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Tap / Die UNC and UNF

Discussion in '"Stock" Alpine' started by am99ey, Jan 27, 2013.

  1. am99ey

    am99ey Gold Level Sponsor

    Could someone possibly, who is familiar with the threads used on Alpines, give me some advice or tipps?
    I would like to purchase a set of tap and die to rework or clean some threads occasionally on my SV. Is it the kind (Imperial ?) of bolts and nuts used on Alpines.
    Thank you, Andy

    PS: I am aware of the quality according to the price.
  2. puff4

    puff4 Diamond Level Sponsor

    The tap and die set you linked to will do just fine. Most all of the threads on the Alpine are UNC/UNF. The exceptions are with the carburettors and on many of the Lucas parts, where they are BS/BA, and with the pipe threads, where it is BSP (corrected! Thanks, Nick!).

    Of course, as you noted, price = quality when it comes to machine tools like this. I buy very good taps and dies because I hate like heck when using cheap ones and they just don't do the job. Having to re-tap or (God forbid) braking one off in the work is just not something I want to deal with. I buy Hanson brand and they have lasted me a great many years... not cheap, but they work superbly.
  3. Nickodell

    Nickodell Donation Time

    BSF or BSP?
  4. puff4

    puff4 Diamond Level Sponsor

    BSP. I mis-spoke.
  5. dmich2

    dmich2 Diamond Level Sponsor

    Andy. I have a t&d set very much like the one you show. I think it has been the most useful tool I've used with my Alpine over the years. Everyone needs one.

  6. RootesRich

    RootesRich Donation Time

    I'm sure this is going to set off a firestorm of responses, but here goes...
    If you are looking at restoring/ repairing existing threads, you really want a set of thread chasers. Thread chasers are made specifically for this task where as a tap and die set are for cutting new threads only.
    Using a tap and die set on an existing thread is in essence cutting a new thread into the existing and could lead to damage. Chasers, on the other hand, will not cut a new thread and thus will restore the thread to a near, as original, condition.
  7. Bill Blue

    Bill Blue Platinum Level Sponsor

    I really see no problem with using taps and dies to chase threads, just be sure it is started correctly or the threads will not only be damaged, they will be ruined. That should be a problem only if the first thread is goobered. I find dies to be especially difficult to start.

    On the other hand, when using chasers, I have had real problems cleaning up damaged threads on hard bolts. The chaser would just polish the damaged area. They are good for cleaning threads, not so much for damaged threads.

  8. agmason54

    agmason54 Donation Time

    To me a bolt and a nut is a tap and die.If one won't clean up the other I wing it over my shoulder then dump out a five gallon bucket of bolts and start Roote-ing...
  9. Bikesandfires

    Bikesandfires Donation Time

    X 2 on price equals quality...That set is comparable to our Harbor Freight quality...NOT GOOD....Buyer Beware...I think that set will cause you grief if not used VERY carefully.
  10. puff4

    puff4 Diamond Level Sponsor

    Totally agree with you, Rich. I also have a small set of chasers and in fact just used them the other day whilst restoring a set of Zenith-Strombergs - the air filtre bolt holes needed clearing.
  11. Bill Blue

    Bill Blue Platinum Level Sponsor

    Same here, but I seldom throw them away. Sometimes I file a couple of grooves lengthwise of the bolt to allow the rust to accumulate. Wire wheels work great on cruddy bolts.

    I don't understand the problem of with running a 1/2-20 tap down a 1/2-20 threaded hole. I can usually get the job done using nothing but finger power.

    I bought a set of Harbor Freight tap and dies many years ago. Not properly sharpened and some of them had mystery threads, neither SAE or Metric, at least not not to any standard I could compare them to.


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