Using a live endmill instead of a trepan question.

I have a new lathe job to program that requires a fair amount of metal removal using a trepan tool. A core drill would do some of it, but we don't have one and wouldn't buy one. 2024-T4 aluminum. Using a K-Drill (which gives a very nice flat bottom) to go to Z-.553. There are two sections below this depth that require the use of a trepan tool, but I'd like to go in with a 1/4 inch endmill in a live tool to remove the material in the first section. Need to go .128 deeper. Finish diameters are 1.188 and .563. Will leave .01 on both diameters for finishing with the trepan tool.

The only way I know to use the 1/4 inch endmill is to use a G112. I'd have to either plunge straight in with a center cutting 2-flute endmill or add another tool to drill a hole first for the endmill.

What I'd really like to do is ramp in as the tool moves around the arc. Problem is G112 does not allow any Z-axis moves. Any of you brainiacs know of another method to accomplish this goal? Thanks.

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What I'd really like to do is ramp in as the tool moves around the arc. Problem is G112 does not allow any Z-axis moves.

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hy :) that may be a spec / option; just feed z, then cut a circle, then feed z again, and so on ...

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Any of you brainiacs know of another method to accomplish this goal?

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in house, craft a tool / kindly :)

I know I can feed in Z and then make my circle cut using the G112/G12.1 method. What I don't have any idea how to do is ramp in Z-axis while making the circle cut. I don't think it is possible on a Fanuc control, but I know there are guys here that are a 1000 times more knowledgeable about Fanuc controls than I am.

A sister company makes .125 wide trepan tools for us. Has been for years, but they will have to be modified for this job as the DOC is .254 if all dimensions are perfect. Current tools will only clear about .185 (inches, not metric).

We have an excellent man in our Tool Room that can easily make the modification to the trepan tool.

EDIT: Will be using the 1/4 inch endmill in a live tooling holder regardless of whether or not it is possible to ramp in Z-axis while cutting a circle. Imagine it will take slightly longer, but I want to eliminate some of the (roughing) work the trepan tool would have to do.

hello again :) if ramp is relatively small, then there is no big difference if you use a helix or not :)

if that endmill is 1/4, then your part does not seem too big ... maybe is long ?

i did not had yet the patience to convert those to metric, and picture your part : please, will you share a rough sketch ? maybe there is something else besides endmill, trepan / kindly :)

Well...I sat down to write the program today. That is when I realized I didn't need to use G112/G12.1. Still had to feed to Z-depth before making the circle though.

Follow up because I know not everyone does. My original program didn't work. Had to go back to the G112 idea. Plunge in and contour. Worked great. Lot less work for the trepan tool. I didn't get to see the whole job run last night. Setup guy comes in late and stays late. I had to leave for blood work. I'll get to see Monday how everything else worked.