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Benchmaster progress

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  • #16
    Originally posted by interiorpainter
    It looks like the rule you are using to messure is prefered over a camelback.
    This one you can clamp down.
    That's a parallel, used to "extend" the surface so it can be measured in the vertical direction. The spindle is the reference, and it isn't located in such a way that two measurements can be taken in a vertical line.... So the parallel "extends the surface" to allow that.

    it isn't used as a reference for scraping. In this case a small granite flat was used for that.
    CNC machines only go through the motions


    • #17
      Have not posted much about the work on the Benchmaster... refurb work does not seem to interest many here.

      But, in the process of working on the Benchmaster and its vertical head, I have had to adjust tram a good deal. The Benchmaster does not make this easy at all, so I wanted a better way than just clouting on one side and the other until it came out right.

      So, I made a worm gear head adjuster for the unit. It takes up some ram extension space, that I may want someday, but it has advantages also. (it might be possible to make one that fits between the ram supports, but I decided not to mess with that.

      The worm runs a bronze worm-gear with a key that turns the head as you turn the worm. A half turn is about 4 degrees, so the thing is capable of fairly close adjustment of angle. Time will tell how much I like it, but so far I do like it, FAR easier to do precise setting than trying to do it by hand, with much tapping this way and that.

      The parts laid out

      The worm in the housing

      The greased wormgear in place with key and newly cut keyway in the ram

      Last edited by J Tiers; 01-24-2017, 12:09 AM.
      CNC machines only go through the motions


      • #18
        Gearbox screwed in place

        Gearbox, motor, and all, with the cheezy worn belt that needs to be replaced. (yes, the table is off the unit again, I have to correct an alignment)

        I expect I will take it apart again, prime it, and paint it. The shiny aluminum look just isn't a good one......
        Last edited by J Tiers; 01-24-2017, 12:07 AM.
        CNC machines only go through the motions


        • #19
          You made great progress on the ways. Any idea how many hours you put into them?

          I watched Tony's video where he scraped the dovetails on his grinder. It made scraping the flats look easy by comparison. So little room to work.


          • #20
            Very nice job indeed!


            • #21
              I like that tram assist... slick.


              • #22
                Originally posted by pinstripe View Post
                You made great progress on the ways. Any idea how many hours you put into them?

                I watched Tony's video where he scraped the dovetails on his grinder. It made scraping the flats look easy by comparison. So little room to work.
                Dovetails are no real problem if you first relieve the inside corner by cutting it back (preferably rounded), and second have another scraper blade that is ground away on top to fit down in the space. And the dovetails tend to go fast, as there is little area to be done.

                Then also, if there is an "American gib", the strip of metal type adjusted with several screws, there is no need to scrape the screw adjust portion, so you only need to do 3 of the 4 surfaces of dovetail.

                A mistake many make is to go for a "surface plate finish". For sliding ways, it is sufficient to have about 15 spots per square inch, evenly distributed, with a good percentage of contact area. More than that may actually be counterproductive, leaving less area for oil reservoir, and approaching a flat ground surface that is "sticky".

                I have no idea of the time, I have not kept a record. I have done some on this, some on that, skipped from project to project, so it's tough to keep any record, and I am not that worried about it anyhow.
                CNC machines only go through the motions


                • #23
                  Looks good Jerry
                  in Toronto Ontario - where are you?


                  • #24
                    Jerry, That head tilt gearbox is super nice.
                    Simple and elegant. Like !



                    • #25
                      The idea came straight out of a recent HSM or MW, whichever had the article on holding the tram on a Rockwell mill. The author kindly showed the innards of the adjuster that is supplied on the Rockwell, which is pretty much like that on a Bridgeport etc.

                      The actual article there was not about that part, though, it had to do with something I had also considered at one time, a screw-pushed lever arm to HOLD the tram. Apparently the author's unit had a mismatch between the clamp holes and the ram, and would not hold the ram tightly. The pics of the existing unit were nice to have though, they caused one of those "I can make that" moments.

                      All I did was figure out a suitable gear that I could cut, plus making a 3D model and extracting plans from it. (and of course, I did finally get around to MAKING the thing) No big deal.
                      CNC machines only go through the motions


                      • #26
                        very tidy! A lick of paint and it'll look factory. I can't speak for others here but I love refurb threads, especially with some machining content. I may have missed it, but how did you cut the gear? Is the worm an acme or square thread? I would have been tempted to put a GITS oiler at the top, but I imagine for how much you'll use it a squidge of grease would be sufficient.

                        I've heard that those small bench horizontals and verticals are surprisingly stout for their size..


                        • #27
                          Thank you. The idea was to look as factory as possible. I sorta wish I had rounded the corners more, so it would resemble a casting better, just because. But I don't know that I care enough to go back and do that at this stage. Paint is in the plan, though. Maybe I'll do it before painting... or not.

                          I sort of split up the thing in different threads.
                          The threads are linked below, but the short story is that the worm is acme, the gear was cut with a dividing head and involute cutter. It amounts to mating a helical gear and matching angled rack.


                          I did consider an oiler. Kinda funny why, besides the obvious issue of lubrication..... I had a chunk of steel to use, but it had a couple holes in it that I could not avoid entirely, one was going to be showing no matter what I did. So in the best tradition of misdirection, I was going to label it "Oil"..... but it was really going to be FOR oil.. because it could be located where oil was needed..! Sort of a double joke.

                          The piece ended up looking like too much trouble to work with, and the housing did not really need or want to be steel, better either CI or aluminum, either of which would be easier to cut. CI would have worn better. I still have the option of using an oilite bearing, but I doubt I will wear out the aluminum any time soon.

                          I would have put the oiler lower down, though. I do not expect the top of the gear to ever get used, and I don't know why I bothered putting grease on that area. It didn't even need teeth, most likely. It's not as if I will have the head doing barrel rolls in place..... With the oiler down by the worm, a couple drilled holes could distribute oil to all locations where needed (or grease for that matter), other than any thrust or wear against the housing. And I expect the overflow lube would take care of that.
                          Last edited by J Tiers; 01-25-2017, 02:18 AM.
                          CNC machines only go through the motions


                          • #28
                            The one thing I don't like about my Klopp universal mill is there is no provision for tramming the head. There are four bolts that hold the head fixed. A scale on the round part with a hash mark on the frame for alignment. So it is whack, check, whack, check, opps to much, whack other direction, check, too much back, whack, screw it that is close enough. A typical tram session for me. The head can be rotated but I don't do it much because it is difficult to get it back in tram.
                            Location: The Black Forest in Germany

                            How to become a millionaire: Start out with 10 million and take up machining as a hobby!


                            • #29
                              Nice job on the gearbox. I also have a Benchmaster mill and I think that it will come in handy.

                              In another thread you mentioned that you are looking for a rotary table. I think I wouldn't go with anything over 6" diameter. The height of the rotary table is more important than the diameter, since the headroom is so short.



                              • #30
                                Yes, the "whack and check" method gets old. The Benchmaster has just enough friction in the turning that you nearly never can turn just a little, minimum is maybe 2 degrees. After that, "whack and check". But no more of that!

                                And, yes, it looks as if 6" is about right. It may still fit OK on the Lewis if needed. The "daylight" issue is common to both, and to many small mills. Even to Bridgeports, or the column extenders would not have been made.

                                Apparently a lot of people have Benchmaster mills. Maybe this could be a project article for the magazine. It is not really special to Benchmaster, it would work for other round ram machines, if the gear size is made suitable for the ram size. So it might have a wide enough appeal.
                                CNC machines only go through the motions