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Thread: New 8L Lathe

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  1. #21
    Join Date
    Nov 2007
    Posts
    2151

    Re: New 8L Lathe

    Sprutcam drives expensive live tool machines so simple xz. Lathe axis is no problem to get everything in the right direction. Using slant pro post of course. Would be difficult with no cam experience but I think that's the case anyway.
    Setup o.d. threading ops today. Wanted to zero in on what cam settings do what. And how to present the model. Very cool to watch it cut threads for first time. Made some thumb screw forms in 8-32. 10-24 and 25-20 threads. Then saved the op setups for future use. Next is rigid tapping op setups. Then boring, reamjng and internal threading. This should give me some experience with most of the op and tool setup types. Hoping to leverage my cam experience to automate most of this. Maybe get my moneys worth out of cam finally and get good use from the lathe also.

  2. #22
    Join Date
    Nov 2007
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    2151

    Re: New 8L Lathe

    After using this machine for a few weeks its not hard to see one part of the lathe market this machine fits into well!
    Precision threading collet lathes.
    And I'm guessing this is one of the reasons it has x axis set opposite of many cnc lathes.. After running a number of test forms and threaded profiles It seams like this machine will make small fasteners with exceptional accuracy. I setup a range of thread profiles in cam and cut them with no problem at all. Making super nice fitting threads. Betting conversation ops are not hard to also setup.
    It is time consuming and tedious to setup tools accurately. The payoff is so far it appears to be freaky accurate.

  3. #23
    Join Date
    Jun 2006
    Posts
    3063

    Re: New 8L Lathe

    Quote Originally Posted by mountaindew View Post
    After using this machine for a few weeks its not hard to see one part of the lathe market this machine fits into well!
    Precision threading collet lathes.
    And I'm guessing this is one of the reasons it has x axis set opposite of many cnc lathes.. After running a number of test forms and threaded profiles It seams like this machine will make small fasteners with exceptional accuracy. I setup a range of thread profiles in cam and cut them with no problem at all. Making super nice fitting threads. Betting conversation ops are not hard to also setup.
    It is time consuming and tedious to setup tools accurately. The payoff is so far it appears to be freaky accurate.
    MD - are you using Tormach threading tools? I started with their standard OD threading tool for the SBL-15 and am finding a lot of tweaking necessary to get a reasonable, let alone truly accurate, fit. I'll be looking over NYCCNC's thread milling spreadsheet in detail before doing any thing critical in future and just armed myself with 0-1, 1-2, and 2-3 thread mics from Shars. I really detest fiddling with thread wires and their illegitimate cousins (thread triangles on a rope)..

  4. #24
    Join Date
    Nov 2007
    Posts
    2151

    Re: New 8L Lathe

    Quote Originally Posted by MichaelHenry View Post
    MD - are you using Tormach threading tools? I started with their standard OD threading tool for the SBL-15 and am finding a lot of tweaking necessary to get a reasonable, let alone truly accurate, fit. I'll be looking over NYCCNC's thread milling spreadsheet in detail before doing any thing critical in future and just armed myself with 0-1, 1-2, and 2-3 thread mics from Shars. I really detest fiddling with thread wires and their illegitimate cousins (thread triangles on a rope)..
    I dont have a way to measure threads to be honest. I was just using store purchased fasteners to compare fit. I used a generic axa size threading tool with a generic insert. Plugged standard numbers from HSM advisor tab on thread forms into sprutcam and tested 4 small sizes 8-32 to 3/8 - 16. I left sprutcam settings for how it cuts the threads as default 10 pass alternating side with variable depth per pass. I was expecting hours of fiddling around with numbers to get a decent fit as you mentioned and was surprised to get decent results first time with little effort. Figured at that point if you refine your process with better tooling, cam and setups it will only get better.
    To be clear this was the first time I ever setup and cut threads on a cnc lathe and with only few hours of sprutcam lathe experience total to do it!

