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  • #31
    Originally posted by cameron View Post
    Looking carefully at the compound screw and the screw beneath, it appears they are not the same pitch. There's almost a half pitch difference in 29 threads. Doesn't that suggest the compound thread pitch is 2.5mm?

    (2.54 -2.5)X29 = 1.16mm = .046", roughly 1/2 pitch.
    I noticed that too ! You can see that the threads on the rod start to get ahead of the threads on the original screw. You can forget reding the dial with that rod. Did you check with the Clausing service center to see if the screw and nut are still available???

    JL...............

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    • #32
      I've run into this acme thread incompatibility phenomenon a couple times, the latest also being a Clausing in the 100 series.

      Lane said he had seen it often also and thought it was that the mfg did proprietary threads??

      I also got a length of 1/2-10 thread from Mcmaster, but I also got one of their 'general purpose' acme nuts that matches it also. Your existing nut looks exactly like mine did, 3/4 diameter?? - what I did was to turn the Mcmaster nut down to 3/4" dia and then mill the existing nut/threads away to match the diameter of the new nut and silver soldered them together (take care to get the new nut in line with the travel path) I also did this on a cross feed screw and also with a tail stock screw.

      http://www.mcmaster.com/#general-pur...e-nuts/=jw1gq9
      If everything seems to be going well, you have obviously overlooked something........

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      • #33
        Originally posted by JoeLee View Post
        I noticed that too ! ........
        I did as well, but is seemed so slight I figured it was parallax and maybe a bit of wear at one end.... oxford, since you're the only who can view and test, what say you? are they in fact the same pitch when compared over their lengths?
        in Toronto Ontario - where are you?

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        • #34
          Originally posted by JoeLee View Post
          I wouldn't make the nut out of any plastic type material, simple reason being it's too soft and will give too much under a load.
          I don't agree with that at all.


          Originally posted by oxford View Post


          As far as making a acetel nut using Evans method, how would you go about making a nut like this. I was thinking of making a nut out of some crs but instead of threading just make a straight bore then doing a slight press of the molded acetel nut into it then putting a roll pin through to hold it in place. Any other ideas.
          That's exactly what I did on my lathe and it worked just fine.
          Peter - novice home machinist, modern motorcycle enthusiast.

          Denford Viceroy 280 Synchro (11 x 24)
          Herbert 0V adapted to R8 by 'Sir John'.
          Monarch 10EE 1942

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          • #35
            As far as I can tell by eye the thread pitches are the same. It will sit tooth to valley with no apparent gaps(except in depth). I will agree that they do look different in the picture. I think it is camera angle and shadows and the original screw didn't lay exactly flat next to the new screw.

            As far as a manufacture specific thread, it could be though the piece of 5/8-10 LH acme rod that I got for the cross slide fits into that nut. That nut is also wore pretty bad so it may not be saying much. I know that the nut is available from Clausing and probably the screw as well although I don't think I would want to know what the cost of the screw would be.

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            • #36
              Well last year I replaced the cross slide screw on my 5900 and the screw and nut assy. cost me $225. There was a bit more work involved in making that screw because my lathe has the taper attachment, the dial end of the screw is splined or broached internally and the opposite end is turned down to fit the end bushing. Your compound screw is short and simple, so is the nut..... it's not a T nut. It has to be less than what I paid for my cross slide screw. I would with out a doubt at least inquire about the price.

              JL................

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              • #37
                Was that $225 the cost from Clausing? I was quoted over the $300 mark($325 I think) for the cross slide shaft and $56 for the nut. This was for the standard screw, not the one for the taper attachment. I got a piece of precision threaded rod for that to splice in and I am going to attempt making a steel t-nut with the Evan acetal nut insert.

                I was going to do the same for the compound except re-use the old screw since it didn't look like there that much wear on it. I then decided it would probably be easier to get a piece of rod, make a tap and a solid nut of acetal. Thats where the problems started.

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                • #38
                  Yes the $225 was the cost of the cross slide screw and nut. This was the screw used if your lathe had the taper att. Internally splined as I mentioned in my previous post. The standard screw (no taper att.) was much cheaper.
                  I just can't see that short screw and nut costing $300. Something doesn't sound right.
                  Below is a picture of my cross slide screw.

                  JL...............


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                  • #39
                    The cross slide screw was $300+, I didn't get a price for the compound screw.

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                    • #40
                      Usually the screw comes with the nut. Your 5914 is a little bigger of a machine than my 5900, but I can't see there being that much difference.
                      Perhaps the price has gone up?? The compound screw should be much cheaper.

                      JL...................

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                      • #41
                        oxford, you were on the right track with buying threaded rod.....and the wheels fell off the cart on it fitting the nut. So the next step is measuring - did get a chance you to measure the threads as suggested? Measure the one you bought and an unworn section of original with mic and thread wires. If you don't have them, you can use wire in a pinch but the thread wires can be bought for small dollars and are something the tool box should have Since pitch, direction and starts aren't the issue, there are only so many things it could be - all determined by measuring

                        1) the threaded rod you bought is out of tolerance
                        2) the threaded rod is a stub acme
                        3) the original screw is custom size

                        1 & 2 get fixed by getting the right thread stock. 3) gets fixed by making the screw yourself. Not hard since you've measured with thread wires an unworn section of the original.


                        Originally posted by oxford View Post
                        The cross slide screw was $300+, I didn't get a price for the compound screw.


                        They send a machine shop the drawing, then mark it up 100% or more. The markup on parts is rude.

                        With more money than time I can't fault buying it out, otoh hand we have lathes and its a good project. Buying a length of acme threaded rod saves some of work, or you could just make the whole thing.
                        Last edited by Mcgyver; 10-27-2012, 11:43 AM.
                        in Toronto Ontario - where are you?

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                        • #42
                          I measured the depth of thread the best I could. The book I have here at the house said depth should be 1/2 of the pitch plus .010" for clearance for standard acme. So 3/8-10 should be .060" with clearance. It did not give specs for stub acme in it. The old screw I got right around .060" in the center and a little less on the ends. The rod from McMaster only measured around .041" of depth. I think that this would make it a stub acme from what I can gather for specs on the internet (I saw where it is around 2/3 less depth than regular acme). I guess I am going to have to give McMaster a call, I hope they don't plan on having me pay for the return shipping.

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                          • #43
                            stub should be 1/3P (yes I had to look it up lol), plus some clearance (and inaccuracies in measuring if you say you are using the rod of a caliper or such....not sure how you're going at it) .041 could be stub. As I think about, depending on the class of thread, there might be that much clearance. It's certainly not 1/2P that you want so I'd say Duffy was right.

                            i agree call them...imo the easiest path to fixing the problem imo is getting back on the one you were on....but with the right screw stock. I'd use the original nut, it does not affect accuracy.
                            in Toronto Ontario - where are you?

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                            • #44
                              I was measuring the best I could with a drill bit, although I am lacking on the small wire sizes. I checked the original screw with a .062" drill bit that I ground the sides on. I know not the best but probably pretty close.

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