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Improving a 5" x 7" tilting angle-plate

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  • Improving a 5" x 7" tilting angle-plate

    I bought a 5" x 7" tilting angle plate some while ago at a used machinery place. It looked quite new and had a worm and wheel adjustment which I wanted as it is easier to set the "tilt" angle up.

    It has sat in my shop and never been used, so I got it out and put it on my mill table to see how accurate (or not) it was. It was not accurate at all other than the male/female cylinder which was very good as regards size and fit.

    I thought I'd post the process using links instead of pics as VP limits pics to 4 per post (links are unlimited) and I had in mind the "dial-up" users as well as those who will be "pee-ed off" with the large number/s and repetition of multiple sequential posts and pics.

    It might help if the reader has 2 sessions/copies of the Forum running on their computer - one for text and the other for the links/pics and just "click" between them.

    I thought I'd do the job on my pretty basic HF-45 vertical column mill and use basic tools that just about any member will have or be able to buy at minimum cost. I used basic procedures that are not too "up-market" that should be able to be understood by newer or less experienced members and last and by no means least to "get back to basics and fundamentals" without the/any "high-end" stuff.

    Everything was going to be relative to the "cylinder" on which the tilting table operates.

    This is the angle-plate on the mill table.
    http://i200.photobucket.com/albums/a...ilt_table1.jpg

    I set the cylinder parallel to the mill table by using a precision round pieces of tool steel that was tangent to the cylinder and the square parallel strips and the parallel strips abutting a straight edge (not shown) that was pressed against the side of the mill table.

    I used a 0.01mm (0.0004") test dial indicator (TDI) to find the errors in the table which were:
    - 0.50mm (0.020") "end-to-end";
    - 0.20mm (0.008") "twist" with the left end of the table set to zero and re-checked at the right end; and
    - the edges of the table 0.0.50mm (0.020") out of parallel with the mill table and the "cylinder" centre line.

    I had previously checked that I could use bevels at the top of my mill table fastening grooves (for "T" nuts etc.) as reliable "V"-blocks. I put 20mm (any size around an inch will do) cold-rolled steel rods in the "V" blocks and checked for any movement on the sides (and the tops) of the rods when traversing in "X" (with "Y" fastened) on my mill table. It was pretty well "dead on" (as I knew it to be).

    These three pics are of the cutter I used. It is about 80mm (mean) diameter, has TC inserts with about 10 degree positive rake and about 45 degree positive "lead angle" and the "flat" bottoms of the teeth act as "scrapers". This cutter is in effect a multi-tooth fly-cutter that is specifically designed to minimise load (and therefore "chatter") on the mill - and works very well indeed. It should work very well on smaller mills as well.
    http://i200.photobucket.com/albums/a...ilt_table2.jpg
    http://i200.photobucket.com/albums/a...ilt_table3.jpg
    http://i200.photobucket.com/albums/a...ilt_table4.jpg

    This is the under-side of the tilting table top showing the "cylinder" and the worm drive (to control the table tilt):
    http://i200.photobucket.com/albums/a...ilt_table5.jpg

    This is the "bottom" of the tilting table set into and bolted to the mill table slots (as "V" blocks). I used the "rounded" washers (made to suit the "curve") that came with the tilting table. The pic shows the "bottom" face after being machined.
    http://i200.photobucket.com/albums/a...ilt_table6.jpg

    I re-assembled the tilting table, set the "cylinder" parallel to the table (rod and straight-edges) as previously (see first pic), bolted it down (re-checked - all OK), set the table top "flat" with the dial indicator and fastened it.

    This pic shows the table top after being machined with the big cutter and in the process of having the tilting table "T" slot sides being machined with a multi-spiral "T" slot cutter.
    http://i200.photobucket.com/albums/a...ilt_table7.jpg

    This pic shows the end mill "true-ing up" the sides and ends of the tilting table. This cutter also machined the sides of the "T" slots.
    http://i200.photobucket.com/albums/a...ilt_table8.jpg

    This pic shows the last of the "T" slot (under-sides of "over-hang") being machined. Note that the cutter has spiral teeth with alternate/successive teeth having spirals of "opposite hand" (ie left-right-left-right etc.)
    http://i200.photobucket.com/albums/a...ilt_table9.jpg

    This pic shows the bevels that I put on the edges of the "T" slots and the edges and sides of the tilting table top. It also shows the simple (and cheap and very effective) bevel guage I used to hand-grind (on an emery wheel on a common pedestal grinder - just as you'd buy one) the 45 degree bevels and clearances on both "teeth" of an old high speed steel (HSS) centre drill. (I could have used just about any old broken twist drill if needs be). This 45 degree cutter worked fine. As the material to be cut was cast-iron I left the centre drill "back rake "as is" (zero). If had been for brass I'd have left it at zero as well - or for mild steel I'd have used 10 to 15 degree.

