Milling – Squaring An Inside Radius Of A Corner

[Peter GoodchildParticipant @petergoodchild34034]

What would be the approaches to doing this? All I could find was stuff about a Bridgeport slotting, shaper attachment.

Thanks.

[Peter GoodchildParticipant @petergoodchild34034]

[FulmenParticipant @fulmen]

It can be done with a 45° mill if you can tilt the head 45° in both X and Y.

[GazParticipant @gaz13336]

Finish with a file? Or use a boring head with a HSS with a 90 deg and broach it.

[Anonymous]

There are a number of options:

1. Change the design so that a sharp internal cormer is not needed

2. Drill a hole centred on the intersection; then a milling cutter less than half the diameter of the drill will leave two edges that theoretically intersect at the desired point

3. Run the cutter beyond the edge in one direction to leave a semi-circular cutout

4. Use files, start with a square file and finish with a three square needle file to get a nice crisp internal corner

5. Use a slotting head, I happen to have one on the back of the Bridgeport

A slotting head is particularly useful for blind holes:

Andrew

[JasonBModerator @jasonb]

Latest issue of ME has a good article on doing this using a slotting method with home made tooling

[noel shelleyParticipant @noelshelley55608]

The seldom mentioned shaper would do the job ? Noel.

[HOWARDTParticipant @howardt]

Usually where two faces at 90 deg in a slot are needed to be in contact with another part either the internal corner is removed by pre drilling or milling out the corner or the external part has the corner removed sufficiently to allow full face contact.

[Peter GoodchildParticipant @petergoodchild34034]

OK cheers.

[John Ockleshaw 1Participant @johnockleshaw1]

Hello Peter, This is a good job for a spark eroder even if it is a blind cavity

[Nigel Graham 2Participant @nigelgraham2]

Peter –

Have you managed to complete the work by now?

It's occurred to me the simplest might just be to use a small-diameter cutter to reduce the corner radii to a minimum, then round the edges of the mating part.

Or use a small slot drill to overcut the corners a little, more or less as others suggest. The cutter needs only go slightly past both of the meeting faces, to create a small concave corner.

[Author]

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