Threading 1/8 stainless steel

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Threading 1/8 stainless steel

Home Forums General Questions Threading 1/8 stainless steel

Viewing 25 posts - 1 through 25 (of 29 total)
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  • #407180
    Eric Cox
    Participant
      @ericcox50497

      I'm trying to cut a 5BA thread on 1/8" stainless steel rod held in the 3jaw lathe chuck. The die starts to cut then the rod slips in the chuck marking the rod. Would I be better off using a 1/8 c0llet chuck.

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      #26584
      Eric Cox
      Participant
        @ericcox50497
        #407185
        Dennis Pataki
        Participant
          @dennispataki22631

          I expect you will have the same results using a collet. At least, that was my experience.

          I would recommend you use a Jacobs type chuck. I have one that threads directly onto my spindle, and that's what I use when trying to thread rod or bar stock using a die. It holds much tighter than my 3 jaw, 4 jaw, or collets.

          You may need to rig up some way to hold the Jacobs chuck. Perhaps threaded onto a straight shank, held in the 4 Jaw. You may need to drill a clearance hole through the shank if threading the ends of long rod.

          Hope this is helpful.

          #407189
          ega
          Participant
            @ega

            Are you using a suitable cutting oil or paste?

            I would certainly try the collet.

            How about screwcutting?

            #407190
            JasonB
            Moderator
              @jasonb

              Collet usually works better for me and if it does slip won't mark the work as much. Open up the die for the first cut as much as you can then run it down again to get the required fit. Once the die has started squarely you may want to transfer to the bench vice.

              #407204
              Mark P.
              Participant
                @markp

                Try opening your die up a smidge for the first pass.

                Mark P.

                #407209
                SillyOldDuffer
                Moderator
                  @sillyoldduffer

                  Could your stainless be the horrible work-hardening variety? Some of it is evil. Stainless can be difficult to thread and risks blunting the die making the job impossible. Might be worth testing the metal with a blunt saw to see if it hardens. (I've had some success cutting horrid stainless vigorously after the normal approach failed, but you can't really do that with a die.)

                  Dave

                  #407221
                  JohnF
                  Participant
                    @johnf59703

                    You will do better with a a high quality ground thread HSS die IMO.

                    John

                    #407246
                    Eric Cox
                    Participant
                      @ericcox50497

                      I'll try the collet

                      #407249
                      CHARLES lipscombe
                      Participant
                        @charleslipscombe16059

                        Which raises the question of die material. I have heard it said on the forum that carbon steel dies can be sharper than HSS dies and may be a better choice for some materials e.g. brass or stainless steel. That may be the case but would a CS die wear more rapidly than HSS? In my case this is important because I do repetitive tapping of 5mm * 0.8 mm in 303 stainless when making my motorcycle levers.

                        Trying to thread stainless of any variety with a die that is not quite sharp is only going to lead to tears on this may be a factor in the OP's posting

                        Chas

                        #407261
                        Simon Collier
                        Participant
                          @simoncollier74340

                          I use 1/8 316 for brake rods and thread by first turning down the diameter. I use a collet, a dedicated die and plenty of Rocol.

                          #407265
                          Pero
                          Participant
                            @pero

                            I have had the same experience when threading 3 mm 316 rod (and 6 mm and 12 mm) and have adopted the practice of putting a taper on the end of the rod, getting the thread ( just ) started in the lathe and then moving on to the bench vice.

                            Using lots of tapping paste but it doesn't seem to help much with the lathe part.

                            I have had similar slipping problems with threading in the bench vise when using aluminium soft jaws and have had to resort to the very grippy hard steel jaws. It works but the result is not pretty.

                            At this point I should mention that I have old injuries to my wrists that limit the amount of pressure I can apply to chuck keys and vise handles at times which probably adds to my problem here.

                            I also get the feeling that there may be a slippery surface coating on stainless steel rod, possibly a residue of the polishing process, which adds to the problem.

                            On my next outing I intend to try a clean down with acetone before using an ER collet in the lathe. Further experiments to follow …..

                            Pero

                             

                            Edited By Pero on 01/05/2019 04:56:53

                            #407270
                            Boiler Bri
                            Participant
                              @boilerbri

                              The jaws will only have a very small amount of contact with the bar.

                              I make aluminium blocks for small work holding, about 25mm long. Bore a hole to size and split the block on one side then hold in the 4 jaw chuck. The Ali has a better grip on the bar.

                              Bri

                              #407280
                              S.D.L.
                              Participant
                                @s-d-l
                                Posted by Eric Cox on 30/04/2019 16:04:52:

                                I'm trying to cut a 5BA thread on 1/8" stainless steel rod held in the 3jaw lathe chuck. The die starts to cut then the rod slips in the chuck marking the rod. Would I be better off using a 1/8 c0llet chuck.

                                Better with a collet, Degrease material with Acetone or IPA to improve grip.

