Announcement

Collapse
No announcement yet.

Hi Everyone, new member here, lots of questions.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Hi Everyone, new member here, lots of questions.

    Hi Everybody,

    I just wanted to stop by in introduce myself. I'm a relative newb to machining. I took a metal shop class in high school and always wanted to get more involved. I picked up a 7x10 mini-lathe a few years ago and have made a few little items with it.

    My biggest problem so far seems to be wearing out HSS lathe bits and not really knowing how to sharpen them again. That and the incredibly short working area on the 7x10. Oh, yeah, and wearing out drill bits on mild steel. I've got to learn how to sharpen those too. So much to learn.

    Last minute insert: I just went out to the shed and replaced the stock grinder wheel with a "green" wheel and found that my new green wheel has these awful little plastic hub adaptors. When installed, they slide out to the side (under the domed washers) and the wheel wobbles like crazy. Would it be a good idea to make an aluminum hub adaptor on the lathe?

    I just discovered this message board and for the last few days I've been going through the "Shop Made Tools" thread. Wow, what a bunch of amazing devices you guys have come up with.

    My next project is going to be a lathe milling attachment, the one that's floating around the net in PDF form from the June 1958 issue of Science and Mechanics.

    http://www.vintageprojects.com/machi...tach-plans.pdf

    I love the way the author takes advantage of the dimensions of CRS to make a milling attachment without requiring the use of a mill.

    I was hoping to get some advice from you guys before I get too far into this. Is there anything about that project that jumps out a you as being a bad idea? Does any advice come to mind?

    I was also wondering why they thread the handle end of the lead screw with 1/4 28 threads, while the rest of the feed screw is 1/4 20 threads. The 1/4 20 threads make sense because it makes for easy division on the dial, but I can't figure out why they felt the need to do 1/4 28 for the handle. I don't really want to buy 1/4 28 tap and die if I don't have to...

    Also, I need to a take a piece of 3/8 x 3 x 3 angle iron and turn it into an accurate mounting bracket. I'm thinking that to do that I can square it up by bolting a known square bracket to the faceplate, and then clamping the angle iron to that and facing it off. Is there any easier way to do that?

    My ultimate goal is to make a nice, worm drive telescope mount, but I have a feeling that's a long way off.

    As a small contribution, here is a really neat link I found the other day. It describes how to calculate the angle between two sides of a pyramid. This is going to come in handy if I ever get around to making a nice, sturdy plywood base for my Harbor Freight bandsaw.

    http://mathforum.org/library/drmath/view/55203.html

    Thanks in advance for helping. I'm sorry my first post is so full of problems. I've googled and continue to google, but there's nothing like asking people who know what they are doing.
    Lee

  • #2
    Welcome aboard.

    For HSS cutter grinding, try the search function or just cut to the chase, pop some popcorn, get a cold one, and search tubal cain on you-tube. His tool sharpening videos give an excellent starting point for free hand grinding, IMHO.

    As far as the grinding wheel, seems to me green 'uns are for carbide cutters. I use grey wheels for HSS, but I hear the white wheels cut the HSS faster with less burning.

    1/4 -28 is a finer thread and will hold a bit better when bottomed out. A jam nut will probably be needed too.

    As a start, I don't like to rain on your parade, but you mention the small work window on your lathe, and now you want to add a milling attachment? that will make the work envelope even smaller...

    Facing the angle to make an accurate angle plate is essentially how Gingery did his. He worked with Aluminum mostly with light loads and less deflection than you can expect with your smaller lathe.
    Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

    Comment


    • #3
      Welcome. Here's a couple of links that I enjoy.

      http://techtv.mit.edu/collections/ehs-videos/videos

      This one had some video of sharpening HSS, posted at about 4 months ago.

      http://www.youtube.com/user/mrpete222#p/u

      Comment


      • #4
        Hi ldn and welcome to the forum.

        I think you are in good company here if you plan to learn more about machining.

        Just ask away if you have questions. There are a lot of experts here to help.

        Brian

        PS. Glad you like the Shop Made Tools thread. I never would have thought there would be that much input when I started that thread.
        OPEN EYES, OPEN EARS, OPEN MIND

        THINK HARDER

        BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

        MY NAME IS BRIAN AND I AM A TOOLOHOLIC

        Comment


        • #5
          Welcome ldn, here is a web site by Little Machine Shop that might help answer some of you questions. Seems geared to us beginers.
          http://www.littlemachineshop.com/Ref.../reference.php Also check out their Learning Center.
          Last edited by lugnut; 06-16-2010, 08:29 PM.
          _____________________________________________

          I would rather have tools that I never use, than not have a tool I need.

          Comment


          • #6
            Welcome IDN. Don't let these guys fool you, I have a 7 X 10 "Horror Firght" lathe and do some amazing things with it. Little Machine Shop has quite a few instructional vidoes and articles. I seem to recall Chris has a very good article on sharpening HSS tool bits. On a machine like this, I actually prefer HSS bits, since I can sharpen them. Insert bits or carbides are usually done if you chip them (yes, I know they can be sharpened, but not easily)

            Dulling tool bits is usually from trying to machine hard metal...or...not setting the bit up properly. A tool bit meeting the work too low or too high can get dull in a hurry, even in aluminum. If you're still using the tool holder that came with the lathe, I'd suggest you look into the Aloris type quick change tool holders LMS sells. They are simple to set up and don't require shims to bring the bits to the correct height.

