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  1. #681
    Quote Originally Posted by njhussey View Post
    Ultimately it won't matter as I'll be doing the T slotted base thingy...but it's still annoying!
    Neil are you thinking to T-slot the bed on the machine using the spindle.? IF so then you'll struggle because the spindle is far too fast for T-slot cutters.
    Personally I find a matrix of tapped holes is far more versatile than T-slot and easy to do on the machine.

    Sorry to see snapped tap.!! Done it my self so know how it feels.!. . . Proper B@~~rd to get out. I just pecked away at it with pointy centre punch and kind of half destroyed it untill came came apart and loosened.

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  3. #682
    njhussey's Avatar
    Lives in Gloucester, United Kingdom. Current Activity: Viewing NEW MEMBER: H! Has been a member for 6-7 years. Has a total post count of 1,292. Received thanks 104 times, giving thanks to others 86 times.
    Quote Originally Posted by JAZZCNC View Post
    Neil are you thinking to T-slot the bed on the machine using the spindle.? IF so then you'll struggle because the spindle is far too fast for T-slot cutters.
    Personally I find a matrix of tapped holes is far more versatile than T-slot and easy to do on the machine.

    Sorry to see snapped tap.!! Done it my self so know how it feels.!. . . Proper B@~~rd to get out. I just pecked away at it with pointy centre punch and kind of half destroyed it untill came came apart and loosened.
    No I'm cutting 16mm wide by 6mm deep horizontally and then putting 5mm flat strip over the top to create it....
    Neil...

    Build log...here

  4. #683
    njhussey's Avatar
    Lives in Gloucester, United Kingdom. Current Activity: Viewing NEW MEMBER: H! Has been a member for 6-7 years. Has a total post count of 1,292. Received thanks 104 times, giving thanks to others 86 times.
    The one thing I've found from playing with my router so far is that I need home switches as I can't consistently home to the same place if Mach is switched off or sometimes even if I load a different program...first job on the list after doing some plastic thrust bearings for an urgent breakdown job for Cadburys......
    Neil...

    Build log...here

  5. #684
    njhussey's Avatar
    Lives in Gloucester, United Kingdom. Current Activity: Viewing NEW MEMBER: H! Has been a member for 6-7 years. Has a total post count of 1,292. Received thanks 104 times, giving thanks to others 86 times.
    Been making chips today...plastic ones after surfacing the spoil board.



    Can't seem to get a good surface finish on a 1mm depth cut on the UHMWPE, can get a nice finish when going 2mm deep on cutting the I'D & ODs....using a single flute carbide cutter....needs more playing
    Neil...

    Build log...here

  6. #685
    njhussey's Avatar
    Lives in Gloucester, United Kingdom. Current Activity: Viewing NEW MEMBER: H! Has been a member for 6-7 years. Has a total post count of 1,292. Received thanks 104 times, giving thanks to others 86 times.
    One thing I'm happy with is the Z axis. I was expecting to have to loosen bolts on the Y & Z axis to adjust the spindle to get it at 90 to cut flat. I did a pocket with a 0.4 stepover and it was so smooth I reckon that by sheer bloody luck the spindle is almost exactly at 90. When I surfaced the bed this morning (pocketing at 7000mm/min, 6mm 2 flute coated carbide bit at 0.4 stepover and 0.5mmdepth of cut) I couldn't notice any ridge at all, totally smooth.....jammy bugger, makes up for the broken tap in the base!
    Last edited by njhussey; 19-09-2015 at 07:39 PM.
    Neil...

    Build log...here

  7. #686
    Sorry to hear about the tap! So annoying and as they are very brittle it's not easy to tell that they are about to go.

    I've seen them spark eroded out, but it takes ages and I think is done underwater (?!).

    I've had success with Jazz's method of pecking it out with hard tools and getting lucky until I could unscrew it. Sometimes there's enough sticking out to get a mole wrench on it, but not with yours.

    If you definitely need the hole at that location and it won't budge then one option is to use the CNC machine to cut out a large through hole around the tap (say 30mm diameter) so that a nice round cylinder of aluminium is removed containing the tap. Then machine a round pocket (say 60mm diameter and 5mm deep) centred on the same hole. On the lathe turn up a part which fits the 60mm dia pocket and has a shank of ~30mm which goes right to the bottom of the hole -essentially a plug the same shape as the removed material. Drill a couple of countersunk holes (to keep the bolts flush) into the top flange of the plug, and through into the bed. Tap the bed and bolt the plug in place. Then drill and tap the centre hole again with a new tap!