    I guess maybe I was lucky, I dont have big dollar name brand tools to measure much of anything! Just some basics to get me going in the right direction and a microscope to look at fit and finish. Someday I guess I will add more tech. These days my tools have tools that have boxes of tools and now I need tools to verify my tools that have tools


    Numbers I use

    Pitch
    major dia max- min "somewhere between these numbers"
    unr / v-height "somewhere between these values"


    Attachment 457482

  5. #25
    Join Date
    Nov 2007
    Posts
    2151

    Re: New 8L Lathe

    Mike! Quick picture of results of the thread test forms I did on 8l lathe. I used standard nuts for fit test.
    All done in sprutcam very first try I have to say I have done threading on a manual lathes and this process / machine kicks ass!
    Watched nycnc video and they had their 8l opened up and apart. It looked silly small compared to his other machines. But it fits perfect in my shop
    The machine is new and it has a few issues they are working on. But for a garage shop proto-typists it shines imho.
    Attachment 457574

    by 4th profile I was testing knurl operation tool paths.
    Not a standard operation in sprutcam
    Background is a number of 8-32 threaded profiles with different knurl tests screwed into a 8-32 test block.
    And also I tiny chess pawn.

  6. #26
    Join Date
    Jun 2006
    Posts
    3063

    Re: New 8L Lathe

    Those look pretty good MD. I too usually use a standard nut or bolt to check machined threads but a recent project needed 2-1/8x6 male and female threads in parts that need to fit together. I couldn't find a cheap, quick source of fittings in the sizes so needed to make them fairly close to design dimensions,

    I'll have to play around with SC for threading and get comfortable with it as well as review NYCCNC's available spreadsheet and video(s). I recently hand tapped 16 holes in aluminum, 1/4x3/4 deep and that was no fun. A thread mill would have been far faster so I'm thinking about getting a few sizes of single point thread mills.

  7. #27
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    Nov 2007
    Posts
    2151

    Re: New 8L Lathe

    Quote Originally Posted by MichaelHenry View Post
    Those look pretty good MD. I too usually use a standard nut or bolt to check machined threads but a recent project needed 2-1/8x6 male and female threads in parts that need to fit together. I couldn't find a cheap, quick source of fittings in the sizes so needed to make them fairly close to design dimensions,

    I'll have to play around with SC for threading and get comfortable with it as well as review NYCCNC's available spreadsheet and video(s). I recently hand tapped 16 holes in aluminum, 1/4x3/4 deep and that was no fun. A thread mill would have been far faster so I'm thinking about getting a few sizes of single point thread mills.
    Thanks Mike!
    I have decent amount of experience getting sprutcam to do what I want. "one way or another" I count the experience in dog years and I have 64 years of it.
    The standard lathe machine schema I use for 8l lathe would not be a simple thing to setup and use with confidence without knowing the program well.
    They have the 8l reversed from most cam / cnc lathe designs and this would cause problems for most Sprutcam users. I had to go back and change everything around and experiment with setups until the post spit out code I understood would work.
    I use the most recent version and its not clear how much they improve the lathe section of this program over the years. After using it for a few weeks I see a number of job selection issues that bug me and would like them fixed. I would think someone would have complained about these issues years ago. But again this is all in how the program is used and the workflow of the user. I tend to use the sprutcam with a much different workflow then others.
    In short Sprutcam lathe section so far works well and posts good code using the 15L post with my lathe machine schema setup the way I have it.
    I did spend time setting up tool table near exactly as they set on rack . I dont see how you can get accurate results without carefully doing this. Path pilot is also setup with same but Sprutcam only uses PP offset numbers, not tool data.
    The threading section of Sprutcam has a database you can keep all the setting for any thread form standard or custom. One of the reasons I went thru the process of setting up and testing a few thread forms all at same time was to populate this database with MY numbers. Now I can use them with confidence and no need to load a thread reference chart to get numbers unless its new .

    Attachment 457688

    I don't have nycnc's thread mill spreadsheet those come around after I learned how to do this. I have always used formulas from CNC Programming Handbook "large section on cnc threading of all types" and numbers from HSM advisor reference tabs and or machinist handbook. Combine them in sprutcam and I often get good results first time.
    After I setup an operation like this I refine it and then save it to a list of named user operations like thread mill 25-20. Then 1 week or 1 year later it takes only seconds to setup and use. After a while you get a long list of these to work with and before you know it it only takes a couple minutes to setup a complete part.

    I do need to add some high quality test and measure tools to my boxes. That way I can be a real machinist not a "technologist" besides I dont think I chase my tail enough.
    A good tach would be nice start! Spindle speeds on all 3 machines are little suspect and I would like to check them and understand more. 1 thing in a long list!

