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Aloris wedge toolpost - any adjustment on qty of wedge?

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  • #31
    Originally posted by eKretz View Post

    You mentioned wondering about wear; I would be awfully surprised to see wear on the wedges. I might expect to see wear inside the toolpost on the multiple start thread that drives the wedges up and down. That could perhaps cause your handle to spin a little farther than you'd like.

    I compared my Aloris toolpost's handle position with yours and mine definitely doesn't turn as far with Aloris holders. I don't get to the 6 o'clock position with any of them, most are fully tight at about the 5 o'clock position. The Shars holders I have, on the other hand, tighten up at about the 7 o'clock position, just a little bit before the end of travel, but still good.
    Thank You for your response!It's good to have a direct comparison of handle travel. If the internal thread on my tool post is worn that would explain why both wedge positions have equal handle rotation for a given tool holder. Now I'm feeling a touch guilty about 5 free toolholders that I needed to rework to make fit - they just **might** have been acceptable if my toolpost engaged earlier.
    Metro Detroit

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    • #32
      Are you off one thread with the wedge to screw relationship?

      Comment


      • #33
        Originally posted by aribert View Post

        Thank You for your response!It's good to have a direct comparison of handle travel. If the internal thread on my tool post is worn that would explain why both wedge positions have equal handle rotation for a given tool holder. Now I'm feeling a touch guilty about 5 free toolholders that I needed to rework to make fit - they just **might** have been acceptable if my toolpost engaged earlier.
        If they measured oversize, they measured oversize. And I wouldn't worry too much, they certainly aren't going to lose sleep over it.

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        • #34
          Originally posted by eKretz View Post

          If they measured oversize, they measured oversize. And I wouldn't worry too much, they certainly aren't going to lose sleep over it.
          What!? What is your point?

          I know tools. What is your point? JR

          Comment


          • #35
            Originally posted by JRouche View Post

            What!? What is your point?

            I know tools. What is your point? JR
            My point is that if the holders measured oversize they aren't made correctly anyway. (Thought I saw mention that he was comparing dovetail dimensions over rounds with the Aloris). If the handle clocks farther than with the Aloris holders when tight I'd say they're bigger than they ought to be regardless.

            Also that the holders were probably made for a couple dollars apiece. If a few get returned it's not the end of the world. The Shars examples I've got are certainly not made to high standards. Aloris holders are FAR better made. More uniform size, way higher quality fasteners, better finishes where it counts, etc. These import holders are not high dollar items. A few returned, even if they might technically have been borderline, won't hurt the manufacturer or reseller any.

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            • #36
              Originally posted by SVS View Post
              Are you off one thread with the wedge to screw relationship?
              I have no idea - I have never taken a tool post apart before. Something I expect to remedy fairly shortly.
              Metro Detroit

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              • #37
                I do not have an Aloris tool post, but I think I understand how a dovetail grips and tightens. The two sides of the dovetail are not the complete picture. When the post is tightened, the two dovetail surfaces on the tool post are moved further away from each other. They spread apart due to the motion of the movable one while the stationary one does not move. This, in turn, tries to draw the holder into or towards the post until the face of the post (between the dovetails) rests against the flat area of the holder (also between the holder's dovetails). Once these two faces come into contact the holder can no longer move toward the post and the dovetails can lock the holder in position. My point being that there are THREE pairs of surfaces at work here, not just the two which form the dovetails.

                So far all the suggestions seem to be to add additional material to the dovetail surfaces. And I think all the suggestions are about how to do this to those dovetail surfaces on the holder, not on the post. But adding material to ANY of the THREE surfaces of the holder should make the fit tighter.

                So, and I am just spitballing here, why not add a shim to the flat on the inside of the dovetail of the holder which is between the two dovetail surfaces? The holder will come in contact sooner and less movement of the movable dovetail on the post would be needed.

                A benefit of this would be that this pair of flat surfaces (holder and post) do not slide across each other while tightening. They simply press directly into each other. So many of the objections as to the method of attaching this extra material become irrelevant. I would suggest that a hard aluminum alloy, shim material be used as it could conform itself to any irregularities in the mating surface upon the first few usages and then would change little after that. And I would suggest an epoxy adhesive applied in a minimum amount so that the aluminum contacts the surface of the holder at least at a few places.

                The use of two round pins is a good way of measuring the needed thickness of this shim. The shim material can just be placed inside the holder's dovetail and the measurement made and compared with that of a known good holder.

