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  • keyway broaches

    https://www.ebay.ca/sch/i.html?_saca...y+broach+1%2F8

    This site lists an "A" type and a "B" type keyway bushing. - each one would cut a 1/8 inch keyway.. While these use (require?) a shim I have noted in other catalogs that some require a shim while others do not (I think?).. Then, there is the question of bushings...

    So, what do I need to cut a 1/8 inch (internal) keyway in a pulley bore that is 1/2 inch diameter? And, 5/8 inch diameter?

    Just call me confused.
    Thanks.

  • #2
    The bigger the key the deeper the cut. 1/8 key way can be cut in one pass. 3/8 key way 3 passes. 2nd pass use 1 shim, 3rd pass 2 shims.

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    • #3
      You need a 1/2" bushing and a 5/8" bushing, and a broach. The bushings are easy to make from mild steel, the broach costs $100. and you need a press to push the broach thru the bushing to cut the key. You can make your own shims out of shim stock.
      Brian Rupnow

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      • #4
        A step bore?

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        • #5
          Bushings are easy to make if you have wheel cutters of correct size, and a mill.
          broaches are or were well under a hundred and sets were fairly reasonable so long as you use them enough.
          Last edited by 754; 02-25-2020, 11:44 PM.

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          • #6
            The OP was about the difference between the "A" and the "B" type of broach. Also what thickness of shim stock would you use if you did make your own? the one time I borrowed a Dumont set it had all the pieces but I don't recall "A" and "B" broaches, the shims seemed to all be the same as I recall, but it has been a while since I used it.

            Look forward to any additional info.

            TX
            Mr fixit for the family
            Chris

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            • #7
              Correct me if I am understanding this wrong, but,
              Style A, B, C, refers to the bushing and the 'spine' of the broach that fits said bushing,
              For every 'spine' and bushing there is more than one size teeth.
              Example, there may two different fractional size teeth and a couple metrics, that all use the same bushing & spine. (A, B, C)

              ​​​​​​https://www.accusizetools.com/h-s-s-...yle-e-style-f/

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              • #8
                From my understanding it had to do with the "angle" and how much was taken off per tooth. A low letter broach would do only short keyways, but in one pass, and a high letter broach would do long keyways, but require many passes. but I don't see a 100% correlation to that given the link.
                21" Royersford Excelsior CamelBack Drillpress Restoration
                1943 Sidney 16x54 Lathe Restoration

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                • #9
                  Originally posted by The Metal Butcher View Post
                  From my understanding it had to do with the "angle" and how much was taken off per tooth. A low letter broach would do only short keyways, but in one pass, and a high letter broach would do long keyways, but require many passes. but I don't see a 100% correlation to that given the link.
                  The letters are the "body" size, a C broach will not pass through a 1/2" hole even without the bushing, it is simply too big.
                  The shims reduce the required length of a push broach, if it becomes overly long it will break easily before full depth is achieved.

                  Often I have to go Old School, this is a keyseater, it is rude crude and noisy but effective, up to 1" wide keys.
                  The feed advance is charming when it works.
                  Last edited by Bented; 02-24-2020, 10:23 PM.

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                  • #10
                    For the relevant data-

                    https://dumont.com/our-broaches/push...ican-standard/


                    The B style broaches and bushings will produce both the 1/2 x 1/8" and the 5/8 x 3/16" standard bore and key combinations. The A style will only give you the 1/2 x 1/8" standard bore and key combination.

                    A full B and C set can be had on Ebay for not unreasonable money(no affiliation)

                    https://www.ebay.com/itm/VINTAGE-MAC...cAAOSw6VteVEv-
                    Last edited by wierdscience; 02-24-2020, 10:55 PM.
                    I just need one more tool,just one!

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                    • #11
                      McMaster explains some of this on these pages:

                      https://www.mcmaster.com/keyway-broach-shims

                      https://www.mcmaster.com/keyway-broach-bushings

                      https://www.mcmaster.com/keyway-broaches

                      Click on the word "More".
                      Paul A.
                      SE Texas

                      Make it fit.
                      You can't win and there IS a penalty for trying!

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                      • #12
                        I don't see where you need a "wheel cutter", whatever that is, of any size. Chuck up a piece of round stock 1/4" larger in diameter than your bushing in your lathe. You don't even have to worry about centering so a three jaw is just fine. Turn about 1" (more or less depending on the length of your needed keyway) of it down to that desired diameter. You want an easy fit in the holes to be broached, perhaps 0.001" under. Part it off about 1/8" to 3/16" longer than your turned section: that forms a collar of the OD of the stock. That collar is optional. Now, take it to the mill and mill the slot. Done. Well, you may want to clean up the edges.

                        I don't see where any special cutting tools come in either at the lathe or mill. Oh, and that slot could be easily milled in the lathe with a milling attachment. It is just a simple slot.

                        The shims can be easy to make also, you just need to have some shim stock and a way to cut it, up to 1/16" thickness.

                        Some have even made the broaches, but that's another story. If you want to do that, I would suggest waiting until your second broach: buy the first one and see how things work.

                        PS: I Googled "wheel cutter". Seems they are cutters for pipe and tubing. How would you use that here? I don't know. You need a SOLID bushing, not a piece of pipe or tubing. The broach will be pushing against the bottom of the slot in the bushing. With the cutting forces, it needs a very solid backing. You need to make the bushing from solid round stock, not tube or pipe. And for most jobs, having a collar on the bushing is a definite plus.



                        Originally posted by 754 View Post
                        Bushings are easy to make if you have wheel cuttersmof correct size, and a mill
                        broached are or were well under a hundred and sets were fairly reasonable so long as you use them.
                        Last edited by Paul Alciatore; 02-25-2020, 05:23 PM.
                        Paul A.
                        SE Texas

                        Make it fit.
                        You can't win and there IS a penalty for trying!

                        Comment


                        • #13
                          Wheel cutter:

                          1) Watch gear tooth cutter

                          2) possibly any H-mill cutter

                          3) maybe a Woodruff keyway cutter??

                          The free dictionary gives: Wheel cutter. a machine for shaping the cogs of gear wheels; a gear cutter.

                          Not sure just how that or #1 above apply
                          Last edited by J Tiers; 02-25-2020, 05:49 PM.
                          1601

                          Keep eye on ball.
                          Hashim Khan

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                          • #14
                            Horizontal mill cutters, in some places are referred to as wheel cutters. Call them what you will. No endmill I have, will ever make as nice a slot for a broach, as a wheel cutter. I use a stub arbor in a BP type mill. Turn bushing in lathe, mount stock in mill vise, mill slot, then part and face, I have built quite a few.
                            and a few tapered bushing, and a bigger bushing with a 1/2 bore, then then takes the smallest broached mounted in a 1/2 bushing.

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                            • #15
                              Originally posted by 754 View Post
                              Horizontal mill cutters, in some places are referred to as wheel cutters. Call them what you will. No endmill I have, will ever make as nice a slot for a broach, as a wheel cutter. I use a stub arbor in a BP type mill. Turn bushing in lathe, mount stock in mill vise, mill slot, then part and face, I have built quite a few.
                              and a few tapered bushing, and a bigger bushing with a 1/2 bore, then then takes the smallest broached mounted in a 1/2 bushing.
                              McMaster Carr calls them slitting cutters, for slitting, slotting, and cut-off.
                              North Central Arkansas

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