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Question on Facing and Faceplate

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  • Question on Facing and Faceplate

    Can our experienced machinists help me with another question?

    Here's the problem. I need to face a piece of steel (4x3x.375) by attaching it to a faceplate. But I can't drill holes in the work and attach it by screws through to the faceplate. The entire work must be faced, so I can't use clamping (T type) bolts that hook over the edge of the work and hold it in place.

    A friend of mine offered one solution.
    He said that while in the Navy his unit had come up against a similar problem and solved it in the following way. The work was placed in the approximate center of the faceplate and then bolts were put on each of the four sides (up against the edge of the work). The bolt head was pressed against the work on all four sides, in effect, wedging the work into place. The nuts were tightened on the faceplate from behind. Because the bolt head was lower (less than) the thickness of the work, the heads did not get in the way of the facing operation and the entire piece could be faced.
    "But how did they make sure that the bolt heads were firm up against the work?" I asked. "Weren't they worried the work would shift or move?"
    "They used a large C-clamp against the bolt heads on opposite sides of the work to press the heads securely against the work edge," he replied. " Then they tightened the nuts behind the faceplate. There wasn't that much to worry about. The bolts prevented the work from moving laterally across the faceplate. Because the facing tool pressed inward (toward the spindle) the cutting force was directed against the faceplate."

    So my questions to you...
    Is it possible to mount a piece of work this way? Is it safe?
    Is there a better (different) way to mount work on a faceplate and face the entire surface without drilling mounting holes in it?

    Thanks much for your help.

  • #2

    I'd be inclined to bolt a good clean, flat, piece of aluminum to the faceplate, put double-sided tape on it, and stick the work to the aluminum plate. With clean surfaces, double-sided tape will hold a surprising amount...but don't rely just on that.

    Also drill/tap the aluminum plate and fabricate some side clamps on all four sides to keep the work from shifting...sort of like your idea of the bolts, but I think I'd be a little more formal about it. The work is pretty thin relative to its other dimensions, so it won't have any tendancy to tip. With the tape, you ought to be fine.

    Then turn in slow backgear. Relatively light cuts, of course.....

    [This message has been edited by SGW (edited 10-29-2003).]
    Try to make a living, not a killing. -- Utah Phillips
    Don't believe everything you know. -- Bumper sticker
    Everybody is ignorant, only on different subjects. -- Will Rogers
    There are lots of people who mistake their imagination for their memory. - Josh Billings
    Law of Logical Argument - Anything is possible if you don't know what you are talking about.
    Don't own anything you have to feed or paint. - Hood River Blackie


    • #3
      Is this a special piece to be done? Can you not make a piece oversize and bolt it conventionally and then cut to size afterward?
      Free software for calculating bolt circles and similar: Click Here


      • #4
        I have had good results by liberally coating the faceplate with white woodworking PVA glue, then stick a sheet of decent drawing paper to it, coat the top side with PVA again and clamp your piece to it and allow to dry.
        As it's square it would help to have a couple of bolts at the cormers to act as driving dogs and stop the interupted cut from ripping it off.
        Obviously light cuts need to be taken.
        I have used this method to machine stainless disks down to 10 thou in the recess on some parts.

        To remove from the faceplate just run under very hot water and the glue will let go.

        John S.

        Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


        • #5
          One option I have used is to cross drill and tap the bolt heads, which are then bolted to the faceplate in the appropriate positions. Using setscrews will allow you to tighten against the work, and gives some small room to shift the workpiece around. The setscrews can be used as is, with a small concave to give some grip, or ground to a point, or to a flat. The flat will leave less mark on the workpiece, but could allow slippage.
          Press the piece up against the faceplate, tighten the setscrews, and face.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


          • #6
            How about rigging a Magnetic Clamp to the face plate?


            • #7
              Thanks for the many responses posted so far.
              Here's a little more info.

              -The work piece is already at size and so there is no excess where I could drill holts and attach it that way.

              -We only need to face about .010 from it.

              -Mr. Stevenson. I'm very intrigued by your idea with the glue. I assume that the faceplate must be very clean (of oil etc.) for the glue to adhere properly. Have you tried other glues? I'm thinking of contact cement which I know is sometimes used to bond certain metals in the aircraft industry.

              Again thanks for all your comments and help


              • #8
                If you mill the bolt heads at an angle they will be drawn into the workpiece as you tighten them.....sort of like the bench dogs on a woodworking bench.


                • #9
                  Does both sides need to be faced?
                  Could a piece of pipe be tack welded to the back side and latter be ground off?
                  I am glad you asked this question as I have a project comming up quite simmilar to yours but the metal will be about 1.250" thick.
                  Good luck
                  Don\'t ask me to do a dam thing, I\'m retired.


                  • #10
                    Did something similar by using 4 jaw chuck.

                    Put in chuck, with parallels under to let it stand just past the ends of the jaws. Tightened it up, and ran slow and easy with a sharp cutter. If it had shifted, the cut would have told me in time to stop it.

                    PS take out the parallels before starting machine!

                    These days, I would just slap it on the shaper table, using toe dogs and a stop to hold down, and plane off whatever is required.

                    Another approach if you have a milling attachment is to fly cut the surface while holding the part in the milling attachment. Flycutter goes in chuck, end mill adapter, or collet. Its a pain to set up, but it works.

                    [This message has been edited by Oso (edited 10-29-2003).]


                    • #11
                      I'm with Osso: use a 4 jaw chuck as he has described, unless you have access to one of those wonderful litle obselete machines called a "Shaper"!!


                      • #12
                        Superglue and solvent to release.
                        I just need one more tool,just one!


                        • #13
                          I have a face plate with 4 jaws but you can make "jaws" for your face plate. I wouldn't use the "wedge" method--too risky. They can be made from square stock.

                          Drill and tap two holes in the block. One will be perpendicular to the other. Bolt the block down to the face plate with one and run a bolt through the other. You could even put a step in the blocks if necessary.

                          I guess you don't have a mill?


                          • #14
                            I would use the doublestick tape and clamps to secure the work. Also a couple of stop blocks the direction of rotation. Do the face from the center out until near the clamps. Then remove the clamps and bring the tailstock up to help keep clamping pressure on the work. Very light cuts and stop blocks keep the work from twisting off the tape.
                            Makes me appreciate my mill, but I'm also learning about work holding and I don't know all the tricks yet. Please let us know what you try and how it works out.




                            • #15
                              I would use the double sided (carpet) tape route. For anyone who doesn’t know, when using tape or contact cement, hammer the part down to (sometimes dramatically) increase the bond. Instead of making custom bolts, I would simply drill a couple of holes in some 1/4" or 5/16â€‌ bar, and bolt that up tight to the sides. Put the bolts well beyond the part so clearance isn’t a problem. I would probably stick it right to the faceplate. As said, slow feed/speed, small nose radius, and easy on the lead angle. Shouldn’t be a problem, just a few minutes to set up.
                              Now that I think about it, how about a “Vâ€‌ notch on the 2 pieces of bar. Put them on opposite corners, that would positively locate the part.
                              Location: North Central Texas