Undercutting bits

[Voicecoil]

So I need to machine some aluminium parts that have a number of undercut retaining lugs - pretty small maybe 2mm high undercut by 0.5...0.7mm. I think I can sort the Gcode by getting the CAM to make the overall path and frigging the in and out paths by manual editing. BUT I need an appropriate cutter - a bit like what you'd use for making T-slots but much smaller - anyone got any ideas please?

BTW, the simple manual approach using a file isn't possible since these lugs are down inside a cavity :-(

[JAZZCNC]

Slotting disc will do the job if it will fit inside the cavity. Various ways to do the code but easy way is to treat it like an end mill following a profile path with a DOC to suit slot disc and use Diamater offset for the under cut depth.

[johngoodrich]

or something like this
https://www.ebay.co.uk/itm/HSS-WOODRUFF-CUTTER-KEY-No-203-303-403-204-304-404-507-806-MILLING-CUTTERS/272019210105?hash=item3f559bbf79:m:m4QsLpUrW7UUhGA-6Zoi_AQ

[Voicecoil]

Slotting disc will do the job if it will fit inside the cavity. Various ways to do the code but easy way is to treat it like an end mill following a profile path with a DOC to suit slot disc and use Diamater offset for the under cut depth.

Thanks for the idea. I seem to remember seeing some small slitting saws and an arbor in father's watchmaking gear when I cleared the house - I'll go have a root and see what I can find.

[Voicecoil]

or something like this
https://www.ebay.co.uk/itm/HSS-WOODRUFF-CUTTER-KEY-No-203-303-403-204-304-404-507-806-MILLING-CUTTERS/272019210105?hash=item3f559bbf79:m:m4QsLpUrW7UUhGA-6Zoi_AQ
They look good too, if I can't find the saw bits I might order one up - shame they're mostly imperial sizes though!

[m_c]

If you're limited for space, then these indexable cutters go down to 10mm diameter - https://www.cutwel.co.uk/milling-tools/groove-and-thread-milling-tools/simmill-groove-and-thread-milling-pxsxuxvx-series/simmill-pxsxuxvx-holders/steel-through-coolant-weldon-shank-groove-milling-holder-simtek-simmill-pxsxuxvx

They are pricey, but I have the smallest size, and it's saved me from having to make fixtures to machine the opposite side a few times.

[Voicecoil]

Those are cool - just wondering whether the client will wear the cost though :whistle: