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  • Steady Finger Opinions

    The fingers on this steady have been run so long at a consistent diameter that they have worn to match it. They works fine at that diameter, but on something larger only the outside tips hit, and on aluminum at least, it's not long before the surface is galled all to hell.

    Click image for larger version

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    You can see here what they started out as

    Click image for larger version

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    The options I see for fixing them are:
    1. Face them off flat
    2. Brass braze them back to original
    3. Bronze braze them back to original
    Now I won't be using them for 1/2" stock so I don't mind if I lose a bit of capacity on the low end. But it seems like brass or bronze would be a better friction material than cast. Thoughts? TIA
    21" Royersford Excelsior CamelBack Drillpress Restoration
    1943 Sidney 16x54 Lathe Restoration

  • #2
    The coefficient of friction for lubricated cast iron on steel is actually lower than for brass/bronze on steel, assuming im reading this bloody chart properly:
    https://www.engineeringtoolbox.com/f...nts-d_778.html

    In addition, the cast iron is probably more wear-resistant, for this application at least. Id just face the fingers off flat, that is as long as the casting material isnt complete crap and you can get a good finish off of it. Should also mention im assuming those are cast iron and not cast steel

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    • #3
      I think any of your ideas would be just fine.

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      • #4
        I use ball bearings or bronze, depending. Cast iron might have a better coefficient of friction, but bronze bearing I believe is consider to wear better. Speed may play factor in which does better, certainly cast iron has been used as a bearing material...and if they are already cast iron its an easy fix. Anecdotally though, how many cast iron lathe bearings have there been in the last 120 years....vs bronze? Kowing bronze is more expensive, it suggests the people making machine bearings see it advantageous as a bearing material.

        If you go bronze (forget brass, too soft), I wouldn't braze them. Brazing temps will anneal many/most copper alloys....soft solder or mechanically attach them
        in Toronto Ontario - where are you?

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        • #5
          Just recut the faces to flat, and recut the angle faces so the fingers close up more than they do now. It isn't a super precision operation.
          'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

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          • #6
            I would use a bolted on replacement I think. If you just face it off it will wear into the slot making the next repair even tougher. Make the wear part from whatever is on hand. Even aluminum would be fine I’m sure. Make them simple so replacement is easy.

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            • #7
              If you face them off flat, what capacity will you end up with on the low end before you run out of slot on the finger?

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              • #8
                Depending on the size, you could mill down the front or back of each finger and drill a hole for holding a small sealed ball race. I made a set of fingers with ball races in them to use as the original design didn't make it easy to modify. Also the original brass/bronze tips were in new condition.

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                • #9
                  Originally posted by epicfail48 View Post
                  The coefficient of friction for lubricated cast iron on steel is actually lower than for brass/bronze on steel, assuming im reading this bloody chart properly:
                  https://www.engineeringtoolbox.com/f...nts-d_778.html

                  In addition, the cast iron is probably more wear-resistant, for this application at least. Id just face the fingers off flat, that is as long as the casting material isnt complete crap and you can get a good finish off of it. Should also mention im assuming those are cast iron and not cast steel
                  those tables are highly unreliable. if you study them they are full of contradictions. the reason is clear. the surface condition is as important as the alloy itself. another factor is speed.

                  (i remember a paper on static friction of bolted joints. they used hundreds of samples but couldnt get a statistcally significant resuls. because even such a simple situation has too many variables to account for.)
                  Last edited by dian; 02-21-2021, 03:03 AM.

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                  • #10
                    Thanks all for the opinions. I opted for Bronze. I'll try them out next weekend hopefully. More here.

                    21" Royersford Excelsior CamelBack Drillpress Restoration
                    1943 Sidney 16x54 Lathe Restoration

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                    • #11
                      Nice. It's a good idea to have a few different types of fingers for different applications.
                      For mine I have the original cast iron ones, have a set with ball bearings and a set that I made from hard maple. I don't really care for the ball bearing ones because of swarf that may get run over by the bearing, then you get a speed bump in your cut. I don't use them unless the steady is positioned far enough away from the tool post and it's usually for soft materials. If for some reason, and there has been a few where the steady has to be close to the cut I try and shield that end from flying swarf.

                      JL........

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                      • #12
                        Originally posted by JoeLee View Post
                        Nice. It's a good idea to have a few different types of fingers for different applications.
                        For mine I have the original cast iron ones, have a set with ball bearings and a set that I made from hard maple. I don't really care for the ball bearing ones because of swarf that may get run over by the bearing, then you get a speed bump in your cut. I don't use them unless the steady is positioned far enough away from the tool post and it's usually for soft materials. If for some reason, and there has been a few where the steady has to be close to the cut I try and shield that end from flying swarf.

                        JL........
                        Thanks JoeLee. I haven't tried bearing ones. I assume they would be good for doing a lot of work on highspeed for finished shafts, like chrome rod. But I don't do much steady work at all, so I think that they will be fine for my limited, low speed use. I have to agree on the swarf. Makes sense for a commercial shop to have a piece of gasket paper sized for every imaginable piece of stock, less so for a hobbyist.
                        21" Royersford Excelsior CamelBack Drillpress Restoration
                        1943 Sidney 16x54 Lathe Restoration

                        Comment


                        • #13
                          Perhaps consider the type of lube you use with it. I've had pretty good luck with TriFlow, and with a metal treatment- one I use is called Prolong.
                          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                          • #14
                            Originally posted by The Metal Butcher View Post

                            I have to agree on the swarf. Makes sense for a commercial shop to have a piece of gasket paper sized for every imaginable piece of stock,

                            less so for a hobbyist.
                            I don't know// So much.

                            I am the hobbyist you spoke of. JR

                            Edit: My friends have 12" augers to remove the aluminum chips from the stations. JR
                            Last edited by JRouche; 02-15-2021, 03:48 AM.

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                            • #15
                              Originally posted by darryl View Post
                              Perhaps consider the type of lube you use with it. I've had pretty good luck with TriFlow, and with a metal treatment- one I use is called Prolong.
                              I'm sure that lubricant matters. But I wasn't the one that wore it out. The 77 years and 20-40k hours before me did. I doubt if it will have more than the slightest dimples by the time I/it dies.

                              In the past I've used #00 cornhead grease as it's cheap. With the bronze, I get an intuition that I should use something a bit lighter, like regular old way oil. I'm sure it will work fine.
                              21" Royersford Excelsior CamelBack Drillpress Restoration
                              1943 Sidney 16x54 Lathe Restoration

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