Announcement

Collapse
No announcement yet.

Building the Trent Pinion Mill

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #46
    Just make sure the lap is softer than the cast iron and it won't embed.
    in Toronto Ontario - where are you?

    Comment


    • #47
      I see I managed to mis-spell.... it is a "Kingway" tool.

      Image search to assist your visualizing it

      https://www.google.com/search?q=king...=1920&bih=1085

      BTW, the trickiest thing about it is to ge the clamps so that they DO clamp. But if you used split cotters, or the like, it would not be as difficult. I wanted mine to look slick like the original, and made mine so they are one piece and bend to clamp. I had to file he dickens out of the brackets to get them to bend and clamp decently.

      Originally posted by Mcgyver View Post
      Just make sure the lap is softer than the cast iron and it won't embed.
      I very much suspect that the plan in the build instructions is to lap one against the other..... In which case it obviously becomes a concern again.
      Last edited by J Tiers; 04-16-2017, 05:31 PM.
      CNC machines only go through the motions

      Comment


      • #48
        Originally posted by Mcgyver View Post
        Just make sure the lap is softer than the cast iron and it won't embed.
        Uhh, in this case we would be lapping the table and knee together. No other laps would be used.

        It would be a form of wet lapping with rolling abrasion, which is a very common method. Even if the lap is softer the abrasive can still embed depending on the material being lapped and the abrasive type.

        Sent from my XT1053 using Tapatalk

        Comment


        • #49
          Originally posted by J Tiers View Post
          I very much suspect that the plan in the build instructions is to lap one against the other..... In which case it obviously becomes a concern again.
          You are correct that is exactly what the build instructions mention.



          Sent from my BLN-L24 using Tapatalk
          Max
          http://joyofprecision.com/

          Comment


          • #50
            then you're better off, imo, to scrape or leave it milled. I'm not a fan or lapping with out a lap ....no control over where material is removed. is this a moving slide, or move it to position and lock? If the later I suppose it matters less
            Last edited by Mcgyver; 04-16-2017, 06:58 PM.
            in Toronto Ontario - where are you?

            Comment


            • #51
              Originally posted by Mcgyver View Post
              then you're better off, imo, to scrape or leave it milled. I'm not a fan or lapping with out a lap ....no control over where material is removed. is this a moving slide, or move it to position and lock? If the later I suppose it matters less
              The column dovetail does not slide during cutting, but the other dovetail (for the bed) slides in both directions during cutting.

              Sent from my BLN-L24 using Tapatalk
              Max
              http://joyofprecision.com/

              Comment


              • #52
                Yea, but most of those articles for making involute cutters do not make involute cutters. They make circular form cutters. The approximation may be fairly good, but it is still just an approximation.

                I often wonder about commercial involute cutters. Are they really involute shaped or just circular approximations.



                Originally posted by enginuity View Post
                The latest issue (March / April) of HSM has a great article on making your own involute cutters. Martin's method is one of pure simplicity and is extremely practical. That article is worth subscribing to HSM for the next 5 years. (Not sure if Martin reads this - but thanks for putting it together!).
                Paul A.
                SE Texas

                And if you look REAL close at an analog signal,
                You will find that it has discrete steps.

                Comment


                • #53
                  A thought on your dual feed idea: screw/hand wheel and lever. It sounds like a complicated mechanism and I would consider adding a motor feed to the screw. With a variable speed control, you can have both slow and fast feed rates.

                  I would consider a stepper motor and a simple circuit for the variable speed. Probably add a gear to the screw, behind the hand wheel and make the motor mount so that it can swing out to disengage the gears or in to engage them. The control could be made with either conventional digital chips driven by an variable frequency oscillator for he speed control or a microprocessor like the Arduino or a similar one.

                  This would provide a smooth, constant feed for both slow and fast feed rates. I find that a constant feed rate is one of the most important factors in getting a good finish when milling. Really rapid slew rates could be provided for positioning for the next pass; with the cutting tool retracted, of course.
                  Paul A.
                  SE Texas

                  And if you look REAL close at an analog signal,
                  You will find that it has discrete steps.

                  Comment


                  • #54
                    Here is a picture of my old scraper holder. It's nothing more than a piece of aluminum with a T slot on the bottom and a clamp screw to pinch it in place. There is a threaded hole on the backside to attach a handle to.

                    Sent from my XT1053 using Tapatalk

                    Comment


                    • #55
                      Quick update, I finally uploaded part 4 of the video series last night:

                      https://youtu.be/0YR_7YjxpQY

                      Last edited by mars-red; 07-24-2017, 06:10 PM.
                      Max
                      http://joyofprecision.com/

                      Comment


                      • #56
                        Originally posted by mars-red View Post
                        Quick update, I finally uploaded part 4 of the video series last night:
                        Good to see you back in the saddle, so to speak.

                        I'm surprised there is so little extra material on those castings.

                        Comment


                        • #57
                          Originally posted by Dan_the_Chemist View Post
                          Good to see you back in the saddle, so to speak.

                          I'm surprised there is so little extra material on those castings.
                          Thanks!

                          I was a bit surprised at first, but really it doesn't matter as long as you're careful. If they had specified 0.1" less on a couple of the dimensions it wouldn't have made a lick of difference to how the machine functions and the castings would have then seemed pretty generous. The column casting had plenty of extra material. We'll see how the indexing head and tailstock castings are.
                          Max
                          http://joyofprecision.com/

                          Comment


                          • #58
                            Originally posted by Andre3127 View Post
                            Here is a picture of my old scraper holder. It's nothing more than a piece of aluminum with a T slot on the bottom and a clamp screw to pinch it in place. There is a threaded hole on the backside to attach a handle to.

                            Sent from my XT1053 using Tapatalk
                            Thanks for taking the trouble to share that pic, Andre, that's very helpful!
                            Max
                            http://joyofprecision.com/

                            Comment


                            • #59
                              Originally posted by Paul Alciatore View Post
                              A thought on your dual feed idea: screw/hand wheel and lever. It sounds like a complicated mechanism and I would consider adding a motor feed to the screw. With a variable speed control, you can have both slow and fast feed rates.

                              I would consider a stepper motor and a simple circuit for the variable speed. Probably add a gear to the screw, behind the hand wheel and make the motor mount so that it can swing out to disengage the gears or in to engage them. The control could be made with either conventional digital chips driven by an variable frequency oscillator for he speed control or a microprocessor like the Arduino or a similar one.

                              This would provide a smooth, constant feed for both slow and fast feed rates. I find that a constant feed rate is one of the most important factors in getting a good finish when milling. Really rapid slew rates could be provided for positioning for the next pass; with the cutting tool retracted, of course.
                              That's perfectly sensible, and most people would probably go that route, but for the most part wires and electric motors turn me right off. Unless there's a really compelling reason for me to go that route, I'll generally choose a mechanical option first. The mechanical option in this case really isn't terribly complicated, and let's not forget one of the biggest advantages of lever feed for small work... the tactile feedback. For that reason alone, I'd be inclined to stick with the mechanical approach for this.
                              Max
                              http://joyofprecision.com/

                              Comment


                              • #60
                                Just want to say, enjoying your work and videos very much!
                                Len

                                Comment

                                Working...
                                X