    Another option if you manage to get the tap out but damage the thread too much is to use a heli-coil which uses as oversized tapped hole to insert a spring shaped piece of metal which then creates the original thread diameter again.
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  8. #687
    njhussey's Avatar
    Lives in Gloucester, United Kingdom. Current Activity: Viewing NEW MEMBER: H! Has been a member for 6-7 years. Has a total post count of 1,292. Received thanks 104 times, giving thanks to others 86 times.
    Quote Originally Posted by routercnc View Post
    Sorry to hear about the tap! So annoying and as they are very brittle it's not easy to tell that they are about to go.

    I've seen them spark eroded out, but it takes ages and I think is done underwater (?!).

    I've had success with Jazz's method of pecking it out with hard tools and getting lucky until I could unscrew it. Sometimes there's enough sticking out to get a mole wrench on it, but not with yours.

    If you definitely need the hole at that location and it won't budge then one option is to use the CNC machine to cut out a large through hole around the tap (say 30mm diameter) so that a nice round cylinder of aluminium is removed containing the tap. Then machine a round pocket (say 60mm diameter and 5mm deep) centred on the same hole. On the lathe turn up a part which fits the 60mm dia pocket and has a shank of ~30mm which goes right to the bottom of the hole -essentially a plug the same shape as the removed material. Drill a couple of countersunk holes (to keep the bolts flush) into the top flange of the plug, and through into the bed. Tap the bed and bolt the plug in place. Then drill and tap the centre hole again with a new tap!

    Another option if you manage to get the tap out but damage the thread too much is to use a heli-coil which uses as oversized tapped hole to insert a spring shaped piece of metal which then creates the original thread diameter again.
    Cheers Barry, im favouring trying the smash it out with a hard pointed punch. The annoying thing was that I was backing the tap out the hole...

    I like the plug idea, ive got to surface the Ali base at some point so might turn a press fit plug.
    Neil...

    Build log...here

  9. #688
    Quote Originally Posted by njhussey View Post
    One thing I'm happy with is the Z axis. I was expecting to have to loosen bolts on the Y & Z axis to adjust the spindle to get it at 90 to cut flat. I did a pocket with a 0.4 stepover and it was so smooth I reckon that by sheer bloody luck the spindle is almost exactly at 90. When I surfaced the bed this morning (pocketing at 7000mm/min, 6mm 2 flute coated carbide bit at 0.4mm stepover and 0.5mmdepth of cut) I couldn't notice any ridge at all, totally smooth.....jammy bugger, makes up for the broken tap in the base!
    Why such a small step over neil.? . . . . With 0.4mm it must have took for ever.?

    The Acid test for tram is when you use a wide cutter.!! Try 50mm with 75% step over and see what happens.? 6mm with only 0.4mm step over will hide most error. Also cut both X & Y direction.
    Last edited by JAZZCNC; 18-09-2015 at 10:30 PM.

  10. #689
    njhussey's Avatar
    Lives in Gloucester, United Kingdom. Current Activity: Viewing NEW MEMBER: H! Has been a member for 6-7 years. Has a total post count of 1,292. Received thanks 104 times, giving thanks to others 86 times.
    Quote Originally Posted by JAZZCNC View Post
    Why such a small step over neil.? . . . . With 0.4mm it must have took for ever.?

    The Acid test for tram is when you use a wide cutter.!! Try 50mm with 75% step over and see what happens.? 6mm with only 0.4mm step over will hide most error. Also cut both X & Y direction.
    The step over was what was in Cambam and gave a good finish so I kept it, yes took a while to surface it. I'm going to get a small fly cutter to do the surfacing in the future so we'll see then!

    Going to be spending the next few weeks playing with speeds and feeds on various different materials...looking forward to it
    Neil...

    Build log...here

  11. #690
    Quote Originally Posted by njhussey View Post
    I'm going to get a small fly cutter to do the surfacing in the future so we'll see then!
    Wide cutter will give you perfect finish if trammed correct and take fraction of the time.

    Wouldn't get a fly cutter these spindles don't like them. Get one of these with indexed tips http://www.wealdentool.com/acatalog/...nning_928.html

    Or if on budget one of these. http://www.wealdentool.com/acatalog/..._Wing_250.html

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