    Here are 2 pics of the tilting tabletop being used a s"V" blocks - works beautifully:
    http://i200.photobucket.com/albums/a...lt_table11.jpg
    http://i200.photobucket.com/albums/a...lt_table12.jpg

    These pics show the T-slot cutter and several other fly-cutters that I use. The small ones in the wooden block were bought as shown. The larger one was made from a lathe tool-holder and "balanced" to minimise "throw"/"out-of-balance" conditions under load. I could not see the sense or need to make the square holes. It is used for heavier stuff and is mounted in an ER-32 20mm (0.800") collet and works very well.
    http://i200.photobucket.com/albums/a...lt_table13.jpg
    http://i200.photobucket.com/albums/a...lt_table14.jpg

    The project of "recovering" or "true-ing up" the tilting table was very successful and I am very pleased with it as it is very accurate, easy to use and reliable.

    The only thing I will do yet to the table is to fit (say) 1" x 1/4" flat bars with 1/4" + slotted holes as "fences" or "stops" to locate and locate from the edges (similar to those on many magnetic chucks). They just slide under the plane of the tilting table top when nor in use or required.

    I deliberately used "climb" milling as opposed to "conventional" milling as I was using light cuts on soft material with sharp cutters (all with positive rakes) and did not want to the cutters to "rub" instead of "cut" at the commencement of cut so as to minimise tool/cutter deflection. I deliberatly "balanced" the larger-width cuts of the large cutter to minimise "pull" on the cutter when "climb" milling. For illustrations of milling and cutter and see the following link. See the end of the link for explanations of "climb" and "conventional" milling etc. http://en.wikipedia.org/wiki/Milling_cutter

    I'd suggest reading the whole link as it is a very informative read. The links here will help as well:
    http://en.wikipedia.org/wiki/Special...ulltext=Search

    I hope that this project and post has been of assistance to some of the newer members of the Forum and particularly to those who are just "starting out" with machining.

  • #2
    Thanks very much for a well written and great pictures article. You should submit that fine article to the HSM magazine. JIM
    jim

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    • #3
      Very well done article and I second Jim's motion to submit it to the magazine for publication as not all subscribers are on line.

      Comment


      • #4
        Tiffie...great article. I also have one of those that I havn't used yet and will do the same as per your article. One thing I am not clear on though is how you went about setting the base up to machine so as the "0" mark on the scale was absolutely bottom dead center as shown in your link.

        http://i200.photobucket.com/albums/a...ilt_table6.jpg

        I would think you would need to do that before you indicated and machined it otherwise the scale would maybe be out. Yes? no? maybe?
        Ernie (VE7ERN)

        May the wind be always at your back

        Comment


        • #5
          Great post, Tiffie - it's missing this link, but I found it

          http://i200.photobucket.com/albums/a...lt_table10.jpg

          Comment


          • #6
            You're right

            Originally posted by dockrat
            Tiffie...great article. I also have one of those that I haven't used yet and will do the same as per your article. One thing I am not clear on though is how you went about setting the base up to machine so as the "0" mark on the scale was absolutely bottom dead center as shown in your link.

            http://i200.photobucket.com/albums/a...ilt_table6.jpg

            I would think you would need to do that before you indicated and machined it otherwise the scale would maybe be out. Yes? no? maybe?
            Thanks to all for kind remarks.

            Yes Ernie (dockrat), I did forget to mention that. It was as much by good luck as by good planning as I did check it after I'd milled it and it was spot on as you say. Due to the set-up, the only real way was to approximate it, machine it and if the zero index was out, I'd have had to "move" it after I'd finished. I was dead lucky but there was no other realistic way that I could see to go about it. Also realistically, the index is only an approximation at the best of times as I'd have used a protractor or sine bar (dependent upon accuracy required) to set it up.

            Comment

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