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IndustryArena Forum > MetalWorking Machines > Uncategorised MetalWorking Machines > hmm..drawbar force seems to be 245 lbs?
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  1. #13
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    Quote Originally Posted by DaOne View Post
    I am in the process of building a clamprite style for my 40 taper Haas. Since this is more less a hobby machine I cant justify spending that much on the tool. I am planing to use this as my ram...

    10 Ton Hydraulic Short Body Ram

    coupled to this...

    5000 PSI Filled Gauge

    and turn the threads off a thru coolant pull stud. Weld on a extended shank that will attach to a A frame style clamp that this piston will go in at the bottom of a 1 inch holder. this should work perfectly as I can preload the pull stud by screwing it into the clamp and the flange of the pull stud will be sitting on top of the holder just as it would normally. I will have to post some pics when I finish it.
    AH-HA! a short stroke hydraulic actuator! and the gauge!!! nice find!!

    so the drawbar pulling up will compress the ram via the frame/clamp you will be making right? can you link to a pic of what the clamp will look like? i cant seem to find one. crap i think i may go buy those parts and give this a shot...

    i dont think this will be a big issue, but how do you fill the ram and the gauge with hydraulic fluid and bleed it of air? maybe the bleeding isnt needed because the preload can compress the air to nothing?

    hmm i think you should start a separate thread dedicated to this project..alot of people will probably follow in your footsteps..including me if it looks like it will work lol

    btw some good news on the strain gages for anyone interested in that:

    from what ive read online, some strain gages can be bonded using just super glue. it depends on the backing material and the strain required. and Omega offers a $10 kit with bonding agent..so its not hundreds of dollars. there are also youtube videos showing strain gage bonding procedures..so this is all very inexpensive and accessible. omegas adhesives are here:

    http://www.omega.com/pptst/Strain_Gage_Adhesives.html

    and, i found lots of inexpensive strain gages on ebay, including a 45 degree rosette that will allow torsion and shear stress measurements, and its only $7.50 shipped for a single one! the average price for linear singles and rosettes is about $40 shipped for qty 5..


    Budd Strain Gage Rosettes C12 111 R3A 120 Ohm Gage Factor 2 01 NOS Qty of 1 | eBay

    the 45 degree one is really not meant for tension measurements..in fact i think its specfically designed to null out non torsional/shear forces. but it was so cheap i figure if i can get it to work then ill by the tension style ones. like this 2 gage rosette 5-pack for $35 shipped!

    5 New Vishay mm WK 00 250TB 10c Precision Strain Gage 1000? ±0 4 w Opt W | eBay

    so i bought the 45 degree rosette and im going to try bonding it to something and getting some kind of meaningful measurement, maybe some kind of torque wrench verifier lol. i have a differential amp with a 7 segment display from a different project so I think I should be able to measure the output, although I may need to make a bridge of some kind.

    there is a very small chance that i may end up attempting to use it in a drawbar force gauge somehow..but it looks like DaOne's items up there would be perfect.

  2. #14
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    Here is a photo of what I mean. Basically 3 parts required to be made and if you own a mill it should be easy to make.
    Attached Thumbnails Attached Thumbnails Tool Assembly 2.jpg   Tool Assembly.jpg  

  3. #15
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    Oh and on the oil and air part. I was going to use a lightweight oil and actuate the piston to bleed out as much air as I can. Then assemble the piston to the gauge while its submerged in the oil.

  4. #16
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    Quote Originally Posted by DaOne View Post
    Oh and on the oil and air part. I was going to use a lightweight oil and actuate the piston to bleed out as much air as I can. Then assemble the piston to the gauge while its submerged in the oil.
    okay i think i get your textual description of the device but i cant seem to make it jive with the drawing...

    the idea is that the hydraulic ram gets squished by the pulling force of the draw bar, via the pull stud, right?

    so the pull stud force is transmitted through the toolholder via the rod, which is connected to the _far_ side of the hydraulic ram, so that its a compressive force (far side of ram being crushed against toolholder).

    but i dont see how thats happening in the drawing, the square shaped object seems to be free floating?

    can you describe it a bit more plz

  5. #17
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    The ram rests against this surface. The square loop is pulled against the other side of the ram squishing it. The pull stud rod is threaded into the square loop so the whole thing can be preloaded by screwing the pull stud down.

  6. #18
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    Maybe this pic will help. The square loop and pull stud are connected. The spacer is connected to the holder. When force is applied to the pull stud the ram is squeezed between the loop and the spacer.
    Attached Thumbnails Attached Thumbnails Tool Assembly4.JPG  

  7. #19
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    Quote Originally Posted by DaOne View Post
    Maybe this pic will help. The square loop and pull stud are connected. The spacer is connected to the holder. When force is applied to the pull stud the ram is squeezed between the loop and the spacer.
    ahh i see now..i thought the ram piston or possibly housing was in the drawing..now i see that the drawing is the custom parts you will be making..this is very nice..i would really like to see how this turns out..

    id like to make this..i need to get a coolant pass through BT30 like you mentioned...

  8. #20
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    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.

  9. #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

  10. #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.

  11. #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.

  12. #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?

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