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Plain bearing machine spindles - maximum speed?

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  • Plain bearing machine spindles - maximum speed?

    I've a few machines with plain bearings I'm setting up the drives for, ie hardinge benchtop horizontal mill and a holbrook b8 lathe.

    What's your guys opinion on the maximum safe speed for these sorts of spindle/bearing arrangements?

    thanks
    in Toronto Ontario - where are you?

  • #2
    For a Rivett 608, drip oiled plain bearings, top speed is 1560 rpm.

    Spindle takes 5C At least mine does, , so is around 40mm diameter at the bearing.
    1601

    Keep eye on ball.
    Hashim Khan

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    • #3
      wow, i'd not have guessed that high....you also have a hardinge benchtop mill correct? About the same for it? It's mostly a function of bearing diameter?

      I'd like to have the max possible obviously, but not wreck anything.
      in Toronto Ontario - where are you?

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      • #4
        Are they bushings or bearings. If bushings, like my southbend the headstock never warms at 850 RPM (max speed). So I would say that is ok for a large bushing, easy for a hard metal bearing. JR

        Oh? Went to Lathes.co to get a looksee of a Holbrook lathe. WoW. Oldie but heavy. NICE!!
        Last edited by JRouche; 03-26-2016, 11:20 PM.
        My old yahoo group. Bridgeport Mill Group

        https://groups.yahoo.com/neo/groups/...port_mill/info

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        • #5
          Brown and Sharpe OD grinders using 12 Inch Diameter diamond wheels, we ran at 1725 rpm. Bearings were tapered bronze, about 2 1/2"diameter on big end, used drip feed oilers on each bearing. Most used #10 spindle oil, one required #6 to keep from overheating. These grinders were 80-95 years old when brought into our shop.
          North Central Arkansas

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          • #6
            It depends on the spindle. The standard South Bend 9 was made with non-hardened spindles and will run up to about 800 rpm nicely. The 12 speed SB's have hardened spindles and will run up to 1600 or so.

            However, it also very much depends on the oiling system. Jet turbines use plain spindles and some run at 40,000 rpm. They have pressure oiling and there is never metal on metal.
            Free software for calculating bolt circles and similar: Click Here

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            • #7
              Originally posted by JRouche View Post
              Oh? Went to Lathes.co to get a looksee of a Holbrook lathe. WoW. Oldie but heavy. NICE!!
              yeah, the Holbrooks are nice, same class as monarch, DSG, Pacemaker imo. The b8 is neat in that its all that quality in benchtop package....here's a pic on Tony's site http://www.lathes.co.uk/holbrookB8/img2.gif. Mines the only one I've ever seen so I doubt they are common this side of the pond (would love to hear of any other B8's out there)

              It reminds me a lot of the Rivett 608 of which i;ve got one (sadly don't have room for both) but the B8 is V way and came with a taper attachment. both are works of art imo - the rivett for example was guaranteed to hold a tenth over half a foot and was made in the late 1800's

              just gearing up to scrape the holbrook....but got working on drives this weekend (both will be DC)

              I just spotted on Tony's site 1340 for the Holbrook, so thats in keeping with what you guys are saying.
              Last edited by Mcgyver; 03-26-2016, 11:42 PM.
              in Toronto Ontario - where are you?

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              • #8
                Cincinnatti No 2 surface grinder had bronze bearings running at about 3600 rpm. Delta tool and cutter grinder had bronze bearings and 2 speed pulleys. Lowest speed (from memory) is about 3600 rpm. Bear in mind that these spindles were designed to run at these speeds. Low viscosity spindle oil is used. If the oil is too viscous the bearings run hot.

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                • #9
                  Originally posted by Mcgyver View Post
                  came with a taper attachment.
                  Now yer just braggin. You, ,,,, you,, damm! That is prolly rare.. Nice that you got her fully equipped. JR
                  My old yahoo group. Bridgeport Mill Group

                  https://groups.yahoo.com/neo/groups/...port_mill/info

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                  • #10
                    Try these for a good start:

                    https://en.wikipedia.org/wiki/Plain_bearing

                    https://www.google.com.au/search?q=g...n+handbook+pdf

                    Machinery's Hand Book.

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                    • #11
                      I'm surprised at the speeds recommended so far for plain bearing machines. I have an early 1900's Seneca Falls Star #20 lathe (9") with plain bearings. The maximum speed is 366 rpm. Even the larger 13" machine is only rated to run at 557 rpm.

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                      • #12
                        Originally posted by JRouche View Post
                        Now yer just braggin. You, ,,,, you,, damm! That is prolly rare.. Nice that you got her fully equipped. JR
                        it is fun getting new toys . When they're that old they're not big dollars and come with a dark side, the burden of reconditioning.....so its ten parts self flagellation for every one part of brag.....but I do marvel at the quality of these older best of breed machines. What an effort went into them
                        in Toronto Ontario - where are you?

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                        • #13
                          Simple put if look at a model airplane engine some will turn over 20,000 RPM
                          Now what will limit the RPM is max speed of your chuck, gears and belts

                          Dave

                          Originally posted by Mcgyver View Post
                          I've a few machines with plain bearings I'm setting up the drives for, ie hardinge benchtop horizontal mill and a holbrook b8 lathe.

                          What's your guys opinion on the maximum safe speed for these sorts of spindle/bearing arrangements?

                          thanks

                          Comment


                          • #14
                            The max speed of a Myford Super Severn which has a tapered bronze bearing at the front is 2100rpm. This according to the Myford Web site.

                            Geoff

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                            • #15
                              Originally posted by Mcgyver View Post
                              I've a few machines with plain bearings I'm setting up the drives for, ie hardinge benchtop horizontal mill and a holbrook b8 lathe.

                              What's your guys opinion on the maximum safe speed for these sorts of spindle/bearing arrangements?

                              thanks
                              Brown & Sharp #2 plain bearing surface grinder, nom. 3450 RPM
                              But I've never seen lathes or mills much above ~1300 RPM
                              Thermal runaway in a loaded thrust condition is no doubt exponential

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