Mild steel machining dilemma - Page 3
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  1. #41
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    Quote Originally Posted by EmanuelGoldstein View Post
    Ah, the old "put it in neutral then spin the chuck by hand" trick
    You got it.

    And this method works better finish-wise with water based coolant than oil in my experience. Shinier finish obtainable for sure. Oil is better for large surfaces where tool dulling will cause problems with flatness And I have broad-nosed several HBM tables on a planer, it does produce an excellent table surface - it would appear that G&L also originally used this method. Others such as Deckel as well from what I've seen of their table surfaces.

  2. #42
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    Similar to Crabtree-Use a tool with a radius ground on.Drop your feed and increase your feed-Keep increasing the feed untill you hit the sweet spot

  3. #43
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    52130e7d-2493-450f-80b7-39f773fdae2f.jpg
    Quote Originally Posted by eKretz View Post
    You got it.

    And this method works better finish-wise with water based coolant than oil in my experience. Shinier finish obtainable for sure. Oil is better for large surfaces where tool dulling will cause problems with flatness And I have broad-nosed several HBM tables on a planer, it does produce an excellent table surface - it would appear that G&L also originally used this method. Others such as Deckel as well from what I've seen of their table surfaces.
    I was somewhat skeptical of the difference that one might see using oil (as I did before) vs water-based fluid. Indeed it did! The chip that formed with water was broader and more less fractured than the oil lubed chip. I set up again on the 1018 and did also hone the cutting edge to a mirror. I brushed on Kool Mist and did get a noticeably better finish that did approach chrome. I also peeled off the tinsel-like swarf Crabtree mentioned. Here is pic of the finish and a video.



    I think it is going to be true that the more finely honed the cutting edge the finer the finish.


    Denis
    Attached Thumbnails Attached Thumbnails d79b2af1-aa23-4bed-99d1-d2bb66756e52.jpg  

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  5. #44
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    Yes the finer the edge the finer the finish. And you should be peeling chips that look much like foil, as Crabtree described. It is a quite useful method now and then.

    Edit: Just now watched your video. If you can drop the RPM even lower it will get shinier.

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    Just for fun tried on 1" / 25mm 1213 material with SECO CNMG120404 inserts. 1000rpm and 1.5mm / 0.06" deep cut (0.75mm per side). No more welding happening but the surface is rough as sand paper. Well that's only around 260 SFM but its quite impossible to get 1000 from old manual lathe..

  7. #46
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    Swiss type cam screw machines have always used a square fronted tool(maybe 2mm wide) for turning. Spindle speed? Whatever was recommended for that particular material but certainly not slow.


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