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The PF Bolt and Thread guru thread

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  • Peter B - CV8
    replied
    ^^^ Jesus wept !!! I can just imagine the look on your face...

    Leave a comment:


  • Jack Nicholson
    replied
    So after successfully fixing this issue in my own car, I had a customer bring his in today for the same fix.

    Got the broken gear off his pedal box, and thought "I'll just try the new brass gear on the spindle first, before re-cutting the thread"

    Well fuck my brown dog, the fucken gear spun freely onto the spindle, no binding or grabbing, it was fucking perfect.

    What. The. Fuck.

    His being built in mid-2006, vs mine mid-2004, apart from that, all the same shit.

    So I don't know...

    I tried his original gear on the ACME threaded rod "gauge" and it's even looser than my original gear.

    Fucking cars.

    Leave a comment:


  • Jack Nicholson
    replied
    Originally posted by gmx View Post
    Caliper bolts with a cast caliper and alloy upright should be plated or some sort of SS grade?
    Bolt I'm left with is Zinc flake coated M12x43, 1.5 pitch. Shortening this to 40mm length, fucks the coating doesn't it?
    I would be looking to get a suitable bolt from an OEM parts bin.

    M12x40 should be reasonably common I guess.

    EDIT

    Yeah https://www.brit-car.co.uk/product.p...__flanged_head



    These ones with the thread locker on them out of the bag are for mounting brake calipers.

    Leave a comment:


  • gmx
    replied
    Caliper bolts with a cast caliper and alloy upright should be plated or some sort of SS grade?
    Bolt I'm left with is Zinc flake coated M12x43, 1.5 pitch. Shortening this to 40mm length, fucks the coating doesn't it?

    Leave a comment:


  • mrniceguy
    replied
    Sounds like you got it sorted, but ACME threads and nuts are common in low end CNC stuff.

    https://buildyourcnc.com/Item/mechan...-starts-10-tpi

    Leave a comment:


  • LINCOLN
    replied
    Originally posted by Gammaboy View Post
    Trefolex. Guys love it, chicks can't stand the smell.
    Haha I prefer rocol for my scent.

    Leave a comment:


  • Gammaboy
    replied
    Originally posted by Bob Vegana. View Post
    I think a small amount of lube would be more appropriate.
    Trefolex. Guys love it, chicks can't stand the smell.

    Leave a comment:


  • Gammaboy
    replied
    If you want to modify the die so you can bottom it out on one side, send it up and I'll sort it.

    Leave a comment:


  • Bob Vegana.
    replied
    I think a small amount of lube would be more appropriate.

    Leave a comment:


  • Sloth
    replied
    Originally posted by 9triton View Post
    .that's nuts : a thread that didn't spiral into oblivion.


    locktite the thread now!
    ftfy

    Leave a comment:


  • 9triton
    replied
    .that's nuts : a thread that didn't spiral into oblivion.


    lock the thread now!

    Leave a comment:


  • Jack Nicholson
    replied
    The PF Bolt and Thread guru thread

    Finally...

    My 1/2-10 ACME die arrived from the USA



    Made in fucking China of course...

    Had to get a 27mm deep socket...



    But it recut the thread on the spindle and the brass gear spins freely on it now.



    Because the die is symmetrical, thread can be started on either side, I couldn't cut the last few mm of the thread on the spindle, but that's about as good as it's gonna get...

    Leave a comment:


  • Gin Kii
    replied
    So different minor and major diametres... kinda what I mentioned in my previous post.

    Leave a comment:


  • Jack Nicholson
    replied
    OK so might have a bit of a breakthrough on this. Stopped in an another machinist (guy who did some work for me a few years ago) and explained/showed him the problem.

    There is ACME thread, then there is Stub ACME thread. Seems likely that the spindle in the car could be a Stub ACME thread.
    He pretty much told me to eat a dick when I asked if he could cut me a female Stub ACME thread in 1/2"-10 though...

    Stub ACME being the same pitch, same 29deg, but the depth of the threads is shallower. So you can screw a Stub ACME nut onto regular ACME male thread, but not vice-versa.

    Looking at the ACME threaded rod I bought in, compared to the spindle in the car, yeah the threads on the ACME rod are much deeper, even just by looking at them.

    In theory, you could run an ACME die over the Stub ACME thread and cut them a bit deeper. Which is where i'm at now...

    Leave a comment:


  • BigMuz
    replied
    Normally you need the make part to make the female part. The difference between going on half a nut and sloppy as hell is a couple of tenths Max. Can you find someone with a lathe to scratch it a bit deeper? It's a pretty simple job.

    Leave a comment:

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