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Best Practices for Flycutting / Interrupted Cuts On Bridgeport

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  • tomato coupe
    replied
    Originally posted by BCRider View Post
    That helps. But really the whole idea of how any variations stack up due to the large face diameter and consistency on the shoulder of the arbor. Or are you saying that when assembled and running that the max variation is around a thou?
    Yes, but I thought you were asking about the height variation of the inserts due to how they sit in their respective pockets. My present setup consists of medium quality 2.5" and 5" face mills on higher quality CAT40 arbors. I don't see any indication of the face mills being out of alignment with the arbor, just some small (<.001") random height variation between inserts.

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  • BCRider
    replied
    That helps. But really the whole idea of how any variations stack up due to the large face diameter and consistency on the shoulder of the arbor. Or are you saying that when assembled and running that the max variation is around a thou?

    Leave a comment:


  • tomato coupe
    replied
    Originally posted by BCRider View Post
    TC, what HP motor is in your BP? I'm running one of the smaller knee mills so I've got a whopping 1.5HP running on 220v single phase.
    I don't have that machine anymore, but it had a 3 HP motor on it. I ran it from single phase 220 V using a static phase convertor, however, so it was effectively more like 2 HP.

    Another question for those that have used the big facing cutters that fit onto separate shell mill arbors. Like THIS STYLE on THIS ARBOR Did you find that the cutters all zero up well? I'm wondering if I should look at an arbor and then a couple of sizes of that style in something like 3" and 5" to cover all my needs.
    Are you asking about the variation in height of the inserts compared to each other? I think that would be highly dependent on the quality of the face mill. (My face mills are of medium quality and the inserts are within a .001" range.)

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  • BCRider
    replied
    TC, what HP motor is in your BP? I'm running one of the smaller knee mills so I've got a whopping 1.5HP running on 220v single phase.

    Another question for those that have used the big facing cutters that fit onto separate shell mill arbors. Like THIS STYLE on THIS ARBOR Did you find that the cutters all zero up well? I'm wondering if I should look at an arbor and then a couple of sizes of that style in something like 3" and 5" to cover all my needs.

    Leave a comment:


  • tomato coupe
    replied
    Originally posted by mattthegamer463 View Post
    That tip about removing inserts is a great idea, there's nothing saying the cutter needs all six installed. I am pretty excited to see how it works out.

    The new mill is a Bridgeport clone so it should be able to eat up material pretty well. Won't be carving out engine blocks from billet (not that I would be anyway) but it's going to be heaven compared to 10 minute passes with the fly cutter and mill drill.
    I bought a 5" eight-insert face mill many years ago when I had a Bridgeport, with the same idea that I could remove inserts if I needed to. In reality, however, I never had to do so.

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  • RB211
    replied
    I just picked up one of these and love it. It cleaned the mill scale right off some HRS and made it look like tool steel.
    https://www.amazon.com/gp/aw/d/B00PW...+endmill&psc=1


    Sent from my iPhone using Tapatalk Pro

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  • mattthegamer463
    replied
    That tip about removing inserts is a great idea, there's nothing saying the cutter needs all six installed. I am pretty excited to see how it works out.

    The new mill is a Bridgeport clone so it should be able to eat up material pretty well. Won't be carving out engine blocks from billet (not that I would be anyway) but it's going to be heaven compared to 10 minute passes with the fly cutter and mill drill.

    Leave a comment:


  • JoeLee
    replied
    I'll bet it puts a nice polish on the spindle nose after a while.

    JL................

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  • old mart
    replied
    A six tip shell mill has even more versatility than BCRider says, it will still be balanced with 4 tips and even with only one tip, the out of balance forces will be less than a fly cutter.

    Leave a comment:


  • BCRider
    replied
    Originally posted by mattthegamer463 View Post
    T.....I just ordered an import 6 insert face mill to try, at least it can be fed at a more reasonable rate and should give a nice finish with purpose-designed inserts instead of the triangle and round types which seem to need just the right feed rate to leave a nice surface......
    Someone above mentioned about the power needs if you're removing that much stock. You didn't say what size mill you bought but it's quite possible that the higher load you can produce with a 6 tooth cutter will bog the machine down when fed at the rate for the best finish. I'll be very interested in reading your results.

    If you find that the poor mill isn't happy with pushing 6 teeth through a wide cut there is an option though. Remove three of the teeth so only one is taking the big cut across the middle and when two are engaged it is on the entry and exit. Not only will this reduce the load on the motor but it should smooth up the interruptions. And if that still proves to be too much go for two opposed teeth so it's still only one tooth at a time in the cut. But at least with something like that you've got options.

    The only downside of a large face mill of that sort is that it's a fixed diameter setup. Mind you I can't see this being a big deal. I'd think that a couple of sizes and any of us home shop types would/should consider ourselves well set up.

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  • Rich Carlstedt
    replied
    As Paul said in post 15, you want to have a slight drag on the spindle which protects the spline on the spindle and does not pound it

    A quick and easy method ( and cheap !) used by old timers was to place a wine cork against the spindle nose using the indicator clamp hole on the right side of the Bridgeport Head for mounting.

    Also use your knee for Z moves with the quill full retracted.


    Rich

    For Clarity:
    Using a "L" shaped 1/4 rod, they drill a 3/16 hole through the cork and forced the rod through it and then swung it into position. I am sure lunch was a fun time as the bottle could not be plugged after ...
    Last edited by Rich Carlstedt; 03-20-2018, 11:17 AM.

    Leave a comment:


  • Mcgyver
    replied
    best practices?

    - use the right size fly cutter. To large for the work and you have to run it more slowly than it needs to be

    - have it enter at close to a tangent - minimized pounding

    - grind the cutter properly!! Very often I see people use the equivalent of a knife tool when what it requires is a facing tool. Think through the tool geometry, where the cutting edge is, direction of cut and where the rake is - a knife tool shape is what you want for boring, i.e. plunging, not fly cutting. Like facing with a knife tool in the lathe, it will work, but its not optimal or a best practice.....here's my go to facing tool, lots of rake established by a chip breaker. Use the same grind in a fly cutter for best performance.

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  • old mart
    replied
    Is there a way of balancing in the design of flycutters?

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  • sandiapaul
    replied
    Get yourself one of these:

    https://www.youtube.com/watch?v=Y2Xa0PMHM1U

    I have probably a half dozen flycutters, some homemade and some commercial, the superfly blows them all out of the water. BTW, I use them on manual machines as well as cnc the equal effect.

    Leave a comment:


  • EVguru
    replied
    You can put a drag on the spindle to keep the quill splines loaded. I did it once with an Aluminium disk and a couple of hard drive head magnets.

    I've seen it done with a set of vanes driven from the end of the drawbar.

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