Trying to find out how fast can tap aluminum

[REVCAM_Bob]

I have some production parts I am quoting and my customer is telling me they have (what appear to be) rediculously low prices.....

So I am wondering how fast would a production house do the following taping, or for what cost:

Tap (12) 1/4-20 blind threads, 0.38 dp. full threads, will a roll thread, and minimal drilling depth i.e. just drill deep enought to get the tap thread depth.

and (4) no. 4-40 threads, 0.31 dp full threads, again with a roll thread,
and the same on the drill, just deep enough to get the thread done....

The material is aluminum, supposed to be the best machining aluminum, I think 6061.

Any thoughts would be appreciated!
Thanks!

[Geof]

Just the tapping?

Depending on the machine 2000rpm, maybe faster.

[davereagan]

If it's only one part per run, the machine might spend longer changing tools than drilling and tapping. How many parts can be fit on the table?

[REVCAM_Bob]

Good point, that might save a lot of time!.... maybe thats how they are getting the price down low.....

Thanks!

[Geof]

I should have been less cryptic in my answer but you did ask how fast the tapping could be done.

Dave is absolutely correct for tapping one hole on just about any machine the tool change time will be anywhere from twice to maybe six times the time spent drilling and tapping.

How big are these things and how many would you be doing? Likely it would be a pallet situation; load one pallet with numerous parts while the machine is processing a pallet load.

[REVCAM_Bob]

they are about 8" x 12".....

[fuzzyracing1967]

Anouther way of saving time would be to tap some if not all the holes outside the machine.In the time it takes to drill those holes you may be able to tap them on a drill press using a tapping head,(like jarvis),so you end up drilling and tapping in the time it takes to drill.
The down side to that is you can only run that machine no writing programs or quoting other work as the machine runs,but then again this isn't a problem if there is a operator running them.Just a thought.