threading on the lahte

[lathe nut]

Fellows I know there is much more going on here that is important, but I need some help, been threading on the lathe any junk bolt or rod that I have in the shop for practice, is there a chart with the major and minor Dia. that is needed to get the best of cut, help if someone can, Lathe Nut, would make lathe Nut very happy

 

[jonesie]

just google thread cutting and you will get all you need,or just google the thread size you are cutting and you will find it . get yourself a machinist handbook it is all in there.jonesie

 

[Twmaster]

There are thread/bold charts all over the Internet. As suggested a good book like 'Machinery's Handbook' is a must have reference. (IMHO) Older editions can be found on FeeBay for $20 or so.

Also, there are some terrific videos on YouTube.

 

[Ken I]

Whilst on the subject of screw cutting on a lathe - a tip.

I always screw cut in reverse - away from the job - with the tool in upside down.

Particularly when working in a blind bore or to a shoulder.

This allows me to be sure that I have properly engaged the lead screw in the right place - if you've ever crossed a thread on the last cut you'll know what I mean.

I can also run at higher rpm's for better cutting speeds. When working towards a shoulder you daren't go too fast - unless your lathe has an auto-disengage stop - my cheapie doesn't.

Engage the nut - roll the chuck by hand to check you are in the right place - set to depth - turn on - stopping is no longer critical as you are going away.

This is also handy when screwing odd-pitch threads (metric off an imperial lead screw and vice versa - or any thread that is not a neat multiple of your lead-screw is "odd-pitch"). Don't disengage the screw - just keep going from reverse to stop to forward etc. etc.

You obviously start from an undercut at the shoulder or the bottom of the blind bore. With an uspide down internal threading tool you are working on the "away" side of the bore.

I've had too many disasters working off the indicator to trust the thing.

Ken

 

[steamer]

Hi Lathe Nut,

I attached a sheet that is a start in the right direction...
I can dig through more stuff perhaps this evening........

Dave

View attachment THREAD_EQUIVALENTS[1].pdf

 

[steamer]

And one tid bit....The depth of cut for a sharp corner thread is equal to the pitch if your cutting via the set over method (compound at 29 degrees)

I believe Marv has code to calculate the depth of cut for you, but there are hand book lists available as was already stated....

Talk to you later.

Dave

 

[briankenyn]

Lathe Nut,
Here's a reference table that should help.

http://www.engineershandbook.com/Tables/threadlimits.htm

brian

 

[Tin Falcon]

IIRC the good brand fishtail gauges thread Gage has half depths stamped on them. but I agree machinery's handbook its the best it is what I was taught with.
Tin

 

[lathe nut]

Thanks fellows, been threading on some junk stuff be having a ball just wanted to fine tune it a little more, last night I took a piece of half stock and threaded it with a 20TPI left and right thread going to bring it to the office today see how many can figure it out, let you know the out come, thanks again, Lathe Nut