                This seems like an easy and inexpensive fix for inexpensive holders that are too loose on the post.
                Paul A.
                SE Texas

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

                Comment


                • #38
                  Originally posted by Paul Alciatore View Post
                  So, and I am just spitballing here, why not add a shim to the flat on the inside of the dovetail of the holder which is between the two dovetail surfaces? The holder will come in contact sooner and less movement of the movable dovetail on the post would be needed.
                  .
                  A few people have suggested this.
                  Read above.

                  -D
                  Last edited by Doozer; 07-18-2022, 02:47 PM.
                  DZER

                  Comment


                  • #39
                    Originally posted by Paul Alciatore View Post
                    I do not have an Aloris tool post, but I think I understand how a dovetail grips and tightens. The two sides of the dovetail are not the complete picture. When the post is tightened, the two dovetail surfaces on the tool post are moved further away from each other. They spread apart due to the motion of the movable one while the stationary one does not move. This, in turn, tries to draw the holder into or towards the post until the face of the post (between the dovetails) rests against the flat area of the holder (also between the holder's dovetails). Once these two faces come into contact the holder can no longer move toward the post and the dovetails can lock the holder in position. My point being that there are THREE pairs of surfaces at work here, not just the two which form the dovetails.

                    So far all the suggestions seem to be to add additional material to the dovetail surfaces. And I think all the suggestions are about how to do this to those dovetail surfaces on the holder, not on the post. But adding material to ANY of the THREE surfaces of the holder should make the fit tighter.

                    So, and I am just spitballing here, why not add a shim to the flat on the inside of the dovetail of the holder which is between the two dovetail surfaces? The holder will come in contact sooner and less movement of the movable dovetail on the post would be needed.

                    A benefit of this would be that this pair of flat surfaces (holder and post) do not slide across each other while tightening. They simply press directly into each other. So many of the objections as to the method of attaching this extra material become irrelevant. I would suggest that a hard aluminum alloy, shim material be used as it could conform itself to any irregularities in the mating surface upon the first few usages and then would change little after that. And I would suggest an epoxy adhesive applied in a minimum amount so that the aluminum contacts the surface of the holder at least at a few places.

                    The use of two round pins is a good way of measuring the needed thickness of this shim. The shim material can just be placed inside the holder's dovetail and the measurement made and compared with that of a known good holder.

                    This seems like an easy and inexpensive fix for inexpensive holders that are too loose on the post.
                    Your comments are spot on with regard to a piston type toolpost, but totally wrong for the wedge type - as the holding surfaces are just not the same.

                    There are three holding surfaces involved with the piston type - the two dovetail flanks and the piston against the bottom surface of the toolholder dovetail. The pressure of the piston pushes the toolholder away from the toolpost, and the shoulders of the toolpost dovetail do not contact the shoulders of the toolholder.

                    With the wedge type, the expansion of the dovetail by the wedge draws the toolholder in toward the toolpost. What stops it? Two possibilities - the outer surface of the toolpost dovetail against the bottom surface of the toolholder dovetail (similar to the contact surface of the piston type post), or the shoulders of the toolpost dovetail against the shoulders of the toolholder. In every wedge type toolpost I’ve seen, it’s the shoulders that contact - and there is a gap between the outer surface of the toolpost dovetail and the bottom surface of the toolholder dovetail.

                    So, if you want to tighten up the fit, you would need to add shims or weld material to the toolholder on either the dovetail flanks or on the shoulders. Adding to the bottom of the toolholder dovetail would completely change the manner in which the toolholder is held on a wedge type toolpost, and would negate its holding power and repeatability.

                    I had one BXA toolholder that was too tight on my import wedge type toolpost - a used, USA-made Armstrong holder. Put it on the surface grinder and took a bit off the flat shoulder surface and it fit fine. And there was still a gap between the outer surface of the toolpost and the bottom of the toolholder dovetail.

                    I have made a half dozen or so toolholders. Well, not really “made” - I started with large 1-1/4 and 1-1/2 inch square toolholders (available dirt cheap on you know where) and cut dovetails into them and added height studs and nuts. I cut the dovetail flanks on a shaper, which was pretty tricky as the holders were pretty tough stuff and it was easy to go too far. Which I did on a couple of them, and built one flank back up with a stick welder. I could have cut the dovetails on the small side and then surface ground the side of the toolholder, but wanted to keep them full size.

