Threading from left to right?

[jonathan01]

Hello, I never got a lathe yet, but I am planing a future project for when I get my lathe. I will have a piece of ss rod,probably 440c, it will have a OD of about 1/2", with a hole drilled in one end about an inch deep, and I need to thread it from just about the bottom to about a 1/2" to 1/4" from the top. So, I will have threads about a 1/2" to 3/4" long starting at the bottom of the hole and coming to the top. Because the threads need to be just about to the bottom of the hole, I am thinking if it is able to be done, start threading at the bottom and work towards the top of the hole. Would this be done by reversing the spindle and reversing the power feed? The threads I would be cutting will be standard RH threads, I am not sure of the size right now, I could check the size and the dimensions when I get home if that matters.

The reason I am thinking of doing it this way is so I don't have to worry about stopping the power feed at exactly the right time. I am worry that if I let the power feed go a second to long it will crash into the bottom of the hole.

 

[75Plus]

I am having trouble visualizing your project. From the way I read it you intend to bore a non specified size hole in a piece 1/2" round stock to a depth of 1". You then propose to thread the hole starting from the bottom.

It sounds like you want a threaded hole 1" deep with the first 1/4 to 1/2" freebored. This sounds like a job for a tap rather than a lathe. With the OD being 1/2" I cannot see ANY size hole in it which would allow for internal threading on a lathe.

Perhaps I am missing something.

Joe

 

[jonathan01]

I am having trouble visualizing your project. From the way I read it you intend to bore a non specified size hole in a piece 1/2" round stock to a depth of 1". You then propose to thread the hole starting from the bottom.

It sounds like you want a threaded hole 1" deep with the first 1/4 to 1/2" freebored. This sounds like a job for a tap rather than a lathe. With the OD being 1/2" I cannot see ANY size hole in it which would allow for internal threading on a lathe.

Perhaps I am missing something.

Joe

I will get the sizes when I get home this evening. The hole may be 5/16, I will have to check, it's been a while since i looked at the part. I was thinking I could probably thread the whole hole and than drill the first part of the threads out. But, I see what you are saying about the small hole, will any type of thread cutter fit in there. How hard is it to tap 440c ss?

 

[Tony Wells]

<snip> How hard is it to tap 440c ss?

Much, much easier than single pointing, especially in that small size. Be sure and measure the tap actual OD.. They are at times a little larger than nominal thread size. If you are concerned with the clearance hole, like for a seal or something, it matters.

 

[jonathan01]

Much, much easier than single pointing, especially in that small size. Be sure and measure the tap actual OD.. They are at times a little larger than nominal thread size. If you are concerned with the clearance hole, like
for a seal or something, it matters.

I think the smooth portion of the hole is to fit over a slightly larger od portion of the shaft that this part threads onto, no kind of seal just to fit onto the shaft.

 

[12bolts]

hi John,
Can you divulge any info on what you are joining this SS shaft to? Or its purpose?
Some here may have a different suggestion for how to approach the task.

Cheers Phil

 

[jonathan01]

I am measuring it right now, and i will draw it up. i had a drawing of it before, but i can't find it right now.

 

[Hawkeye]

If the smooth part of the bore is larger than the outside diameter of the tap, start by drilling the tap drill size to depth, plus what you will need for the tip of the tap... huh? Then drill a clearance hole to the desired depth - or slightly less than clearance for the tap. This will help guide the tap in straight, without the work of tapping the whole length first.

After that, drill the smooth section to fit the shaft. The job will work best if you have the full set of taps - taper, plug and bottoming.

 

[12bolts]

......full set of taps - taper, plug and bottoming.

Not to run this post off track, but interestingly here in Oz, a plug tap is a bottoming tap.
We have taper, intermediate and plug in a set.

Cheers Phil

 

[75Plus]

While we are discussing stainless steel and taps this might be a good time to say that High Speed Steel (HSS) taps would be preferred over carbon steel ones.

Joe