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Hand held tool turning on metal lathe

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  • BCRider
    replied
    Originally posted by danlb View Post
    I forgot to mention; an L shaped rest (aka angle iron) can also be easily fastened to a QCTP tool holder, though the body of the QCTP can cause problems. But what happens when you use a boring bar for a rest? It's common to have one that is hanging out many inches.

    Dan
    A longer boring bar or a piece of round stock of the same size in a holder would also work just fine. Not too big mind you as a larger size shifts the support point further off the work than we'd want. But something like 1/2 to 5/8inch would be fine.

    Keep in mind though that the bar needs to be able to be lowered so the top of the bar is well below center by the thickness of the turning tool. That factor would likely mean that one would need to use a fairly small diameter bar in the holder and then lower it all the way. In my case I've only got enough room to permit the use of a 3/8 rod. a 1/2" bar or rod would not give me enough room for the turning tool to be at the spindle axis.

    Instead of this I think you have the right idea with the angle iron. But perhaps I'm seeing it used in a different way.... because of this height issue I see a piece of 3/4 or 1" angle iron set into a tool holder with the vertical flange downwards and the turning tool resting on the edge of the flat upper. This way we get our rigidity and we can adjust easily to bring the rest up so the scraper tool for brass or plastic is angled for a slight negative top rake and the tool only glides along the edge of the rest and not on the flat.

    Tom, I can see avoiding turning wood on some metal lathes. But now and then I've done a job on my own metal lathe which just wasn't really viable or would have been awkward on the wood lathe for some reason. I didn't worry about it other than the extra cleaning since my carriage has felt wipers to block swarf and wood chips from going where they don't belong. It IS an oily mess to clean though.

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  • tom_d
    replied
    Originally posted by BCRider View Post
    Every now and then it would be handy to do simple hand held turning on the metal lathe. For me this came up yesterday when I spent the afternoon sprucing up my shaper. One of the lower doors had no handle at all and the other had the wrong sort of handle. So I made up two small handles that closely match the stock handles on the other access doors for the shaper.

    After turning the back taper, drilling and threading I realized that it would be a lot easier if I could "hand turn" the domed shape for the top of the knobs. This led to making up the quickie simple rest shown in this picture which shows turning a similar simple dome on some plastic bar.


    It's just a piece of angle iron cut and drilled and the height was set so that with the scraper tool shown the cutting height would be slightly above center if the tool is held dead level. This promotes a slight negative top rake which works very nicely on plastics and even wood.

    Here's a shot showing the height and negative angle used for the best results for turning plastics like this.

    And a shot of one of the knobs turned for the shaper.

    The scraper tool for this is one I use for wood turning frequently. I've used this same plain rest with the same scraper tool for smaller brass items as well.

    Hope this idea for a simple plain rest for freehand turning helps a few to give it a try.

    Speed, feed, tool geometry. The machine doesn't know what it's doing. It only responds based on the inputs. Some metal turning lathes simply lack the spindle speed to do small hand part turning. I was brought up in the old school where you don't do wood turning on a metal lathe primarily because of the wood dust potentially causing problems with the all important lubrication system. A problem, but not impossible to deal with. Of course this was in a shop already set up with a separate, well equipped wood turning area.

    Nice looking finished part. Thanks for sharing the process.

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  • Fasturn
    replied
    Originally posted by danlb View Post
    I forgot to mention; an L shaped rest (aka angle iron) can also be easily fastened to a QCTP tool holder, though the body of the QCTP can cause problems. But what happens when you use a boring bar for a rest? It's common to have one that is hanging out many inches.

    Dan
    Center line is center line. I just rest a mill file with a grind on the end aginist the QCTool holder. Done this quite a few times, but never need a fancy tool rest, cuz it was a Gee- job and didnt require anything precision. Was going to make a ball turning tool for my lathe, but with point to point YZ Tabulations and a file, I am good.
    Last edited by Fasturn; 10-14-2021, 12:08 PM.

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  • danlb
    replied
    I forgot to mention; an L shaped rest (aka angle iron) can also be easily fastened to a QCTP tool holder, though the body of the QCTP can cause problems. But what happens when you use a boring bar for a rest? It's common to have one that is hanging out many inches.

    Dan

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  • danlb
    replied
    I was making pens a few years back as an intro to wood turning. My tool rest was ,simplicity itself. I cut a 6 inch piece of angle aluminum, and drilled a hole in one side to match the hold down stud of the QCTP. Off comes the QCTP, on goes the rest. Adjust to be close to the work so that the force of the tool cutting is overcome by the leverage of the longer handle.