                                How are you holding the die?

                                You could take a couple of thou off diameter

                                Steve

                                #407302
                                Eric Cox
                                Participant
                                  @ericcox50497

                                  The die is mounted in a die holder in the tail stock.

                                  plan of attack is,

                                  clean with acetone

                                  open die fully

                                  use aluminium block

                                  plenty of Rocol

                                  pray

                                  #407325
                                  S.D.L.
                                  Participant
                                    @s-d-l
                                    Posted by Eric Cox on 01/05/2019 10:14:14:

                                    The die is mounted in a die holder in the tail stock.

                                    plan of attack is,

                                    clean with acetone

                                    open die fully

                                    use aluminium block

                                    plenty of Rocol

                                    pray

                                    Check how central the die is in the tailstock die holder. Some have large clearance bores for the dies to be split open and when used push the die up to .75mm (20thou) off centre which is a lot on basically a 3mm thread.

                                    If this is a problem add 3 tapped holes to die holder at 90 degree intervals so that die can be centered , can then be closed up using two side screws.

                                    Steve

                                    #407326
                                    Ian S C
                                    Participant
                                      @iansc

                                      I die cut some 10 32 threads on 3/16" stainless rod for displacer rods for hot air motors, I found that I had to cut to size first go as the stainless rod work hardened. The first thread cut I took in stages, and after the second cut that was that, I did get there eventually but the die was shot (good HSS dies used).

                                      Ian S C

                                      #407334
                                      Nigel McBurney 1
                                      Participant
                                        @nigelmcburney1

                                        Use a ER collet in a hexagon collet block (from arc euro trade) those collets will grip anything,dont try try using precision lathe collets ,usually morse taper,trying to grip too tightly can spoil them. larger ER collets will even hold 1 1/8 Whit taps without slipping ,and they are superb for making double ended Whitworth studs,no more problems with slippage. Best tooling I have bought in recent years as I do a lot of restoration work, I use ER 32 and 40 sizes

                                        #407356
                                        David Jupp
                                        Participant
                                          @davidjupp51506

                                          1/8" (3.175mm) is at the maximum of major diameter for a 5BA male thread, according to BS93. That is before any oversize tolerance of the rod, or any extrusion of metal when cutting the thread (which is quite likely with tough materials).

                                          I can see why Simon mentioned turning down the diameter as a first step.

                                          #407360
                                          Lambton
                                          Participant
                                            @lambton

                                            Eric,

                                            You have received lots of good advice about gripping the job and die adjustment .

                                            May I recommend that you try Ambersil "Tufcut" lubricant .that is specifically formulated for turning, drilling, reaming thread cutting and tapping tough materials such as titanium, stainless steel, high tensile steel and high carbon steels. I have used it for years with every success. It is available from Cromwell Tools or most other good tool suppliers.

                                            II have no connection with Ambersil other than as a very satisfied user of Tufcut.

                                            Eric

                                            #407369
                                            Tim Stevens
                                            Participant
                                              @timstevens64731

                                              It might be that the rod is hard-drawn, so the surface has been work-hardened in manufacture. If your job does not need the top end of the high-tensile capability, try the effect of softening the rod with heat.

                                              Cheers, Tim

                                              #407389
                                              Dave Smith 14
                                              Participant
                                                @davesmith14

                                                For what its worth, I use Ambersil Tufcut to power cut M6 threads on 303 stainless cold drawn rod with no problem, using an WM250V lathe on the lowest speed setting.

                                                Dave

                                                #407430
                                                Hopper
                                                Participant
                                                  @hopper

                                                  Two old dodges you might try: Machine the bar down .005" undersize before attempting to thread it, plus a good chamfer on the end to get things started.

                                                  And wrap a small piece of emery cloth, paper or tape around the job before nipping up the chuck jaws to help stop slipping. Make the emery cloth piece long enough to cover full length of contact between job and jaws to get best grip.

                                                  Edited By Hopper on 02/05/2019 01:54:31

                                                  #407432
                                                  Paul Lousick
                                                  Participant
                                                    @paullousick59116

                                                    I just cut an M3 thread on 316 stainless. Held in a collet in the lathe but cut thread manually, backing off every time to break the chip. HSS die and cutting fluid used.

                                                    Paul.

                                                    #407433
                                                    jimmy b
                                                    Participant
                                                      @jimmyb

                                                      I have cut a massive amount of M6 threads in 304 and 316 stainless.

                                                      I have found the only cutting to work for me is Rocol RTD liquid.

                                                      I only use "spiral entry" HSS dies (any GOOD supplier of dies will know what these are, they do not need backing off).

                                                      I would also only use bored soft jaws or ER collet to hold the stock.

                                                      I'd guess at 200 rpm if I was to have a go at 1/8" in stainless.

                                                      Good luck!

                                                      Jim

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