    Note on single point thread milling!
    Just my opinion if your chasing a thread mill operation I found the single point / form thread mill tool can be the problem. Some are not ground as accurate as others! Here is where super accurate measurements of the cutter form would be handy and explain a lot to the end user. maritool i found are best that i have,

  8. #28
    Join Date
    Nov 2007
    Posts
    2151

    Re: New 8L Lathe

    Quick note on 8l lathe threading and this might apply to 15l and others.
    The thread tool / holder and in my case the tool post has to be carefully swept in with an indicator. Verify it is as close to parallel or perpendicular to the center line of spindle as possible across the tools x or z axis range. Found the tool post on my 8l lathe got bumped out of alignment slightly and it showed up just seconds later with poor / bad thread operation! The alignment was not even noticeable on other operations but stuck out big time when inspecting threads "they were bad". Re- aligned the tool post and double checked threading tools and I was back making decent threads. Found that I will need to keep an eye on the tool post and its alignment to spindle when using this machine.

  9. #29

    Re: New 8L Lathe

    Greetings! Look up three wire thread measurement. With a micrometer, a bit of clay or a sense of humor to juggle/control three wires, and a couple of tables you can measure most threads. PeeDee sells a low cost set of thread measuring wires. For one off, you can buy a cheap large assortment of sewing needles and measure out several sets of three to cover most common smaller threads. Old school, not sexy like super precision thread measuring micrometers and the like, but works just fine. It's a step up from testing with off the shelf hardware, and sufficient for many folks who only have occasional need to do better that "does it fit the nut?" thread cutting.

  10. #30
    Join Date
    Nov 2007
    Posts
    2151

    Re: New 8L Lathe

    Quote Originally Posted by Stan Stocker View Post
    Greetings! Look up three wire thread measurement. With a micrometer, a bit of clay or a sense of humor to juggle/control three wires, and a couple of tables you can measure most threads. PeeDee sells a low cost set of thread measuring wires. For one off, you can buy a cheap large assortment of sewing needles and measure out several sets of three to cover most common smaller threads. Old school, not sexy like super precision thread measuring micrometers and the like, but works just fine. It's a step up from testing with off the shelf hardware, and sufficient for many folks who only have occasional need to do better that "does it fit the nut?" thread cutting.
    8-32 threads measured using the 3 wire method would be well beyond my finger dexterity! What can I say im handicapped

  11. #31
    Join Date
    Nov 2011
    Posts
    107

    Re: New 8L Lathe

    Quote Originally Posted by mountaindew View Post
    8-32 threads measured using the 3 wire method would be well beyond my finger dexterity! What can I say im handicapped
    How About the precision?? Can it hold +0.000 ,- 0.001in on a 0.75in OD shaft along a 7in lenght bar using the tailstock? I have the 15L but im limited by the lack of the tailstock in some circumstances

  12. #32

    Re: New 8L Lathe

    Without a tail stock, on any lathe, cutting a 3/4" bar with that much stick out would be difficult to keep those tolerances.

  13. #33
    Join Date
    Dec 2007
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    379
    Is it possible to turn a 10 inch long part with the 3 jaw chuck or is 10 inches only with the 5c collets. I just ordered and 8L without thinking about this (lol) and could be problem for me.

  14. #34
    Join Date
    Nov 2007
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    2151

    Re: New 8L Lathe

    Anyone with manual oiler trouble shooting experience? My 8l lathe gas one and its not working like it did. Pull handle and it would slowly return in. Now it returns back fast like its not pushing oil into system.
    I have no experience with these one shot type oilers. So any ideas on how to fix one would be great.

  15. #35
    Join Date
    Aug 2010
    Posts
    130

    Re: New 8L Lathe

    It sounds like a line came loose or got damaged, or you are out of oil. I don't know the 8L oil system, but the 1100 manual has the system schematic. You can check the connections at the end points, at any manifolds, or if there is a splitter. See if you can see any oil dripping or pooling.

  16. #36
    Join Date
    Nov 2007
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    2151

    Re: New 8L Lathe

    Ok didn't even think of that. I was focused on the pump itself. Will look over lines. There is not much to it.
    Thanks for info.

  17. #37
    Join Date
    Jan 2016
    Posts
    99

    Re: New 8L Lathe

    l know this is an older thread, but if you need to measure with wires, here is a site that will allow you to enter the size wires you have and give you what size to measure over the wires as well as other info.
    Learned the hard way to put a rag over the ways or at the very least clean out the chip pan before using wires.
    I now have 3 thread multi anvil mics from shars.

    Theoretical Machinist


    Dave

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