Hi all, I am trying to make a small aluminum manifold for a flood coolant system for my Taig 2019 CNC mill. I need to drill and tap 3 1/8" NPT holes into 6061 aluminum. I am pretty new to metalworking in general, so yesterday I picked up a cheap tap set at Harbor Freight that included a 1/8" tap. I drilled the hole properly and then set to tapping it. I got about 3/8" in before I felt like I would break the tap if I pushed any harder.
The problem, of course, is that NPT is tapered and I drilled a straight hole. Reading more about the subject, it seems I need a NPT reamer and to ream out the hole before tapping it. The cheapest reamer I can find is about $20 before shipping.
This got me thinking about the perfectly functional CNC mill I have sitting on my bench. Could I make this job easier with it?
I thought I'd ask and see if anyone has any suggestions for me. Consider me a total newbie but willing to learn and work
I want to drill and tap 3 1/8" NPT holes about 3/4" deep in 6061 aluminum. I have:
Taig 2019 CNC mill
1/6", 1/8" and 1/4" endmills
A 1/8" NPT hand tap
I've been thinking that I could probably at least use the mill to "ream" the hole out without spending another $20 on a specialized tool. But what about thread milling? Can I buy a small thread mill and just throw my hand taps away forever?
I've also been thinking about making a tooling plate with a bunch of 10-32 holes in it and it would sure be easier to have my mil cut all those threads for me than to hand tap them all.
Thanks,
Jason