                    Comment


                    • #40
                      Aribert, I'm happy that you aren't seeing any warping. For my own future learning on this did you pre-heat the holders before starting to build up the surfaces?

                      SVS, if his post is anything like my import copy then it's a VERY coarse acme like thread to get the movement needed from only half a turn. Might even be a two start.... So if it was out by a turn or a start point then even the proper fit holders would not tighten at all. He's got the right idea that it's the dovetail to back faces relationship that is wonky.
                      Chilliwack BC, Canada

                      Comment


                      • #41
                        Originally posted by BCRider View Post
                        Aribert, I'm happy that you aren't seeing any warping. For my own future learning on this did you pre-heat the holders before starting to build up the surfaces?
                        BCRider
                        No preheat. I did not even consider that (this time of year) - I figured the risk was small and I only did two of the four in case there was an issue I would only scrap two. I do most all of my preheat in winter time over a kerosene heater -- I have a wire grid that I place on the heater that gives me a surface about a foot above the heater to lay the part being heated (sometimes with an inverted metal bucket on the grid, over the part, to retain more heat). BTW, I was born in BC, in the big town to the west of you but left as a toddler as my parents, indirectly, migrated to Texas.
                        Metro Detroit

                        Comment


                        • #42
                          Good to know. I'm the worrier that would have done at least a bit of pre-heat. But then I seldom weld and usually it's more to just glue things together with no thought of what the heat can do. So I err heavily on the side of caution. Your results will ease some of that for similar projects. So thanks for that.

                          I'm a Vancouver baby as well. Manufactured in St Paul's just on the edge of the downtown area. I just live at this end of the valley now. But the big city is catching up with me. We actually have developed a "rush half hour" in the last half of the 12 years I've been out here. It sucks....
                          Chilliwack BC, Canada

                          Comment


                          • #43
                            I beg your pardon, but I did not have it totally wrong. I did say the holder was drawn toward the tool post. I only got what stopped that motion wrong and I thank you for correcting me on that. Now that I read your post, I slap myself on the forehead for not realizing that the dovetail holders work much like other dovetails where it is, indeed, the flanks that come into contact, not the underbelly. It was late at night and I was not thinking well. And yes, those flanks are the logical place for shims. I would strongly favor shims there over having them on one of the dovetail surfaces.

                            Thanks for the correction.



                            Originally posted by JohnMartin View Post

                            Your comments are spot on with regard to a piston type toolpost, but totally wrong for the wedge type - as the holding surfaces are just not the same.

                            There are three holding surfaces involved with the piston type - the two dovetail flanks and the piston against the bottom surface of the toolholder dovetail. The pressure of the piston pushes the toolholder away from the toolpost, and the shoulders of the toolpost dovetail do not contact the shoulders of the toolholder.

                            With the wedge type, the expansion of the dovetail by the wedge draws the toolholder in toward the toolpost. What stops it? Two possibilities - the outer surface of the toolpost dovetail against the bottom surface of the toolholder dovetail (similar to the contact surface of the piston type post), or the shoulders of the toolpost dovetail against the shoulders of the toolholder. In every wedge type toolpost I’ve seen, it’s the shoulders that contact - and there is a gap between the outer surface of the toolpost dovetail and the bottom surface of the toolholder dovetail.

                            So, if you want to tighten up the fit, you would need to add shims or weld material to the toolholder on either the dovetail flanks or on the shoulders. Adding to the bottom of the toolholder dovetail would completely change the manner in which the toolholder is held on a wedge type toolpost, and would negate its holding power and repeatability.

                            I had one BXA toolholder that was too tight on my import wedge type toolpost - a used, USA-made Armstrong holder. Put it on the surface grinder and took a bit off the flat shoulder surface and it fit fine. And there was still a gap between the outer surface of the toolpost and the bottom of the toolholder dovetail.

                            I have made a half dozen or so toolholders. Well, not really “made” - I started with large 1-1/4 and 1-1/2 inch square toolholders (available dirt cheap on you know where) and cut dovetails into them and added height studs and nuts. I cut the dovetail flanks on a shaper, which was pretty tricky as the holders were pretty tough stuff and it was easy to go too far. Which I did on a couple of them, and built one flank back up with a stick welder. I could have cut the dovetails on the small side and then surface ground the side of the toolholder, but wanted to keep them full size.
                            Paul A.
                            SE Texas

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

                            Comment

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