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IndustryArena Forum > MetalWorking Machines > Uncategorised MetalWorking Machines > hmm..drawbar force seems to be 245 lbs?
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  1. #21
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    Quote Originally Posted by DaOne View Post
    Well the coolant pass pull stud is just used to line up the threaded extension. Sure it can be done without one.I was just gonna turn dow that rod to fit in the hole of the stud to hold it in place while I tig weld it to the pull stud.
    so you need to core out the toolholder about 3/8" or so for that rod right? is that hard to do? i.e. if i try to do that on the lathe at work, am i going to need a special method or could i literally just drill it through? its just a clearance hole right, i.e. not precise

  2. #22
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    The cat40 holder I have has a hole straight through. I just machined the threads off the pull stud on the lathe.

    I went ahead and purchased both the gauge and the ram. I used lightweight air tool oil so I could get all the air out easy. I filled the ram and installed the gauge. One thing you must note is that the diameter of the ram is approximately 1.5 inches. This gives a surface area of 1.7671458676442586. So what ever the gauge reads you must multiply by that number to get the corrected PSI. The formula for the corrected PSI is: area = Pi * radius^2. I am gonna search for a 1500 PSI gauge so I can get better resolution.

  3. #23
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    If you wanted to make the gauge read correctly you will need to fabricate a ram that is 1.1284 inches in diameter.

  4. #24
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    Quote Originally Posted by DaOne View Post
    The cat40 holder I have has a hole straight through. I just machined the threads off the pull stud on the lathe.

    I went ahead and purchased both the gauge and the ram. I used lightweight air tool oil so I could get all the air out easy. I filled the ram and installed the gauge. One thing you must note is that the diameter of the ram is approximately 1.5 inches. This gives a surface area of 1.7671458676442586. So what ever the gauge reads you must multiply by that number to get the corrected PSI. The formula for the corrected PSI is: area = Pi * radius^2. I am gonna search for a 1500 PSI gauge so I can get better resolution.
    wow i cant wait to see this...

    so the "preload" adjustment takes all the slack out of the assembly so that the stud is firmly seated on the top of the toolholder and any additional force will compress the ram right?

    how big of a rod can you fit in the coolant passage on the toolholder? are you using the toolholder as-is and only modifying the pull stud?

  5. #25
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    Yes you will preload it by screwing the pull stud into the clap until the needle just does move. This removes all the takeup and will make sure the pull stud movement is minimal when the drawbar pulls on it.


    No mods to the tool holder. The threads are turned off the pull stud just enough so that the one in the tool holder hold it center and it does not catch on the threads in the holder. As for the rod you could make it as big as a half inch but I feel thats way overkill and I want some room to weld it. I will prob make it out of a 3/8 grade 8 bolt with the head turned off and weld it to the pull stud. The coolant hole would only be used as a guide to make the rod concentric while I weld it to the pull stud.

  6. #26
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    Quote Originally Posted by DaOne View Post
    Yes you will preload it by screwing the pull stud into the clap until the needle just does move. This removes all the takeup and will make sure the pull stud movement is minimal when the drawbar pulls on it.


    No mods to the tool holder. The threads are turned off the pull stud just enough so that the one in the tool holder hold it center and it does not catch on the threads in the holder. As for the rod you could make it as big as a half inch but I feel thats way overkill and I want some room to weld it. I will prob make it out of a 3/8 grade 8 bolt with the head turned off and weld it to the pull stud. The coolant hole would only be used as a guide to make the rod concentric while I weld it to the pull stud.
    could you suggest a cheap toolholder that has those dimensions? im not familiar with pass-thru coolant toolholders, is the coolant passage diameter standardized?

  7. #27
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    Well just about every holder i own is like this. I know some of the Shars have it to where its threaded inside so you can use a stop. The holder I am using is just a standard 1 inch tool holder. Its old and I really never use it anymore anyways so its a good one to make use of. You should be able to modify the design to fit and holder you got that is around that size. Nothing special about it.

  8. #28
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    Quote Originally Posted by DaOne View Post
    Well just about every holder i own is like this. I know some of the Shars have it to where its threaded inside so you can use a stop. The holder I am using is just a standard 1 inch tool holder. Its old and I really never use it anymore anyways so its a good one to make use of. You should be able to modify the design to fit and holder you got that is around that size. Nothing special about it.
    well shiver me timbers yer right..i just looked at my 3/4 toolholder with no pull stud and its just cored out all the way through..

    there is a harbor freight not 10 minutes from my house..guess where im going tomorrow morning lolzors

    so i have a few gauges..

    an omega 2000 psi pressure sensor.
    a "no shok" 2000psi gauge (ironically i just opened the box and all the glycerin had leaked out the gauge..wtf?)
    a chinese 4000psi gauge from my old argon gas welding regulator..not sure its okay to use that on liquid but hey lets try it!

    so i just need the hydraulic ram and i think i can actually pull this off tomorrow! or pull it UP if you get my meaning? oh man


  9. #29
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    any idea what kind of fitting we are going to be dealing with on that ram? is it some weird hydraulic + chinese + badly machined thing?

  10. #30
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    Zero fitting. It should work great. Biggest issue with it is the multiplier to get the correct PSI. But is sure beats making your own ram.

