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Thread: SAE J512 seat cuter

  1. #1
    Join Date
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    Default SAE J512 seat cuter

    Looking for either plans to make a j512 cutter or someone who is interested in making several different ones. This is the cutter to create Inverted 45 degree seats for various sized tubing i.e. 3/16,1/4,5/16,3/8. These are used for automotive applications - brake,fuel,etc.


    There are several manufactures for these but the tools are cost prohibitive , their tooling is for thousands of cycles.


    Any help appreciated. Regards Joe

  2. #2

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    So you're wanting to do the male end like the various fittings available? For small quantities I don't see what the problem is just machining them to spec. You've got a 45 degree nose, a short straight section and then the threads. If you wanted to do the two smooth surfaces and the thread OD all in one shot in a lathe, you could easily enough make the profile out of oil hardening steel and have your tool. Doing long profiles would be prone to chatter, so if I were doing any form tooling at all, I'd do just the angle that way since the other sections can be an ordinary lathe tool.

    OTOH, if you're thinking of using a mill tool on a workpiece in a vise it gets more complicated. Once again it's a form tool but you might get some wisdom out of looking up turret lathe tooling and seeing how in might be adapted. Once again chatter is likely to be a problem, but I suppose if the hole is already present you could pilot on that helping to steady the whole operation.

    If you can say more about what direction you're headed now in terms of machines and the workpieces and quantities it might help give better advice.
    .
    "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

  3. #3
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    Look up the specs on J512. Only the tubing and tubing fittings are 45* flairs, the seats are 42* for the female and one form tool is for each size of tubing/fitting. The taps for cutting the threads are also special--They need clearance around the inverted taper and threads must cut to bottom. Whether you're cutting one seat or a thousand, the tool must hold up to the material being cut. Typical price for the "Custom" cutter is in the $300 range for each size. Taps are extra.

  4. #4
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    Default

    Thanks for the info. Really looking to do small quantities i.e. a couple that would use brass -- some of these 45 degree IFFs are really getting hard to come up with. I stumbled on a u tube where someone had built the cutter I think from HSS and the tap was a bottom that had been hollowed out with an EDM so it could bottom in the fitting. One of the cutter tool manufactures has drawings on their web site - Tri Star Eng.


    I looking to be pointed in the right direction to create as least the cutter for really small quantities. Hoping there was someone on the forum who had actually built a cutter. Haven't given up yet!

    Thanks


    The $300 each I can't justify.
    .

  5. #5
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    Cant you just form tool the 45, then thread the rest single point ?

  6. #6
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    How long are they, what diameter, and what thread on the other end.
    We would cut AN fittings down to a smaller size, they were npt on other endm i think.

  7. #7
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    Quote Originally Posted by tooladdict View Post
    Thanks for the info. Really looking to do small quantities i.e. a couple that would use brass -- some of these 45 degree IFFs are really getting hard to come up with. I stumbled on a u tube where someone had built the cutter I think from HSS and the tap was a bottom that had been hollowed out with an EDM so it could bottom in the fitting. One of the cutter tool manufactures has drawings on their web site - Tri Star Eng.


    I looking to be pointed in the right direction to create as least the cutter for really small quantities. Hoping there was someone on the forum who had actually built a cutter. Haven't given up yet!

    Thanks


    The $300 each I can't justify.
    .

    Female end looks like really ****ty fitting to make in home shop.
    For one-off quanties lathe would be the first choice, but even then the threading operation looks less than fun with little space to work.e. And if you need to make the fitting to some cumbersome part like brake caliper?

    Making the seat a separate part would simplifiy the machining and tooling greatly. Saw a pic of SAE 512 fitting with separate seat insert but can't find it again..

  8. #8
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    Finally found the fitting pic with separate seat insert:
    http://www.proflow.com.au/catalog/7195

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