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Thread: Rookie lathe user needs some advice

  1. #21
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    Quote Originally Posted by J Tiers View Post
    Interesting.

    Which side of the multi-V do you have toward the pulley?

    How smooth is the pulley?

    That type belt has been recommended enough that it was on my list to use when the existing belt wears out.
    Like Stepside, I used an automotive serpentine belt with multi-v grooves on my SB 9". I placed the grooved side against the pulleys because I felt the outside of the belt was too slippery. After two years, the pulleys are nice and smooth with no evidence of grooves worn in and the belt will still slip if I jam a parting tool.
    I did not split my belt, however. I disassembled my spindle which doesn't take long on a model 405. I had to look through the Gates part numbers and do a little math to find just the right length.

  2. #22
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    There are a number of books available for lathe users, full of information on getting the cutting tools the best shape for different jobs. I recommend you get one of your tools exactly on the centre line, check by taking test facing cuts, and using the height of the tip of the tool to make a gauge which sits on the lathe bed. Then shimming tools to the correct height is much easier.
    I'm amazed that this thread is progressing without the piss takers emerging, this must be a first!

  3. #23
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    I was taught to place a 6" ruler between the tool bit and the item to be machined, run the bit in, and if the ruler was 90 degrees vertical to the bed, the bit was right on the centerline.

  4. #24
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    Quote Originally Posted by old mart View Post
    There are a number of books available for lathe users, full of information on getting the cutting tools the best shape for different jobs. I recommend you get one of your tools exactly on the centre line, check by taking test facing cuts, and using the height of the tip of the tool to make a gauge which sits on the lathe bed. Then shimming tools to the correct height is much easier.
    I'm amazed that this thread is progressing without the piss takers emerging, this must be a first!
    A very easy way to get one.s tools very very near centre height involves only the use of a 6" steel rule.
    Take a piece of stock anything from about 1/2" dia to 1 1/2" dia is convenient. fasten in 3 jaw chuck with about 1 1/2" sticking out Simply turn about a 3/4 " or so at the outer end of it till it runs truly, stop lathe back your tool off about 1/8" off the work, hold the rule( Graduation side to the part you turned true) and then gently pinch it with the tool.
    If the rule stands vertically your tool is on centre, if the top of the rule is tipped away from you the tool is too high, if the top of the rule is tipped towards you the tool is too low.
    It will take you less time than it took me to write this outburst,
    Hope it helps someone. Regards David Powell.

  5. #25
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    David's advice is good. I do the same. I was surprised when a machinist said that it was only step one. Step two is to face that piece until the nub in the center is shaved off.

    Why? It was explained that a random cutoff may or may not be turned round. Then you put it in a 3 jaw chuck and the bar may be clamped in place several thousandths of an inch off axis in a random direction. That may result in your centering the tool against a rod that is several thousandths higher or lower than expected. That makes a difference.

    With facing the bar as final step you are sure that the the tool is at the center of the axis of rotation regardless of the centering of the rod in the chuck.

    Of course this does not always work since there are some turning tools that don't lend themselves to facing without changing orientation. That's why it's suggested that you make a height gage that will sit on the bed or on the cross slide.


    Dan
    At the end of the project, there is a profound difference between spare parts and extra parts.

  6. #26
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    Quote Originally Posted by Corbettprime View Post
    I was taught to place a 6" ruler between the tool bit and the item to be machined, run the bit in, and if the ruler was 90 degrees vertical to the bed, the bit was right on the centerline.
    I used to do that too. It's a good way to check things. But to keep from knicking the ruler I tended to use light pressure. And sometimes the darn thing slipped and fell. Or I'd be trying to use two hands to hold the ruler and adjust the cutter and tighten the holder where we really need three hands and the ruler would slip and fall into the chip tray again. And that meant that I had to pass my hand through the "Gates of Hell" AKA the oily operation rods and lower side of the bed to retrieve it. So while it works well I always felt that there had to be a better way.

    Plus don't a lot of carbide insert cutters tend to chip the tips if pressed up against something like a ruler and not under the directed load of cutting? Again, with good care there should not be a problem. But one little misfeed and "tick".....
    Last edited by BCRider; 02-04-2019 at 04:40 PM. Reason: spelling

  7. #27
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    Quote Originally Posted by danlb View Post
    David's advice is good. I do the same. I was surprised when a machinist said that it was only step one. Step two is to face that piece until the nub in the center is shaved off.

    Why? It was explained that a random cutoff may or may not be turned round. Then you put it in a 3 jaw chuck and the bar may be clamped in place several thousandths of an inch off axis in a random direction. That may result in your centering the tool against a rod that is several thousandths higher or lower than expected. That makes a difference. ...
    But not if you use David's FIRST step of taking a skim cut. Doing that ensures that the short ruler width length of the cut is actually on axis. Then you don't need to confirm it with the facing cut.

    If the part you use for this is the raw stock you'll be turning into a usable part anyway then it's a great method since you don't need to do much to check it. And if the cutter you're setting is one for finishing cuts and the part already has some turned and on axis surfaces you can use for the ruler check you don't need to skim anything. Just set the height and check it.

    But it still doesn't make doing any "three handed" adjusting of the height with the ruler method any less risky for dropping the darn ruler into the sevenths circle of Hell known as the chip tray....

    Signed;
    Butterfingers

  8. #28
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    Quote Originally Posted by BCRider View Post
    But not if you use David's FIRST step of taking a skim cut.
    My apologies to David. I skimmed his post because I was already familiar with the basics. Thus I missed his first step.

    Dan
    At the end of the project, there is a profound difference between spare parts and extra parts.

  9. #29
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    Quote Originally Posted by BCRider View Post
    But not if you use David's FIRST step of taking a skim cut. Doing that ensures that the short ruler width length of the cut is actually on axis. Then you don't need to confirm it with the facing cut.

    If the part you use for this is the raw stock you'll be turning into a usable part anyway then it's a great method since you don't need to do much to check it. And if the cutter you're setting is one for finishing cuts and the part already has some turned and on axis surfaces you can use for the ruler check you don't need to skim anything. Just set the height and check it.

    But it still doesn't make doing any "three handed" adjusting of the height with the ruler method any less risky for dropping the darn ruler into the sevenths circle of Hell known as the chip tray....

    Signed;
    Butterfingers
    I do not try to adjust the tool height and hold the rule at the same time. Both my lathes have quick change toolposts
    I simply slack the height setting nuts off a fair bit, lift or lower the toolholder an eyeball measurement or feel with a finger change of height what I think is what I need, tighten the clamp, check with rule, redo if needed, when happy reset the height setting nuts and locknuts.
    Arthritis makes this harder and slower than it used to be,usually two tries get me pretty damn near. I dare not go fishing in swarf trays, I am on blood thinners and bleed like a pig from the least cut.
    I am sure there is a relationship between the dia of the piece and the amount the rule tips and the height discrepancy but life is far too short for me to worry, I just want the tool on "( or very very near) centre height so I can get on building my steam engines. regards David Powell.

  10. #30
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    I'm sure there's tricks I could use to make life easier. Like a bit of ruler like flat stock with a glued or soldered on step that would stop the "rule" from falling away if pressure is lost for a millisecond. But since I made up the little Joe Pie inspired height gauge and started using it I've found that it's so much easier and just as quick or perhaps quicker and with no dropsie risk that it's now my standard method.

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