    - - - Updated - - -

    Oh and the ram has a 1/4 npt female thread that fits most gauges.

  11. #31
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    Quote Originally Posted by DaOne View Post
    Zero fitting. It should work great. Biggest issue with it is the multiplier to get the correct PSI. But is sure beats making your own ram.

    - - - Updated - - -

    Oh and the ram has a 1/4 npt female thread that fits most gauges.
    welp im officially excited...dont know if i will be able to sleep tonight with thoughts of unlimited drawbar force measurement just hours away...

    hmm funny what things i look forward to these days.. :/

  12. #32
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    so far so good!

    the sherline turned down the threads and doubled as a way to hold the rod to the stud for welding

    i think i may try making my own ram..just for fun. i can make the piston on the sherline and i have orings. parkers oring calc says itll be good to 1500psi. i just need to bore a fairly accurate hole in something..












  13. #33
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    the piston!

    i had some new orings and a piece of stainless lying around that fit the bill

    designed according to parkers inphorm gland calculator and some online standard gland dimensions..should be good to 1500 psi




  14. #34
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    Hi....is that just to measure the drawbar pull?
    Ian.

  15. #35
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    Wow your quick! So I see your gonna make your own ram? I might do the same down the road to get that gauge to read what it actually is. Looking good! More pics the better!

  16. #36
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    Quote Originally Posted by DaOne View Post
    Wow your quick! So I see your gonna make your own ram? I might do the same down the road to get that gauge to read what it actually is. Looking good! More pics the better!
    yop i have drawbar on the brain. thanks for inspiring me! im totally just copying your great ideas!

    this little project has gone surprisingly easy and surprisingly well so far....hope i dont jinx it..its even been fun so far

    i decided to make my own ram because ive never made a high pressure bore seal like this and id like to get a little experience with it

    note to self: next time try two orings so the piston doesnt wobble around so much..i would assume two orings spaced apart would eliminate the pivot point of one oring

    so i took a 1" thick piece of aluminum, and milled out a 1.25" diameter pocket, as deep as the piston. (oops)..should made it slightly deeper..but it turned out okay because the piston has enough thickness above the oring to allow for say a 1/16" gap in the cylinder to be filled with the fluid.

    i drilled a 0.155" dia hole into the chamber on the floor of the cylinder from the long end of the stock, and then tapped a 1/4npt into it

    i tested it first with my 2000 psi gauge. i stood on the piston, no leaks! and it jumped up to about 3 marks on the gauge which is somewhere between 150 and 200 psi...should be about 175psi since i weigh about 220 and the 1.25" diameter piston reduces it to that

    so then i hooked up a 15 psi gauge, and put a 5 lb block on the ram. the gauge shows 4psi, right where it should!!

    more fun tomorrow with my new toy, including making the final two pieces in your design DaOne so i can actually use this thing for drawbar testing

    funny..a ram with a gauge..this seems like a very useful little tool..you could measure vice force with it? im starting to think maybe this is a cheap off the shelf item

    the machining for all these parts has been very easy so far..i am starting to re-doubt the $700+ price tag for a clamp rite. if you make a ram that doesnt leak, then you just buy a nist calibrated gauge and the rest of the parts are super low precision. toolholders come with big holes in them already, and modifying a pull stud to connect to a rod is super easy..ummmmmmm

    imma try to think of things i can do with this "meter" now..

    -vice clamping force
    -drill press quill force
    -drawbar force
    -z axis force (might not be wise)
    -?


  17. #37
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    Looking good... you wanna just make me one too since your having so much fun? I always questioned the $700 + price tag on these. This is why I designed one that was this easy to build. I think its a tool everyone that owns a CNC mill should have. Maybe I should get off my butt and make mine since you proved the design works.

  18. #38
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    Quote Originally Posted by DaOne View Post
    Looking good... you wanna just make me one too since your having so much fun? I always questioned the $700 + price tag on these. This is why I designed one that was this easy to build. I think its a tool everyone that owns a CNC mill should have. Maybe I should get off my butt and make mine since you proved the design works.
    thanks!

    i wish i could build more, but it just used scrap i had around and i dont have any more stainless. plus im about 3 unnecessary projects deep from working on what im supposed to be working on lol...

    i wouldnt count our chickens just yet..once i finish fabbing it and actually try it out, and maybe find some way to double check its readings at multi-hundred pound forces, then we can call this example of your design a success..but until then im still suspicious that either there really is a reason the clamp rites cost at least a few hundred, or that maybe something i thought would work wouldnt (like my homemade ram)

    if it all works out great then i may think about making another refined one (this ones sorta clunky and id probably change a few things about it on a second round

  19. #39
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    The ram is the only part that I question. The rest is sound. I would have used a lip seal instead of orings but the orings should work if they are tight. The ram will be pushed equally so I wouldn't worry that it can wiggle. It will be held straight when clamped. Also the plunger in the ram really only need to stick out a small amount over the ram body as it should not move but a tiny amount when force is applied.

  20. #40
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    This should help ya on your cylinder size to corrected psi. A little calculator I whipped up.
    Attached Files Attached Files

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