If you need a good laugh...

[ccfl]

I need to poke a 1" hole through this massive piece of 4140HT ('4142', whatever). It's not gonna happen, is it?

[Rich_Carlstedt]

All things are possible !
The process depends on the tools available.
I assume you mean to get a bored hole ?
Probably the first thing that needs to be done for work that is reaching the limit of the machine tool.....in this case your lathe
is to add accessories to it to make it more viable. In this case, you need a steady rest for support.
Remove the tailstock and use the carriage to drill the hole/bore.
You may have to do both ends in separate operations.
You also may use a drill press, or even a hand-drill (!)
Use the lathe to get a pilot hole through, and then hand drill the rest.
You most likely do not have adequate power to drill anything large on the lathe, but boring takes little power to do.
You will need massive amounts of time , but it is possible

So, make a steady rest - either fabbed or borrowed.
Drill both ends with 1/4" drill , and then do a deep drill pass to adjust the " intersection " of the two drill paths.
Hand drill to 1/2 " ~ roughly
Replace in chuck and bore to size.
Looks like a 15 hour job to me .

Rich

[Steggy]

I need to poke a 1" hole through this massive piece of 4140HT ('4142', whatever). It's not gonna happen, is it?

To borrow a line from the movie "Jaws", you're gonna need a bigger lathe.

[John Hasler]

With a bit of fabrication you might be able to gun drill the pilot hole from the headstock end.

[curtis cutter]

You may find some accessories here that may be wise to use during this operation as you drill for your live center.
https://www.rockymountainatvmc.com/c/16 ... iding-Gear
They sell helmets as well.

[ccfl]

HA! Well, as dangerous as it was I managed to square up both ends and drill one center hole. Low speed, very sharp HSS, and yes I know it would have been like a medium-size bomb going off if something had gone wrong. The piece is just over 8" long now, but the part hidden inside it is only 5.75" long, so it needs to be bandsawed before anything else. And no I don't have a bandsaw either. Or know anyone local who does.

Honestly I think the solution here is to have someone else do it. At least the cutting and rough drilling. I can do the rest once it's a bit shorter and I can stick a center in it.

[SteveHGraham]

How accurate does it need to be?

[curtis cutter]

HA! Well, as dangerous as it was I managed to square up both ends and drill one center hole. Low speed, very sharp HSS, and yes I know it would have been like a medium-size bomb going off if something had gone wrong. The piece is just over 8" long now, but the part hidden inside it is only 5.75" long, so it needs to be bandsawed before anything else. And no I don't have a bandsaw either. Or know anyone local who does.

Honestly I think the solution here is to have someone else do it. At least the cutting and rough drilling. I can do the rest once it's a bit shorter and I can stick a center in it.

Where do you live?

[John Hasler]

So the real task is not to bore a 1" hole through 8", it's to shorten that piece by 2.25". Quite a different problem. Use a parting tool to make a groove (don't try to part it off!) and finish the cut with a hacksaw. If you do the hacksawing on the lathe take the part off when you've got 1/2" left and finish on the bench.

[ccfl]

Steve: This will be a new quill for my hot rod drill press/fake mill designed around larger bearings (and a new spindle). When it's done if I get more than 2 tenths runout between the OD and the bearing bores I will be a little disappointed in myself, even though that's completely silly given the other weaknesses of the machine. The section between bearing bores is just clearance and a drilled hole at around 1-1/8" would be perfectly fine for that part.

curtis: East Mississippi, roughly 100 miles any direction from nominal civilization. Draw a rough circle around Jackson, Memphis, Birmingham, & Mobile, I'm right in the middle of it. Nowhere.

John: I have a crunchy shoulder and this thing is 3.125" OD, you'd need a rather large suitcase full of money to get me to go anywhere near it with a hacksaw. I have hacksawed 2.375" 6061 a few times and that's more than enough to tell me this would be an absolute nightmare. I'm crazy but not that crazy. Yes, I really really need some flavor of bandsaw.

Oh, and at the current 3.125" diameter it hits the compound rest base. I will have to turn down the OD in sections starting at the tail just to gain clearance to move the carriage along.

[John Hasler]

Pay somebody to wield the hacksaw for you.

[spro]

Then what to do. I have a used Milwaukee Portaband. It uses the more expensive needle bearing guides but things have changed. For years, HF has been selling a portable bandsaw and they are inexpensive. It isn't about many repetitive strokes here. It IS about following the initial cuts and the blade follows them.