Announcement

Collapse
No announcement yet.

Adventures with a sawblade

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Adventures with a sawblade

    So, I decide to open up the arbor hole on a little plywood blade from 10mm to 1.775". I don't have any real problem doing it, but it's not fun... something is wrong. I don't know if the blade was work hardening, or what. But things are working, so I proceed. As I approach the final size, I see the end of the boring bar flex a little. I'm using a light lathe so it's expected sometimes. But not when boring in a piece of glorified sheet metal. So I don't mess up the final cut, I stop, tighten all the gibs, and replace the boring bar with one that's shorter.

    I take a little cut and I get a tight gold then blue shaving. It's hair-thin. MUCH better. I can only suppose the blade is work-hardening.

    Then I realize what I've done - I was cutting with flex and slop, and I removed it. But I neglected to recheck the cut before resuming. Sans slop and flex, the boring bar is not cutting in the same place. I make the hole's diameter .025" too large and the blade rattles on the arbor.

    Oh well, I consider it $6 of tuition. I'll purchase a new blade tomorrow.

    Still better than watching TV

  • #2
    Cut it even larger, then turn up a ring to press-fit. Turn the ID of the ring before parting it off, and turn it larger than desired by the amount of press fit since it will shrink when fitted. Saves a blade, and it's still better than watching teevee.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

    Comment


    • #3
      Anything is BETTER than watching that stupid TV programming!!

      Comment


      • #4
        Thought about a bushing, but the blade's maybe 1/32 thick. This has to fit on my spin-index. The "amusing" part is that the sawblade is a lot thinner than the standard spin-index plate. So I had to make a spacer (glorified washer) so the tightening nut would do its job. OF COURSE, the spacer fits on the shaft with no slop at all.

        Comment


        • #5
          Enquiring minds want to know, why are you mounting a saw blade on your spindexer? Is that bit to follow or in another thread?

          Comment


          • #6
            It's in a thread that already exists. It's to allow me to make dials with 100 divisions. My spindexer only makes divisions that divide 360 evenly. 100 isn't one of these. The sawblade has 100 teeth. The next thing will be to make a pawl.

            Comment


            • #7
              Originally posted by Tony Ennis View Post
              It's in a thread that already exists. It's to allow me to make dials with 100 divisions. My spindexer only makes divisions that divide 360 evenly. 100 isn't one of these. The sawblade has 100 teeth. The next thing will be to make a pawl.
              I have read about some guys using a piece of bandsaw blade with the required number of teeth for an indexer. You can get exactly the number of divisions that you need.

              Brian
              OPEN EYES, OPEN EARS, OPEN MIND

              THINK HARDER

              BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

              MY NAME IS BRIAN AND I AM A TOOLOHOLIC

              Comment


              • #8
                Originally posted by Tony Ennis View Post
                Thought about a bushing, but the blade's maybe 1/32 thick. This has to fit on my spin-index. The "amusing" part is that the sawblade is a lot thinner than the standard spin-index plate. So I had to make a spacer (glorified washer) so the tightening nut would do its job. OF COURSE, the spacer fits on the shaft with no slop at all.
                Put a bevel on the spacer to fit the blade.
                Definition: Racecar - a device that turns money into noise.

                Comment


                • #9
                  Originally posted by Tony Ennis View Post
                  I make the hole's diameter .025" too large and the blade rattles on the arbor.
                  I'd be lying if I said, "I've never done that before"! I remember a similar problem when using my Smithy. I had ground a HSS boring bar in such a way that it could cut in either direction. I thought I was real clever because I was through-boring a piece of stock and this way I didn't have any wasted motion. I get to the end of the hole and move the crossfeed and take a cut on my way back out of the hole. Things were going great but the last "spring" pass was going in so I had to withdraw the tool. I didn't even think about it, I just left the crossfeed where it was and withdrew the tool - of course it cut on the way out and left me with a spiral "oil groove"


                  On my Smithy, I usually had to take 2-4 passes without moving the crossfeed to get all the spring out of the setup. However, this experience taught me that things change on the way out. Maybe it had to do with the geometry I ground on the other side of the bit, but it seemed that cutting while withdrawing the tool tends to pull the tool into the work so even when there is basically no material cutting on the way in, there will be on the way out.
                  Last edited by Fasttrack; 04-08-2013, 11:49 AM.

                  Comment


                  • #10
                    Tony,I used to bore lot's of saw blade both carbide and tool steel.Either one the saw plates were made from 41V50 which can be a real PITA to work.

                    For fixing the oversized hole I used to put the blade flat on a heavy slug of steel we had for an anvil and go around the hole about 1/8" out with a series of center punch marks spaced about 1/8" apart all the way round the bore.The CP marks would upset the metal allowing it to be bored to the correct size.
                    I just need one more tool,just one!

                    Comment


                    • #11
                      Originally posted by bborr01 View Post
                      I have read about some guys using a piece of bandsaw blade with the required number of teeth for an indexer. You can get exactly the number of divisions that you need.

                      Brian
                      I, however, have never heard that. It sounds like an inspired idea.
                      ----
                      Proud machining permanoob since September 2010

                      Comment


                      • #12
                        What was your blade again?
                        if you can't take criticism, do the right thing.

                        Comment


                        • #13
                          A garden-variety 5.5" Chicom 100 tooth saw blade for plywood.

                          Comment

                          Working...
                          X