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  1. J

    pre drilling for holes

    I think the diameter difference is the root of the problem. The larger drill probably screwed itself into the pilot hole destroying the cutting lips on the drill. For a pilot drill pick one just larger than the web thickness of the larger drill. If you are enlarging a hole by 1mm or less the...
  2. J

    Centring in a 4-Jaw Chuck

    Joe Pie rocks. If you don't want to mess with indicators make a sleeve with an ID equal to the diagonal of the bar. Split the sleeve. Put the bar in the sleeve and stick it in the 3 jaw.
  3. J

    Bending brass tubing

    Sometimes it is necessary to start with a longer tube. You need enough length on the back end to get a firm hold and enough to establish the tangent at the end of the bend. The excess can be trimmed off after the bend.
  4. J

    Safety Turning

    If using carbide inserts purchase those with a chipbreaker for light finishing. Attempt to run them at the manufacturers suggested feed rate. Depth of cut should be no less than the nose radius. If the chips do not break try a higher feed rate. Most hobby lathes probably lack the power or...
  5. J

    Soft copper tubing?

    The best reference I have found for specifications and availability is here; https://www.mcmaster.com/copper-tubing. For short radius bends there are inexpensive tubing benders available. Check the auto parts stores or Amazon. I was never a fan of the spring type benders that slip over the...
  6. J

    Tapered thread

    When you start a thread with the die holder against the tailstock quill it is possible to let the die get ahead of the quill and get a cockeyed start. It is also possible to overfeed the tailstock quill and mess up the threads. I assume you are backing off the tailstock before you back off the...
  7. J

    Tapered thread

    Describe your setup, please. How are you holding the work? How are you holding the die? Is the die being guided?
  8. J

    Definite Blunder

    A good friend of mine lost her finger in a similar way. She was jumping down from the bed of a truck when her wedding ring caught on the stock rack of the truck.
  9. J

    Definite Blunder

    A few years ago a damned fool posted pictures. He had left the key in his lathe chuck. He put it through the windshield of his Porsche. Look at any of the photos of a machine shop from the early 20th century. Many of the workers were actually wearing suits, including vest and necktie...
  10. J

    Problems with face cutting on lathe, wavy pattern

    Keep our tool sharp. Hone it until it shines. Zero or neg. rake, up to 5*. Small end radius. Keep the tool stickout as short as possible. You should be fine. You may want to rig a chip deflector close to the tool. Bronze sprays ships everywhere.
  11. J

    Problems with face cutting on lathe, wavy pattern

    If changing the tooling does not work then investigate problems with the machine.
  12. J

    Problems with face cutting on lathe, wavy pattern

    The material and the tool can be interacting to produce the pattern. Some bronzes require a very sharp tool to cut them. If you are using carbide inserts with a honed edge that might be the problem. As the tool is fed into the work it tries to penetrate the metal but doesn't, deflecting the...
  13. J

    Suggestions to remove broken drill, and repair some small holes?

    Chinese vendors sell diamond tipped core drills in small diameters, 3mm, I think. They are very cheap. You would probably need a continuous flush of coolant through flush cuttings and prevent the aluminum from binding onto the diamonds.
  14. J

    Tapping and threading question

    I've had good luck with taps from Shars. YG tools from Amazon are very good.
  15. J

    Test Dial indicator sticking?

    The first thing to try is solvent on the stem. That is where they usually stick. Get some naptha (paint thinner) and apply it to the stem with a Q tip. Work the stem in and out. That usually solves the problem.
  16. J

    Reamer question

    Adjustable blade reamers really need to be started with a pilot. ID slips onto end of shank. OD is tapered to center in the hole. Chinese and India made reamers are crap. If re-ground they may be OK.
  17. J

    Tapping and threading question

    Evan, I will search my assortment of taps tomorrow. If I find a 9/16 -18 I will be happy to lend it to you. Evan, I have the tap. Check postage both ways. It might be cheaper to buy new on eBay. PM me if you want me to send the tap. It is a plug tap, not bottoming.
  18. J

    Help with making eccentric on a 4 jaw chuck

    I think I would do it in the mill. Indicate on the OD and dial in the the offset for the hole. There is a formula to calculate the height of the packing BaronJ mentioned. Unfortunately I caan't remember where I saved it.
  19. J

    Tapping and threading question

    Evan, You said tap & die set. Most packaged sets are of questionable quality. If you need taps and dies buy them as you need them. Puchase them from established tooling vendors like Victor, Travers,or eve (God forbid) MSC, or one of many others. Try to buy name brand tools. Irwin quality...
  20. J

    modified bottom tap

    Like WOB said. Look at an inverted flare fitting. All have a projection to engage the inside of the tube flare. Without it your flare on the tubing will crush.
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