.jpg

  5. #205
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    Hi Roger,

    To be honest I do not remember exactly

    As far as I remember the white body is just covering and it is pressed into the front frame.

    Use a small screw driver and gently get it off.

    The black portion (with your Yellow sticker) should be pushed out of the white part as you already
    removed the retaining screws.

    As for the needle it is held with screw that has a hole in it. Due to vibration of the machine
    it rotated and as a result the needle got out of the hole.

    Be careful when you play with a needle shaft. It is connected to a flat Snail like spring and it
    is very delicate. In may case the spring was bent and it took me about 2 hours with a tweesers and
    an eye lupa to fix it.

    In my case the spring broke off and I had to solder it back. My luck was that it broke near the solder
    point.

    Hope that helped.

  6. #206
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    Yes, thank you, I'll give it another shot.

  7. #207
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    Just to make it complete
    We are talking Sag12 and Sag12S here but does one know there is a successor of the SAG12S
    The Maho graziano GR100W
    The variator on the 12S was not a succes I think
    On this machine they went back to the clutches The innerparts are identical to the SAG12

    Toolroom lathe Maho Graziano GR100W | Veltman Machines

    Peter

  8. #208
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    Nice looking machine. I can see that it still has many of the same parts as the 12S. I love the DRO display integrated with the control panel on a swing arm! Also the turret carriage stop is neat. 4kw motor power and larger tailstock taper suggest even more of a beast than it’s predecessors.


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