[keithmcelhinney]

I have a couple of parts that I have deep holes in. I have to go 2.25 inches down and 51/64" in diameter. I have been drilling a 1/4" hole half way through, taking it out of the mill and working up to 1/2" drill in my drill press. Then I would put it back in the mill and use a 3/8" long endmill to finish to diameter. This was mainly because tool changes were such a pita that it was quicker.

Now that I have TTS I am thinking that I can just do all the drilling on the mill and maybe even drill out the final diameter. I am afraid to push the mill too hard though. I was thinking of this:

1/4" drill half way
1/2" drill half way
1/4" drill full depth
1/2" drill full depth
3/4" drill full depth
51/64" drill full depth

Does this seem doable on a 135? I am thinking that running the 1/4" all the way down first pass would be too much...

I appreciate any advice, I am still a noob at this...

-Keith

[keithmcelhinney]

Also any speeds and feeds would be appreciated. I am cutting 6061..

I usually drill pretty slow (1.5ipm @3500rpm) but have been experimenting with faster peck drilling but it seems like when I go fast I am chewing drill bits. Could have been the bit though...

[SCzEngrgGroup]

Keith,

Deep holes are tricky, because as you go deeper, you need to reduce RPM, and reduce peck depth. It is also necessary to withdraw the bit more often to clear the chips. You'll also need coolant, if not lubricant, and keep an eye on the tool temperature. You'll have the most trouble with the smaller bits. By the time you get up to 3/8 or so, it should be easier, unless you're light on spindle power.

Regards,
Ray L.

[UniqueMachining]

Keith

Have you considered circular interpolation ?

John

[keithmcelhinney]

Right now I am doing circular interpolation, but even that is tough because of try to get the chips out of there. The little 135 doesn't have much power so I guess I am going to stick with what I am doing now (until I get the pro). Was hoping there would be a "just try this" suggestion that would make my life easier...

Thanks guys!
-Keith

[zero_divide]

I am not sure how much power you have.
But for drilling 1/4" I usually go 5000 rpm and 45 IPM in aluminum.
Yes its 45.0 not 4.5!
Using flood coolant and peck every 0.2" for regular drill.
You can drill 10x deep easy.
Reduce your cutting speed if you have not enough coolant.

But drilling is nor really required.
You can do everything with just a 1/2" 2 flute carbide endmill.
Helical interpolation works well.
We go 5000 rpm 60 IPM Widiah a ramp angle of about 2.5-3 degrees.
Again you need a way to lupricate and remove chips.

Aluminum does not like to be cut dry.

[keithmcelhinney]

My machine has a max 3500rpm. I use flood coolant. The only time I tried using a 1/2" endmill, my machine did not like it at all. I am going to experiment tonight and see what happens... I don't think my machine would do 45ipm ever...

-Keith

[Hirudin]

Is this a through hole or a blind hole?

If it goes through, I would drill the largest hole I could all the way through in one shot. Do you think it can do a 3/8" drill? Then use an end mill to cut the rest of it. If chips are able to fall out of the bottom it'll go a lot easier.

[keithmcelhinney]

Technically it is a through hole, but it is on a jig so the chips can't all out the bottom. The piece is held to the jig with a 3/8 bolt aftre the hole is drilled/milled...

[Hirudin]

Ah, darn.

Just to make sure I understand...
The jig is placed under the piece you're drilling *before* you start drilling.

Do the threads of the 3/8" bolt hole fill with chips? Could the bottom of that bolt hole be cut out to make it more like a through hole?

[keithmcelhinney]

Not really. I don't want to recut the jig since I am a couple of months out of getting the Torus Pro. I use a shop vac one the hole gets deep enough to try to keep the chips out of the threads. It works most of the time...

[LeeWay]

All drill bits are not created equal either.
These are the bits I use exclusively now. Been using them for about 8 years now. Absolutely the best drill bits I have ever used.

McMaster-Carr