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  • Need some machining help(?)

    Hi,

    Would apprecaite any suggestions on how to machine this part. It isn't that critical measurement wise, they are just motor covers for my telescope E/Q mount. Of course I want them to look like I knew what I was doing. Oh, it's aluminum and 1 3/4" in height. I'm still learning so take it easy on me with all the termnology and endmills needed. I do have a older BP and a rotary table (which I've never used yet).

    http://www.pbase.com/smokedaddy/image/60089637/large

    Thanks in advance,
    -SD:
    Last edited by Smokedaddy; 05-13-2006, 03:32 AM.

  • #2
    Help?

    SD, if you made all the parts in your gallery; I wouldn't think you need help to make that part. Fine work! Making that part should be a piece of cake. That looks like a heavy lathe also. Not knowing the dimensions...I would hog out the pocket first, cut the radii on the rotary or vice versa.

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    • #3
      If it's not critical, why not just make it round, instead of oblong. That way you could do it on a lathe with a boring bar. Use the mill to do the square hole as a second op.

      Even if it has to be oblong, I'd do most of the material removal on a lathe. If it's circular with flattened sides, you can do it all on a lathe with a 4-jaw chuck.

      I can't tell from the picture if it's a circle with two sides flattened or a rectangle with the ends radiused.

      Roger
      Any products mentioned in my posts have been endorsed by their manufacturer.

      Comment


      • #4
        Tig

        SD, I used to build those high pressure stainless assemblies like that .....but YOUR tigging, would put mine to shame and I was good at the time. Makes me glad I'm retired and don't have to lust over beads like that. Excellent work.

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        • #5
          What tig beads??? I flipped through the pics and I didn't see any. What did I miss?
          I have tools I don't even know I own...

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          • #6
            Click galleries, top left corner. I don't know for sure if that's SD's pics or not.

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            • #7
              Ah..ok I see them. Up here you'd better be that good to work in the pulp mills.
              The big joint done by the robot in the pics...we do them by hand. First couple are fun but after that it's pure drudgery.
              I have tools I don't even know I own...

              Comment


              • #8
                Cool stuff. Looks like something for an Intel chip fab since one of the prints says "Intel". I like the sippy bottle full of alcohol. Too bad its Isopropyl! The gizmos that check the weld are cool too.

                But there's more. Takahashi Hydrogen Alpha scope setup for viewing the sun, cool custom knives, motorcycles. Life is good there!

                That part looks to me like it was made with CNC originally.

                Best,

                BW
                ---------------------------------------------------

                http://www.cnccookbook.com/index.htm
                Try G-Wizard Machinist's Calculator for free:
                http://www.cnccookbook.com/CCGWizard.html

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                • #9
                  Hi,

                  Yes, I made everything you see in the gallery but it took me forever, and numerous attempts too. <grin> I still haven't finished my Domino jig either and this is my 3rd attempt.

                  http://www.pbase.com/smokedaddy/image/60113712

                  I'm still learning about Solar imaging. Still haven't prefected the technique but I'm getting pretty close. Hopefullyl I'll it nailed down in the next few months, weather and seeing conditions permiting.

                  http://www.pbase.com/smokedaddy/image/60113215

                  As far a the welding goes, those were high pressure (10,000psi) socket welds, all 100% x-ray (not that it was a big deal). It does take a lot of practice but that's all it is, practice. Below is a picture of a semi-conductor high-purity orbital weld (207 machine).

                  http://www.pbase.com/smokedaddy/image/14820901
                  http://www.pbase.com/smokedaddy/image/14820897
                  http://www.pbase.com/smokedaddy/image/14820903


                  and this one is a narrow groove diametric video welding machine we used on the nukes (Palo Verde).

                  http://www.pbase.com/smokedaddy/image/46174648
                  http://www.pbase.com/smokedaddy/image/46174648
                  http://www.pbase.com/smokedaddy/image/46228543

                  Okay, now back to my problem. <smile> I never thought about doing the operation on a lathe. Oh, no ... it can't be round. It must be as pictured. I can get the aluminum free, but can't get the experience free. <grin> I wasn't sure how to setup the rotary table since I've never used it.

                  Got'a go,
                  -SD:

                  Comment


                  • #10
                    I made a sketch using an oblong with a length of 3" and a width of 2.5".

                    If you start with a 3" diameter and flatten two sides so the width is 2.5", the length of the flattenned side is about 1.6". The angle where the curve meets the flat is approximately 148 degrees.

                    If you start with a rectangle and do a full radius on both ends, the length of the flat is only 0.5 inch. The flat is tangent to the curve.

                    If you start with a 3" round, you can clamp it in the vise on the mill, take off a quarter inch, flip it over, and take off a quarter inch on the other side. Ease the corners with a little hand filing, and you're done with the outside.

                    If you start with a 3" x 2.5" rectangle, you need a long end mill to do the entire side in one pass. I'd guess a 1" diameter with a 2" length of cut would do it. Clamp the part to the RT with the center of the part offset .25" from the center of the RT. Cut the radius on one end (two corners), then offset the center .25" in the other direction for the other end.

                    I think I'd use the lathe, a 4-jaw chuck, and a boring bar to do the inside. Center the part to remove most of the material, then offset it .25" each way to get the ends. That'll leave you some minor bumps on the inside, but they probably won't be much.

                    I can't figure out an easy way to hold the part on the RT for machining the inside. Maybe you could mount the 4-jaw on the RT. That would give pretty good support and let you see the thickness of the sides as you work.

                    Roger
                    Last edited by winchman; 05-13-2006, 07:27 PM.
                    Any products mentioned in my posts have been endorsed by their manufacturer.

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                    • #11
                      Thanks Roger,

                      I knew it wouldn't be easy. Seems like everything I want to make is a PITA. <g>

                      -SD:

                      Comment


                      • #12
                        Originally posted by winchman
                        I can't figure out an easy way to hold the part on the RT for machining the inside. Maybe you could mount the 4-jaw on the RT. That would give pretty good support and let you see the thickness of the sides as you work.

                        Roger
                        If you cut the inside pocket first, you could use the holes to bolt the part to a fixture plate in order to do the outside.

                        BW
                        ---------------------------------------------------

                        http://www.cnccookbook.com/index.htm
                        Try G-Wizard Machinist's Calculator for free:
                        http://www.cnccookbook.com/CCGWizard.html

                        Comment


                        • #13
                          If you have plenty of free material, I would mill out the basic length and width of the final part but leave about 1/4" extra on the thickness. Drill shallow locating holes at the center point of each arc opposite what will be the pocket. These would sit on a corresponding pin at the center of your RT(if you don't have this, that's your first project). You can clamp the part with one center located and cut your inside and outside arcs( a little at a time) and then with one point located on the outside flat, flip the part and cut the other remaining arcs. After the arcs are cut you can return the RT to 0 degrees(you did start at zero right) and cut the flats and remove the waste in the pocket. After all the rotary table work is finished you can remove the material with the locating holes in it and drill your holes and mill the box. Yes, clear as mud I'm sure. God bless CNC.
                          Good luck.

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                          • #14
                            Just how big is this part? After reading all the responses, I would hog out the OD dimensions, clamp it in a vise and plunge and finish the ID. The OD can then be dimensioned on a belt sander. Just how tight are the tolerances? There has to be some limits on all dimensions.

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                            • #15
                              Is there a reason you can't use round covers fastened to a flat adapter plate?
                              Free software for calculating bolt circles and similar: Click Here

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