            As far as limited space on the ways. I suppose you know the tailstock does come off, and here again a quick change tool holder would give much better access.

            The grinding wheels have never been a problem, with me. Usually the cheap plastic hubs only come out if you don't tighten the washers enough.

            Chuck St. Louis did an article for the magazine where he replaced the plastic hubs on grinding wheels with lead, then chucked up the wheel on his lathe and bored/reamed the lead insert to the correct size for a wheel that runs very concentric and true. If melting wheel weights and pouring molten lead isn't for you, try making them from aluminum. But beware of the fact that aluminum expands quite a bit when it's hot, and could fracture the grinder wheel..not good Ju-Ju....

            Remember, it's the man running the machine that makes things, not the machine. The best (or worst) machine in the world won't make you any better or worse. Above all ask questions, and have fun!
            No good deed goes unpunished.

            Comment


            • #7
              Originally posted by ldn
              My biggest problem so far seems to be wearing out HSS lathe bits and not really knowing how to sharpen them again. Oh, yeah, and wearing out drill bits on mild steel. I've got to learn how to sharpen those too. So much to learn.

              Last minute insert: I just went out to the shed and replaced the stock grinder wheel with a "green" wheel and found that my new green wheel has these awful little plastic hub adaptors. When installed, they slide out to the side (under the domed washers) and the wheel wobbles like crazy. Would it be a good idea to make an aluminum hub adaptor on the lathe?


              My next project is going to be a lathe milling attachment
              .
              Ok thats enough to reply to for one post!
              First off: Diamond coated laps are wonderful for sharpning HSS lathe bits, usally grinding the side faces/form and leaving the top untouched or just lightly dressed.

              Wearing out drill bits on mild steel: Use less rpms, 500 or less typicaly unless the drill is under 3/16", and high feed pressures. Use cutting oil. Higher rpms can instantly burn out new bits. Using high pressure and low rpms and oil you can drill though inchs of mild steel with a single drill bit easily without sharpening it.
              And by use 500rpm I mean, buy a 500rpm drill or use the 500rpm setting on your drill press, do NOT just use your 1800rpm drill at 500rpms, it will not have nearly enough torque and if you push it you'll cook the motor.

              Green wheels are typicaly for carbide/gems and not for HSS
              For grinding HSS/Drill bits, you typicaly want a white or pink or blue wheel
              mild steel, Grey or brown (general perpose wheel)
              Of course, any wheel will do for anything to some degree, but green wheels are best avoided unless you are indeed doing carbide.
              Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

              Comment


              • #8
                Thanks for the warm welcome everyone!

                I'm looking forward to posting pictures as I make progress on the milling attachment. Hopefully in a few weeks I'll be able to make my own post to the shop mode tools thread.

                Yes, I made a mistake with the green wheel, I bought it back when I thought that the carbide bits were "better" and then forgot what it was supposed to be for.

                Everyone, thanks for all the links. I've made a list of all of the resources that you guys listed and am starting to go through those.

                Black Moons, thanks for the drilling tips, I knew that I need to run slow but I didn't know it was that slow.

                saltmine, I think the 7x10 is definitely a pretty good little machine. Once though I was drilling a 1/2" hole into the end of a 5" piece of stock, and I ended up removing the tailstock (with drill bit) and holding it in place with just 1/2" of the tailstock in contact with the ways. That actually worked better than I would have expected.

                That's a REALLY good point about the hubs expanding with heat. I'll use steel instead, which has half the expansion of aluminum. By my quick and dirty calculations I can expect a diameter increase of .003 with a temperature rise of 250 degrees C, so I should be OK if I leave a few thousandths wiggle room. Maybe I'll wrap it with electrical tape to take
                up the last little bit.

                camdigger, I should have thought to look at the gingery books. I bought them a few years back and pretty much forgot about them. I've known about them since I was a teenager and was fascinated by the idea, but after I read them I realized that the amount of work involved was staggering.

                Yes, I wish I'd been smart enough to buy a 7x14 version instead. What I didn't know at the time is that the lathe is not a large proportion of the total cost of being in this hobby, and I would have been better off spending a little more.

                On the other hand, I have limited space and the 7x10 fits nicely on my workbench.

                When I started looking at making a telescope mount, I realized that decent accuracy requires a large worm wheel. 6 inches is the bare minimum and at that size I'd need to machine it very carefully. Using a larger wheel would make it easier to get the accuracy needed, but of course that's not really possible on the 7x10... Unless... I could make some kind of booster seat for the headstock... Hmm...
                Last edited by ldn; 06-17-2010, 02:48 AM.
                Lee

                Comment


                • #9
                  Originally posted by bborr01
                  PS. Glad you like the Shop Made Tools thread. I never would have thought there would be that much input when I started that thread.
                  I'm only halfway through that thread... Did you ever make the website you were talking about?
                  Lee

                  Comment


                  • #10
                    Oh, another tip about drills: you can either cut the shank down, or buy 'stub' aka 'screw machine' drills that are MUCH shorter. much more suitable for use in small lathes.
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                    Comment


                    • #11
                      Nothing gets blunt faster than a slighly blunt tool.

                      I often wipe over cutting edges with a diamond lap between cuts and rarely ever have to actually grind tools. Likewise with drills, I often touch up the cutting edges with a lap.
                      Paul Compton
                      www.morini-mania.co.uk
                      http://www.youtube.com/user/EVguru

                      Comment

                      Working...
                      X