Small lathe- without foot brake?? and threading.

[LC Tikka]

Hi
I'm looking at a Hafco AL960B lathe, approx a 12x36". As there is no foot brake what effect will this have when threading to a shoulder or other general use. Is there a trick or method to reduce the risk of over-run at the end of a thread while the chuck is coming to a stop.
Imperial lead screw, so can't disengage half nuts during metric threading I assume.
LC

 

[Erik Cortina]

Re: Small lathe- without foot brake??

Disengage half nut and back out cross slide at the same time. I thread at 180 RPM and thread to .020" from shoulder and even though I have a brake, I don't need it.

 

[jkohler]

Re: Small lathe with no foot brake

You don't need a foot brake to thread up to a shoulder. Just setup a dial indicator to make one full revolution where you want to end your thread then disengage your half nut and back out your compound. You should go and watch some YouTube videos on threading to get the idea.

 

[DCRYDER]

Re: Small lathe- without foot brake??

It would be handy to have when cutting metric threads. Can't disengage half nut.

 

[Erik Cortina]

Re: Small lathe- without foot brake??

It would be handy to have when cutting metric threads. Can't disengage half nut.

Thread in reverse with tool upside down.

 

[Gundoktr]

Re: Small lathe- without foot brake??

You've still got to stop it sometime. If you don't have some type of clutch or brake, starting at the same place can be a task.

 

[jscandale]

Re: Small lathe- without foot brake??

Is there a trick or method to reduce the risk of over-run at the end of a thread while the chuck is coming to a stop.
LC

Yes! There is one foolproof method of accomplishing this if you use an internal threading bar and run the lathe in reverse, cutting on the backside of the work piece. See the link from another thread on this forum. I single point thread at speeds over 300 RPM and use a carbide insert and I couldn't imagine doing it the old way ever again. The finished thread looks like it is ground, you can always start the thread at a precise location, and you never have to worry about crashing the tool, ever.
http://forum.accurateshooter.com/index.php?topic=3818716.msg36248822#msg36248822

JS

 

[ridgeway]

Re: Small lathe- without foot brake??

Check this out for some engineering and slick threading at 400 RPM!...

http://vimeo.com/84476330

 

[DCRYDER]

Re: Small lathe- without foot brake??

It would be handy to have when cutting metric threads. Can't disengage half nut.

Thread in reverse with tool upside down.

By golly, I never thunk of that!!!!! Lol.

I like my method for cutting metric threads better...... Just say NO!!!!

 

[LC Tikka]

Re: Small lathe- without foot brake??

Thanks all
I have experience in simple turning but none threading, so needed a few answers regarding the lathe function and if the brake was necessary or just good to have. The technique to turn on the back side is interesting, what happens on female threads. Is there a clutch or inching lever on some machines.
Whether you buy an imp or metric lathe, I guess you get caught with the other thread type?
With experience it is probably not an issue anyway.
LC

 

[Ggmac]

Re: Small lathe- without foot brake??

A book How To Run A Lathe ,is available . Its from the South Bend Corp . It was used as a teaching tool in shop classes , it was printed in the 1940-50 s . Its basic but can walk you thru the essentials .

 

[Hondo]

Re: Small lathe- without foot brake??

Turn tool upside down run lathe in reverse cut from shoulder out.

 

[jscandale]

Re: Small lathe- without foot brake??

Why is it you can't disengage the halfnut when cutting metric threads?

JS

 

[jkohler]

Re: Small lathe- without foot brake??

Most lathes come with a Inch lead screw.

 

[Erik Cortina]

Re: Small lathe- without foot brake??

I'm sure we're going to deep into it.

Refer to replies #1 and #2 to thread up to shoulder.

 

[Macropod]

Re: Small lathe- without foot brake??

Why is it you can't disengage the halfnut when cutting metric threads?

JS

Timing. If you have a lathe with an imperial lead screw (most common) then the half nuts need to stay engaged.
Disengage and you will enter a world of head banging regret. :-[

 

[jscandale]

Re: Small lathe- without foot brake??

Why is it you can't disengage the halfnut when cutting metric threads?

JS

Timing. If you have a lathe with an imperial lead screw (most common) then the half nuts need to stay engaged.
Disengage and you will enter a world of head banging regret. :-[

What if you just engaged on the same number on the thread dial each time while testing a crap piece and record that number? I don't think I have ever had a call to cut a metric thread, nor have I ever installed the gears that the lathes came with for metric, so I am in learning mode here.
The only thing that I would be very concerned with in regard to not disengageing the half nut is the need to back the tool out when going in reverse due to the any slop in the gears and lead screw.

JS

 

[jkohler]

Re: Small lathe- without foot brake??

There is one other way I know how to cut metric threads on a lathe with a inch lead screw. You can thread up to your point to where you end your thread. disengage your half nuts back out your cross slide shut the lathe off. then put your lathe in revers tell the number on your threading dial is lined back up with the number again. engage your half nuts back the carriage to the start of your thread and have at it.

 

[Macropod]

Re: Small lathe- without foot brake??

Why is it you can't disengage the halfnut when cutting metric threads?

JS

Timing. If you have a lathe with an imperial lead screw (most common) then the half nuts need to stay engaged.
Disengage and you will enter a world of head banging regret. :-[

What if you just engaged on the same number on the thread dial each time while testing a crap piece and record that number? I don't think I have ever had a call to cut a metric thread, nor have I ever installed the gears that the lathes came with for metric, so I am in learning mode here.
The only thing that I would be very concerned with in regard to not disengageing the half nut is the need to back the tool out when going in reverse due to the any slop in the gears and lead screw.

JS

You can cut metric threads with an imperial lead screw if you have the right gears to swap over on the leadscrew drive. The threading dial still remains imperial even though you are cutting a metric thread. There is no correlation whatsoever. To get it to marry up you would have to change the leadscrew and threading dial to metric specific ones. Confused? Don't be. It is all to do with the gearing.

 

[Eddie Harren]

Re: Small lathe- without foot brake??

If someone had the metric gears, we wouldn't be having this conversation.