    The pen was made on this minilathe.

    A better choice than aluminum would be angle Iron (old bed frame, anyone???), cut or shimmed to the right height and top edge somewhat polished.

    Click image for larger version

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  • BCRider
    replied
    Tom S, I've seen the videos on the Turnado and similar setups using a hand held post on a flat table. It might happen at some point for working with steel. But for now the simple angle iron plain rest and wood working tools works for softer metals and plastics.

    A few years back I made this handle for my shaper which had come without a hand crank for the table screws. The turn'y bit was roughed out using a round nose HSS tool to get things close. Then I started with a coarse file. That got old REALLY fast and I stopped, removed the tool post, laid an old bed sheet over the bed and finished it with an angle grinder and flap disc then polished with fine emery cloth strip. It also changed a lot under the control and power of that flap disc from looking a lot like a club to what you see below. Size wise it is 4" long by 3/4" diameter.

    MOST things can be done by the numbers for sure. And to be fair if I had done the shape in CAD then made up a table of steps and cuts it could well have been done with a series of "by the numbers" plunge cuts with a smaller radius round nose form tool. Then a once over to remove the worst of the peaks between those and a LOT of file work. But sometimes it's fun to more or less wing it.....

    Click image for larger version

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  • J Tiers
    replied
    I've done that by cranking the dials, then blended it with a lathe file. Seems to turn out fine, no fixture making, pretty easy to crank dials to get what is wanted..

    I've done the graver on the watch lathe, and that was fine also.

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  • Rich Carlstedt
    replied
    Nice, Mcgyver, Nice
    I am a numbers guy myself, but appreciate the artists in this group !

    Rich

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  • Mcgyver
    replied
    I'd say the majority of watch repair work is done with a hand tool, i.e. balance staffs are turned by hand.

    I've done it a number of times on bigger lathes. Some people have made a complete accessory kit for this - flat surface on the cross slide with a block that floats on it and holds the tool which would make it easier. I've always just used a large boring bar as a rest and a heavy bit of hss firmly held in vise grips. (low brow free hand turning). Zero rake to limit the DOC (stops digging in). Very handy for handles. Two examples

    one by Levin, one by me (just the handle portion)





    one by Schaublin, one by me


    Last edited by Mcgyver; 09-16-2021, 08:55 PM.

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  • Fasturn
    replied
    Originally posted by BCRider View Post
    I have a wood lathe too. But for this case and others like it I don't have an easy way to hold the work. So about a half hour of work to make the tool rest for the metal lathe opened up a lot more of a flexible options.
    Good stuff, been doing this for a long time. Use drills to chamfered holes before threading same way. Aluminum is " white pine" for most of us. I would never of posted this for the Flames, but you did it in a friendly way! I think we / some have a few very dirty tricks making things. Some of mine are on the edge of the cliff ! LOL~ THANKS .

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  • Tom S
    replied
    There’s actually a fellow out of Aus who has designed and sells a system for easy freehand turning on a metal lathe (other than with a graver and hand rest). His system has a table that mounts to the lathe bed and a puck holding a 0-rake insert that slides on the table. There are a few attachments to allow for ball turning or following a template, or you can operate the puck free hand.

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  • Paul Alciatore
    replied
    I have a couple of wood turning tools which I have used on the odd occasions for making wood parts on my SB-9. I have used tool blanks and bent square stock as rests.

    But I am not sure I recommend it. I do clean up the wood chips and saw dust well after such a session.

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  • Paul Alciatore
    replied
    "which are always being re-written"

    Boy, that is the most intelligent thing about physics that I have heard from someone else in a long time. ALL of science is ALWAYS being revised! And that most particularly includes climate science. Science is a constant cycle of observation and the creation of theories and more observation and then the creation of new theories, etc. That process, that cycle never ends.

    This is the essence of science which many people do not realize or understand. All too many of those people are practicing scientists and they think their latest theories are the be-all and end-all of science and they refuse to tolerate the questioning of those theories. This is not a recent thing. Unfortunately the history of science is filled with such, closed minded people.

    The giants in the field are the ones who do question and who do have imaginations.



    Originally posted by Doozer View Post
    You are only limited by your imagination.
    And the laws of physics.
    (which are always being re-written).

    -D

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  • BCRider
    replied
    I have a wood lathe too. But for this case and others like it I don't have an easy way to hold the work. So about a half hour of work to make the tool rest for the metal lathe opened up a lot more of a flexible options.

    Leave a comment:


  • JoeLee
    replied
    Just like using a wood lathe. Great for odd shapes / contouring where accuracy isn't critical.

    JL..............

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